File:  [LON-CAPA] / loncom / interface / lonhelper.pm
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Wed Aug 13 14:52:08 2003 UTC (20 years, 10 months ago) by bowersj2
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    1: # The LearningOnline Network with CAPA
    2: # .helper XML handler to implement the LON-CAPA helper
    3: #
    4: # $Id: lonhelper.pm,v 1.43 2003/08/13 14:52:08 bowersj2 Exp $
    5: #
    6: # Copyright Michigan State University Board of Trustees
    7: #
    8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
    9: #
   10: # LON-CAPA is free software; you can redistribute it and/or modify
   11: # it under the terms of the GNU General Public License as published by
   12: # the Free Software Foundation; either version 2 of the License, or
   13: # (at your option) any later version.
   14: #
   15: # LON-CAPA is distributed in the hope that it will be useful,
   16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   18: # GNU General Public License for more details.
   19: #
   20: # You should have received a copy of the GNU General Public License
   21: # along with LON-CAPA; if not, write to the Free Software
   22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   23: #
   24: # /home/httpd/html/adm/gpl.txt
   25: #
   26: # http://www.lon-capa.org/
   27: #
   28: # (Page Handler
   29: #
   30: # (.helper handler
   31: #
   32: 
   33: =pod
   34: 
   35: =head1 lonhelper - HTML Helper framework for LON-CAPA
   36: 
   37: Helpers, often known as "wizards", are well-established UI widgets that users
   38: feel comfortable with. It can take a complicated multidimensional problem the
   39: user has and turn it into a series of bite-sized one-dimensional questions.
   40: 
   41: For developers, helpers provide an easy way to bundle little bits of functionality
   42: for the user, without having to write the tedious state-maintenence code.
   43: 
   44: Helpers are defined as XML documents, placed in the /home/httpd/html/adm/helpers 
   45: directory and having the .helper file extension. For examples, see that directory.
   46: 
   47: All classes are in the Apache::lonhelper namespace.
   48: 
   49: =head2 lonhelper XML file format
   50: 
   51: A helper consists of a top-level <helper> tag which contains a series of states.
   52: Each state contains one or more state elements, which are what the user sees, like
   53: messages, resource selections, or date queries.
   54: 
   55: The helper tag is required to have one attribute, "title", which is the name
   56: of the helper itself, such as "Parameter helper". The helper tag may optionally
   57: have a "requiredpriv" attribute, specifying the priviledge a user must have
   58: to use the helper, or get denied access. See loncom/auth/rolesplain.tab for
   59: useful privs. Default is full access, which is often wrong!
   60: 
   61: =head2 State tags
   62: 
   63: State tags are required to have an attribute "name", which is the symbolic
   64: name of the state and will not be directly seen by the user. The helper is
   65: required to have one state named "START", which is the state the helper
   66: will start with. By convention, this state should clearly describe what
   67: the helper will do for the user, and may also include the first information
   68: entry the user needs to do for the helper.
   69: 
   70: State tags are also required to have an attribute "title", which is the
   71: human name of the state, and will be displayed as the header on top of 
   72: the screen for the user.
   73: 
   74: =head2 Example Helper Skeleton
   75: 
   76: An example of the tags so far:
   77: 
   78:  <helper title="Example Helper">
   79:    <state name="START" title="Demonstrating the Example Helper">
   80:      <!-- notice this is the START state the wizard requires -->
   81:      </state>
   82:    <state name="GET_NAME" title="Enter Student Name">
   83:      </state>
   84:    </helper>
   85: 
   86: Of course this does nothing. In order for the wizard to do something, it is
   87: necessary to put actual elements into the wizard. Documentation for each
   88: of these elements follows.
   89: 
   90: =head2 Creating a Helper With Code, Not XML
   91: 
   92: In some situations, such as the printing wizard (see lonprintout.pm), 
   93: writing the helper in XML would be too complicated, because of scope 
   94: issues or the fact that the code actually outweighs the XML. It is
   95: possible to create a helper via code, though it is a little odd.
   96: 
   97: Creating a helper via code is more like issuing commands to create
   98: a helper then normal code writing. For instance, elements will automatically
   99: be added to the last state created, so it's important to create the 
  100: states in the correct order.
  101: 
  102: First, create a new helper:
  103: 
  104:  use Apache::lonhelper;
  105: 
  106:  my $helper = Apache::lonhelper::new->("Helper Title");
  107: 
  108: Next you'll need to manually add states to the helper:
  109: 
  110:  Apache::lonhelper::state->new("STATE_NAME", "State's Human Title");
  111: 
  112: You don't need to save a reference to it because all elements up until
  113: the next state creation will automatically be added to this state.
  114: 
  115: Elements are created by populating the $paramHash in 
  116: Apache::lonhelper::paramhash. To prevent namespace issues, retrieve 
  117: a reference to that has with getParamHash:
  118: 
  119:  my $paramHash = Apache::lonhelper::getParamHash();
  120: 
  121: You will need to do this for each state you create.
  122: 
  123: Populate the $paramHash with the parameters for the element you wish
  124: to add next; the easiest way to find out what those entries are is
  125: to read the code. Some common ones are 'variable' to record the variable
  126: to store the results in, and NEXTSTATE to record a next state transition.
  127: 
  128: Then create your element:
  129: 
  130:  $paramHash->{MESSAGETEXT} = "This is a message.";
  131:  Apache::lonhelper::message->new();
  132: 
  133: The creation will take the $paramHash and bless it into a
  134: Apache::lonhelper::message object. To create the next element, you need
  135: to get a reference to the new, empty $paramHash:
  136: 
  137:  $paramHash = Apache::lonhelper::getParamHash();
  138: 
  139: and you can repeat creating elements that way. You can add states
  140: and elements as needed.
  141: 
  142: See lonprintout.pm, subroutine printHelper for an example of this, where
  143: we dynamically add some states to prevent security problems, for instance.
  144: 
  145: Normally the machinery in the XML format is sufficient; dynamically 
  146: adding states can easily be done by wrapping the state in a <condition>
  147: tag. This should only be used when the code dominates the XML content,
  148: the code is so complicated that it is difficult to get access to
  149: all of the information you need because of scoping issues, or so much
  150: of the information used is persistent because would-be <exec> or 
  151: <eval> blocks that using the {DATA} mechanism results in hard-to-read
  152: and -maintain code.
  153: 
  154: It is possible to do some of the work with an XML fragment parsed by
  155: lonxml; again, see lonprintout.pm for an example. In that case it is 
  156: imperative that you call B<Apache::lonhelper::registerHelperTags()>
  157: before parsing XML fragments and B<Apache::lonhelper::unregisterHelperTags()>
  158: when you are done. See lonprintout.pm for examples of this usage in the
  159: printHelper subroutine.
  160: 
  161: =cut
  162: 
  163: package Apache::lonhelper;
  164: use Apache::Constants qw(:common);
  165: use Apache::File;
  166: use Apache::lonxml;
  167: 
  168: # Register all the tags with the helper, so the helper can 
  169: # push and pop them
  170: 
  171: my @helperTags;
  172: 
  173: sub register {
  174:     my ($namespace, @tags) = @_;
  175: 
  176:     for my $tag (@tags) {
  177:         push @helperTags, [$namespace, $tag];
  178:     }
  179: }
  180: 
  181: BEGIN {
  182:     Apache::lonxml::register('Apache::lonhelper', 
  183:                              ('helper'));
  184:       register('Apache::lonhelper', ('state'));
  185: }
  186: 
  187: # Since all helpers are only three levels deep (helper tag, state tag, 
  188: # substate type), it's easier and more readble to explicitly track 
  189: # those three things directly, rather then futz with the tag stack 
  190: # every time.
  191: my $helper;
  192: my $state;
  193: my $substate;
  194: # To collect parameters, the contents of the subtags are collected
  195: # into this paramHash, then passed to the element object when the 
  196: # end of the element tag is located.
  197: my $paramHash; 
  198: 
  199: # Note from Jeremy 5-8-2003: It is *vital* that the real handler be called
  200: # as a subroutine from the handler, or very mysterious things might happen.
  201: # I don't know exactly why, but it seems that the scope where the Apache
  202: # server enters the perl handler is treated differently from the rest of
  203: # the handler. This also seems to manifest itself in the debugger as entering
  204: # the perl handler in seemingly random places (sometimes it starts in the
  205: # compiling phase, sometimes in the handler execution phase where it runs
  206: # the code and stepping into the "1;" the module ends with goes into the handler,
  207: # sometimes starting directly with the handler); I think the cause is related.
  208: # In the debugger, this means that breakpoints are ignored until you step into
  209: # a function and get out of what must be a "faked up scope" in the Apache->
  210: # mod_perl connection. In this code, it was manifesting itself in the existence
  211: # of two seperate file-scoped $helper variables, one set to the value of the
  212: # helper in the helper constructor, and one referenced by the handler on the
  213: # "$helper->process()" line. The second was therefore never set, and was still
  214: # undefined when I tried to call process on it.
  215: # By pushing the "real handler" down into the "real scope", everybody except the 
  216: # actual handler function directly below this comment gets the same $helper and
  217: # everybody is happy.
  218: # The upshot of all of this is that for safety when a handler is  using 
  219: # file-scoped variables in LON-CAPA, the handler should be pushed down one 
  220: # call level, as I do here, to ensure that the top-level handler function does
  221: # not get a different file scope from the rest of the code.
  222: sub handler {
  223:     my $r = shift;
  224:     return real_handler($r);
  225: }
  226: 
  227: # For debugging purposes, one can send a second parameter into this
  228: # function, the 'uri' of the helper you wish to have rendered, and
  229: # call this from other handlers.
  230: sub real_handler {
  231:     my $r = shift;
  232:     my $uri = shift;
  233:     if (!defined($uri)) { $uri = $r->uri(); }
  234:     $ENV{'request.uri'} = $uri;
  235:     my $filename = '/home/httpd/html' . $uri;
  236:     my $fh = Apache::File->new($filename);
  237:     my $file;
  238:     read $fh, $file, 100000000;
  239: 
  240: 
  241:     # Send header, don't cache this page
  242:     if ($r->header_only) {
  243:         if ($ENV{'browser.mathml'}) {
  244:             $r->content_type('text/xml');
  245:         } else {
  246:             $r->content_type('text/html');
  247:         }
  248:         $r->send_http_header;
  249:         return OK;
  250:     }
  251:     if ($ENV{'browser.mathml'}) {
  252:         $r->content_type('text/xml');
  253:     } else {
  254:         $r->content_type('text/html');
  255:     }
  256:     $r->send_http_header;
  257:     $r->rflush();
  258: 
  259:     # Discard result, we just want the objects that get created by the
  260:     # xml parsing
  261:     &Apache::lonxml::xmlparse($r, 'helper', $file);
  262: 
  263:     my $allowed = $helper->allowedCheck();
  264:     if (!$allowed) {
  265:         $ENV{'user.error.msg'} = $ENV{'request.uri'}.':'.$helper->{REQUIRED_PRIV}.
  266:             ":0:0:Permission denied to access this helper.";
  267:         return HTTP_NOT_ACCEPTABLE;
  268:     }
  269: 
  270:     $helper->process();
  271: 
  272:     $r->print($helper->display());
  273:     return OK;
  274: }
  275: 
  276: sub registerHelperTags {
  277:     for my $tagList (@helperTags) {
  278:         Apache::lonxml::register($tagList->[0], $tagList->[1]);
  279:     }
  280: }
  281: 
  282: sub unregisterHelperTags {
  283:     for my $tagList (@helperTags) {
  284:         Apache::lonxml::deregister($tagList->[0], $tagList->[1]);
  285:     }
  286: }
  287: 
  288: sub start_helper {
  289:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  290: 
  291:     if ($target ne 'helper') {
  292:         return '';
  293:     }
  294: 
  295:     registerHelperTags();
  296: 
  297:     Apache::lonhelper::helper->new($token->[2]{'title'}, $token->[2]{'requiredpriv'});
  298:     return '';
  299: }
  300: 
  301: sub end_helper {
  302:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  303:     
  304:     if ($target ne 'helper') {
  305:         return '';
  306:     }
  307: 
  308:     unregisterHelperTags();
  309: 
  310:     return '';
  311: }
  312: 
  313: sub start_state {
  314:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  315: 
  316:     if ($target ne 'helper') {
  317:         return '';
  318:     }
  319: 
  320:     Apache::lonhelper::state->new($token->[2]{'name'},
  321:                                   $token->[2]{'title'});
  322:     return '';
  323: }
  324: 
  325: # Use this to get the param hash from other files.
  326: sub getParamHash {
  327:     return $paramHash;
  328: }
  329: 
  330: # Use this to get the helper, if implementing elements in other files
  331: # (like lonprintout.pm)
  332: sub getHelper {
  333:     return $helper;
  334: }
  335: 
  336: # don't need this, so ignore it
  337: sub end_state {
  338:     return '';
  339: }
  340: 
  341: 1;
  342: 
  343: package Apache::lonhelper::helper;
  344: 
  345: use Digest::MD5 qw(md5_hex);
  346: use HTML::Entities;
  347: use Apache::loncommon;
  348: use Apache::File;
  349: 
  350: sub new {
  351:     my $proto = shift;
  352:     my $class = ref($proto) || $proto;
  353:     my $self = {};
  354: 
  355:     $self->{TITLE} = shift;
  356:     $self->{REQUIRED_PRIV} = shift;
  357:     
  358:     # If there is a state from the previous form, use that. If there is no
  359:     # state, use the start state parameter.
  360:     if (defined $ENV{"form.CURRENT_STATE"})
  361:     {
  362: 	$self->{STATE} = $ENV{"form.CURRENT_STATE"};
  363:     }
  364:     else
  365:     {
  366: 	$self->{STATE} = "START";
  367:     }
  368: 
  369:     $self->{TOKEN} = $ENV{'form.TOKEN'};
  370:     # If a token was passed, we load that in. Otherwise, we need to create a 
  371:     # new storage file
  372:     # Tried to use standard Tie'd hashes, but you can't seem to take a 
  373:     # reference to a tied hash and write to it. I'd call that a wart.
  374:     if ($self->{TOKEN}) {
  375:         # Validate the token before trusting it
  376:         if ($self->{TOKEN} !~ /^[a-f0-9]{32}$/) {
  377:             # Not legit. Return nothing and let all hell break loose.
  378:             # User shouldn't be doing that!
  379:             return undef;
  380:         }
  381: 
  382:         # Get the hash.
  383:         $self->{FILENAME} = $Apache::lonnet::tmpdir . md5_hex($self->{TOKEN}); # Note the token is not the literal file
  384:         
  385:         my $file = Apache::File->new($self->{FILENAME});
  386:         my $contents = <$file>;
  387: 
  388:         # Now load in the contents
  389:         for my $value (split (/&/, $contents)) {
  390:             my ($name, $value) = split(/=/, $value);
  391:             $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
  392:             $self->{VARS}->{$name} = $value;
  393:         }
  394: 
  395:         $file->close();
  396:     } else {
  397:         # Only valid if we're just starting.
  398:         if ($self->{STATE} ne 'START') {
  399:             return undef;
  400:         }
  401:         # Must create the storage
  402:         $self->{TOKEN} = md5_hex($ENV{'user.name'} . $ENV{'user.domain'} .
  403:                                  time() . rand());
  404:         $self->{FILENAME} = $Apache::lonnet::tmpdir . md5_hex($self->{TOKEN});
  405:     }
  406: 
  407:     # OK, we now have our persistent storage.
  408: 
  409:     if (defined $ENV{"form.RETURN_PAGE"})
  410:     {
  411: 	$self->{RETURN_PAGE} = $ENV{"form.RETURN_PAGE"};
  412:     }
  413:     else
  414:     {
  415: 	$self->{RETURN_PAGE} = $ENV{REFERER};
  416:     }
  417: 
  418:     $self->{STATES} = {};
  419:     $self->{DONE} = 0;
  420: 
  421:     # Used by various helpers for various things; see lonparm.helper
  422:     # for an example.
  423:     $self->{DATA} = {};
  424: 
  425:     $helper = $self;
  426: 
  427:     # Establish the $paramHash
  428:     $paramHash = {};
  429: 
  430:     bless($self, $class);
  431:     return $self;
  432: }
  433: 
  434: # Private function; returns a string to construct the hidden fields
  435: # necessary to have the helper track state.
  436: sub _saveVars {
  437:     my $self = shift;
  438:     my $result = "";
  439:     $result .= '<input type="hidden" name="CURRENT_STATE" value="' .
  440:         HTML::Entities::encode($self->{STATE}) . "\" />\n";
  441:     $result .= '<input type="hidden" name="TOKEN" value="' .
  442:         $self->{TOKEN} . "\" />\n";
  443:     $result .= '<input type="hidden" name="RETURN_PAGE" value="' .
  444:         HTML::Entities::encode($self->{RETURN_PAGE}) . "\" />\n";
  445: 
  446:     return $result;
  447: }
  448: 
  449: # Private function: Create the querystring-like representation of the stored
  450: # data to write to disk.
  451: sub _varsInFile {
  452:     my $self = shift;
  453:     my @vars = ();
  454:     for my $key (keys %{$self->{VARS}}) {
  455:         push @vars, &Apache::lonnet::escape($key) . '=' .
  456:             &Apache::lonnet::escape($self->{VARS}->{$key});
  457:     }
  458:     return join ('&', @vars);
  459: }
  460: 
  461: # Use this to declare variables.
  462: # FIXME: Document this
  463: sub declareVar {
  464:     my $self = shift;
  465:     my $var = shift;
  466: 
  467:     if (!defined($self->{VARS}->{$var})) {
  468:         $self->{VARS}->{$var} = '';
  469:     }
  470: 
  471:     my $envname = 'form.' . $var . '.forminput';
  472:     if (defined($ENV{$envname})) {
  473:         if (ref($ENV{$envname})) {
  474:             $self->{VARS}->{$var} = join('|||', @{$ENV{$envname}});
  475:         } else {
  476:             $self->{VARS}->{$var} = $ENV{$envname};
  477:         }
  478:     }
  479: }
  480: 
  481: sub allowedCheck {
  482:     my $self = shift;
  483: 
  484:     if (!defined($self->{REQUIRED_PRIV})) { 
  485:         return 1;
  486:     }
  487: 
  488:     return Apache::lonnet::allowed($self->{REQUIRED_PRIV}, $ENV{'request.course.id'});
  489: }
  490: 
  491: sub changeState {
  492:     my $self = shift;
  493:     $self->{STATE} = shift;
  494: }
  495: 
  496: sub registerState {
  497:     my $self = shift;
  498:     my $state = shift;
  499: 
  500:     my $stateName = $state->name();
  501:     $self->{STATES}{$stateName} = $state;
  502: }
  503: 
  504: sub process {
  505:     my $self = shift;
  506: 
  507:     # Phase 1: Post processing for state of previous screen (which is actually
  508:     # the "current state" in terms of the helper variables), if it wasn't the 
  509:     # beginning state.
  510:     if ($self->{STATE} ne "START" || $ENV{"form.SUBMIT"} eq "Next ->") {
  511: 	my $prevState = $self->{STATES}{$self->{STATE}};
  512:         $prevState->postprocess();
  513:     }
  514:     
  515:     # Note, to handle errors in a state's input that a user must correct,
  516:     # do not transition in the postprocess, and force the user to correct
  517:     # the error.
  518: 
  519:     # Phase 2: Preprocess current state
  520:     my $startState = $self->{STATE};
  521:     my $state = $self->{STATES}->{$startState};
  522:     
  523:     # For debugging, print something here to determine if you're going
  524:     # to an undefined state.
  525:     if (!defined($state)) {
  526:         return;
  527:     }
  528:     $state->preprocess();
  529: 
  530:     # Phase 3: While the current state is different from the previous state,
  531:     # keep processing.
  532:     while ( $startState ne $self->{STATE} && 
  533:             defined($self->{STATES}->{$self->{STATE}}) )
  534:     {
  535: 	$startState = $self->{STATE};
  536: 	$state = $self->{STATES}->{$startState};
  537: 	$state->preprocess();
  538:     }
  539: 
  540:     return;
  541: } 
  542: 
  543: # 1: Do the post processing for the previous state.
  544: # 2: Do the preprocessing for the current state.
  545: # 3: Check to see if state changed, if so, postprocess current and move to next.
  546: #    Repeat until state stays stable.
  547: # 4: Render the current state to the screen as an HTML page.
  548: sub display {
  549:     my $self = shift;
  550: 
  551:     my $state = $self->{STATES}{$self->{STATE}};
  552: 
  553:     my $result = "";
  554: 
  555:     if (!defined($state)) {
  556:         $result = "<font color='#ff0000'>Error: state '$state' not defined!</font>";
  557:         return $result;
  558:     }
  559: 
  560:     # Phase 4: Display.
  561:     my $stateTitle = $state->title();
  562:     my $bodytag = &Apache::loncommon::bodytag("$self->{TITLE}",'','');
  563: 
  564:     $result .= <<HEADER;
  565: <html>
  566:     <head>
  567:         <title>LON-CAPA Helper: $self->{TITLE}</title>
  568:     </head>
  569:     $bodytag
  570: HEADER
  571:     if (!$state->overrideForm()) { $result.="<form name='helpform' method='POST'>"; }
  572:     $result .= <<HEADER;
  573:         <table border="0" width='100%'><tr><td>
  574:         <h2><i>$stateTitle</i></h2>
  575: HEADER
  576: 
  577:     $result .= "<table cellpadding='10' width='100%'><tr><td rowspan='2' valign='top'>";
  578: 
  579:     if (!$state->overrideForm()) {
  580:         $result .= $self->_saveVars();
  581:     }
  582:     $result .= $state->render();
  583: 
  584:     $result .= "</td><td valign='top' align='right'>";
  585: 
  586:     # Warning: Copy and pasted from below, because it's too much trouble to 
  587:     # turn this into a subroutine
  588:     if (!$state->overrideForm()) {
  589:         if ($self->{STATE} ne $self->{START_STATE}) {
  590:             #$result .= '<input name="SUBMIT" type="submit" value="&lt;- Previous" />&nbsp;&nbsp;';
  591:         }
  592:         if ($self->{DONE}) {
  593:             my $returnPage = $self->{RETURN_PAGE};
  594:             $result .= "<a href=\"$returnPage\">End Helper</a>";
  595:         }
  596:         else {
  597:             $result .= '<nobr><input name="back" type="button" ';
  598:             $result .= 'value="&lt;- Previous" onclick="history.go(-1)" /> ';
  599:             $result .= '<input name="SUBMIT" type="submit" value="Next -&gt;" /></nobr>';
  600:         }
  601:     }
  602: 
  603:     $result .= "</td></tr><tr><td valign='bottom' align='right'>";
  604: 
  605:     # Warning: Copy and pasted from above, because it's too much trouble to 
  606:     # turn this into a subroutine
  607:     if (!$state->overrideForm()) {
  608:         if ($self->{STATE} ne $self->{START_STATE}) {
  609:             #$result .= '<input name="SUBMIT" type="submit" value="&lt;- Previous" />&nbsp;&nbsp;';
  610:         }
  611:         if ($self->{DONE}) {
  612:             my $returnPage = $self->{RETURN_PAGE};
  613:             $result .= "<a href=\"$returnPage\">End Helper</a>";
  614:         }
  615:         else {
  616:             $result .= '<nobr><input name="back" type="button" ';
  617:             $result .= 'value="&lt;- Previous" onclick="history.go(-1)" /> ';
  618:             $result .= '<input name="SUBMIT" type="submit" value="Next -&gt;" /></nobr>';
  619:         }
  620:     }
  621: 
  622:     #foreach my $key (keys %{$self->{VARS}}) {
  623:     #    $result .= "|$key| -> " . $self->{VARS}->{$key} . "<br />";
  624:     #}
  625: 
  626:     $result .= "</td></tr></table>";
  627: 
  628:     $result .= <<FOOTER;
  629:               </td>
  630:             </tr>
  631:           </table>
  632:         </form>
  633:     </body>
  634: </html>
  635: FOOTER
  636: 
  637:     # Handle writing out the vars to the file
  638:     my $file = Apache::File->new('>'.$self->{FILENAME});
  639:     print $file $self->_varsInFile();
  640: 
  641:     return $result;
  642: }
  643: 
  644: 1;
  645: 
  646: package Apache::lonhelper::state;
  647: 
  648: # States bundle things together and are responsible for compositing the
  649: # various elements together. It is not generally necessary for users to
  650: # use the state object directly, so it is not perldoc'ed.
  651: 
  652: # Basically, all the states do is pass calls to the elements and aggregate
  653: # the results.
  654: 
  655: sub new {
  656:     my $proto = shift;
  657:     my $class = ref($proto) || $proto;
  658:     my $self = {};
  659: 
  660:     $self->{NAME} = shift;
  661:     $self->{TITLE} = shift;
  662:     $self->{ELEMENTS} = [];
  663: 
  664:     bless($self, $class);
  665: 
  666:     $helper->registerState($self);
  667: 
  668:     $state = $self;
  669: 
  670:     return $self;
  671: }
  672: 
  673: sub name {
  674:     my $self = shift;
  675:     return $self->{NAME};
  676: }
  677: 
  678: sub title {
  679:     my $self = shift;
  680:     return $self->{TITLE};
  681: }
  682: 
  683: sub preprocess {
  684:     my $self = shift;
  685:     for my $element (@{$self->{ELEMENTS}}) {
  686:         $element->preprocess();
  687:     }
  688: }
  689: 
  690: # FIXME: Document that all postprocesses must return a true value or
  691: # the state transition will be overridden
  692: sub postprocess {
  693:     my $self = shift;
  694: 
  695:     # Save the state so we can roll it back if we need to.
  696:     my $originalState = $helper->{STATE};
  697:     my $everythingSuccessful = 1;
  698: 
  699:     for my $element (@{$self->{ELEMENTS}}) {
  700:         my $result = $element->postprocess();
  701:         if (!$result) { $everythingSuccessful = 0; }
  702:     }
  703: 
  704:     # If not all the postprocesses were successful, override
  705:     # any state transitions that may have occurred. It is the
  706:     # responsibility of the states to make sure they have 
  707:     # error handling in that case.
  708:     if (!$everythingSuccessful) {
  709:         $helper->{STATE} = $originalState;
  710:     }
  711: }
  712: 
  713: # Override the form if any element wants to.
  714: # two elements overriding the form will make a mess, but that should
  715: # be considered helper author error ;-)
  716: sub overrideForm {
  717:     my $self = shift;
  718:     for my $element (@{$self->{ELEMENTS}}) {
  719:         if ($element->overrideForm()) {
  720:             return 1;
  721:         }
  722:     }
  723:     return 0;
  724: }
  725: 
  726: sub addElement {
  727:     my $self = shift;
  728:     my $element = shift;
  729:     
  730:     push @{$self->{ELEMENTS}}, $element;
  731: }
  732: 
  733: sub render {
  734:     my $self = shift;
  735:     my @results = ();
  736: 
  737:     for my $element (@{$self->{ELEMENTS}}) {
  738:         push @results, $element->render();
  739:     }
  740: 
  741:     return join("\n", @results);
  742: }
  743: 
  744: 1;
  745: 
  746: package Apache::lonhelper::element;
  747: # Support code for elements
  748: 
  749: =pod
  750: 
  751: =head2 Element Base Class
  752: 
  753: The Apache::lonhelper::element base class provides support for elements
  754: and defines some generally useful tags for use in elements.
  755: 
  756: B<finalcode tag>
  757: 
  758: Each element can contain a "finalcode" tag that, when the special FINAL
  759: helper state is used, will be executed, surrounded by "sub { my $helper = shift;"
  760: and "}". It is expected to return a string describing what it did, which 
  761: may be an empty string. See course initialization helper for an example. This is
  762: generally intended for helpers like the course initialization helper, which consist
  763: of several panels, each of which is performing some sort of bite-sized functionality.
  764: 
  765: B<defaultvalue tag>
  766: 
  767: Each element that accepts user input can contain a "defaultvalue" tag that,
  768: when surrounded by "sub { my $helper = shift; my $state = shift; " and "}",
  769: will form a subroutine that when called will provide a default value for
  770: the element. How this value is interpreted by the element is specific to
  771: the element itself, and possibly the settings the element has (such as 
  772: multichoice vs. single choice for <choices> tags). 
  773: 
  774: This is also intended for things like the course initialization wizard, where the
  775: user is setting various parameters. By correctly grabbing current settings 
  776: and including them into the helper, it allows the user to come back to the
  777: helper later and re-execute it, without needing to worry about overwriting
  778: some setting accidentally.
  779: 
  780: Again, see the course initialization helper for examples.
  781: 
  782: B<validator tag>
  783: 
  784: Some elements that accepts user input can contain a "validator" tag that,
  785: when surrounded by "sub { my $helper = shift; my $state = shift; my $element = shift; my $val = shift " 
  786: and "}", where "$val" is the value the user entered, will form a subroutine 
  787: that when called will verify whether the given input is valid or not. If it 
  788: is valid, the routine will return a false value. If invalid, the routine 
  789: will return an error message to be displayed for the user.
  790: 
  791: Consult the documentation for each element to see whether it supports this 
  792: tag.
  793: 
  794: B<getValue method>
  795: 
  796: If the element stores the name of the variable in a 'variable' member, which
  797: the provided ones all do, you can retreive the value of the variable by calling
  798: this method.
  799: 
  800: =cut
  801: 
  802: BEGIN {
  803:     &Apache::lonhelper::register('Apache::lonhelper::element',
  804:                                  ('nextstate', 'finalcode',
  805:                                   'defaultvalue', 'validator'));
  806: }
  807: 
  808: # Because we use the param hash, this is often a sufficent
  809: # constructor
  810: sub new {
  811:     my $proto = shift;
  812:     my $class = ref($proto) || $proto;
  813:     my $self = $paramHash;
  814:     bless($self, $class);
  815: 
  816:     $self->{PARAMS} = $paramHash;
  817:     $self->{STATE} = $state;
  818:     $state->addElement($self);
  819:     
  820:     # Ensure param hash is not reused
  821:     $paramHash = {};
  822: 
  823:     return $self;
  824: }   
  825: 
  826: sub start_nextstate {
  827:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  828: 
  829:     if ($target ne 'helper') {
  830:         return '';
  831:     }
  832:     
  833:     $paramHash->{NEXTSTATE} = &Apache::lonxml::get_all_text('/nextstate',
  834:                                                              $parser);
  835:     return '';
  836: }
  837: 
  838: sub end_nextstate { return ''; }
  839: 
  840: sub start_finalcode {
  841:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  842: 
  843:     if ($target ne 'helper') {
  844:         return '';
  845:     }
  846:     
  847:     $paramHash->{FINAL_CODE} = &Apache::lonxml::get_all_text('/finalcode',
  848:                                                              $parser);
  849:     return '';
  850: }
  851: 
  852: sub end_finalcode { return ''; }
  853: 
  854: sub start_defaultvalue {
  855:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  856: 
  857:     if ($target ne 'helper') {
  858:         return '';
  859:     }
  860:     
  861:     $paramHash->{DEFAULT_VALUE} = &Apache::lonxml::get_all_text('/defaultvalue',
  862:                                                              $parser);
  863:     $paramHash->{DEFAULT_VALUE} = 'sub { my $helper = shift; my $state = shift;' .
  864:         $paramHash->{DEFAULT_VALUE} . '}';
  865:     return '';
  866: }
  867: 
  868: sub end_defaultvalue { return ''; }
  869: 
  870: sub start_validator {
  871:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  872: 
  873:     if ($target ne 'helper') {
  874:         return '';
  875:     }
  876:     
  877:     $paramHash->{VALIDATOR} = &Apache::lonxml::get_all_text('/validator',
  878:                                                              $parser);
  879:     $paramHash->{VALIDATOR} = 'sub { my $helper = shift; my $state = shift; my $element = shift; my $val = shift;' .
  880:         $paramHash->{VALIDATOR} . '}';
  881:     return '';
  882: }
  883: 
  884: sub end_validator { return ''; }
  885: 
  886: sub preprocess {
  887:     return 1;
  888: }
  889: 
  890: sub postprocess {
  891:     return 1;
  892: }
  893: 
  894: sub render {
  895:     return '';
  896: }
  897: 
  898: sub overrideForm {
  899:     return 0;
  900: }
  901: 
  902: sub getValue {
  903:     my $self = shift;
  904:     return $helper->{VARS}->{$self->{'variable'}};
  905: }
  906: 
  907: 1;
  908: 
  909: package Apache::lonhelper::message;
  910: 
  911: =pod
  912: 
  913: =head2 Element: message
  914: 
  915: Message elements display the contents of their <message_text> tags, and
  916: transition directly to the state in the <nextstate> tag. Example:
  917: 
  918:  <message>
  919:    <nextstate>GET_NAME</nextstate>
  920:    <message_text>This is the <b>message</b> the user will see, 
  921:                  <i>HTML allowed</i>.</message_text>
  922:    </message>
  923: 
  924: This will display the HTML message and transition to the <nextstate> if
  925: given. The HTML will be directly inserted into the helper, so if you don't
  926: want text to run together, you'll need to manually wrap the <message_text>
  927: in <p> tags, or whatever is appropriate for your HTML.
  928: 
  929: Message tags do not add in whitespace, so if you want it, you'll need to add
  930: it into states. This is done so you can inline some elements, such as 
  931: the <date> element, right between two messages, giving the appearence that 
  932: the <date> element appears inline. (Note the elements can not be embedded
  933: within each other.)
  934: 
  935: This is also a good template for creating your own new states, as it has
  936: very little code beyond the state template.
  937: 
  938: =cut
  939: 
  940: no strict;
  941: @ISA = ("Apache::lonhelper::element");
  942: use strict;
  943: 
  944: BEGIN {
  945:     &Apache::lonhelper::register('Apache::lonhelper::message',
  946:                               ('message'));
  947: }
  948: 
  949: sub new {
  950:     my $ref = Apache::lonhelper::element->new();
  951:     bless($ref);
  952: }
  953: 
  954: # CONSTRUCTION: Construct the message element from the XML
  955: sub start_message {
  956:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  957: 
  958:     if ($target ne 'helper') {
  959:         return '';
  960:     }
  961: 
  962:     $paramHash->{MESSAGE_TEXT} = &Apache::lonxml::get_all_text('/message',
  963:                                                                $parser);
  964: 
  965:     if (defined($token->[2]{'nextstate'})) {
  966:         $paramHash->{NEXTSTATE} = $token->[2]{'nextstate'};
  967:     }
  968:     return '';
  969: }
  970: 
  971: sub end_message {
  972:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
  973: 
  974:     if ($target ne 'helper') {
  975:         return '';
  976:     }
  977:     Apache::lonhelper::message->new();
  978:     return '';
  979: }
  980: 
  981: sub render {
  982:     my $self = shift;
  983: 
  984:     return $self->{MESSAGE_TEXT};
  985: }
  986: # If a NEXTSTATE was given, switch to it
  987: sub postprocess {
  988:     my $self = shift;
  989:     if (defined($self->{NEXTSTATE})) {
  990:         $helper->changeState($self->{NEXTSTATE});
  991:     }
  992: 
  993:     return 1;
  994: }
  995: 1;
  996: 
  997: package Apache::lonhelper::choices;
  998: 
  999: =pod
 1000: 
 1001: =head2 Element: choices
 1002: 
 1003: Choice states provide a single choice to the user as a text selection box.
 1004: A "choice" is two pieces of text, one which will be displayed to the user
 1005: (the "human" value), and one which will be passed back to the program
 1006: (the "computer" value). For instance, a human may choose from a list of
 1007: resources on disk by title, while your program wants the file name.
 1008: 
 1009: <choices> takes an attribute "variable" to control which helper variable
 1010: the result is stored in.
 1011: 
 1012: <choices> takes an attribute "multichoice" which, if set to a true
 1013: value, will allow the user to select multiple choices.
 1014: 
 1015: <choices> takes an attribute "allowempty" which, if set to a true 
 1016: value, will allow the user to select none of the choices without raising
 1017: an error message.
 1018: 
 1019: B<SUB-TAGS>
 1020: 
 1021: <choices> can have the following subtags:
 1022: 
 1023: =over 4
 1024: 
 1025: =item * <nextstate>state_name</nextstate>: If given, this will cause the
 1026:       choice element to transition to the given state after executing. If
 1027:       this is used, do not pass nextstates to the <choice> tag.
 1028: 
 1029: =item * <choice />: If the choices are static,
 1030:       this element will allow you to specify them. Each choice
 1031:       contains  attribute, "computer", as described above. The
 1032:       content of the tag will be used as the human label.
 1033:       For example,  
 1034:       <choice computer='234-12-7312'>Bobby McDormik</choice>.
 1035: 
 1036:       <choice> can take a parameter "eval", which if set to
 1037:       a true value, will cause the contents of the tag to be
 1038:       evaluated as it would be in an <eval> tag; see <eval> tag
 1039:       below.
 1040: 
 1041: <choice> may optionally contain a 'nextstate' attribute, which
 1042: will be the state transisitoned to if the choice is made, if
 1043: the choice is not multichoice.
 1044: 
 1045: =back
 1046: 
 1047: To create the choices programmatically, either wrap the choices in 
 1048: <condition> tags (prefered), or use an <exec> block inside the <choice>
 1049: tag. Store the choices in $state->{CHOICES}, which is a list of list
 1050: references, where each list has three strings. The first is the human
 1051: name, the second is the computer name. and the third is the option
 1052: next state. For example:
 1053: 
 1054:  <exec>
 1055:     for (my $i = 65; $i < 65 + 26; $i++) {
 1056:         push @{$state->{CHOICES}}, [chr($i), $i, 'next'];
 1057:     }
 1058:  </exec>
 1059: 
 1060: This will allow the user to select from the letters A-Z (in ASCII), while
 1061: passing the ASCII value back into the helper variables, and the state
 1062: will in all cases transition to 'next'.
 1063: 
 1064: You can mix and match methods of creating choices, as long as you always 
 1065: "push" onto the choice list, rather then wiping it out. (You can even 
 1066: remove choices programmatically, but that would probably be bad form.)
 1067: 
 1068: B<defaultvalue support>
 1069: 
 1070: Choices supports default values both in multichoice and single choice mode.
 1071: In single choice mode, have the defaultvalue tag's function return the 
 1072: computer value of the box you want checked. If the function returns a value
 1073: that does not correspond to any of the choices, the default behavior of selecting
 1074: the first choice will be preserved.
 1075: 
 1076: For multichoice, return a string with the computer values you want checked,
 1077: delimited by triple pipes. Note this matches how the result of the <choices>
 1078: tag is stored in the {VARS} hash.
 1079: 
 1080: =cut
 1081: 
 1082: no strict;
 1083: @ISA = ("Apache::lonhelper::element");
 1084: use strict;
 1085: 
 1086: BEGIN {
 1087:     &Apache::lonhelper::register('Apache::lonhelper::choices',
 1088:                               ('choice', 'choices'));
 1089: }
 1090: 
 1091: sub new {
 1092:     my $ref = Apache::lonhelper::element->new();
 1093:     bless($ref);
 1094: }
 1095: 
 1096: # CONSTRUCTION: Construct the message element from the XML
 1097: sub start_choices {
 1098:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1099: 
 1100:     if ($target ne 'helper') {
 1101:         return '';
 1102:     }
 1103: 
 1104:     # Need to initialize the choices list, so everything can assume it exists
 1105:     $paramHash->{'variable'} = $token->[2]{'variable'} if (!defined($paramHash->{'variable'}));
 1106:     $helper->declareVar($paramHash->{'variable'});
 1107:     $paramHash->{'multichoice'} = $token->[2]{'multichoice'};
 1108:     $paramHash->{'allowempty'} = $token->[2]{'allowempty'};
 1109:     $paramHash->{CHOICES} = [];
 1110:     return '';
 1111: }
 1112: 
 1113: sub end_choices {
 1114:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1115: 
 1116:     if ($target ne 'helper') {
 1117:         return '';
 1118:     }
 1119:     Apache::lonhelper::choices->new();
 1120:     return '';
 1121: }
 1122: 
 1123: sub start_choice {
 1124:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1125: 
 1126:     if ($target ne 'helper') {
 1127:         return '';
 1128:     }
 1129: 
 1130:     my $computer = $token->[2]{'computer'};
 1131:     my $human = &Apache::lonxml::get_all_text('/choice',
 1132:                                               $parser);
 1133:     my $nextstate = $token->[2]{'nextstate'};
 1134:     my $evalFlag = $token->[2]{'eval'};
 1135:     push @{$paramHash->{CHOICES}}, [$human, $computer, $nextstate, 
 1136:                                     $evalFlag];
 1137:     return '';
 1138: }
 1139: 
 1140: sub end_choice {
 1141:     return '';
 1142: }
 1143: 
 1144: sub render {
 1145:     my $self = shift;
 1146:     my $var = $self->{'variable'};
 1147:     my $buttons = '';
 1148:     my $result = '';
 1149: 
 1150:     if ($self->{'multichoice'}) {
 1151:         $result .= <<SCRIPT;
 1152: <script>
 1153:     function checkall(value, checkName) {
 1154: 	for (i=0; i<document.forms.helpform.elements.length; i++) {
 1155:             ele = document.forms.helpform.elements[i];
 1156:             if (ele.name == checkName + '.forminput') {
 1157:                 document.forms.helpform.elements[i].checked=value;
 1158:             }
 1159:         }
 1160:     }
 1161: </script>
 1162: SCRIPT
 1163:     }
 1164: 
 1165:     # Only print "select all" and "unselect all" if there are five or
 1166:     # more choices; fewer then that and it looks silly.
 1167:     if ($self->{'multichoice'} && scalar(@{$self->{CHOICES}}) > 4) {
 1168:         $buttons = <<BUTTONS;
 1169: <br />
 1170: <input type="button" onclick="checkall(true, '$var')" value="Select All" />
 1171: <input type="button" onclick="checkall(false, '$var')" value="Unselect All" />
 1172: <br />&nbsp;
 1173: BUTTONS
 1174:     }
 1175: 
 1176:     if (defined $self->{ERROR_MSG}) {
 1177:         $result .= '<br /><font color="#FF0000">' . $self->{ERROR_MSG} . '</font><br />';
 1178:     }
 1179: 
 1180:     $result .= $buttons;
 1181:     
 1182:     $result .= "<table>\n\n";
 1183: 
 1184:     my %checkedChoices;
 1185:     my $checkedChoicesFunc;
 1186: 
 1187:     if (defined($self->{DEFAULT_VALUE})) {
 1188:         $checkedChoicesFunc = eval ($self->{DEFAULT_VALUE});
 1189:         die 'Error in default value code for variable ' . 
 1190:             $self->{'variable'} . ', Perl said: ' . $@ if $@;
 1191:     } else {
 1192:         $checkedChoicesFunc = sub { return ''; };
 1193:     }
 1194: 
 1195:     # Process which choices should be checked.
 1196:     if ($self->{'multichoice'}) {
 1197:         for my $selectedChoice (split(/\|\|\|/, (&$checkedChoicesFunc($helper, $self)))) {
 1198:             $checkedChoices{$selectedChoice} = 1;
 1199:         }
 1200:     } else {
 1201:         # single choice
 1202:         my $selectedChoice = &$checkedChoicesFunc($helper, $self);
 1203:         
 1204:         my $foundChoice = 0;
 1205:         
 1206:         # check that the choice is in the list of choices.
 1207:         for my $choice (@{$self->{CHOICES}}) {
 1208:             if ($choice->[1] eq $selectedChoice) {
 1209:                 $checkedChoices{$choice->[1]} = 1;
 1210:                 $foundChoice = 1;
 1211:             }
 1212:         }
 1213:         
 1214:         # If we couldn't find the choice, pick the first one 
 1215:         if (!$foundChoice) {
 1216:             $checkedChoices{$self->{CHOICES}->[0]->[1]} = 1;
 1217:         }
 1218:     }
 1219: 
 1220:     my $type = "radio";
 1221:     if ($self->{'multichoice'}) { $type = 'checkbox'; }
 1222:     foreach my $choice (@{$self->{CHOICES}}) {
 1223:         $result .= "<tr>\n<td width='20'>&nbsp;</td>\n";
 1224:         $result .= "<td valign='top'><input type='$type' name='$var.forminput'"
 1225:             . "' value='" . 
 1226:             HTML::Entities::encode($choice->[1]) 
 1227:             . "'";
 1228:         if ($checkedChoices{$choice->[1]}) {
 1229:             $result .= " checked ";
 1230:         }
 1231:         my $choiceLabel = $choice->[0];
 1232:         if ($choice->[4]) {  # if we need to evaluate this choice
 1233:             $choiceLabel = "sub { my $helper = shift; my $state = shift;" .
 1234:                 $choiceLabel . "}";
 1235:             $choiceLabel = eval($choiceLabel);
 1236:             $choiceLabel = &$choiceLabel($helper, $self);
 1237:         }
 1238:         $result .= "/></td><td> " . $choiceLabel . "</td></tr>\n";
 1239:     }
 1240:     $result .= "</table>\n\n\n";
 1241:     $result .= $buttons;
 1242: 
 1243:     return $result;
 1244: }
 1245: 
 1246: # If a NEXTSTATE was given or a nextstate for this choice was
 1247: # given, switch to it
 1248: sub postprocess {
 1249:     my $self = shift;
 1250:     my $chosenValue = $ENV{'form.' . $self->{'variable'} . '.forminput'};
 1251: 
 1252:     if (!defined($chosenValue) && !$self->{'allowempty'}) {
 1253:         $self->{ERROR_MSG} = "You must choose one or more choices to" .
 1254:             " continue.";
 1255:         return 0;
 1256:     }
 1257: 
 1258:     if (ref($chosenValue)) {
 1259:         $helper->{VARS}->{$self->{'variable'}} = join('|||', @$chosenValue);
 1260:     }
 1261: 
 1262:     if (defined($self->{NEXTSTATE})) {
 1263:         $helper->changeState($self->{NEXTSTATE});
 1264:     }
 1265:     
 1266:     foreach my $choice (@{$self->{CHOICES}}) {
 1267:         if ($choice->[1] eq $chosenValue) {
 1268:             if (defined($choice->[2])) {
 1269:                 $helper->changeState($choice->[2]);
 1270:             }
 1271:         }
 1272:     }
 1273:     return 1;
 1274: }
 1275: 1;
 1276: 
 1277: package Apache::lonhelper::dropdown;
 1278: 
 1279: =pod
 1280: 
 1281: =head2 Element: dropdown
 1282: 
 1283: A drop-down provides a drop-down box instead of a radio button
 1284: box. Because most people do not know how to use a multi-select
 1285: drop-down box, that option is not allowed. Otherwise, the arguments
 1286: are the same as "choices", except "allowempty" is also meaningless.
 1287: 
 1288: <dropdown> takes an attribute "variable" to control which helper variable
 1289: the result is stored in.
 1290: 
 1291: B<SUB-TAGS>
 1292: 
 1293: <choice>, which acts just as it does in the "choices" element.
 1294: 
 1295: =back
 1296: 
 1297: =cut
 1298: 
 1299: no strict;
 1300: @ISA = ("Apache::lonhelper::element");
 1301: use strict;
 1302: 
 1303: BEGIN {
 1304:     &Apache::lonhelper::register('Apache::lonhelper::dropdown',
 1305:                               ('dropdown'));
 1306: }
 1307: 
 1308: sub new {
 1309:     my $ref = Apache::lonhelper::element->new();
 1310:     bless($ref);
 1311: }
 1312: 
 1313: # CONSTRUCTION: Construct the message element from the XML
 1314: sub start_dropdown {
 1315:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1316: 
 1317:     if ($target ne 'helper') {
 1318:         return '';
 1319:     }
 1320: 
 1321:     # Need to initialize the choices list, so everything can assume it exists
 1322:     $paramHash->{'variable'} = $token->[2]{'variable'} if (!defined($paramHash->{'variable'}));
 1323:     $helper->declareVar($paramHash->{'variable'});
 1324:     $paramHash->{CHOICES} = [];
 1325:     return '';
 1326: }
 1327: 
 1328: sub end_dropdown {
 1329:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1330: 
 1331:     if ($target ne 'helper') {
 1332:         return '';
 1333:     }
 1334:     Apache::lonhelper::dropdown->new();
 1335:     return '';
 1336: }
 1337: 
 1338: sub render {
 1339:     my $self = shift;
 1340:     my $var = $self->{'variable'};
 1341:     my $result = '';
 1342: 
 1343:     if (defined $self->{ERROR_MSG}) {
 1344:         $result .= '<br /><font color="#FF0000">' . $self->{ERROR_MSG} . '</font><br />';
 1345:     }
 1346: 
 1347:     my %checkedChoices;
 1348:     my $checkedChoicesFunc;
 1349: 
 1350:     if (defined($self->{DEFAULT_VALUE})) {
 1351:         $checkedChoicesFunc = eval ($self->{DEFAULT_VALUE});
 1352:         die 'Error in default value code for variable ' . 
 1353:             $self->{'variable'} . ', Perl said: ' . $@ if $@;
 1354:     } else {
 1355:         $checkedChoicesFunc = sub { return ''; };
 1356:     }
 1357: 
 1358:     # single choice
 1359:     my $selectedChoice = &$checkedChoicesFunc($helper, $self);
 1360:     
 1361:     my $foundChoice = 0;
 1362:     
 1363:     # check that the choice is in the list of choices.
 1364:     for my $choice (@{$self->{CHOICES}}) {
 1365: 	if ($choice->[1] eq $selectedChoice) {
 1366: 	    $checkedChoices{$choice->[1]} = 1;
 1367: 	    $foundChoice = 1;
 1368: 	}
 1369:     }
 1370:     
 1371:     # If we couldn't find the choice, pick the first one 
 1372:     if (!$foundChoice) {
 1373: 	$checkedChoices{$self->{CHOICES}->[0]->[1]} = 1;
 1374:     }
 1375: 
 1376:     $result .= "<select name='${var}.forminput'>\n";
 1377:     foreach my $choice (@{$self->{CHOICES}}) {
 1378:         $result .= "<option value='" . 
 1379:             HTML::Entities::encode($choice->[1]) 
 1380:             . "'";
 1381:         if ($checkedChoices{$choice->[1]}) {
 1382:             $result .= " selected";
 1383:         }
 1384:         my $choiceLabel = $choice->[0];
 1385:         if ($choice->[4]) {  # if we need to evaluate this choice
 1386:             $choiceLabel = "sub { my $helper = shift; my $state = shift;" .
 1387:                 $choiceLabel . "}";
 1388:             $choiceLabel = eval($choiceLabel);
 1389:             $choiceLabel = &$choiceLabel($helper, $self);
 1390:         }
 1391:         $result .= ">" . $choiceLabel . "\n";
 1392:     }
 1393:     $result .= "</select>\n";
 1394: 
 1395:     return $result;
 1396: }
 1397: 
 1398: # If a NEXTSTATE was given or a nextstate for this choice was
 1399: # given, switch to it
 1400: sub postprocess {
 1401:     my $self = shift;
 1402:     my $chosenValue = $ENV{'form.' . $self->{'variable'} . '.forminput'};
 1403: 
 1404:     if (!defined($chosenValue) && !$self->{'allowempty'}) {
 1405:         $self->{ERROR_MSG} = "You must choose one or more choices to" .
 1406:             " continue.";
 1407:         return 0;
 1408:     }
 1409: 
 1410:     if (defined($self->{NEXTSTATE})) {
 1411:         $helper->changeState($self->{NEXTSTATE});
 1412:     }
 1413:     
 1414:     foreach my $choice (@{$self->{CHOICES}}) {
 1415:         if ($choice->[1] eq $chosenValue) {
 1416:             if (defined($choice->[2])) {
 1417:                 $helper->changeState($choice->[2]);
 1418:             }
 1419:         }
 1420:     }
 1421:     return 1;
 1422: }
 1423: 1;
 1424: 
 1425: package Apache::lonhelper::date;
 1426: 
 1427: =pod
 1428: 
 1429: =head2 Element: date
 1430: 
 1431: Date elements allow the selection of a date with a drop down list.
 1432: 
 1433: Date elements can take two attributes:
 1434: 
 1435: =over 4
 1436: 
 1437: =item * B<variable>: The name of the variable to store the chosen
 1438:         date in. Required.
 1439: 
 1440: =item * B<hoursminutes>: If a true value, the date will show hours
 1441:         and minutes, as well as month/day/year. If false or missing,
 1442:         the date will only show the month, day, and year.
 1443: 
 1444: =back
 1445: 
 1446: Date elements contain only an option <nextstate> tag to determine
 1447: the next state.
 1448: 
 1449: Example:
 1450: 
 1451:  <date variable="DUE_DATE" hoursminutes="1">
 1452:    <nextstate>choose_why</nextstate>
 1453:    </date>
 1454: 
 1455: =cut
 1456: 
 1457: no strict;
 1458: @ISA = ("Apache::lonhelper::element");
 1459: use strict;
 1460: 
 1461: use Time::localtime;
 1462: 
 1463: BEGIN {
 1464:     &Apache::lonhelper::register('Apache::lonhelper::date',
 1465:                               ('date'));
 1466: }
 1467: 
 1468: # Don't need to override the "new" from element
 1469: sub new {
 1470:     my $ref = Apache::lonhelper::element->new();
 1471:     bless($ref);
 1472: }
 1473: 
 1474: my @months = ("January", "February", "March", "April", "May", "June", "July",
 1475: 	      "August", "September", "October", "November", "December");
 1476: 
 1477: # CONSTRUCTION: Construct the message element from the XML
 1478: sub start_date {
 1479:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1480: 
 1481:     if ($target ne 'helper') {
 1482:         return '';
 1483:     }
 1484: 
 1485:     $paramHash->{'variable'} = $token->[2]{'variable'};
 1486:     $helper->declareVar($paramHash->{'variable'});
 1487:     $paramHash->{'hoursminutes'} = $token->[2]{'hoursminutes'};
 1488: }
 1489: 
 1490: sub end_date {
 1491:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1492: 
 1493:     if ($target ne 'helper') {
 1494:         return '';
 1495:     }
 1496:     Apache::lonhelper::date->new();
 1497:     return '';
 1498: }
 1499: 
 1500: sub render {
 1501:     my $self = shift;
 1502:     my $result = "";
 1503:     my $var = $self->{'variable'};
 1504: 
 1505:     my $date;
 1506:     
 1507:     # Default date: The current hour.
 1508:     $date = localtime();
 1509:     $date->min(0);
 1510: 
 1511:     if (defined $self->{ERROR_MSG}) {
 1512:         $result .= '<font color="#FF0000">' . $self->{ERROR_MSG} . '</font><br /><br />';
 1513:     }
 1514: 
 1515:     # Month
 1516:     my $i;
 1517:     $result .= "<select name='${var}month'>\n";
 1518:     for ($i = 0; $i < 12; $i++) {
 1519:         if ($i == $date->mon) {
 1520:             $result .= "<option value='$i' selected>";
 1521:         } else {
 1522:             $result .= "<option value='$i'>";
 1523:         }
 1524:         $result .= $months[$i] . "</option>\n";
 1525:     }
 1526:     $result .= "</select>\n";
 1527: 
 1528:     # Day
 1529:     $result .= "<select name='${var}day'>\n";
 1530:     for ($i = 1; $i < 32; $i++) {
 1531:         if ($i == $date->mday) {
 1532:             $result .= '<option selected>';
 1533:         } else {
 1534:             $result .= '<option>';
 1535:         }
 1536:         $result .= "$i</option>\n";
 1537:     }
 1538:     $result .= "</select>,\n";
 1539: 
 1540:     # Year
 1541:     $result .= "<select name='${var}year'>\n";
 1542:     for ($i = 2000; $i < 2030; $i++) { # update this after 64-bit dates
 1543:         if ($date->year + 1900 == $i) {
 1544:             $result .= "<option selected>";
 1545:         } else {
 1546:             $result .= "<option>";
 1547:         }
 1548:         $result .= "$i</option>\n";
 1549:     }
 1550:     $result .= "</select>,\n";
 1551: 
 1552:     # Display Hours and Minutes if they are called for
 1553:     if ($self->{'hoursminutes'}) {
 1554:         # Build hour
 1555:         $result .= "<select name='${var}hour'>\n";
 1556:         $result .= "<option " . ($date->hour == 0 ? 'selected ':'') .
 1557:             " value='0'>midnight</option>\n";
 1558:         for ($i = 1; $i < 12; $i++) {
 1559:             if ($date->hour == $i) {
 1560:                 $result .= "<option selected value='$i'>$i a.m.</option>\n";
 1561:             } else {
 1562:                 $result .= "<option value='$i'>$i a.m</option>\n";
 1563:             }
 1564:         }
 1565:         $result .= "<option " . ($date->hour == 12 ? 'selected ':'') .
 1566:             " value='12'>noon</option>\n";
 1567:         for ($i = 13; $i < 24; $i++) {
 1568:             my $printedHour = $i - 12;
 1569:             if ($date->hour == $i) {
 1570:                 $result .= "<option selected value='$i'>$printedHour p.m.</option>\n";
 1571:             } else {
 1572:                 $result .= "<option value='$i'>$printedHour p.m.</option>\n";
 1573:             }
 1574:         }
 1575: 
 1576:         $result .= "</select> :\n";
 1577: 
 1578:         $result .= "<select name='${var}minute'>\n";
 1579:         for ($i = 0; $i < 60; $i++) {
 1580:             my $printedMinute = $i;
 1581:             if ($i < 10) {
 1582:                 $printedMinute = "0" . $printedMinute;
 1583:             }
 1584:             if ($date->min == $i) {
 1585:                 $result .= "<option selected>";
 1586:             } else {
 1587:                 $result .= "<option>";
 1588:             }
 1589:             $result .= "$printedMinute</option>\n";
 1590:         }
 1591:         $result .= "</select>\n";
 1592:     }
 1593: 
 1594:     return $result;
 1595: 
 1596: }
 1597: # If a NEXTSTATE was given, switch to it
 1598: sub postprocess {
 1599:     my $self = shift;
 1600:     my $var = $self->{'variable'};
 1601:     my $month = $ENV{'form.' . $var . 'month'}; 
 1602:     my $day = $ENV{'form.' . $var . 'day'}; 
 1603:     my $year = $ENV{'form.' . $var . 'year'}; 
 1604:     my $min = 0; 
 1605:     my $hour = 0;
 1606:     if ($self->{'hoursminutes'}) {
 1607:         $min = $ENV{'form.' . $var . 'minute'};
 1608:         $hour = $ENV{'form.' . $var . 'hour'};
 1609:     }
 1610: 
 1611:     my $chosenDate = Time::Local::timelocal(0, $min, $hour, $day, $month, $year);
 1612:     # Check to make sure that the date was not automatically co-erced into a 
 1613:     # valid date, as we want to flag that as an error
 1614:     # This happens for "Feb. 31", for instance, which is coerced to March 2 or
 1615:     # 3, depending on if it's a leapyear
 1616:     my $checkDate = localtime($chosenDate);
 1617: 
 1618:     if ($checkDate->mon != $month || $checkDate->mday != $day ||
 1619:         $checkDate->year + 1900 != $year) {
 1620:         $self->{ERROR_MSG} = "Can't use " . $months[$month] . " $day, $year as a "
 1621:             . "date because it doesn't exist. Please enter a valid date.";
 1622:         return 0;
 1623:     }
 1624: 
 1625:     $helper->{VARS}->{$var} = $chosenDate;
 1626: 
 1627:     if (defined($self->{NEXTSTATE})) {
 1628:         $helper->changeState($self->{NEXTSTATE});
 1629:     }
 1630: 
 1631:     return 1;
 1632: }
 1633: 1;
 1634: 
 1635: package Apache::lonhelper::resource;
 1636: 
 1637: =pod
 1638: 
 1639: =head2 Element: resource
 1640: 
 1641: <resource> elements allow the user to select one or multiple resources
 1642: from the current course. You can filter out which resources they can view,
 1643: and filter out which resources they can select. The course will always
 1644: be displayed fully expanded, because of the difficulty of maintaining
 1645: selections across folder openings and closings. If this is fixed, then
 1646: the user can manipulate the folders.
 1647: 
 1648: <resource> takes the standard variable attribute to control what helper
 1649: variable stores the results. It also takes a "multichoice" attribute,
 1650: which controls whether the user can select more then one resource. The 
 1651: "toponly" attribute controls whether the resource display shows just the
 1652: resources in that sequence, or recurses into all sub-sequences, defaulting
 1653: to false. The "suppressEmptySequences" attribute reflects the 
 1654: suppressEmptySequences argument to the render routine, which will cause
 1655: folders that have all of their contained resources filtered out to also
 1656: be filtered out.
 1657: 
 1658: B<SUB-TAGS>
 1659: 
 1660: =over 4
 1661: 
 1662: =item * <filterfunc>: If you want to filter what resources are displayed
 1663:   to the user, use a filter func. The <filterfunc> tag should contain
 1664:   Perl code that when wrapped with "sub { my $res = shift; " and "}" is 
 1665:   a function that returns true if the resource should be displayed, 
 1666:   and false if it should be skipped. $res is a resource object. 
 1667:   (See Apache::lonnavmaps documentation for information about the 
 1668:   resource object.)
 1669: 
 1670: =item * <choicefunc>: Same as <filterfunc>, except that controls whether
 1671:   the given resource can be chosen. (It is almost always a good idea to
 1672:   show the user the folders, for instance, but you do not always want to 
 1673:   let the user select them.)
 1674: 
 1675: =item * <nextstate>: Standard nextstate behavior.
 1676: 
 1677: =item * <valuefunc>: This function controls what is returned by the resource
 1678:   when the user selects it. Like filterfunc and choicefunc, it should be
 1679:   a function fragment that when wrapped by "sub { my $res = shift; " and
 1680:   "}" returns a string representing what you want to have as the value. By
 1681:   default, the value will be the resource ID of the object ($res->{ID}).
 1682: 
 1683: =item * <mapurl>: If the URL of a map is given here, only that map
 1684:   will be displayed, instead of the whole course.
 1685: 
 1686: =back
 1687: 
 1688: =cut
 1689: 
 1690: no strict;
 1691: @ISA = ("Apache::lonhelper::element");
 1692: use strict;
 1693: 
 1694: BEGIN {
 1695:     &Apache::lonhelper::register('Apache::lonhelper::resource',
 1696:                               ('resource', 'filterfunc', 
 1697:                                'choicefunc', 'valuefunc',
 1698:                                'mapurl'));
 1699: }
 1700: 
 1701: sub new {
 1702:     my $ref = Apache::lonhelper::element->new();
 1703:     bless($ref);
 1704: }
 1705: 
 1706: # CONSTRUCTION: Construct the message element from the XML
 1707: sub start_resource {
 1708:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1709: 
 1710:     if ($target ne 'helper') {
 1711:         return '';
 1712:     }
 1713: 
 1714:     $paramHash->{'variable'} = $token->[2]{'variable'};
 1715:     $helper->declareVar($paramHash->{'variable'});
 1716:     $paramHash->{'multichoice'} = $token->[2]{'multichoice'};
 1717:     $paramHash->{'suppressEmptySequences'} = $token->[2]{'suppressEmptySequences'};
 1718:     $paramHash->{'toponly'} = $token->[2]{'toponly'};
 1719:     return '';
 1720: }
 1721: 
 1722: sub end_resource {
 1723:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1724: 
 1725:     if ($target ne 'helper') {
 1726:         return '';
 1727:     }
 1728:     if (!defined($paramHash->{FILTER_FUNC})) {
 1729:         $paramHash->{FILTER_FUNC} = sub {return 1;};
 1730:     }
 1731:     if (!defined($paramHash->{CHOICE_FUNC})) {
 1732:         $paramHash->{CHOICE_FUNC} = sub {return 1;};
 1733:     }
 1734:     if (!defined($paramHash->{VALUE_FUNC})) {
 1735:         $paramHash->{VALUE_FUNC} = sub {my $res = shift; return $res->{ID}; };
 1736:     }
 1737:     Apache::lonhelper::resource->new();
 1738:     return '';
 1739: }
 1740: 
 1741: sub start_filterfunc {
 1742:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1743: 
 1744:     if ($target ne 'helper') {
 1745:         return '';
 1746:     }
 1747: 
 1748:     my $contents = Apache::lonxml::get_all_text('/filterfunc',
 1749:                                                 $parser);
 1750:     $contents = 'sub { my $res = shift; ' . $contents . '}';
 1751:     $paramHash->{FILTER_FUNC} = eval $contents;
 1752: }
 1753: 
 1754: sub end_filterfunc { return ''; }
 1755: 
 1756: sub start_choicefunc {
 1757:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1758: 
 1759:     if ($target ne 'helper') {
 1760:         return '';
 1761:     }
 1762: 
 1763:     my $contents = Apache::lonxml::get_all_text('/choicefunc',
 1764:                                                 $parser);
 1765:     $contents = 'sub { my $res = shift; ' . $contents . '}';
 1766:     $paramHash->{CHOICE_FUNC} = eval $contents;
 1767: }
 1768: 
 1769: sub end_choicefunc { return ''; }
 1770: 
 1771: sub start_valuefunc {
 1772:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1773: 
 1774:     if ($target ne 'helper') {
 1775:         return '';
 1776:     }
 1777: 
 1778:     my $contents = Apache::lonxml::get_all_text('/valuefunc',
 1779:                                                 $parser);
 1780:     $contents = 'sub { my $res = shift; ' . $contents . '}';
 1781:     $paramHash->{VALUE_FUNC} = eval $contents;
 1782: }
 1783: 
 1784: sub end_valuefunc { return ''; }
 1785: 
 1786: sub start_mapurl {
 1787:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1788: 
 1789:     if ($target ne 'helper') {
 1790:         return '';
 1791:     }
 1792: 
 1793:     my $contents = Apache::lonxml::get_all_text('/mapurl',
 1794:                                                 $parser);
 1795:     $paramHash->{MAP_URL} = $contents;
 1796: }
 1797: 
 1798: sub end_mapurl { return ''; }
 1799: 
 1800: # A note, in case I don't get to this before I leave.
 1801: # If someone complains about the "Back" button returning them
 1802: # to the previous folder state, instead of returning them to
 1803: # the previous helper state, the *correct* answer is for the helper
 1804: # to keep track of how many times the user has manipulated the folders,
 1805: # and feed that to the history.go() call in the helper rendering routines.
 1806: # If done correctly, the helper itself can keep track of how many times
 1807: # it renders the same states, so it doesn't go in just this state, and
 1808: # you can lean on the browser back button to make sure it all chains
 1809: # correctly.
 1810: # Right now, though, I'm just forcing all folders open.
 1811: 
 1812: sub render {
 1813:     my $self = shift;
 1814:     my $result = "";
 1815:     my $var = $self->{'variable'};
 1816:     my $curVal = $helper->{VARS}->{$var};
 1817: 
 1818:     my $buttons = '';
 1819: 
 1820:     if ($self->{'multichoice'}) {
 1821:         $result = <<SCRIPT;
 1822: <script>
 1823:     function checkall(value, checkName) {
 1824: 	for (i=0; i<document.forms.helpform.elements.length; i++) {
 1825:             ele = document.forms.helpform.elements[i];
 1826:             if (ele.name == checkName + '.forminput') {
 1827:                 document.forms.helpform.elements[i].checked=value;
 1828:             }
 1829:         }
 1830:     }
 1831: </script>
 1832: SCRIPT
 1833:         $buttons = <<BUTTONS;
 1834: <br /> &nbsp;
 1835: <input type="button" onclick="checkall(true, '$var')" value="Select All Resources" />
 1836: <input type="button" onclick="checkall(false, '$var')" value="Unselect All Resources" />
 1837: <br /> &nbsp;
 1838: BUTTONS
 1839:     }
 1840: 
 1841:     if (defined $self->{ERROR_MSG}) {
 1842:         $result .= '<br /><font color="#FF0000">' . $self->{ERROR_MSG} . '</font><br /><br />';
 1843:     }
 1844: 
 1845:     $result .= $buttons;
 1846: 
 1847:     my $filterFunc = $self->{FILTER_FUNC};
 1848:     my $choiceFunc = $self->{CHOICE_FUNC};
 1849:     my $valueFunc = $self->{VALUE_FUNC};
 1850:     my $mapUrl = $self->{MAP_URL};
 1851:     my $multichoice = $self->{'multichoice'};
 1852: 
 1853:     # Create the composite function that renders the column on the nav map
 1854:     # have to admit any language that lets me do this can't be all bad
 1855:     #  - Jeremy (Pythonista) ;-)
 1856:     my $checked = 0;
 1857:     my $renderColFunc = sub {
 1858:         my ($resource, $part, $params) = @_;
 1859: 
 1860:         my $inputType;
 1861:         if ($multichoice) { $inputType = 'checkbox'; }
 1862:         else {$inputType = 'radio'; }
 1863: 
 1864:         if (!&$choiceFunc($resource)) {
 1865:             return '<td>&nbsp;</td>';
 1866:         } else {
 1867:             my $col = "<td><input type='$inputType' name='${var}.forminput' ";
 1868:             if (!$checked && !$multichoice) {
 1869:                 $col .= "checked ";
 1870:                 $checked = 1;
 1871:             }
 1872: 	    if ($multichoice) { # all resources start checked; see bug 1174
 1873: 		$col .= "checked ";
 1874: 		$checked = 1;
 1875: 	    }
 1876:             $col .= "value='" . 
 1877:                 HTML::Entities::encode(&$valueFunc($resource)) 
 1878:                 . "' /></td>";
 1879:             return $col;
 1880:         }
 1881:     };
 1882: 
 1883:     $ENV{'form.condition'} = !$self->{'toponly'};
 1884:     $result .= 
 1885:         &Apache::lonnavmaps::render( { 'cols' => [$renderColFunc, 
 1886:                                                   Apache::lonnavmaps::resource()],
 1887:                                        'showParts' => 0,
 1888:                                        'filterFunc' => $filterFunc,
 1889:                                        'resource_no_folder_link' => 1,
 1890:                                        'suppressEmptySequences' => $self->{'suppressEmptySequences'},
 1891:                                        'iterator_map' => $mapUrl }
 1892:                                        );
 1893: 
 1894:     $result .= $buttons;
 1895:                                                 
 1896:     return $result;
 1897: }
 1898:     
 1899: sub postprocess {
 1900:     my $self = shift;
 1901: 
 1902:     if ($self->{'multichoice'} && !$helper->{VARS}->{$self->{'variable'}}) {
 1903:         $self->{ERROR_MSG} = 'You must choose at least one resource to continue.';
 1904:         return 0;
 1905:     }
 1906: 
 1907:     if (defined($self->{NEXTSTATE})) {
 1908:         $helper->changeState($self->{NEXTSTATE});
 1909:     }
 1910: 
 1911:     return 1;
 1912: }
 1913: 
 1914: 1;
 1915: 
 1916: package Apache::lonhelper::student;
 1917: 
 1918: =pod
 1919: 
 1920: =head2 Element: student
 1921: 
 1922: Student elements display a choice of students enrolled in the current
 1923: course. Currently it is primitive; this is expected to evolve later.
 1924: 
 1925: Student elements take three attributes: "variable", which means what
 1926: it usually does, "multichoice", which if true allows the user
 1927: to select multiple students, and "coursepersonnel" which if true 
 1928: adds the course personnel to the top of the student selection.
 1929: 
 1930: =cut
 1931: 
 1932: no strict;
 1933: @ISA = ("Apache::lonhelper::element");
 1934: use strict;
 1935: 
 1936: 
 1937: 
 1938: BEGIN {
 1939:     &Apache::lonhelper::register('Apache::lonhelper::student',
 1940:                               ('student'));
 1941: }
 1942: 
 1943: sub new {
 1944:     my $ref = Apache::lonhelper::element->new();
 1945:     bless($ref);
 1946: }
 1947: 
 1948: sub start_student {
 1949:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1950: 
 1951:     if ($target ne 'helper') {
 1952:         return '';
 1953:     }
 1954: 
 1955:     $paramHash->{'variable'} = $token->[2]{'variable'};
 1956:     $helper->declareVar($paramHash->{'variable'});
 1957:     $paramHash->{'multichoice'} = $token->[2]{'multichoice'};
 1958:     $paramHash->{'coursepersonnel'} = $token->[2]{'coursepersonnel'};
 1959:     if (defined($token->[2]{'nextstate'})) {
 1960:         $paramHash->{NEXTSTATE} = $token->[2]{'nextstate'};
 1961:     }
 1962:     
 1963: }    
 1964: 
 1965: sub end_student {
 1966:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 1967: 
 1968:     if ($target ne 'helper') {
 1969:         return '';
 1970:     }
 1971:     Apache::lonhelper::student->new();
 1972: }
 1973: 
 1974: sub render {
 1975:     my $self = shift;
 1976:     my $result = '';
 1977:     my $buttons = '';
 1978:     my $var = $self->{'variable'};
 1979: 
 1980:     if ($self->{'multichoice'}) {
 1981:         $result = <<SCRIPT;
 1982: <script>
 1983:     function checkall(value, checkName) {
 1984: 	for (i=0; i<document.forms.helpform.elements.length; i++) {
 1985:             ele = document.forms.helpform.elements[i];
 1986:             if (ele.name == checkName + '.forminput') {
 1987:                 document.forms.helpform.elements[i].checked=value;
 1988:             }
 1989:         }
 1990:     }
 1991: </script>
 1992: SCRIPT
 1993:         $buttons = <<BUTTONS;
 1994: <br />
 1995: <input type="button" onclick="checkall(true, '$var')" value="Select All Students" />
 1996: <input type="button" onclick="checkall(false, '$var')" value="Unselect All Students" />
 1997: <br />
 1998: BUTTONS
 1999:     }
 2000: 
 2001:     if (defined $self->{ERROR_MSG}) {
 2002:         $result .= '<font color="#FF0000">' . $self->{ERROR_MSG} . '</font><br /><br />';
 2003:     }
 2004: 
 2005:     my $choices = [];
 2006: 
 2007:     # Load up the non-students, if necessary
 2008:     if ($self->{'coursepersonnel'}) {
 2009: 	my %coursepersonnel = Apache::lonnet::get_course_adv_roles();
 2010: 	for (sort keys %coursepersonnel) {
 2011: 	    for my $role (split /,/, $coursepersonnel{$_}) {
 2012: 		# extract the names so we can sort them
 2013: 		my @people;
 2014: 		
 2015: 		for (split /,/, $role) {
 2016: 		    push @people, [split /:/, $role];
 2017: 		}
 2018: 		
 2019: 		@people = sort { $a->[0] cmp $b->[0] } @people;
 2020: 		
 2021: 		for my $person (@people) {
 2022: 		    push @$choices, [join(':', @$person), $person->[0], '', $_];
 2023: 		}
 2024: 	    }
 2025: 	}
 2026:     }
 2027: 
 2028:     # Constants
 2029:     my $section = Apache::loncoursedata::CL_SECTION();
 2030:     my $fullname = Apache::loncoursedata::CL_FULLNAME();
 2031: 
 2032:     # Load up the students
 2033:     my $classlist = &Apache::loncoursedata::get_classlist();
 2034:     my @keys = keys %{$classlist};
 2035:     # Sort by: Section, name
 2036:     @keys = sort {
 2037:         if ($classlist->{$a}->[$section] ne $classlist->{$b}->[$section]) {
 2038:             return $classlist->{$a}->[$section] cmp $classlist->{$b}->[$section];
 2039:         }
 2040:         return $classlist->{$a}->[$fullname] cmp $classlist->{$b}->[$fullname];
 2041:     } @keys;
 2042: 
 2043:     # username, fullname, section, type
 2044:     for (@keys) {
 2045: 	push @$choices, [$_, $classlist->{$_}->[$fullname], 
 2046: 			 $classlist->{$_}->[$section], 'Student'];
 2047:     }
 2048: 
 2049:     my $name = $self->{'coursepersonnel'} ? 'Name' : 'Student Name';
 2050:     my $type = 'radio';
 2051:     if ($self->{'multichoice'}) { $type = 'checkbox'; }
 2052:     $result .= "<table cellspacing='2' cellpadding='2' border='0'>\n";
 2053:     $result .= "<tr><td></td><td align='center'><b>$name</b></td>".
 2054:         "<td align='center'><b>Section</b></td>" . 
 2055: 	"<td align='center'><b>Role</b></td></tr>";
 2056: 
 2057:     my $checked = 0;
 2058:     for my $choice (@$choices) {
 2059:         $result .= "<tr><td><input type='$type' name='" .
 2060:             $self->{'variable'} . '.forminput' . "'";
 2061:             
 2062:         if (!$self->{'multichoice'} && !$checked) {
 2063:             $result .= " checked ";
 2064:             $checked = 1;
 2065:         }
 2066:         $result .=
 2067:             " value='" . HTML::Entities::encode($choice->[0] . ':' . $choice->[2])
 2068:             . "' /></td><td>"
 2069:             . HTML::Entities::encode($choice->[1])
 2070:             . "</td><td align='center'>" 
 2071:             . HTML::Entities::encode($choice->[2])
 2072:             . "</td>\n<td>" 
 2073: 	    . HTML::Entities::encode($choice->[3]) . "</td></tr>\n";
 2074:     }
 2075: 
 2076:     $result .= "</table>\n\n";
 2077:     $result .= $buttons;    
 2078:     
 2079:     return $result;
 2080: }
 2081: 
 2082: sub postprocess {
 2083:     my $self = shift;
 2084: 
 2085:     my $result = $ENV{'form.' . $self->{'variable'} . '.forminput'};
 2086:     if (!$result) {
 2087:         $self->{ERROR_MSG} = 'You must choose at least one student '.
 2088:             'to continue.';
 2089:         return 0;
 2090:     }
 2091: 
 2092:     if (defined($self->{NEXTSTATE})) {
 2093:         $helper->changeState($self->{NEXTSTATE});
 2094:     }
 2095: 
 2096:     return 1;
 2097: }
 2098: 
 2099: 1;
 2100: 
 2101: package Apache::lonhelper::files;
 2102: 
 2103: =pod
 2104: 
 2105: =head2 Element: files
 2106: 
 2107: files allows the users to choose files from a given directory on the
 2108: server. It is always multichoice and stores the result as a triple-pipe
 2109: delimited entry in the helper variables. 
 2110: 
 2111: Since it is extremely unlikely that you can actually code a constant
 2112: representing the directory you wish to allow the user to search, <files>
 2113: takes a subroutine that returns the name of the directory you wish to
 2114: have the user browse.
 2115: 
 2116: files accepts the attribute "variable" to control where the files chosen
 2117: are put. It accepts the attribute "multichoice" as the other attribute,
 2118: defaulting to false, which if true will allow the user to select more
 2119: then one choice. 
 2120: 
 2121: <files> accepts three subtags. One is the "nextstate" sub-tag that works
 2122: as it does with the other tags. Another is a <filechoice> sub tag that
 2123: is Perl code that, when surrounded by "sub {" and "}" will return a
 2124: string representing what directory on the server to allow the user to 
 2125: choose files from. Finally, the <filefilter> subtag should contain Perl
 2126: code that when surrounded by "sub { my $filename = shift; " and "}",
 2127: returns a true value if the user can pick that file, or false otherwise.
 2128: The filename passed to the function will be just the name of the file, 
 2129: with no path info.
 2130: 
 2131: =cut
 2132: 
 2133: no strict;
 2134: @ISA = ("Apache::lonhelper::element");
 2135: use strict;
 2136: 
 2137: use Apache::lonpubdir; # for getTitleString
 2138: 
 2139: BEGIN {
 2140:     &Apache::lonhelper::register('Apache::lonhelper::files',
 2141:                                  ('files', 'filechoice', 'filefilter'));
 2142: }
 2143: 
 2144: sub new {
 2145:     my $ref = Apache::lonhelper::element->new();
 2146:     bless($ref);
 2147: }
 2148: 
 2149: sub start_files {
 2150:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2151: 
 2152:     if ($target ne 'helper') {
 2153:         return '';
 2154:     }
 2155:     $paramHash->{'variable'} = $token->[2]{'variable'};
 2156:     $helper->declareVar($paramHash->{'variable'});
 2157:     $paramHash->{'multichoice'} = $token->[2]{'multichoice'};
 2158: }    
 2159: 
 2160: sub end_files {
 2161:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2162: 
 2163:     if ($target ne 'helper') {
 2164:         return '';
 2165:     }
 2166:     if (!defined($paramHash->{FILTER_FUNC})) {
 2167:         $paramHash->{FILTER_FUNC} = sub { return 1; };
 2168:     }
 2169:     Apache::lonhelper::files->new();
 2170: }    
 2171: 
 2172: sub start_filechoice {
 2173:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2174: 
 2175:     if ($target ne 'helper') {
 2176:         return '';
 2177:     }
 2178:     $paramHash->{'filechoice'} = Apache::lonxml::get_all_text('/filechoice',
 2179:                                                               $parser);
 2180: }
 2181: 
 2182: sub end_filechoice { return ''; }
 2183: 
 2184: sub start_filefilter {
 2185:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2186: 
 2187:     if ($target ne 'helper') {
 2188:         return '';
 2189:     }
 2190: 
 2191:     my $contents = Apache::lonxml::get_all_text('/filefilter',
 2192:                                                 $parser);
 2193:     $contents = 'sub { my $filename = shift; ' . $contents . '}';
 2194:     $paramHash->{FILTER_FUNC} = eval $contents;
 2195: }
 2196: 
 2197: sub end_filefilter { return ''; }
 2198: 
 2199: sub render {
 2200:     my $self = shift;
 2201:     my $result = '';
 2202:     my $var = $self->{'variable'};
 2203:     
 2204:     my $subdirFunc = eval('sub {' . $self->{'filechoice'} . '}');
 2205:     die 'Error in resource filter code for variable ' . 
 2206:         {'variable'} . ', Perl said:' . $@ if $@;
 2207: 
 2208:     my $subdir = &$subdirFunc();
 2209: 
 2210:     my $filterFunc = $self->{FILTER_FUNC};
 2211:     my $buttons = '';
 2212:     my $type = 'radio';
 2213:     if ($self->{'multichoice'}) {
 2214:         $type = 'checkbox';
 2215:     }
 2216: 
 2217:     if ($self->{'multichoice'}) {
 2218:         $result = <<SCRIPT;
 2219: <script>
 2220:     function checkall(value, checkName) {
 2221: 	for (i=0; i<document.forms.helpform.elements.length; i++) {
 2222:             ele = document.forms.helpform.elements[i];
 2223:             if (ele.name == checkName + '.forminput') {
 2224:                 document.forms.helpform.elements[i].checked=value;
 2225:             }
 2226:         }
 2227:     }
 2228: 
 2229:     function checkallclass(value, className) {
 2230:         for (i=0; i<document.forms.helpform.elements.length; i++) {
 2231:             ele = document.forms.helpform.elements[i];
 2232:             if (ele.type == "$type" && ele.onclick) {
 2233:                 document.forms.helpform.elements[i].checked=value;
 2234:             }
 2235:         }
 2236:     }
 2237: </script>
 2238: SCRIPT
 2239:         $buttons = <<BUTTONS;
 2240: <br /> &nbsp;
 2241: <input type="button" onclick="checkall(true, '$var')" value="Select All Files" />
 2242: <input type="button" onclick="checkall(false, '$var')" value="Unselect All Files" />
 2243: BUTTONS
 2244: 
 2245:         if ($helper->{VARS}->{'construction'}) {
 2246:             $buttons .= <<BUTTONS;
 2247: <input type="button" onclick="checkallclass(true, 'Published')" value="Select All Published" />
 2248: <input type="button" onclick="checkallclass(false, 'Published')" value="Unselect All Published" />
 2249: <br /> &nbsp;
 2250: BUTTONS
 2251:        }
 2252:     }
 2253: 
 2254:     # Get the list of files in this directory.
 2255:     my @fileList;
 2256: 
 2257:     # If the subdirectory is in local CSTR space
 2258:     if ($subdir =~ m|/home/([^/]+)/public_html|) {
 2259:         my $user = $1;
 2260:         my $domain = $Apache::lonnet::perlvar{'lonDefDomain'};
 2261:         @fileList = &Apache::lonnet::dirlist($subdir, $domain, $user, '');
 2262:     } else {
 2263:         # local library server resource space
 2264:         @fileList = &Apache::lonnet::dirlist($subdir, $ENV{'user.domain'}, $ENV{'user.name'}, '');
 2265:     }
 2266: 
 2267:     $result .= $buttons;
 2268: 
 2269:     if (defined $self->{ERROR_MSG}) {
 2270:         $result .= '<br /><font color="#FF0000">' . $self->{ERROR_MSG} . '</font><br /><br />';
 2271:     }
 2272: 
 2273:     $result .= '<table border="0" cellpadding="2" cellspacing="0">';
 2274: 
 2275:     # Keeps track if there are no choices, prints appropriate error
 2276:     # if there are none. 
 2277:     my $choices = 0;
 2278:     # Print each legitimate file choice.
 2279:     for my $file (@fileList) {
 2280:         $file = (split(/&/, $file))[0];
 2281:         if ($file eq '.' || $file eq '..') {
 2282:             next;
 2283:         }
 2284:         my $fileName = $subdir .'/'. $file;
 2285:         if (&$filterFunc($file)) {
 2286: 	    my $status;
 2287: 	    my $color;
 2288: 	    if ($helper->{VARS}->{'construction'}) {
 2289: 		($status, $color) = @{fileState($subdir, $file)};
 2290: 	    } else {
 2291: 		$status = '';
 2292: 		$color = '';
 2293: 	    }
 2294: 
 2295:             # Get the title
 2296:             my $title = Apache::lonpubdir::getTitleString($fileName);
 2297: 
 2298:             # Netscape 4 is stupid and there's nowhere to put the
 2299:             # information on the input tag that the file is Published,
 2300:             # Unpublished, etc. In *real* browsers we can just say
 2301:             # "class='Published'" and check the className attribute of
 2302:             # the input tag, but Netscape 4 is too stupid to understand
 2303:             # that attribute, and un-comprehended attributes are not
 2304:             # reflected into the object model. So instead, what I do 
 2305:             # is either have or don't have an "onclick" handler that 
 2306:             # does nothing, give Published files the onclick handler, and
 2307:             # have the checker scripts check for that. Stupid and clumsy,
 2308:             # and only gives us binary "yes/no" information (at least I
 2309:             # couldn't figure out how to reach into the event handler's
 2310:             # actual code to retreive a value), but it works well enough
 2311:             # here.
 2312:         
 2313:             my $onclick = '';
 2314:             if ($status eq 'Published' && $helper->{VARS}->{'construction'}) {
 2315:                 $onclick = 'onclick="a=1" ';
 2316:             }
 2317:             $result .= '<tr><td align="right"' . " bgcolor='$color'>" .
 2318:                 "<input $onclick type='$type' name='" . $var
 2319:             . ".forminput' value='" . HTML::Entities::encode($fileName) .
 2320:                 "'";
 2321:             if (!$self->{'multichoice'} && $choices == 0) {
 2322:                 $result .= ' checked';
 2323:             }
 2324:             $result .= "/></td><td bgcolor='$color'>" . $file . "</td>" .
 2325:                 "<td bgcolor='$color'>$title</td>" .
 2326:                 "<td bgcolor='$color'>$status</td>" . "</tr>\n";
 2327:             $choices++;
 2328:         }
 2329:     }
 2330: 
 2331:     $result .= "</table>\n";
 2332: 
 2333:     if (!$choices) {
 2334:         $result .= '<font color="#FF0000">There are no files available to select in this directory. Please go back and select another option.</font><br /><br />';
 2335:     }
 2336: 
 2337:     $result .= $buttons;
 2338: 
 2339:     return $result;
 2340: }
 2341: 
 2342: # Determine the state of the file: Published, unpublished, modified.
 2343: # Return the color it should be in and a label as a two-element array
 2344: # reference.
 2345: # Logic lifted from lonpubdir.pm, even though I don't know that it's still
 2346: # the most right thing to do.
 2347: 
 2348: sub fileState {
 2349:     my $constructionSpaceDir = shift;
 2350:     my $file = shift;
 2351:     
 2352:     my $docroot = $Apache::lonnet::perlvar{'lonDocRoot'};
 2353:     my $subdirpart = $constructionSpaceDir;
 2354:     $subdirpart =~ s/^\/home\/$ENV{'user.name'}\/public_html//;
 2355:     my $resdir = $docroot . '/res/' . $ENV{'user.domain'} . '/' . $ENV{'user.name'} .
 2356:         $subdirpart;
 2357: 
 2358:     my @constructionSpaceFileStat = stat($constructionSpaceDir . '/' . $file);
 2359:     my @resourceSpaceFileStat = stat($resdir . '/' . $file);
 2360:     if (!@resourceSpaceFileStat) {
 2361:         return ['Unpublished', '#FFCCCC'];
 2362:     }
 2363: 
 2364:     my $constructionSpaceFileModified = $constructionSpaceFileStat[9];
 2365:     my $resourceSpaceFileModified = $resourceSpaceFileStat[9];
 2366:     
 2367:     if ($constructionSpaceFileModified > $resourceSpaceFileModified) {
 2368:         return ['Modified', '#FFFFCC'];
 2369:     }
 2370:     return ['Published', '#CCFFCC'];
 2371: }
 2372: 
 2373: sub postprocess {
 2374:     my $self = shift;
 2375:     my $result = $ENV{'form.' . $self->{'variable'} . '.forminput'};
 2376:     if (!$result) {
 2377:         $self->{ERROR_MSG} = 'You must choose at least one file '.
 2378:             'to continue.';
 2379:         return 0;
 2380:     }
 2381: 
 2382:     if (defined($self->{NEXTSTATE})) {
 2383:         $helper->changeState($self->{NEXTSTATE});
 2384:     }
 2385: 
 2386:     return 1;
 2387: }
 2388: 
 2389: 1;
 2390: 
 2391: package Apache::lonhelper::section;
 2392: 
 2393: =pod
 2394: 
 2395: =head2 Element: section
 2396: 
 2397: <section> allows the user to choose one or more sections from the current
 2398: course.
 2399: 
 2400: It takes the standard attributes "variable", "multichoice", and
 2401: "nextstate", meaning what they do for most other elements.
 2402: 
 2403: =cut
 2404: 
 2405: no strict;
 2406: @ISA = ("Apache::lonhelper::choices");
 2407: use strict;
 2408: 
 2409: BEGIN {
 2410:     &Apache::lonhelper::register('Apache::lonhelper::section',
 2411:                                  ('section'));
 2412: }
 2413: 
 2414: sub new {
 2415:     my $ref = Apache::lonhelper::choices->new();
 2416:     bless($ref);
 2417: }
 2418: 
 2419: sub start_section {
 2420:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2421: 
 2422:     if ($target ne 'helper') {
 2423:         return '';
 2424:     }
 2425: 
 2426:     $paramHash->{CHOICES} = [];
 2427: 
 2428:     $paramHash->{'variable'} = $token->[2]{'variable'};
 2429:     $helper->declareVar($paramHash->{'variable'});
 2430:     $paramHash->{'multichoice'} = $token->[2]{'multichoice'};
 2431:     if (defined($token->[2]{'nextstate'})) {
 2432:         $paramHash->{NEXTSTATE} = $token->[2]{'nextstate'};
 2433:     }
 2434: 
 2435:     # Populate the CHOICES element
 2436:     my %choices;
 2437: 
 2438:     my $section = Apache::loncoursedata::CL_SECTION();
 2439:     my $classlist = Apache::loncoursedata::get_classlist();
 2440:     foreach (keys %$classlist) {
 2441:         my $sectionName = $classlist->{$_}->[$section];
 2442:         if (!$sectionName) {
 2443:             $choices{"No section assigned"} = "";
 2444:         } else {
 2445:             $choices{$sectionName} = $sectionName;
 2446:         }
 2447:     } 
 2448:    
 2449:     for my $sectionName (sort(keys(%choices))) {
 2450:         
 2451:         push @{$paramHash->{CHOICES}}, [$sectionName, $sectionName];
 2452:     }
 2453: }    
 2454: 
 2455: sub end_section {
 2456:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2457: 
 2458:     if ($target ne 'helper') {
 2459:         return '';
 2460:     }
 2461:     Apache::lonhelper::section->new();
 2462: }    
 2463: 1;
 2464: 
 2465: package Apache::lonhelper::string;
 2466: 
 2467: =pod
 2468: 
 2469: =head2 Element: string
 2470: 
 2471: string elements provide a string entry field for the user. string elements
 2472: take the usual 'variable' and 'nextstate' parameters. string elements
 2473: also pass through 'maxlength' and 'size' attributes to the input tag.
 2474: 
 2475: string honors the defaultvalue tag, if given.
 2476: 
 2477: string honors the validation function, if given.
 2478: 
 2479: =cut
 2480: 
 2481: no strict;
 2482: @ISA = ("Apache::lonhelper::element");
 2483: use strict;
 2484: 
 2485: BEGIN {
 2486:     &Apache::lonhelper::register('Apache::lonhelper::string',
 2487:                               ('string'));
 2488: }
 2489: 
 2490: sub new {
 2491:     my $ref = Apache::lonhelper::element->new();
 2492:     bless($ref);
 2493: }
 2494: 
 2495: # CONSTRUCTION: Construct the message element from the XML
 2496: sub start_string {
 2497:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2498: 
 2499:     if ($target ne 'helper') {
 2500:         return '';
 2501:     }
 2502: 
 2503:     $paramHash->{'variable'} = $token->[2]{'variable'};
 2504:     $helper->declareVar($paramHash->{'variable'});
 2505:     $paramHash->{'nextstate'} = $token->[2]{'nextstate'};
 2506:     $paramHash->{'maxlength'} = $token->[2]{'maxlength'};
 2507:     $paramHash->{'size'} = $token->[2]{'size'};
 2508: 
 2509:     return '';
 2510: }
 2511: 
 2512: sub end_string {
 2513:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2514: 
 2515:     if ($target ne 'helper') {
 2516:         return '';
 2517:     }
 2518:     Apache::lonhelper::string->new();
 2519:     return '';
 2520: }
 2521: 
 2522: sub render {
 2523:     my $self = shift;
 2524:     my $result = '';
 2525: 
 2526:     if (defined $self->{ERROR_MSG}) {
 2527:         $result .= '<br /><font color="#FF0000">' . $self->{ERROR_MSG} . '</font><br /><br />';
 2528:     }
 2529: 
 2530:     $result .= '<input type="string" name="' . $self->{'variable'} . '.forminput"';
 2531: 
 2532:     if (defined($self->{'size'})) {
 2533:         $result .= ' size="' . $self->{'size'} . '"';
 2534:     }
 2535:     if (defined($self->{'maxlength'})) {
 2536:         $result .= ' maxlength="' . $self->{'maxlength'} . '"';
 2537:     }
 2538: 
 2539:     if (defined($self->{DEFAULT_VALUE})) {
 2540:         my $valueFunc = eval($self->{DEFAULT_VALUE});
 2541:         die 'Error in default value code for variable ' . 
 2542:             $self->{'variable'} . ', Perl said: ' . $@ if $@;
 2543:         $result .= ' value="' . &$valueFunc($helper, $self) . '"';
 2544:     }
 2545: 
 2546:     $result .= ' />';
 2547: 
 2548:     return $result;
 2549: }
 2550: 
 2551: # If a NEXTSTATE was given, switch to it
 2552: sub postprocess {
 2553:     my $self = shift;
 2554: 
 2555:     if (defined($self->{VALIDATOR})) {
 2556: 	my $validator = eval($self->{VALIDATOR});
 2557: 	die 'Died during evaluation of evaulation code; Perl said: ' . $@ if $@;
 2558: 	my $invalid = &$validator($helper, $state, $self, $self->getValue());
 2559: 	if ($invalid) {
 2560: 	    $self->{ERROR_MSG} = $invalid;
 2561: 	    return 0;
 2562: 	}
 2563:     }
 2564: 
 2565:     if (defined($self->{'nextstate'})) {
 2566:         $helper->changeState($self->{'nextstate'});
 2567:     }
 2568: 
 2569:     return 1;
 2570: }
 2571: 
 2572: 1;
 2573: 
 2574: package Apache::lonhelper::general;
 2575: 
 2576: =pod
 2577: 
 2578: =head2 General-purpose tag: <exec>
 2579: 
 2580: The contents of the exec tag are executed as Perl code, not inside a 
 2581: safe space, so the full range of $ENV and such is available. The code
 2582: will be executed as a subroutine wrapped with the following code:
 2583: 
 2584: "sub { my $helper = shift; my $state = shift;" and
 2585: 
 2586: "}"
 2587: 
 2588: The return value is ignored.
 2589: 
 2590: $helper is the helper object. Feel free to add methods to the helper
 2591: object to support whatever manipulation you may need to do (for instance,
 2592: overriding the form location if the state is the final state; see 
 2593: lonparm.helper for an example).
 2594: 
 2595: $state is the $paramHash that has currently been generated and may
 2596: be manipulated by the code in exec. Note that the $state is not yet
 2597: an actual state B<object>, it is just a hash, so do not expect to
 2598: be able to call methods on it.
 2599: 
 2600: =cut
 2601: 
 2602: BEGIN {
 2603:     &Apache::lonhelper::register('Apache::lonhelper::general',
 2604:                                  'exec', 'condition', 'clause',
 2605:                                  'eval');
 2606: }
 2607: 
 2608: sub start_exec {
 2609:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2610: 
 2611:     if ($target ne 'helper') {
 2612:         return '';
 2613:     }
 2614:     
 2615:     my $code = &Apache::lonxml::get_all_text('/exec', $parser);
 2616:     
 2617:     $code = eval ('sub { my $helper = shift; my $state = shift; ' .
 2618:         $code . "}");
 2619:     die 'Error in <exec>, Perl said: '. $@ if $@;
 2620:     &$code($helper, $paramHash);
 2621: }
 2622: 
 2623: sub end_exec { return ''; }
 2624: 
 2625: =pod
 2626: 
 2627: =head2 General-purpose tag: <condition>
 2628: 
 2629: The <condition> tag allows you to mask out parts of the helper code
 2630: depending on some programatically determined condition. The condition
 2631: tag contains a tag <clause> which contains perl code that when wrapped
 2632: with "sub { my $helper = shift; my $state = shift; " and "}", returns
 2633: a true value if the XML in the condition should be evaluated as a normal
 2634: part of the helper, or false if it should be completely discarded.
 2635: 
 2636: The <clause> tag must be the first sub-tag of the <condition> tag or
 2637: it will not work as expected.
 2638: 
 2639: =cut
 2640: 
 2641: # The condition tag just functions as a marker, it doesn't have
 2642: # to "do" anything. Technically it doesn't even have to be registered
 2643: # with the lonxml code, but I leave this here to be explicit about it.
 2644: sub start_condition { return ''; }
 2645: sub end_condition { return ''; }
 2646: 
 2647: sub start_clause {
 2648:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2649: 
 2650:     if ($target ne 'helper') {
 2651:         return '';
 2652:     }
 2653:     
 2654:     my $clause = Apache::lonxml::get_all_text('/clause', $parser);
 2655:     $clause = eval('sub { my $helper = shift; my $state = shift; '
 2656:         . $clause . '}');
 2657:     die 'Error in clause of condition, Perl said: ' . $@ if $@;
 2658:     if (!&$clause($helper, $paramHash)) {
 2659:         # Discard all text until the /condition.
 2660:         &Apache::lonxml::get_all_text('/condition', $parser);
 2661:     }
 2662: }
 2663: 
 2664: sub end_clause { return ''; }
 2665: 
 2666: =pod
 2667: 
 2668: =head2 General-purpose tag: <eval>
 2669: 
 2670: The <eval> tag will be evaluated as a subroutine call passed in the
 2671: current helper object and state hash as described in <condition> above,
 2672: but is expected to return a string to be printed directly to the
 2673: screen. This is useful for dynamically generating messages. 
 2674: 
 2675: =cut
 2676: 
 2677: # This is basically a type of message.
 2678: # Programmatically setting $paramHash->{NEXTSTATE} would work, though
 2679: # it's probably bad form.
 2680: 
 2681: sub start_eval {
 2682:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2683: 
 2684:     if ($target ne 'helper') {
 2685:         return '';
 2686:     }
 2687:     
 2688:     my $program = Apache::lonxml::get_all_text('/eval', $parser);
 2689:     $program = eval('sub { my $helper = shift; my $state = shift; '
 2690:         . $program . '}');
 2691:     die 'Error in eval code, Perl said: ' . $@ if $@;
 2692:     $paramHash->{MESSAGE_TEXT} = &$program($helper, $paramHash);
 2693: }
 2694: 
 2695: sub end_eval { 
 2696:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2697: 
 2698:     if ($target ne 'helper') {
 2699:         return '';
 2700:     }
 2701: 
 2702:     Apache::lonhelper::message->new();
 2703: }
 2704: 
 2705: 1;
 2706: 
 2707: package Apache::lonhelper::final;
 2708: 
 2709: =pod
 2710: 
 2711: =head2 Element: final
 2712: 
 2713: <final> is a special element that works with helpers that use the <finalcode>
 2714: tag. It goes through all the states and elements, executing the <finalcode>
 2715: snippets and collecting the results. Finally, it takes the user out of the
 2716: helper, going to a provided page.
 2717: 
 2718: If the parameter "restartCourse" is true, this will override the buttons and
 2719: will make a "Finish Helper" button that will re-initialize the course for them,
 2720: which is useful for the Course Initialization helper so the users never see
 2721: the old values taking effect.
 2722: 
 2723: =cut
 2724: 
 2725: no strict;
 2726: @ISA = ("Apache::lonhelper::element");
 2727: use strict;
 2728: 
 2729: BEGIN {
 2730:     &Apache::lonhelper::register('Apache::lonhelper::final',
 2731:                                  ('final', 'exitpage'));
 2732: }
 2733: 
 2734: sub new {
 2735:     my $ref = Apache::lonhelper::element->new();
 2736:     bless($ref);
 2737: }
 2738: 
 2739: sub start_final { 
 2740:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2741: 
 2742:     if ($target ne 'helper') {
 2743:         return '';
 2744:     }
 2745: 
 2746:     $paramHash->{'restartCourse'} = $token->[2]{'restartCourse'};
 2747: 
 2748:     return ''; 
 2749: }
 2750: 
 2751: sub end_final {
 2752:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2753: 
 2754:     if ($target ne 'helper') {
 2755:         return '';
 2756:     }
 2757: 
 2758:     Apache::lonhelper::final->new();
 2759:    
 2760:     return '';
 2761: }
 2762: 
 2763: sub start_exitpage {
 2764:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2765: 
 2766:     if ($target ne 'helper') {
 2767:         return '';
 2768:     }
 2769: 
 2770:     $paramHash->{EXIT_PAGE} = &Apache::lonxml::get_all_text('/exitpage',
 2771:                                                             $parser);
 2772: 
 2773:     return '';
 2774: }
 2775: 
 2776: sub end_exitpage { return ''; }
 2777: 
 2778: sub render {
 2779:     my $self = shift;
 2780: 
 2781:     my @results;
 2782: 
 2783:     # Collect all the results
 2784:     for my $stateName (keys %{$helper->{STATES}}) {
 2785:         my $state = $helper->{STATES}->{$stateName};
 2786:         
 2787:         for my $element (@{$state->{ELEMENTS}}) {
 2788:             if (defined($element->{FINAL_CODE})) {
 2789:                 # Compile the code.
 2790:                 my $code = 'sub { my $helper = shift; my $element = shift; ' 
 2791:                     . $element->{FINAL_CODE} . '}';
 2792:                 $code = eval($code);
 2793:                 die 'Error while executing final code for element with var ' .
 2794:                     $element->{'variable'} . ', Perl said: ' . $@ if $@;
 2795: 
 2796:                 my $result = &$code($helper, $element);
 2797:                 if ($result) {
 2798:                     push @results, $result;
 2799:                 }
 2800:             }
 2801:         }
 2802:     }
 2803: 
 2804:     my $result;
 2805: 
 2806:     if (scalar(@results) != 0) {
 2807: 	$result .= "<ul>\n";
 2808: 	for my $re (@results) {
 2809: 	    $result .= '    <li>' . $re . "</li>\n";
 2810: 	}
 2811: 	
 2812: 	if (!@results) {
 2813: 	    $result .= '    <li>No changes were made to current settings.</li>';
 2814: 	}
 2815: 	
 2816: 	$result .= '</ul>';
 2817:     }
 2818: 
 2819:     if ($self->{'restartCourse'}) {
 2820:         $result .= "<center>\n" .
 2821:             "<form action='/adm/roles' method='post' target='loncapaclient'>\n" .
 2822:             "<input type='button' onclick='history.go(-1)' value='&lt;- Previous' />" .
 2823:             "<input type='hidden' name='orgurl' value='/adm/menu' />" .
 2824:             "<input type='hidden' name='selectrole' value='1' />\n" .
 2825:             "<input type='hidden' name='" . $ENV{'request.role'} . 
 2826:             "' value='1' />\n<input type='submit' value='Finish Course Initialization' />\n" .
 2827:             "</form></center>";
 2828:     }
 2829: 
 2830:     return $result;
 2831: }
 2832: 
 2833: sub overrideForm {
 2834:     my $self = shift;
 2835:     return $self->{'restartCourse'};
 2836: }
 2837: 
 2838: 1;
 2839: 
 2840: package Apache::lonhelper::parmwizfinal;
 2841: 
 2842: # This is the final state for the parmwizard. It is not generally useful,
 2843: # so it is not perldoc'ed. It does its own processing.
 2844: # It is represented with <parmwizfinal />, and
 2845: # should later be moved to lonparmset.pm .
 2846: 
 2847: no strict;
 2848: @ISA = ('Apache::lonhelper::element');
 2849: use strict;
 2850: 
 2851: BEGIN {
 2852:     &Apache::lonhelper::register('Apache::lonhelper::parmwizfinal',
 2853:                                  ('parmwizfinal'));
 2854: }
 2855: 
 2856: use Time::localtime;
 2857: 
 2858: sub new {
 2859:     my $ref = Apache::lonhelper::choices->new();
 2860:     bless ($ref);
 2861: }
 2862: 
 2863: sub start_parmwizfinal { return ''; }
 2864: 
 2865: sub end_parmwizfinal {
 2866:     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
 2867: 
 2868:     if ($target ne 'helper') {
 2869:         return '';
 2870:     }
 2871:     Apache::lonhelper::parmwizfinal->new();
 2872: }
 2873: 
 2874: # Renders a form that, when submitted, will form the input to lonparmset.pm
 2875: sub render {
 2876:     my $self = shift;
 2877:     my $vars = $helper->{VARS};
 2878: 
 2879:     # FIXME: Unify my designators with the standard ones
 2880:     my %dateTypeHash = ('open_date' => "Opening Date",
 2881:                         'due_date' => "Due Date",
 2882:                         'answer_date' => "Answer Date",
 2883: 			'tries' => 'Number of Tries'
 2884: 			);
 2885:     my %parmTypeHash = ('open_date' => "0_opendate",
 2886:                         'due_date' => "0_duedate",
 2887:                         'answer_date' => "0_answerdate",
 2888: 			'tries' => '0_maxtries' );
 2889:     
 2890:     my $affectedResourceId = "";
 2891:     my $parm_name = $parmTypeHash{$vars->{ACTION_TYPE}};
 2892:     my $level = "";
 2893:     my $resourceString;
 2894:     my $symb;
 2895:     my $paramlevel;
 2896: 
 2897:     # Print the granularity, depending on the action
 2898:     if ($vars->{GRANULARITY} eq 'whole_course') {
 2899:         $resourceString .= '<li>for <b>all resources in the course</b></li>';
 2900:         $level = 9; # general course, see lonparmset.pm perldoc
 2901:         $affectedResourceId = "0.0";
 2902:         $symb = 'a';
 2903:         $paramlevel = 'general';
 2904:     } elsif ($vars->{GRANULARITY} eq 'map') {
 2905:         my $navmap = Apache::lonnavmaps::navmap->new();
 2906:         my $res = $navmap->getByMapPc($vars->{RESOURCE_ID});
 2907:         my $title = $res->compTitle();
 2908:         $symb = $res->symb();
 2909:         $navmap->untieHashes();
 2910:         $resourceString .= "<li>for the map named <b>$title</b></li>";
 2911:         $level = 8;
 2912:         $affectedResourceId = $vars->{RESOURCE_ID};
 2913:         $paramlevel = 'map';
 2914:     } else {
 2915:         my $navmap = Apache::lonnavmaps::navmap->new();
 2916:         my $res = $navmap->getById($vars->{RESOURCE_ID});
 2917:         $symb = $res->symb();
 2918:         my $title = $res->compTitle();
 2919:         $navmap->untieHashes();
 2920:         $resourceString .= "<li>for the resource named <b>$title</b></li>";
 2921:         $level = 7;
 2922:         $affectedResourceId = $vars->{RESOURCE_ID};
 2923:         $paramlevel = 'full';
 2924:     }
 2925: 
 2926:     my $result = "<form name='helpform' method='get' action='/adm/parmset#$affectedResourceId&$parm_name&$level'>\n";
 2927:     $result .= '<p>Confirm that this information is correct, then click &quot;Finish Wizard&quot; to complete setting the parameter.<ul>';
 2928:     
 2929:     # Print the type of manipulation:
 2930:     $result .= '<li>Setting the <b>' . $dateTypeHash{$vars->{ACTION_TYPE}} . '</b>';
 2931:     if ($vars->{ACTION_TYPE} eq 'tries') {
 2932: 	$result .= ' to <b>' . $vars->{TRIES} . '</b>';
 2933:     }
 2934:     $result .= "</li>\n";
 2935:     if ($vars->{ACTION_TYPE} eq 'due_date' || 
 2936:         $vars->{ACTION_TYPE} eq 'answer_date') {
 2937:         # for due dates, we default to "date end" type entries
 2938:         $result .= "<input type='hidden' name='recent_date_end' " .
 2939:             "value='" . $vars->{PARM_DATE} . "' />\n";
 2940:         $result .= "<input type='hidden' name='pres_value' " . 
 2941:             "value='" . $vars->{PARM_DATE} . "' />\n";
 2942:         $result .= "<input type='hidden' name='pres_type' " .
 2943:             "value='date_end' />\n";
 2944:     } elsif ($vars->{ACTION_TYPE} eq 'open_date') {
 2945:         $result .= "<input type='hidden' name='recent_date_start' ".
 2946:             "value='" . $vars->{PARM_DATE} . "' />\n";
 2947:         $result .= "<input type='hidden' name='pres_value' " .
 2948:             "value='" . $vars->{PARM_DATE} . "' />\n";
 2949:         $result .= "<input type='hidden' name='pres_type' " .
 2950:             "value='date_start' />\n";
 2951:     } elsif ($vars->{ACTION_TYPE} eq 'tries') {
 2952: 	$result .= "<input type='hidden' name='pres_value' " .
 2953: 	    "value='" . $vars->{TRIES} . "' />\n";
 2954:     }
 2955: 
 2956:     $result .= $resourceString;
 2957:     
 2958:     # Print targets
 2959:     if ($vars->{TARGETS} eq 'course') {
 2960:         $result .= '<li>for <b>all students in course</b></li>';
 2961:     } elsif ($vars->{TARGETS} eq 'section') {
 2962:         my $section = $vars->{SECTION_NAME};
 2963:         $result .= "<li>for section <b>$section</b></li>";
 2964:         $level -= 3;
 2965:         $result .= "<input type='hidden' name='csec' value='" .
 2966:             HTML::Entities::encode($section) . "' />\n";
 2967:     } else {
 2968:         # FIXME: This is probably wasteful! Store the name!
 2969:         my $classlist = Apache::loncoursedata::get_classlist();
 2970:         my $username = $vars->{USER_NAME};
 2971:         # Chop off everything after the last colon (section)
 2972:         $username = substr($username, 0, rindex($username, ':'));
 2973:         my $name = $classlist->{$username}->[6];
 2974:         $result .= "<li>for <b>$name</b></li>";
 2975:         $level -= 6;
 2976:         my ($uname, $udom) = split /:/, $vars->{USER_NAME};
 2977:         $result .= "<input type='hidden' name='uname' value='".
 2978:             HTML::Entities::encode($uname) . "' />\n";
 2979:         $result .= "<input type='hidden' name='udom' value='".
 2980:             HTML::Entities::encode($udom) . "' />\n";
 2981:     }
 2982: 
 2983:     # Print value
 2984:     if ($vars->{ACTION_TYPE} ne 'tries') {
 2985: 	$result .= "<li>to <b>" . ctime($vars->{PARM_DATE}) . "</b> (" .
 2986: 	    Apache::lonnavmaps::timeToHumanString($vars->{PARM_DATE}) 
 2987: 	    . ")</li>\n";
 2988:     }
 2989:  
 2990:     # print pres_marker
 2991:     $result .= "\n<input type='hidden' name='pres_marker'" .
 2992:         " value='$affectedResourceId&$parm_name&$level' />\n";
 2993:     
 2994:     # Make the table appear
 2995:     $result .= "\n<input type='hidden' value='true' name='prevvisit' />";
 2996:     $result .= "\n<input type='hidden' value='all' name='pschp' />";
 2997:     $result .= "\n<input type='hidden' value='$symb' name='pssymb' />";
 2998:     $result .= "\n<input type='hidden' value='$paramlevel' name='parmlev' />";
 2999: 
 3000:     $result .= "<br /><br /><center><input type='submit' value='Finish Helper' /></center></form>\n";
 3001: 
 3002:     return $result;
 3003: }
 3004:     
 3005: sub overrideForm {
 3006:     return 1;
 3007: }
 3008: 
 3009: 1;
 3010: 
 3011: __END__
 3012: 

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