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Diff for /loncom/interface/lonhelper.pm between versions 1.43 and 1.44

version 1.43, 2003/08/13 14:52:08 version 1.44, 2003/09/02 20:58:31
Line 32 Line 32
   
 =pod  =pod
   
 =head1 lonhelper - HTML Helper framework for LON-CAPA  =head1 NAME
   
 Helpers, often known as "wizards", are well-established UI widgets that users  lonhelper - implements helper framework
   
   =head1 SYNOPSIS
   
   lonhelper implements the helper framework for LON-CAPA, and provides
       many generally useful components for that framework.
   
   Helpers are little programs which present the user with a sequence of
       simple choices, instead of one monolithic multi-dimensional
       choice. They are also referred to as "wizards", "druids", and
       other potentially trademarked or semantically-loaded words.
   
   =head1 OVERVIEWX<lonhelper>
   
   Helpers are well-established UI widgets that users
 feel comfortable with. It can take a complicated multidimensional problem the  feel comfortable with. It can take a complicated multidimensional problem the
 user has and turn it into a series of bite-sized one-dimensional questions.  user has and turn it into a series of bite-sized one-dimensional questions.
   
Line 46  directory and having the .helper file ex Line 60  directory and having the .helper file ex
   
 All classes are in the Apache::lonhelper namespace.  All classes are in the Apache::lonhelper namespace.
   
 =head2 lonhelper XML file format  =head1 lonhelper XML file formatX<lonhelper, XML file format>
   
 A helper consists of a top-level <helper> tag which contains a series of states.  A helper consists of a top-level <helper> tag which contains a series of states.
 Each state contains one or more state elements, which are what the user sees, like  Each state contains one or more state elements, which are what the user sees, like
Line 87  Of course this does nothing. In order fo Line 101  Of course this does nothing. In order fo
 necessary to put actual elements into the wizard. Documentation for each  necessary to put actual elements into the wizard. Documentation for each
 of these elements follows.  of these elements follows.
   
 =head2 Creating a Helper With Code, Not XML  =head1 Creating a Helper With Code, Not XML
   
 In some situations, such as the printing wizard (see lonprintout.pm),   In some situations, such as the printing wizard (see lonprintout.pm), 
 writing the helper in XML would be too complicated, because of scope   writing the helper in XML would be too complicated, because of scope 
Line 146  Normally the machinery in the XML format Line 160  Normally the machinery in the XML format
 adding states can easily be done by wrapping the state in a <condition>  adding states can easily be done by wrapping the state in a <condition>
 tag. This should only be used when the code dominates the XML content,  tag. This should only be used when the code dominates the XML content,
 the code is so complicated that it is difficult to get access to  the code is so complicated that it is difficult to get access to
 all of the information you need because of scoping issues, or so much  all of the information you need because of scoping issues, or would-be <exec> or 
 of the information used is persistent because would-be <exec> or   <eval> blocks using the {DATA} mechanism results in hard-to-read
 <eval> blocks that using the {DATA} mechanism results in hard-to-read  and -maintain code. (See course.initialization.helper for a borderline
 and -maintain code.  case.)
   
 It is possible to do some of the work with an XML fragment parsed by  It is possible to do some of the work with an XML fragment parsed by
 lonxml; again, see lonprintout.pm for an example. In that case it is   lonxml; again, see lonprintout.pm for an example. In that case it is 
Line 210  my $paramHash; Line 224  my $paramHash;
 # mod_perl connection. In this code, it was manifesting itself in the existence  # mod_perl connection. In this code, it was manifesting itself in the existence
 # of two seperate file-scoped $helper variables, one set to the value of the  # of two seperate file-scoped $helper variables, one set to the value of the
 # helper in the helper constructor, and one referenced by the handler on the  # helper in the helper constructor, and one referenced by the handler on the
 # "$helper->process()" line. The second was therefore never set, and was still  # "$helper->process()" line. Using the debugger, one could actually
   # see the two different $helper variables, as hashes at completely
   # different addresses. The second was therefore never set, and was still
 # undefined when I tried to call process on it.  # undefined when I tried to call process on it.
 # By pushing the "real handler" down into the "real scope", everybody except the   # By pushing the "real handler" down into the "real scope", everybody except the 
 # actual handler function directly below this comment gets the same $helper and  # actual handler function directly below this comment gets the same $helper and
Line 748  package Apache::lonhelper::element; Line 764  package Apache::lonhelper::element;
   
 =pod  =pod
   
 =head2 Element Base Class  =head1 Element Base Class
   
 The Apache::lonhelper::element base class provides support for elements  The Apache::lonhelper::element base class provides support for elements
 and defines some generally useful tags for use in elements.  and defines some generally useful tags for use in elements.
   
 B<finalcode tag>  =head2 finalcode tagX<finalcode>
   
 Each element can contain a "finalcode" tag that, when the special FINAL  Each element can contain a "finalcode" tag that, when the special FINAL
 helper state is used, will be executed, surrounded by "sub { my $helper = shift;"  helper state is used, will be executed, surrounded by "sub { my $helper = shift;"
Line 762  may be an empty string. See course initi Line 778  may be an empty string. See course initi
 generally intended for helpers like the course initialization helper, which consist  generally intended for helpers like the course initialization helper, which consist
 of several panels, each of which is performing some sort of bite-sized functionality.  of several panels, each of which is performing some sort of bite-sized functionality.
   
 B<defaultvalue tag>  =head2 defaultvalue tagX<defaultvalue>
   
 Each element that accepts user input can contain a "defaultvalue" tag that,  Each element that accepts user input can contain a "defaultvalue" tag that,
 when surrounded by "sub { my $helper = shift; my $state = shift; " and "}",  when surrounded by "sub { my $helper = shift; my $state = shift; " and "}",
Line 779  some setting accidentally. Line 795  some setting accidentally.
   
 Again, see the course initialization helper for examples.  Again, see the course initialization helper for examples.
   
 B<validator tag>  =head2 validator tagX<validator>
   
 Some elements that accepts user input can contain a "validator" tag that,  Some elements that accepts user input can contain a "validator" tag that,
 when surrounded by "sub { my $helper = shift; my $state = shift; my $element = shift; my $val = shift "   when surrounded by "sub { my $helper = shift; my $state = shift; my $element = shift; my $val = shift " 
Line 791  will return an error message to be displ Line 807  will return an error message to be displ
 Consult the documentation for each element to see whether it supports this   Consult the documentation for each element to see whether it supports this 
 tag.  tag.
   
 B<getValue method>  =head2 getValue methodX<getValue (helper elements)>
   
 If the element stores the name of the variable in a 'variable' member, which  If the element stores the name of the variable in a 'variable' member, which
 the provided ones all do, you can retreive the value of the variable by calling  the provided ones all do, you can retreive the value of the variable by calling
Line 910  package Apache::lonhelper::message; Line 926  package Apache::lonhelper::message;
   
 =pod  =pod
   
 =head2 Element: message  =head1 Element: messageX<message, helper element>
   
 Message elements display the contents of their <message_text> tags, and  Message elements display their contents, and
 transition directly to the state in the <nextstate> tag. Example:  transition directly to the state in the <nextstate> attribute. Example:
   
  <message>   <message nextstate='GET_NAME'>
    <nextstate>GET_NAME</nextstate>     This is the <b>message</b> the user will see, 
    <message_text>This is the <b>message</b> the user will see,                    <i>HTML allowed</i>.
                  <i>HTML allowed</i>.</message_text>  
    </message>     </message>
   
 This will display the HTML message and transition to the <nextstate> if  This will display the HTML message and transition to the 'nextstate' if
 given. The HTML will be directly inserted into the helper, so if you don't  given. The HTML will be directly inserted into the helper, so if you don't
 want text to run together, you'll need to manually wrap the <message_text>  want text to run together, you'll need to manually wrap the message text
 in <p> tags, or whatever is appropriate for your HTML.  in <p> tags, or whatever is appropriate for your HTML.
   
 Message tags do not add in whitespace, so if you want it, you'll need to add  Message tags do not add in whitespace, so if you want it, you'll need to add
Line 998  package Apache::lonhelper::choices; Line 1013  package Apache::lonhelper::choices;
   
 =pod  =pod
   
 =head2 Element: choices  =head2 Element: choicesX<choices, helper element>
   
 Choice states provide a single choice to the user as a text selection box.  Choice states provide a single choice to the user as a text selection box.
 A "choice" is two pieces of text, one which will be displayed to the user  A "choice" is two pieces of text, one which will be displayed to the user
Line 1016  value, will allow the user to select mul Line 1031  value, will allow the user to select mul
 value, will allow the user to select none of the choices without raising  value, will allow the user to select none of the choices without raising
 an error message.  an error message.
   
 B<SUB-TAGS>  =head3 SUB-TAGS
   
 <choices> can have the following subtags:  <choices> can have the following subtags:X<choice, helper tag>
   
 =over 4  =over 4
   
 =item * <nextstate>state_name</nextstate>: If given, this will cause the  =item * <nextstate>state_name</nextstate>: If given, this will cause the
       choice element to transition to the given state after executing. If        choice element to transition to the given state after executing.
       this is used, do not pass nextstates to the <choice> tag.        This will override the <nextstate> passed to <choices> (if any).
   
 =item * <choice />: If the choices are static,  =item * <choice />: If the choices are static,
       this element will allow you to specify them. Each choice        this element will allow you to specify them. Each choice
Line 1033  B<SUB-TAGS> Line 1048  B<SUB-TAGS>
       For example,          For example,  
       <choice computer='234-12-7312'>Bobby McDormik</choice>.        <choice computer='234-12-7312'>Bobby McDormik</choice>.
   
       <choice> can take a parameter "eval", which if set to  <choice> can take a parameter "eval", which if set to
       a true value, will cause the contents of the tag to be  a true value, will cause the contents of the tag to be
       evaluated as it would be in an <eval> tag; see <eval> tag  evaluated as it would be in an <eval> tag; see <eval> tag
       below.  below.
   
 <choice> may optionally contain a 'nextstate' attribute, which  <choice> may optionally contain a 'nextstate' attribute, which
 will be the state transisitoned to if the choice is made, if  will be the state transistioned to if the choice is made, if
 the choice is not multichoice.  the choice is not multichoice. This will override the nextstate
   passed to the parent C<choices> tag.
   
 =back  =back
   
Line 1065  You can mix and match methods of creatin Line 1081  You can mix and match methods of creatin
 "push" onto the choice list, rather then wiping it out. (You can even   "push" onto the choice list, rather then wiping it out. (You can even 
 remove choices programmatically, but that would probably be bad form.)  remove choices programmatically, but that would probably be bad form.)
   
 B<defaultvalue support>  =head3 defaultvalue support
   
 Choices supports default values both in multichoice and single choice mode.  Choices supports default values both in multichoice and single choice mode.
 In single choice mode, have the defaultvalue tag's function return the   In single choice mode, have the defaultvalue tag's function return the 
Line 1278  package Apache::lonhelper::dropdown; Line 1294  package Apache::lonhelper::dropdown;
   
 =pod  =pod
   
 =head2 Element: dropdown  =head2 Element: dropdownX<dropdown, helper tag>
   
 A drop-down provides a drop-down box instead of a radio button  A drop-down provides a drop-down box instead of a radio button
 box. Because most people do not know how to use a multi-select  box. Because most people do not know how to use a multi-select
Line 1288  are the same as "choices", except "allow Line 1304  are the same as "choices", except "allow
 <dropdown> takes an attribute "variable" to control which helper variable  <dropdown> takes an attribute "variable" to control which helper variable
 the result is stored in.  the result is stored in.
   
 B<SUB-TAGS>  =head3 SUB-TAGS
   
 <choice>, which acts just as it does in the "choices" element.  <choice>, which acts just as it does in the "choices" element.
   
 =back  
   
 =cut  =cut
   
 no strict;  no strict;
Line 1426  package Apache::lonhelper::date; Line 1440  package Apache::lonhelper::date;
   
 =pod  =pod
   
 =head2 Element: date  =head2 Element: dateX<date, helper element>
   
 Date elements allow the selection of a date with a drop down list.  Date elements allow the selection of a date with a drop down list.
   
Line 1636  package Apache::lonhelper::resource; Line 1650  package Apache::lonhelper::resource;
   
 =pod  =pod
   
 =head2 Element: resource  =head2 Element: resourceX<resource, helper element>
   
 <resource> elements allow the user to select one or multiple resources  <resource> elements allow the user to select one or multiple resources
 from the current course. You can filter out which resources they can view,  from the current course. You can filter out which resources they can view,
Line 1646  selections across folder openings and cl Line 1660  selections across folder openings and cl
 the user can manipulate the folders.  the user can manipulate the folders.
   
 <resource> takes the standard variable attribute to control what helper  <resource> takes the standard variable attribute to control what helper
 variable stores the results. It also takes a "multichoice" attribute,  variable stores the results. It also takes a "multichoice"X<multichoice> attribute,
 which controls whether the user can select more then one resource. The   which controls whether the user can select more then one resource. The 
 "toponly" attribute controls whether the resource display shows just the  "toponly" attribute controls whether the resource display shows just the
 resources in that sequence, or recurses into all sub-sequences, defaulting  resources in that sequence, or recurses into all sub-sequences, defaulting
Line 1655  suppressEmptySequences argument to the r Line 1669  suppressEmptySequences argument to the r
 folders that have all of their contained resources filtered out to also  folders that have all of their contained resources filtered out to also
 be filtered out.  be filtered out.
   
 B<SUB-TAGS>  =head3 SUB-TAGS
   
 =over 4  =over 4
   
 =item * <filterfunc>: If you want to filter what resources are displayed  =item * <filterfunc>X<filterfunc>: If you want to filter what resources are displayed
   to the user, use a filter func. The <filterfunc> tag should contain    to the user, use a filter func. The <filterfunc> tag should contain
   Perl code that when wrapped with "sub { my $res = shift; " and "}" is     Perl code that when wrapped with "sub { my $res = shift; " and "}" is 
   a function that returns true if the resource should be displayed,     a function that returns true if the resource should be displayed, 
Line 1667  B<SUB-TAGS> Line 1681  B<SUB-TAGS>
   (See Apache::lonnavmaps documentation for information about the     (See Apache::lonnavmaps documentation for information about the 
   resource object.)    resource object.)
   
 =item * <choicefunc>: Same as <filterfunc>, except that controls whether  =item * <choicefunc>X<choicefunc>: Same as <filterfunc>, except that controls whether
   the given resource can be chosen. (It is almost always a good idea to    the given resource can be chosen. (It is almost always a good idea to
   show the user the folders, for instance, but you do not always want to     show the user the folders, for instance, but you do not always want to 
   let the user select them.)    let the user select them.)
   
 =item * <nextstate>: Standard nextstate behavior.  =item * <nextstate>: Standard nextstate behavior.
   
 =item * <valuefunc>: This function controls what is returned by the resource  =item * <valuefunc>X<valuefunc>: This function controls what is returned by the resource
   when the user selects it. Like filterfunc and choicefunc, it should be    when the user selects it. Like filterfunc and choicefunc, it should be
   a function fragment that when wrapped by "sub { my $res = shift; " and    a function fragment that when wrapped by "sub { my $res = shift; " and
   "}" returns a string representing what you want to have as the value. By    "}" returns a string representing what you want to have as the value. By
   default, the value will be the resource ID of the object ($res->{ID}).    default, the value will be the resource ID of the object ($res->{ID}).
   
 =item * <mapurl>: If the URL of a map is given here, only that map  =item * <mapurl>X<mapurl>: If the URL of a map is given here, only that map
   will be displayed, instead of the whole course.    will be displayed, instead of the whole course.
   
 =back  =back
Line 1917  package Apache::lonhelper::student; Line 1931  package Apache::lonhelper::student;
   
 =pod  =pod
   
 =head2 Element: student  =head2 Element: studentX<student, helper element>
   
 Student elements display a choice of students enrolled in the current  Student elements display a choice of students enrolled in the current
 course. Currently it is primitive; this is expected to evolve later.  course. Currently it is primitive; this is expected to evolve later.
Line 2102  package Apache::lonhelper::files; Line 2116  package Apache::lonhelper::files;
   
 =pod  =pod
   
 =head2 Element: files  =head2 Element: filesX<files, helper element>
   
 files allows the users to choose files from a given directory on the  files allows the users to choose files from a given directory on the
 server. It is always multichoice and stores the result as a triple-pipe  server. It is always multichoice and stores the result as a triple-pipe
Line 2118  are put. It accepts the attribute "multi Line 2132  are put. It accepts the attribute "multi
 defaulting to false, which if true will allow the user to select more  defaulting to false, which if true will allow the user to select more
 then one choice.   then one choice. 
   
 <files> accepts three subtags. One is the "nextstate" sub-tag that works  <files> accepts three subtags: 
 as it does with the other tags. Another is a <filechoice> sub tag that  
 is Perl code that, when surrounded by "sub {" and "}" will return a  =over 4
 string representing what directory on the server to allow the user to   
 choose files from. Finally, the <filefilter> subtag should contain Perl  =item * B<nextstate>: works as it does with the other tags. 
 code that when surrounded by "sub { my $filename = shift; " and "}",  
 returns a true value if the user can pick that file, or false otherwise.  =item * B<filechoice>: When the contents of this tag are surrounded by
 The filename passed to the function will be just the name of the file,       "sub {" and "}", will return a string representing what directory
 with no path info.      on the server to allow the user to choose files from. 
   
   =item * B<filefilter>: Should contain Perl code that when surrounded
       by "sub { my $filename = shift; " and "}", returns a true value if
       the user can pick that file, or false otherwise. The filename
       passed to the function will be just the name of the file, with no
       path info. By default, a filter function will be used that will
       mask out old versions of files. This function is available as
       Apache::lonhelper::files::not_old_version if you want to use it to
       composite your own filters.
   
   =back
   
   B<General security note>: You should ensure the user can not somehow 
   pass something into your code that would allow them to look places 
   they should not be able to see, like the C</etc/> directory. However,
   the security impact would be minimal, since it would only expose
   the existence of files, there should be no way to parlay that into
   viewing the files. 
   
 =cut  =cut
   
Line 2141  BEGIN { Line 2173  BEGIN {
                                  ('files', 'filechoice', 'filefilter'));                                   ('files', 'filechoice', 'filefilter'));
 }  }
   
   sub not_old_version {
       my $file = shift;
       
       # Given a file name, return false if it is an "old version" of a
       # file, or true if it is not.
   
       if ($file =~ /^.*\.[0-9]+\.[A-Za-z]+(\.meta)?$/) {
    return 0;
       }
       return 1;
   }
   
 sub new {  sub new {
     my $ref = Apache::lonhelper::element->new();      my $ref = Apache::lonhelper::element->new();
     bless($ref);      bless($ref);
Line 2208  sub render { Line 2252  sub render {
     my $subdir = &$subdirFunc();      my $subdir = &$subdirFunc();
   
     my $filterFunc = $self->{FILTER_FUNC};      my $filterFunc = $self->{FILTER_FUNC};
       if (!defined($filterFunc)) {
    $filterFunc = &not_old_version;
       }
     my $buttons = '';      my $buttons = '';
     my $type = 'radio';      my $type = 'radio';
     if ($self->{'multichoice'}) {      if ($self->{'multichoice'}) {
Line 2264  BUTTONS Line 2311  BUTTONS
         @fileList = &Apache::lonnet::dirlist($subdir, $ENV{'user.domain'}, $ENV{'user.name'}, '');          @fileList = &Apache::lonnet::dirlist($subdir, $ENV{'user.domain'}, $ENV{'user.name'}, '');
     }      }
   
       # Sort the fileList into order
       @fileList = sort @fileList;
   
     $result .= $buttons;      $result .= $buttons;
   
     if (defined $self->{ERROR_MSG}) {      if (defined $self->{ERROR_MSG}) {
Line 2392  package Apache::lonhelper::section; Line 2442  package Apache::lonhelper::section;
   
 =pod  =pod
   
 =head2 Element: section  =head2 Element: sectionX<section, helper element>
   
 <section> allows the user to choose one or more sections from the current  <section> allows the user to choose one or more sections from the current
 course.  course.
Line 2466  package Apache::lonhelper::string; Line 2516  package Apache::lonhelper::string;
   
 =pod  =pod
   
 =head2 Element: string  =head2 Element: stringX<string, helper element>
   
 string elements provide a string entry field for the user. string elements  string elements provide a string entry field for the user. string elements
 take the usual 'variable' and 'nextstate' parameters. string elements  take the usual 'variable' and 'nextstate' parameters. string elements
Line 2575  package Apache::lonhelper::general; Line 2625  package Apache::lonhelper::general;
   
 =pod  =pod
   
 =head2 General-purpose tag: <exec>  =head2 General-purpose tag: <exec>X<exec, helper tag>
   
 The contents of the exec tag are executed as Perl code, not inside a   The contents of the exec tag are executed as Perl code, B<not> inside a 
 safe space, so the full range of $ENV and such is available. The code  safe space, so the full range of $ENV and such is available. The code
 will be executed as a subroutine wrapped with the following code:  will be executed as a subroutine wrapped with the following code:
   
Line 2590  The return value is ignored. Line 2640  The return value is ignored.
 $helper is the helper object. Feel free to add methods to the helper  $helper is the helper object. Feel free to add methods to the helper
 object to support whatever manipulation you may need to do (for instance,  object to support whatever manipulation you may need to do (for instance,
 overriding the form location if the state is the final state; see   overriding the form location if the state is the final state; see 
 lonparm.helper for an example).  parameter.helper for an example).
   
 $state is the $paramHash that has currently been generated and may  $state is the $paramHash that has currently been generated and may
 be manipulated by the code in exec. Note that the $state is not yet  be manipulated by the code in exec. Note that the $state is not yet
Line 2665  sub end_clause { return ''; } Line 2715  sub end_clause { return ''; }
   
 =pod  =pod
   
 =head2 General-purpose tag: <eval>  =head2 General-purpose tag: <eval>X<eval, helper tag>
   
 The <eval> tag will be evaluated as a subroutine call passed in the  The <eval> tag will be evaluated as a subroutine call passed in the
 current helper object and state hash as described in <condition> above,  current helper object and state hash as described in <condition> above,
Line 2708  package Apache::lonhelper::final; Line 2758  package Apache::lonhelper::final;
   
 =pod  =pod
   
 =head2 Element: final  =head2 Element: finalX<final, helper tag>
   
 <final> is a special element that works with helpers that use the <finalcode>  <final> is a special element that works with helpers that use the <finalcode>
 tag. It goes through all the states and elements, executing the <finalcode>  tagX<finalcode, helper tag>. It goes through all the states and elements, executing the <finalcode>
 snippets and collecting the results. Finally, it takes the user out of the  snippets and collecting the results. Finally, it takes the user out of the
 helper, going to a provided page.  helper, going to a provided page.
   
Removed from v.1.43  
changed lines
  Added in v.1.44

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