Annotation of loncom/lonmap.pm, revision 1.3

1.1       foxr        1: # The LearningOnline Network
                      2: #
                      3: #  Read maps into a 'big hash'.
                      4: #
1.3     ! foxr        5: # $Id: lonmap.pm,v 1.2 2011/09/13 10:27:52 foxr Exp $
1.1       foxr        6: #
                      7: # Copyright Michigan State University Board of Trustees
                      8: #
                      9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
                     10: #
                     11: # LON-CAPA is free software; you can redistribute it and/or modify
                     12: # it under the terms of the GNU General Public License as published by
                     13: # the Free Software Foundation; either version 2 of the License, or
                     14: # (at your option) any later version.
                     15: #
                     16: # LON-CAPA is distributed in the hope that it will be useful,
                     17: # but WITHOUT ANY WARRANTY; without even the implied warranty of
                     18: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     19: # GNU General Public License for more details.
                     20: #
                     21: # You should have received a copy of the GNU General Public License
                     22: # along with LON-CAPA; if not, write to the Free Software
                     23: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     24: #
                     25: # /home/httpd/html/adm/gpl.txt
                     26: #
                     27: # http://www.lon-capa.org/
                     28: #
                     29: ###
                     30: 
1.3     ! foxr       31: package Apache::lonmap;
1.1       foxr       32: use strict;
                     33: 
                     34: #------------- Required external modules.
                     35: 
                     36: use Error qw(:try);
                     37: 
                     38: use HTML::TokeParser;
                     39: 
                     40: 
1.2       foxr       41: use LONCAPA;
1.1       foxr       42: use Apache::lonnet;
1.3     ! foxr       43: use Data::Dumper;
        !            44: 
1.1       foxr       45: 
                     46: #------------- File scoped variables:
                     47: 
1.3     ! foxr       48: my $map_number = 0;		# keep track of maps within the course.
1.1       foxr       49: my $course_id;     		# Will be the id of the course being read in.
                     50: 
                     51: #
                     52: # The variables below are auxiliary hashes.  They will be tacked onto the
                     53: # big hash though currently not used by clients.. you never know about later.
                     54: #
                     55: 
                     56: my %randompick;
                     57: my %randompickseed;
                     58: my %randomorder;
                     59: my %encurl;
                     60: my %hiddenurl;
1.2       foxr       61: my %parmhash;
1.1       foxr       62: my @cond;			# Array of conditions.
1.2       foxr       63: my $retfrid;
1.1       foxr       64: #
                     65: #  Other stuff we make global (sigh) so that it does not need
                     66: #  to be passed around all the time:
                     67: #
                     68: 
                     69: my $username;			# User for whom the map is being read.
                     70: my $userdomain;  		# Domain the user lives in.
                     71: my %mapalias_cache;		# Keeps track of map aliases -> resources detects duplicates.
1.3     ! foxr       72: my %cenv;			# Course environment.
1.1       foxr       73: 
                     74: #------------- Executable code: 
                     75: 
                     76: 
                     77: #----------------------------------------------------------------
                     78: #
                     79: #  General utilities:
                     80: 
                     81: 
                     82: #
                     83: #  I _think_ this does common sub-expression simplification and 
                     84: #  optimization for condition strings...based on common pattern matching.
                     85: # Parameters:
                     86: #    expression - the condition expression string.
                     87: # Returns:
                     88: #    The optimized expression if an optimization could be found.
                     89: #
                     90: # NOTE:
                     91: #   Added repetetive optimization..it's possible that an
                     92: #   optimization results in an expression that can be recognized further in
                     93: #   a subsequent optimization pass:
                     94: #
                     95: 
                     96: sub simplify {
                     97:     my $expression=shift;
                     98:     my $prior = '';		# This is safe as a null expression is pretty optimal.
                     99:     
                    100:     while ($prior ne $expression) {
                    101: 	$prior = $expression;	# Stop when the substitutions below do nothing.
                    102: # (0&1) = 1
                    103: 	$expression=~s/\(0\&([_\.\d]+)\)/$1/g;
                    104: # (8)=8
                    105: 	$expression=~s/\(([_\.\d]+)\)/$1/g;
                    106: # 8&8=8
                    107: 	$expression=~s/([^_\.\d])([_\.\d]+)\&\2([^_\.\d])/$1$2$3/g;
                    108: # 8|8=8
                    109: 	$expression=~s/([^_\.\d])([_\.\d]+)(?:\|\2)+([^_\.\d])/$1$2$3/g;
                    110: # (5&3)&4=5&3&4
                    111: 	$expression=~s/\(([_\.\d]+)((?:\&[_\.\d]+)+)\)\&([_\.\d]+[^_\.\d])/$1$2\&$3/g;
                    112: # (((5&3)|(4&6)))=((5&3)|(4&6))
                    113: 	$expression=~
                    114: 	    s/\((\(\([_\.\d]+(?:\&[_\.\d]+)*\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+\))\)/$1/g;
                    115: # ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
                    116: 	$expression=~
                    117: 	    s/\((\([_\.\d]+(?:\&[_\.\d]+)*\))((?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+)\)\|(\([_\.\d]+(?:\&[_\.\d]+)*\))/\($1$2\|$3\)/g;
                    118:     }
                    119:     return $expression;
                    120: }
                    121:     
                    122: 
                    123: #
                    124: #  Merge the conditions into the big hash
                    125: #  these will result in hash entries of the form:
                    126: #   'condition.n'  where 'n' is the array index of the condition in the
                    127: #   @cond array above.
                    128: #
                    129: #  Parameters:
                    130: #    $hash - big hashthat's being built up.
                    131: #
                    132: sub merge_conditions {
                    133:     my $hash = shift;
                    134: 
1.2       foxr      135:     for (my $i = 0; $i < scalar(@cond); $i++) {
1.1       foxr      136: 	$hash->{'condition' . '.' . $i} = $cond[$i];
                    137:     }
                    138: }
                    139: 
                    140: # Merge the contents of a 'child hash' into a parent hash hanging it off another key.
                    141: # This is _not_ done by hanging a reference to the child hash as the parent may be
                    142: # bound to a GDBM file e.g. and shared by more than one process ..and references are
                    143: # pretty clearly not going to work across process boundaries.
                    144: #
                    145: # Parameters:
                    146: #   $parent  - The hash to which the child will be merged (reference)
                    147: #   $key     - The key in the parent hash on which the child elements will be hung.
                    148: #              given a key named $childkey the final parent hash entry will be
                    149: #              $parent . '.' $childkey
                    150: #  $child    - The hash whose contents we merge into the parent (reference)
                    151: #
                    152: sub merge_hash {
                    153:     my ($parent, $key, $child) = @_;
                    154: 
1.3     ! foxr      155:     if ($key ne '') {
        !           156: 	$key .= '.';		# If we are prefixing, prefix then .
        !           157:     }
        !           158: 
1.1       foxr      159:     foreach my $childkey (keys (%$child)) {
1.3     ! foxr      160: 	$parent->{$key . $childkey} = $child->{$childkey};
1.1       foxr      161:     }
                    162: }
                    163: 
                    164: #----------------------------------------------------------------------------------
                    165: #
                    166: #   Code to keep track of map aliases and to determine if there are doubly 
                    167: #   defined aliases.
                    168: #
                    169: 
                    170: #
                    171: #  Maintains the mapalias hash.  This is a hash of arrays.  Each array
                    172: #  is indexed by the alias and contains the set of resource ids pointed to by that
                    173: #  alias.  In an ideal world, there will only be one element in each array.
                    174: #  The point of this, however is to determine which aliases might be doubley defined
                    175: #  due to map nesting e.g.
                    176: #
                    177: #  Parameters:
                    178: #    $value   - Alias name.
                    179: #    $resid   - Resource id pointed to by the alias.
                    180: #
                    181: #    
                    182: sub count_mapalias {
                    183:     my ($value,$resid) = @_;
                    184:     push(@{ $mapalias_cache{$value} }, $resid);
                    185: }
                    186: #
                    187: #  Looks at each key in the mapalias hash and, for each case where an
                    188: #  alias points to more than one value adds an error text to the
                    189: #  result string.'
                    190: #
                    191: #  Parameters:
1.2       foxr      192: #     hash - Reference to the hash we are trying t build up.
1.1       foxr      193: #  Implicit inputs
                    194: #     %mapalias - a hash that is indexed by map aliases and contains for each key
                    195: #                 an array of the resource id's the alias 'points to'.
                    196: # Returns:
                    197: #    A hopefully empty string of messages that descsribe the aliases that have more
                    198: #    than one value.  This string is formatted like an html list.
                    199: #
                    200: #
                    201: sub get_mapalias_errors {
1.2       foxr      202:     my $hash = shift;
1.1       foxr      203:     my $error_text;
                    204:     foreach my $mapalias (sort(keys(%mapalias_cache))) {
                    205: 	next if (scalar(@{ $mapalias_cache{$mapalias} } ) == 1);
                    206: 	my $count;
                    207: 	my $which =
                    208: 	    join('</li><li>', 
                    209: 		 map {
                    210: 		     my $id = $_;
1.2       foxr      211: 		     if (exists($hash->{'src_'.$id})) {
1.1       foxr      212: 			 $count++;
                    213: 		     }
                    214: 		     my ($mapid) = split(/\./,$id);
                    215: 		     &mt('Resource "[_1]" <br /> in Map "[_2]"',
1.2       foxr      216: 			 $hash->{'title_'.$id},
                    217: 			 $hash->{'title_'.$hash->{'ids_'.$hash->{'map_id_'.$mapid}}});
1.1       foxr      218: 		 } (@{ $mapalias_cache{$mapalias} }));
                    219: 	next if ($count < 2);
                    220: 	$error_text .= '<div class="LC_error">'.
                    221: 	    &mt('Error: Found the mapalias "[_1]" defined multiple times.',
                    222: 		$mapalias).
                    223: 		'</div><ul><li>'.$which.'</li></ul>';
                    224:     }
                    225:     &clear_mapalias_count();
                    226:     return $error_text;
                    227: }
                    228: #
                    229: #   Clears the map aliase hash.
                    230: #
                    231: sub clear_mapalias_count {
                    232:     undef(%mapalias_cache);
                    233: }
                    234: 
                    235: #----------------------------------------------------------------
                    236: #
                    237: #  Code dealing with resource versions.
                    238: #
                    239: 
                    240: #
1.2       foxr      241: #  Put a version into a src element of a hash or url:
                    242: #
                    243: #  Parameters:
                    244: #     uri - URI into which the version must be added.
                    245: #    hash - Reference to the hash being built up.
                    246: #    short- Short coursename.
                    247: #
                    248: 
                    249: sub putinversion {
                    250:     my ($uri, $hash, $short) = @_;
                    251:     my $key=$short.'_'.&Apache::lonnet::clutter($uri);
                    252:     if ($hash->{'version_'.$uri}) {
                    253: 	my $version=$hash->{'version_'.$uri};
                    254: 	if ($version eq 'mostrecent') { return $uri; }
                    255: 	if ($version eq &Apache::lonnet::getversion(
                    256: 			&Apache::lonnet::filelocation('',$uri))) 
                    257: 	             { return $uri; }
                    258: 	$uri=~s/\.(\w+)$/\.$version\.$1/;
                    259:     }
                    260:     &Apache::lonnet::do_cache_new('courseresversion',$key,&Apache::lonnet::declutter($uri),600);
                    261:     return $uri;
                    262: }
                    263: 
                    264: 
                    265: #
1.1       foxr      266: #  Create hash entries for each version of the course.
                    267: # Parameters:
                    268: #   $cenv    - Reference to a course environment from lonnet::coursedescription.
                    269: #   $hash    - Reference to a hash that will be populated.
                    270: 
                    271: #
                    272: sub process_versions {
                    273:     my ($cenv, $hash) = @_;
                    274: 
                    275:     
                    276:     my %versions = &Apache::lonnet::dump('resourceversions',
                    277: 					 $cenv->{'domain'},
                    278: 					 $cenv->{'num'});
                    279: 
                    280:     foreach my $ver (keys (%versions)) {
                    281: 	if ($ver =~/^error\:/) { # lonc/lond transaction failed.
                    282: 	    throw Error::Simple('lonc/lond returned error: ' . $ver);
                    283: 	}
                    284: 	$hash->{'version_'.$ver} = $versions{$ver};
                    285:     }
                    286: }
                    287: 
                    288: #
                    289: #  Generate text for a version discrepancy error:
                    290: # Parameters:
                    291: #  $uri   - URI of the resource.
                    292: #  $used  - Version used.
                    293: #  $unused - Veresion of duplicate.
                    294: #
                    295: sub versionerror {
                    296:     my ($uri, $used, $unused) = @_;
                    297:     my ($uri,$usedversion,$unusedversion)=@_;
                    298:     return '<br />'.
                    299: 	&mt('Version discrepancy: resource [_1] included in both version [_2] and version [_3]. Using version [_2].',
                    300: 	    $uri,$used,$unused).'<br />';
                    301: 
                    302: }
                    303: 
                    304: #  Removes the version number from a URI and returns the resulting
                    305: #  URI (e.g. mumbly.version.stuff => mumbly.stuff).
                    306: #
                    307: #   If the URI has not been seen with a version before the
                    308: #   hash{'version_'.resultingURI} is set to the  version number.
                    309: #   If the hash has already been seen, but differs then
                    310: #   an error is raised.
                    311: #
                    312: # Parameters:
                    313: #   $uri  -  potentially with a version.
                    314: #   $hash -  reference to a hash to fill in. 
                    315: # Returns:
                    316: #   URI with the version cut out.
                    317: #
1.3     ! foxr      318: sub versiontrack {
1.1       foxr      319:     my ($uri, $hash) = @_;
                    320: 
                    321: 
                    322:     if ($uri=~/\.(\d+)\.\w+$/) { # URI like *.n.text it's version 'n'
                    323: 	my $version=$1;
                    324: 	$uri=~s/\.\d+\.(\w+)$/\.$1/; # elide the version.
                    325:         unless ($hash->{'version_'.$uri}) {
                    326: 	    $hash->{'version_'.$uri}=$version;
                    327: 	} elsif ($version!=$hash->{'version_'.$uri}) {
1.2       foxr      328: 	    throw Error::Simple(&versionerror($uri, $hash->{'version_'.$uri}, $version));
1.1       foxr      329:         }
                    330:     }
                    331:     return $uri;
                    332: }
                    333: #
                    334: #  Appends the version of a resource to its uri and also caches the 
                    335: #  URI (contents?) on the local server
                    336: #
                    337: #  Parameters:
                    338: #     $uri   - URI of the course (without version informatino.
                    339: #     $hash  - What we have of  the big hash.
                    340: #
                    341: # Side-Effects:
                    342: #   The URI is cached by memcached.
                    343: #
                    344: # Returns:
                    345: #    The version appended URI.
                    346: #
                    347: sub append_version {
                    348:     my ($uri, $hash) = @_;
                    349: 
                    350:     # Create the key for the cache entry.
                    351: 
                    352:     my $key = $course_id . '_' . &Apache::lonnet::clutter($uri);
                    353: 
                    354:     # If there is a version it will already be  in the hash:
                    355: 
                    356:     if ($hash->{'version_' . $uri}) {
                    357: 	my $version = $hash->{'version_' . $uri};
                    358: 	if ($version eq 'mostrecent') {
                    359: 	    return $uri;     # Most recent version does not require decoration (or caching?).
                    360: 	}
                    361: 	if ($version eq 
                    362: 	    &Apache::lonnet::getversion(&Apache::lonnet::filelocation('', $uri))) {
                    363: 	    return $uri;	# version matches the most recent file version?
                    364: 	}
                    365: 	$uri =~ s/\.(\w+)$/\.$version\.$1/; # insert the versino prior to the last .word.
                    366:     }
                    367:  
                    368:    # cache the version:
                    369: 
                    370:    &Apache::lonnet::do_cache_new('courseresversion', $key, 
                    371: 				 &Apache::lonnet::declutter($uri), 600);
                    372: 
                    373:     return $uri;
                    374: 
                    375: }
                    376: #--------------------------------------------------------------------------------
                    377: # Post processing subs:
                    378: sub hiddenurls {
                    379:     my $hash = shift;
                    380: 
1.3     ! foxr      381:     my $uname    = $hash->{'context.username'};
        !           382:     my $udom     = $hash->{'context.userdom'};
        !           383:     my $courseid = $hash->{'context.courseid'};
        !           384: 
1.1       foxr      385:     my $randomoutentry='';
                    386:     foreach my $rid (keys %randompick) {
                    387:         my $rndpick=$randompick{$rid};
                    388:         my $mpc=$hash->{'map_pc_'.$hash->{'src_'.$rid}};
                    389: # ------------------------------------------- put existing resources into array
                    390:         my @currentrids=();
                    391:         foreach my $key (sort(keys(%$hash))) {
                    392: 	    if ($key=~/^src_($mpc\.\d+)/) {
                    393: 		if ($hash->{'src_'.$1}) { push @currentrids, $1; }
                    394:             }
                    395:         }
                    396: 	# rids are number.number and we want to numercially sort on 
                    397:         # the second number
                    398: 	@currentrids=sort {
                    399: 	    my (undef,$aid)=split(/\./,$a);
                    400: 	    my (undef,$bid)=split(/\./,$b);
                    401: 	    $aid <=> $bid;
                    402: 	} @currentrids;
                    403:         next if ($#currentrids<$rndpick);
                    404: # -------------------------------- randomly eliminate the ones that should stay
                    405: 	my (undef,$id)=split(/\./,$rid);
                    406:         if ($randompickseed{$rid}) { $id=$randompickseed{$rid}; }
1.3     ! foxr      407: 	my $rndseed=&Apache::lonnet::rndseed($id, $courseid, $udom, $uname, \%cenv); # use id instead of symb
        !           408: 	&Apache::lonnet::logthis("lonmap random seed: $rndseed");
1.1       foxr      409: 	&Apache::lonnet::setup_random_from_rndseed($rndseed);
                    410: 	my @whichids=&Math::Random::random_permuted_index($#currentrids+1);
                    411:         for (my $i=1;$i<=$rndpick;$i++) { $currentrids[$whichids[$i]]=''; }
1.3     ! foxr      412: 
1.1       foxr      413: # -------------------------------------------------------- delete the leftovers
                    414:         for (my $k=0; $k<=$#currentrids; $k++) {
                    415:             if ($currentrids[$k]) {
1.3     ! foxr      416: 		$hash->{'randomout_'.$currentrids[$k]}='1';
1.1       foxr      417:                 my ($mapid,$resid)=split(/\./,$currentrids[$k]);
                    418:                 $randomoutentry.='&'.
                    419: 		    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},
                    420: 						 $resid,
                    421: 						 $hash->{'src_'.$currentrids[$k]}
                    422: 						 ).'&';
                    423:             }
                    424:         }
                    425:     }
                    426: # ------------------------------ take care of explicitly hidden urls or folders
                    427:     foreach my $rid (keys %hiddenurl) {
1.3     ! foxr      428: 	$hash->{'randomout_'.$rid}='1';
1.1       foxr      429: 	my ($mapid,$resid)=split(/\./,$rid);
                    430: 	$randomoutentry.='&'.
                    431: 	    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},$resid,
                    432: 					 $hash->{'src_'.$rid}).'&';
                    433:     }
                    434: # --------------------------------------- add randomout to the hash.
                    435:     if ($randomoutentry) {
                    436: 	$hash->{'acc.randomout'} = $randomoutentry;
                    437: 
                    438:     }
                    439: }
                    440: 
                    441: #
                    442: # It's not so clear to me what this sub does.
                    443: #
                    444: #  Parameters
                    445: #     uri   - URI from the course description hash.
                    446: #     short - Course short name.
                    447: #     fn    - Course filename.
                    448: #     hash  - Reference to the big hash as filled in so far
                    449: #       
                    450: 
                    451: sub accinit {
1.3     ! foxr      452:     my ($uri, $short, $hash)=@_;
1.1       foxr      453:     my %acchash=();
                    454:     my %captured=();
                    455:     my $condcounter=0;
                    456:     $acchash{'acc.cond.'.$short.'.0'}=0;
                    457: 
                    458:     # This loop is only interested in conditions and 
                    459:     # parameters in the big hash:
                    460: 
                    461:     foreach my $key (keys(%$hash)) {
                    462: 
                    463: 	# conditions:
                    464: 
                    465: 	if ($key=~/^conditions/) {
                    466: 	    my $expr=$hash->{$key};
                    467: 
                    468: 	    # try to find and factor out common sub-expressions
                    469: 	    # Any subexpression that is found is simplified, removed from
                    470: 	    # the original condition expression and the simplified sub-expression
                    471: 	    # substituted back in to the epxression..I'm not actually convinced this
                    472: 	    # factors anything out...but instead maybe simplifies common factors(?)
                    473: 
                    474: 	    foreach my $sub ($expr=~m/(\(\([_\.\d]+(?:\&[_\.\d]+)+\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)+\))+\))/g) {
                    475: 		my $orig=$sub;
                    476: 
                    477: 		my ($factor) = ($sub=~/\(\(([_\.\d]+\&(:?[_\.\d]+\&)*)(?:[_\.\d]+\&*)+\)(?:\|\(\1(?:[_\.\d]+\&*)+\))+\)/);
                    478: 		next if (!defined($factor));
                    479: 
                    480: 		$sub=~s/\Q$factor\E//g;
                    481: 		$sub=~s/^\(/\($factor\(/;
                    482: 		$sub.=')';
                    483: 		$sub=simplify($sub);
                    484: 		$expr=~s/\Q$orig\E/$sub/;
                    485: 	    }
                    486: 	    $hash->{$key}=$expr;
                    487: 
                    488:            # If not yet seen, record in acchash and that we've seen it.
                    489: 
                    490: 	    unless (defined($captured{$expr})) {
                    491: 		$condcounter++;
                    492: 		$captured{$expr}=$condcounter;
                    493: 		$acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
                    494: 	    } 
                    495:         # Parameters:
                    496: 
                    497: 	} elsif ($key=~/^param_(\d+)\.(\d+)/) {
                    498: 	    my $prefix=&Apache::lonnet::encode_symb($hash->{'map_id_'.$1},$2,
                    499: 						    $hash->{'src_'.$1.'.'.$2});
                    500: 	    foreach my $param (split(/\&/,$hash->{$key})) {
                    501: 		my ($typename,$value)=split(/\=/,$param);
                    502: 		my ($type,$name)=split(/\:/,$typename);
                    503: 		$parmhash{$prefix.'.'.&unescape($name)}=
                    504: 		    &unescape($value);
                    505: 		$parmhash{$prefix.'.'.&unescape($name).'.type'}=
                    506: 		    &unescape($type);
                    507: 	    }
                    508: 	}
                    509:     }
                    510:     # This loop only processes id entries in the big hash.
                    511: 
                    512:     foreach my $key (keys(%$hash)) {
                    513: 	if ($key=~/^ids/) {
                    514: 	    foreach my $resid (split(/\,/,$hash->{$key})) {
                    515: 		my $uri=$hash->{'src_'.$resid};
                    516: 		my ($uripath,$urifile) =
                    517: 		    &Apache::lonnet::split_uri_for_cond($uri);
                    518: 		if ($uripath) {
                    519: 		    my $uricond='0';
                    520: 		    if (defined($hash->{'conditions_'.$resid})) {
                    521: 			$uricond=$captured{$hash->{'conditions_'.$resid}};
                    522: 		    }
                    523: 		    if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {
                    524: 			if ($acchash{'acc.res.'.$short.'.'.$uripath}=~
                    525: 			    /(\&\Q$urifile\E\:[^\&]*)/) {
                    526: 			    my $replace=$1;
                    527: 			    my $regexp=$replace;
                    528: 			    #$regexp=~s/\|/\\\|/g;
                    529: 			    $acchash{'acc.res.'.$short.'.'.$uripath} =~
                    530: 				s/\Q$regexp\E/$replace\|$uricond/;
                    531: 			} else {
                    532: 			    $acchash{'acc.res.'.$short.'.'.$uripath}.=
                    533: 				$urifile.':'.$uricond.'&';
                    534: 			}
                    535: 		    } else {
                    536: 			$acchash{'acc.res.'.$short.'.'.$uripath}=
                    537: 			    '&'.$urifile.':'.$uricond.'&';
                    538: 		    }
                    539: 		} 
                    540: 	    }
                    541:         }
                    542:     }
                    543:     $acchash{'acc.res.'.$short.'.'}='&:0&';
                    544:     my $courseuri=$uri;
                    545:     $courseuri=~s/^\/res\///;
                    546:     my $regexp = 1;
                    547:  
                    548:     &merge_hash($hash, '', \%acchash); # there's already an acc prefix in the hash keys.
                    549: 
                    550: 
                    551: }
                    552: 
                    553: 
                    554: #
                    555: #  Traces a route recursively through the map after it has been loaded
                    556: #  (I believe this really visits each resource that is reachable fromt he
                    557: #  start top node.
                    558: #
                    559: #  - Marks hidden resources as hidden.
                    560: #  - Marks which resource URL's must be encrypted.
                    561: #  - Figures out (if necessary) the first resource in the map.
                    562: #  - Further builds the chunks of the big hash that define how 
                    563: #    conditions work
                    564: #
                    565: #  Note that the tracing strategy won't visit resources that are not linked to
                    566: #  anything or islands in the map (groups of resources that form a path but are not
                    567: #  linked in to the path that can be traced from the start resource...but that's ok
                    568: #  because by definition, those resources are not reachable by users of the course.
                    569: #
                    570: # Parameters:
                    571: #   sofar    - _URI of the prior entry or 0 if this is the top.
                    572: #   rid      - URI of the resource to visit.
                    573: #   beenhere - list of resources (each resource enclosed by &'s) that have
                    574: #              already been visited.
                    575: #   encflag  - If true the resource that resulted in a recursive call to us
                    576: #              has an encoded URL (which means contained resources should too). 
                    577: #   hdnflag  - If true,the resource that resulted in a recursive call to us
                    578: #              was hidden (which means contained resources should be hidden too).
                    579: #   hash     - Reference to the hash we are traversing.
                    580: # Returns
                    581: #    new value indicating how far the map has been traversed (the sofar).
                    582: #
                    583: sub traceroute {
1.2       foxr      584:     my ($sofar, $rid, $beenhere, $encflag, $hdnflag, $hash)=@_;
1.1       foxr      585:     my $newsofar=$sofar=simplify($sofar);
                    586: 
                    587:     unless ($beenhere=~/\&\Q$rid\E\&/) {
                    588: 	$beenhere.=$rid.'&';  
                    589: 	my ($mapid,$resid)=split(/\./,$rid);
                    590: 	my $symb=&Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},$resid,
                    591: 					      $hash->{'src_'.$rid});
                    592: 	my $hidden=&Apache::lonnet::EXT('resource.0.hiddenresource',$symb);
                    593: 
                    594: 	if ($hdnflag || lc($hidden) eq 'yes') {
                    595: 	    $hiddenurl{$rid}=1;
                    596: 	}
                    597: 	if (!$hdnflag && lc($hidden) eq 'no') {
                    598: 	    delete($hiddenurl{$rid});
                    599: 	}
                    600: 
                    601: 	my $encrypt=&Apache::lonnet::EXT('resource.0.encrypturl',$symb);
                    602: 	if ($encflag || lc($encrypt) eq 'yes') { $encurl{$rid}=1; }
                    603: 
                    604: 	if (($retfrid eq '') && ($hash->{'src_'.$rid})
                    605: 	    && ($hash->{'src_'.$rid}!~/\.sequence$/)) {
                    606: 	    $retfrid=$rid;
                    607: 	}
                    608: 
                    609: 	if (defined($hash->{'conditions_'.$rid})) {
                    610: 	    $hash->{'conditions_'.$rid}=simplify(
                    611:            '('.$hash->{'conditions_'.$rid}.')|('.$sofar.')');
                    612: 	} else {
                    613: 	    $hash->{'conditions_'.$rid}=$sofar;
                    614: 	}
                    615: 
                    616: 	# if the expression is just the 0th condition keep it
                    617: 	# otherwise leave a pointer to this condition expression
                    618: 
                    619: 	$newsofar = ($sofar eq '0') ? $sofar : '_'.$rid;
                    620: 
                    621: 	# Recurse if the resource is a map:
                    622: 
                    623: 	if (defined($hash->{'is_map_'.$rid})) {
                    624: 	    if (defined($hash->{'map_start_'.$hash->{'src_'.$rid}})) {
                    625: 		$sofar=$newsofar=
                    626: 		    &traceroute($sofar,
                    627: 				$hash->{'map_start_'.$hash->{'src_'.$rid}},
                    628: 				$beenhere,
                    629: 				$encflag || $encurl{$rid},
1.3     ! foxr      630: 				$hdnflag || $hiddenurl{$rid}, $hash);
1.1       foxr      631: 	    }
                    632: 	}
                    633: 
                    634: 	# Processes  links to this resource:
                    635: 	#  - verify the existence of any conditionals on the link to here.
                    636: 	#  - Recurse to any resources linked to us.
                    637: 	#
                    638: 	if (defined($hash->{'to_'.$rid})) {
                    639: 	    foreach my $id (split(/\,/,$hash->{'to_'.$rid})) {
                    640: 		my $further=$sofar;
                    641: 		#
                    642: 		# If there's a condition associated with this link be sure
                    643: 		# it's been defined else that's an error:
                    644: 		#
                    645:                 if ($hash->{'undercond_'.$id}) {
                    646: 		    if (defined($hash->{'condid_'.$hash->{'undercond_'.$id}})) {
                    647: 			$further=simplify('('.'_'.$rid.')&('.
                    648: 					  $hash->{'condid_'.$hash->{'undercond_'.$id}}.')');
                    649: 		    } else {
1.2       foxr      650: 			my $errtext.=&mt('<br />Undefined condition ID: [_1]',$hash->{'undercond_'.$id});
1.1       foxr      651: 			throw Error::Simple($errtext);
                    652: 		    }
                    653:                 }
                    654: 		#  Recurse to resoruces that have to's to us.
                    655:                 $newsofar=&traceroute($further,$hash->{'goesto_'.$id},$beenhere,
1.3     ! foxr      656: 				      $encflag,$hdnflag, $hash);
1.1       foxr      657: 	    }
                    658: 	}
                    659:     }
                    660:     return $newsofar;
                    661: }
                    662: 
                    663: 
                    664: #---------------------------------------------------------------------------------
                    665: #
                    666: #  Map parsing code:
                    667: #
                    668: 
                    669: # 
                    670: #  Parse the <param> tag.  for most parameters, the only action is to define/extend
                    671: #  a has entry for {'param_{refid}'} where refid is the resource the parameter is
                    672: #  attached to and the value built up is an & separated list of parameters of the form:
                    673: #  type:part.name=value
                    674: #
                    675: #   In addition there is special case code for:
                    676: #   - randompick
                    677: #   - randompickseed
                    678: #   - randomorder
                    679: #
                    680: #   - encrypturl
                    681: #   - hiddenresource
                    682: #
                    683: # Parameters:
                    684: #    token - The token array from HTML::TokeParse  we mostly care about element [2]
                    685: #            which is a hash of attribute => values supplied in the tag
                    686: #            (remember this sub is only processing start tag tokens).
                    687: #    mno   - Map number.  This is used to qualify resource ids within a map
                    688: #            to make them unique course wide (a process known as uniquifaction).
                    689: #    hash  - Reference to the hash we are building.
                    690: #
                    691: sub parse_param {
                    692:     my ($token, $mno, $hash)  = @_;
                    693: 
                    694:     # Qualify the reference and name by the map number and part number.
                    695:     # if no explicit part number is supplied, 0 is the implicit part num.
                    696: 
                    697:     my $referid=$mno.'.'.$token->[2]->{'to'}; # Resource param applies to.
                    698:     my $name=$token->[2]->{'name'};	      # Name of parameter
                    699:     my $part;
                    700: 
                    701: 
                    702:     if ($name=~/^parameter_(.*)_/) { 
                    703: 	$part=$1;
                    704:     } else {
                    705: 	$part=0;
                    706:     }
                    707: 
                    708:     # Peel the parameter_ off the parameter name.
                    709: 
                    710:     $name=~s/^.*_([^_]*)$/$1/;
                    711: 
                    712:     # The value is:
                    713:     #   type.part.name.value
                    714: 
                    715:     my $newparam=
                    716: 	&escape($token->[2]->{'type'}).':'.
                    717: 	&escape($part.'.'.$name).'='.
                    718: 	&escape($token->[2]->{'value'});
                    719: 
                    720:     # The hash key is param_resourceid.
                    721:     # Multiple parameters for a single resource are & separated in the hash.
                    722: 
                    723: 
                    724:     if (defined($hash->{'param_'.$referid})) {
                    725: 	$hash->{'param_'.$referid}.='&'.$newparam;
                    726:     } else {
                    727: 	$hash->{'param_'.$referid}=''.$newparam;
                    728:     }
                    729:     #
                    730:     #  These parameters have to do with randomly selecting
                    731:     # resources, therefore a separate hash is also created to 
                    732:     # make it easy to locate them when actually computing the resource set later on
                    733:     # See the code conditionalized by ($randomize) in read_map().
                    734: 
                    735:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { # Random selection turned on
                    736: 	$randompick{$referid}=$token->[2]->{'value'};
                    737:     }
                    738:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { # Randomseed provided.
                    739: 	$randompickseed{$referid}=$token->[2]->{'value'};
                    740:     }
                    741:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { # Random order turned on.
                    742: 	$randomorder{$referid}=$token->[2]->{'value'};
                    743:     }
                    744: 
                    745:     # These parameters have to do with how the URLs of resources are presented to
                    746:     # course members(?).  encrypturl presents encypted url's while
                    747:     # hiddenresource hides the URL.
                    748:     #
                    749: 
                    750:     if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) {
                    751: 	if ($token->[2]->{'value'}=~/^yes$/i) {
                    752: 	    $encurl{$referid}=1;
                    753: 	}
                    754:     }
                    755:     if ($token->[2]->{'name'}=~/^parameter_(0_)*hiddenresource$/) {
                    756: 	if ($token->[2]->{'value'}=~/^yes$/i) {
                    757: 	    $hiddenurl{$referid}=1;
                    758: 	}
                    759:     }
                    760: 
                    761: }
                    762: 
                    763: 
                    764: #
                    765: #  Parses a resource tag to produce the value to push into the
                    766: #  map_ids array.
                    767: # 
                    768: #
                    769: #  Information about the actual type of resource is provided by the file extension
                    770: #  of the uri (e.g. .problem, .sequence etc. etc.).
                    771: #
                    772: #  Parameters:
                    773: #    $token   - A token from HTML::TokeParser
                    774: #               This is an array that describes the most recently parsed HTML item.
                    775: #    $lpc     - Map nesting level (?)
                    776: #    $ispage  - True if this resource is encapsulated in a .page (assembled resourcde).
                    777: #    $uri     - URI of the enclosing resource.
                    778: #    $hash    - Reference to the hash we are building.
                    779: #
                    780: # Returns:
                    781: #   Value of the id attribute of the tag.
                    782: #
                    783: # Note:
                    784: #   The token is an array that contains the following elements:
                    785: #   [0]   => 'S' indicating this is a start token
                    786: #   [1]   => 'resource'  indicating this tag is a <resource> tag.
                    787: #   [2]   => Hash of attribute =>value pairs.
                    788: #   [3]   => @(keys [2]).
                    789: #   [4]   => unused.
                    790: #
                    791: #   The attributes of the resourcde tag include:
                    792: #
                    793: #   id     - The resource id.
                    794: #   src    - The URI of the resource.
                    795: #   type   - The resource type (e.g. start and finish).
                    796: #   title  - The resource title.
                    797: #
                    798: 
                    799: sub parse_resource {
                    800:     my ($token,$lpc,$ispage,$uri, $hash) = @_;
                    801:     
                    802:     # I refuse to countenance code like this that has 
                    803:     # such a dirty side effect (and forcing this sub to be called within a loop).
                    804:     #
                    805:     #  if ($token->[2]->{'type'} eq 'zombie') { next; }
                    806:     #
                    807:     #  The original code both returns _and_ skips to the next pass of the >caller's<
                    808:     #  loop, that's just dirty.
                    809:     #
                    810: 
                    811:     # Zombie resources don't produce anything useful.
                    812: 
                    813:     if ($token->[2]->{'type'} eq 'zombie') {
                    814: 	return undef;
                    815:     }
                    816: 
                    817:     my $rid=$lpc.'.'.$token->[2]->{'id'}; # Resource id in hash is levelcounter.id-in-xml.
                    818: 
                    819:     # Save the hash element type and title:
                    820: 	    
                    821:     $hash->{'kind_'.$rid}='res';
                    822:     $hash->{'title_'.$rid}=$token->[2]->{'title'};
                    823: 
                    824:     # Get the version free URI for the resource.
                    825:     # If a 'version' attribute was supplied, and this resource's version 
                    826:     # information has not yet been stored, store it.
                    827:     #
                    828: 
                    829: 
                    830:     my $turi=&versiontrack($token->[2]->{'src'});
                    831:     if ($token->[2]->{'version'}) {
                    832: 	unless ($hash->{'version_'.$turi}) {
                    833: 
                    834: 	    #Where does the value of $1 below come from?
                    835: 	    #$1 for the regexps in versiontrack should have gone out of scope.
                    836: 	    #
                    837: 	    # I think this may be dead code since versiontrack ought to set
                    838: 	    # this hash element(?).
                    839: 	    #
                    840: 	    $hash->{'version_'.$turi}=$1;
                    841: 	}
                    842:     }
                    843:     # Pull out the title and do entity substitution on &colon
                    844:     # Q: Why no other entity substitutions?
                    845: 
                    846:     my $title=$token->[2]->{'title'};
                    847:     $title=~s/\&colon\;/\:/gs;
                    848: 
                    849: 
                    850: 
                    851:     # I think the point of all this code is to construct a final
                    852:     # URI that apache and its rewrite rules can use to
                    853:     # fetch the resource.   Thi s sonly necessary if the resource
                    854:     # is not a page.  If the resource is a page then it must be
                    855:     # assembled (at fetch time?).
                    856: 
                    857:     unless ($ispage) {
                    858: 	$turi=~/\.(\w+)$/;
                    859: 	my $embstyle=&Apache::loncommon::fileembstyle($1);
                    860: 	if ($token->[2]->{'external'} eq 'true') { # external
                    861: 	    $turi=~s/^https?\:\/\//\/adm\/wrapper\/ext\//;
                    862: 	} elsif ($turi=~/^\/*uploaded\//) { # uploaded
                    863: 	    if (($embstyle eq 'img') 
                    864: 		|| ($embstyle eq 'emb')
                    865: 		|| ($embstyle eq 'wrp')) {
                    866: 		$turi='/adm/wrapper'.$turi;
                    867: 	    } elsif ($embstyle eq 'ssi') {
                    868: 		#do nothing with these
                    869: 	    } elsif ($turi!~/\.(sequence|page)$/) {
                    870: 		$turi='/adm/coursedocs/showdoc'.$turi;
                    871: 	    }
                    872: 	} elsif ($turi=~/\S/) { # normal non-empty internal resource
                    873: 	    my $mapdir=$uri;
                    874: 	    $mapdir=~s/[^\/]+$//;
                    875: 	    $turi=&Apache::lonnet::hreflocation($mapdir,$turi);
                    876: 	    if (($embstyle eq 'img') 
                    877: 		|| ($embstyle eq 'emb')
                    878: 		|| ($embstyle eq 'wrp')) {
                    879: 		$turi='/adm/wrapper'.$turi;
                    880: 	    }
                    881: 	}
                    882:     }
                    883:     # Store reverse lookup, remove query string resource 'ids'_uri => resource id.
                    884:     # If the URI appears more than one time in the sequence, it's resourcde
                    885:     # id's are constructed as a comma spearated list.
                    886: 
                    887:     my $idsuri=$turi;
                    888:     $idsuri=~s/\?.+$//;
                    889:     if (defined($hash->{'ids_'.$idsuri})) {
                    890: 	$hash->{'ids_'.$idsuri}.=','.$rid;
                    891:     } else {
                    892: 	$hash->{'ids_'.$idsuri}=''.$rid;
                    893:     }
                    894:     
                    895: 
                    896: 
                    897:     if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard|viewclasslist)$/) {
                    898: 	$turi.='?register=1';
                    899:     }
                    900:     
                    901: 
                    902:     # resource id lookup:  'src'_resourc-di  => URI decorated with a query
                    903:     # parameter as above if necessary due to the resource type.
                    904:     
                    905:     $hash->{'src_'.$rid}=$turi;
                    906: 
                    907:     # Mark the external-ness of the resource:
                    908:     
                    909:     if ($token->[2]->{'external'} eq 'true') {
                    910: 	$hash->{'ext_'.$rid}='true:';
                    911:     } else {
                    912: 	$hash->{'ext_'.$rid}='false:';
                    913:     }
                    914: 
                    915:     # If the resource is a start/finish resource set those
                    916:     # entries in the has so that navigation knows where everything starts.
                    917:     #   If there is a malformed sequence that has no start or no finish
                    918:     # resource, should this be detected and errors thrown?  How would such a 
                    919:     # resource come into being other than being manually constructed by a person
                    920:     # and then uploaded?  Could that happen if an author decided a sequence was almost
                    921:     # right edited it by hand and then reuploaded it to 'fix it' but accidently cut the
                    922:     #  start or finish resources?
                    923:     #
                    924:     #  All resourcess also get a type_id => (start | finish | normal)    hash entr.
                    925:     #
                    926:     if ($token->[2]->{'type'}) {
                    927: 	$hash->{'type_'.$rid}=$token->[2]->{'type'};
                    928: 	if ($token->[2]->{'type'} eq 'start') {
                    929: 	    $hash->{'map_start_'.$uri}="$rid";
                    930: 	}
                    931: 	if ($token->[2]->{'type'} eq 'finish') {
                    932: 	    $hash->{'map_finish_'.$uri}="$rid";
                    933: 	}
                    934:     }  else {
                    935: 	$hash->{'type_'.$rid}='normal';
                    936:     }
                    937: 
                    938:     # Sequences end pages are constructed entities.  They require that the 
                    939:     # map that defines _them_ be loaded as well into the hash...with this resourcde
                    940:     # as the base of the nesting.
                    941:     # Resources like that are also marked with is_map_id => 1 entries.
                    942:     #
                    943:     
                    944:     if (($turi=~/\.sequence$/) ||
                    945: 	($turi=~/\.page$/)) {
1.3     ! foxr      946: 	$hash->{'is_map_'.$rid}='1'; # String in lonuserstate.
1.1       foxr      947: 	&read_map($turi,$rid, $hash);
                    948:     } 
                    949:     return $token->[2]->{'id'};
                    950: }
                    951: 
                    952: #  Links define how you are allowed to move from one resource to another.
                    953: #  They are the transition edges in the directed graph that a map is.
                    954: #  This sub takes informatino from a <link> tag and constructs the
                    955: #  navigation bits and pieces of a map.  There is no requirement that the
                    956: #  resources that are linke are already defined, however clearly the map is 
                    957: #  badly broken if they are not _eventually_ defined.
                    958: #
                    959: #  Note that links can be unconditional or conditional.
                    960: #
                    961: #  Parameters:
                    962: #     linkpc   - The link counter for this level of map nesting (this is 
                    963: #                reset to zero by read_map prior to starting to process
                    964: #                links for map).
                    965: #     lpc      - The map level ocounter (how deeply nested this map is in
                    966: #                the hierarchy of maps that are recursively read in.
                    967: #     to       - resource id (within the XML) of the target of the edge.
                    968: #     from     - resource id (within the XML) of the source of the edge.
                    969: #     condition- id of condition associated with the edge (also within the XML).
                    970: #     hash     - reference to the hash we are building.
                    971: 
                    972: #
                    973: 
                    974: sub make_link {
                    975:     my ($linkpc,$lpc,$to,$from,$condition, $hash) = @_;
                    976:     
                    977:     #  Compute fully qualified ids for the link, the 
                    978:     # and from/to by prepending lpc.
                    979:     #
                    980: 
                    981:     my $linkid=$lpc.'.'.$linkpc;
                    982:     my $goesto=$lpc.'.'.$to;
                    983:     my $comesfrom=$lpc.'.'.$from;
1.3     ! foxr      984:     my $undercond='0';
1.1       foxr      985: 
                    986: 
                    987:     # If there is a condition, qualify it with the level counter.
                    988: 
                    989:     if ($condition) {
                    990: 	$undercond=$lpc.'.'.$condition;
                    991:     }
                    992: 
                    993:     # Links are represnted by:
                    994:     #  goesto_.fuullyqualifedlinkid => fully qualified to
                    995:     #  comesfrom.fullyqualifiedlinkid => fully qualified from
                    996:     #  undercond_.fullyqualifiedlinkid => fully qualified condition id.
                    997: 
                    998:     $hash->{'goesto_'.$linkid}=$goesto;
                    999:     $hash->{'comesfrom_'.$linkid}=$comesfrom;
                   1000:     $hash->{'undercond_'.$linkid}=$undercond;
                   1001: 
                   1002:     # In addition:
                   1003:     #   to_.fully qualified from => comma separated list of 
                   1004:     #   link ids with that from.
                   1005:     # Similarly:
                   1006:     #   from_.fully qualified to => comma separated list of link ids`
                   1007:     #                               with that to.
                   1008:     #  That allows us given a resource id to know all edges that go to it
                   1009:     #  and leave from it.
                   1010:     #
                   1011: 
                   1012:     if (defined($hash->{'to_'.$comesfrom})) {
                   1013: 	$hash->{'to_'.$comesfrom}.=','.$linkid;
                   1014:     } else {
                   1015: 	$hash->{'to_'.$comesfrom}=''.$linkid;
                   1016:     }
                   1017:     if (defined($hash->{'from_'.$goesto})) {
                   1018: 	$hash->{'from_'.$goesto}.=','.$linkid;
                   1019:     } else {
                   1020: 	$hash->{'from_'.$goesto}=''.$linkid;
                   1021:     }
                   1022: }
                   1023: 
                   1024: # ------------------------------------------------------------------- Condition
                   1025: #
                   1026: #  Processes <condition> tags, storing sufficient information about them
                   1027: #  in the hash so that they can be evaluated and used to conditionalize
                   1028: #  what is presented to the student.
                   1029: #
                   1030: #  these can have the following attributes 
                   1031: #
                   1032: #    id    = A unique identifier of the condition within the map.
                   1033: #
                   1034: #    value = Is a perl script-let that, when evaluated in safe space
                   1035: #            determines whether or not the condition is true.
                   1036: #            Normally this takes the form of a test on an  Apache::lonnet::EXT call
                   1037: #            to find the value of variable associated with a resource in the
                   1038: #            map identified by a mapalias.
                   1039: #            Here's a fragment of XML code that illustrates this:
                   1040: #
                   1041: #           <param to="5" value="mainproblem" name="parameter_0_mapalias" type="string" />
                   1042: #           <resource src="" id="1" type="start" title="Start" />
                   1043: #           <resource src="/res/msu/albertel/b_and_c/p1.problem" id="5"  title="p1.problem" />
                   1044: #           <condition value="&EXT('user.resource.resource.0.tries','mainproblem')
                   1045: #           <2 " id="61" type="stop" />
                   1046: #           <link to="5" index="1" from="1" condition="61" />    
                   1047: #
                   1048: #           In this fragment:
                   1049: #             - The param tag establishes an alias to resource id 5 of 'mainproblem'.
                   1050: #             - The resource that is the start of the map is identified.
                   1051: #             - The resource tag identifies the resource associated with this tag
                   1052: #               and gives it the id 5.
                   1053: #             - The condition is true if the tries variable associated with mainproblem
                   1054: #               is less than 2 (that is the user has had more than 2 tries).
                   1055: #               The condition type is a stop condition which inhibits(?) the associated
                   1056: #               link if the condition  is false. 
                   1057: #             - The link to resource 5 from resource 1 is affected by this condition.    
                   1058: #            
                   1059: #    type  = Type of the condition. The type determines how the condition affects the
                   1060: #            link associated with it and is one of
                   1061: #            -  'force'
                   1062: #            -  'stop'
                   1063: #              anything else including not supplied..which treated as:
                   1064: #            - 'normal'.
                   1065: #            Presumably maps get created by the resource assembly tool and therefore
                   1066: #            illegal type values won't squirm their way into the XML.
                   1067: #   hash   - Reference to the hash we are trying to build up.
                   1068: #
                   1069: # Side effects:
                   1070: #   -  The kind_level-qualified-condition-id hash element is set to 'cond'.
                   1071: #   -  The condition text is pushed into the cond array and its element number is
                   1072: #      set in the condid_level-qualified-condition-id element of the hash.
                   1073: #   - The condition type is colon appneded to the cond array element for this condition.
                   1074: sub parse_condition {
                   1075:     my ($token, $lpc, $hash) = @_;
                   1076:     my $rid=$lpc.'.'.$token->[2]->{'id'};
                   1077:     
                   1078:     $hash->{'kind_'.$rid}='cond';
                   1079: 
                   1080:     my $condition = $token->[2]->{'value'};
                   1081:     $condition =~ s/[\n\r]+/ /gs;
                   1082:     push(@cond, $condition);
                   1083:     $hash->{'condid_'.$rid}=$#cond;
                   1084:     if ($token->[2]->{'type'}) {
                   1085: 	$cond[$#cond].=':'.$token->[2]->{'type'};
                   1086:     }  else {
                   1087: 	$cond[$#cond].=':normal';
                   1088:     }
                   1089: }
                   1090: 
                   1091: #
                   1092: #  Parse mapalias parameters.
                   1093: #  these are tags of the form:
                   1094: #  <param to="nn" 
                   1095: #         value="some-alias-for-resourceid-nn" 
                   1096: #         name="parameter_0_mapalias" 
                   1097: #         type="string" />
                   1098: #  A map alias is a textual name for a resource:
                   1099: #    - The to  attribute identifies the resource (this gets level qualified below)
                   1100: #    - The value attributes provides the alias string.
                   1101: #    - name must be of the regexp form: /^parameter_(0_)*mapalias$/
                   1102: #    - e.g. the string 'parameter_' followed by 0 or more "0_" strings
                   1103: #      terminating with the string 'mapalias'.
                   1104: #      Examples:
                   1105: #         'parameter_mapalias', 'parameter_0_mapalias', parameter_0_0_mapalias'
                   1106: #  Invalid to ids are silently ignored.
                   1107: #
                   1108: #  Parameters:
                   1109: #     token - The token array fromthe HMTML::TokeParser
                   1110: #     lpc   - The current map level counter.
                   1111: #     hash  - Reference to the hash that we are building.
                   1112: #
                   1113: sub parse_mapalias_param {
                   1114:     my ($token, $lpc, $hash) = @_;
                   1115: 
                   1116:     # Fully qualify the to value and ignore the alias if there is no
                   1117:     # corresponding resource.
                   1118: 
                   1119:     my $referid=$lpc.'.'.$token->[2]->{'to'};
                   1120:     return if (!exists($hash->{'src_'.$referid}));
                   1121: 
                   1122:     # If this is a valid mapalias parameter, 
                   1123:     # Append the target id to the count_mapalias element for that
                   1124:     # alias so that we can detect doubly defined aliases
                   1125:     # e.g.:
                   1126:     #  <param to="1" value="george" name="parameter_0_mapalias" type="string" />
                   1127:     #  <param to="2" value="george" name="parameter_0_mapalias" type="string" />
                   1128:     #
                   1129:     #  The example above is trivial but the case that's important has to do with
                   1130:     #  constructing a map that includes a nested map where the nested map may have
                   1131:     #  aliases that conflict with aliases established in the enclosing map.
                   1132:     #
                   1133:     # ...and create/update the hash mapalias entry to actually store the alias.
                   1134:     #
                   1135: 
                   1136:     if ($token->[2]->{'name'}=~/^parameter_(0_)*mapalias$/) {
                   1137: 	&count_mapalias($token->[2]->{'value'},$referid);
                   1138: 	$hash->{'mapalias_'.$token->[2]->{'value'}}=$referid;
                   1139:     }
                   1140: }
                   1141: 
                   1142: 
                   1143: #---------------------------------------------------------------------------------
                   1144: #
                   1145: #  Code to process the map file.
                   1146: 
                   1147: #  read a map file and add it to the hash.  Since a course map can contain resources
                   1148: #  that are themselves maps, read_map might be recursively called.
                   1149: #
                   1150: # Parameters:
                   1151: #   $uri         - URI of the course itself (not the map file).
                   1152: #   $parent_rid  - map number qualified id of the parent of the map being read.
                   1153: #                  For the top level course map this is 0.0.  For the first nested
                   1154: #                  map 1.n  where n is the id of the resource within the
                   1155: #                  top level map and so on.  
                   1156: #   $hash        - Reference to a hash that will become the big hash for the course
                   1157: #                  This hash is modified as per the map description.
                   1158: # Side-effects:
                   1159: #   $map_number - Will be  incremented.   This keeps track of the number of the map
                   1160: #                 we are currently working on (see parent_rid above, the number to the
                   1161: #                 left of the . in $parent_rid is the map number).
                   1162: #
                   1163: #  
                   1164: sub read_map {
                   1165:     my ($uri, $parent_rid, $hash) = @_;
                   1166: 
1.3     ! foxr     1167: 
1.1       foxr     1168:     # Check for duplication: A map may only be included once.
                   1169: 
                   1170:     if($hash->{'map_pc_' . $uri}) {
1.2       foxr     1171: 	throw Error::Simple('Duplicate map: ', $uri);
1.1       foxr     1172:     }
                   1173:     # count the map number and save it locally so that we don't lose it
                   1174:     # when we recurse.
                   1175: 
                   1176:     $map_number++;
                   1177:     my $lmap_no = $map_number;
                   1178: 
                   1179:     # save the map_pc and map_id elements of the hash for this map:
                   1180:     #  map_pc_uri is the map number of the map with that URI.
                   1181:     #  map_id_$lmap_no is the URI for this map level.
                   1182:     #
1.3     ! foxr     1183:     $hash->{'map_pc_' . $uri}     = "$lmap_no"; # string form in lonuserstate.
        !          1184:     $hash->{'map_id_' . $lmap_no} = "$uri";
1.1       foxr     1185: 
                   1186:     # Create the path up to the top of the course.
                   1187:     # this is in 'map_hierarchy_mapno'  that's a comma separated path down to us
                   1188:     # in the hierarchy:
                   1189: 
                   1190:     if ($parent_rid =~/^(\d+).\d+$/) { 
                   1191: 	my $parent_no = $1;	       # Parent's map number.
                   1192: 	if (defined($hash->{'map_hierarchy_' . $parent_no})) {
                   1193: 	    $hash->{'map_hierarchy_' . $lmap_no} =
1.2       foxr     1194: 		$hash->{'map_hierarchy_' . $parent_no} . ',' . $parent_no;
1.1       foxr     1195: 	} else {
                   1196: 	    # Only 1 level deep ..nothing to append to:
                   1197: 
                   1198: 	    $hash->{'map_hierarchy_' . $lmap_no} = $parent_no;
                   1199: 	}
                   1200:     }
                   1201: 
                   1202:     # figure out the name of the map file we need to read.
                   1203:     # ensure that it is a .page or a .sequence as those are the only 
                   1204:     # sorts of files that make sense for this sub 
                   1205: 
                   1206:     my $filename = &Apache::lonnet::filelocation('', &append_version($uri, $hash));
1.3     ! foxr     1207: 
        !          1208: 
1.1       foxr     1209:     my $ispage = ($filename =~/\.page$/);
1.2       foxr     1210:     unless ($ispage || ($filename =~ /\.sequence$/)) {
1.1       foxr     1211: 	throw Error::Simple(&mt("<br />Invalid map: <tt>[_1]</tt>", $filename));
                   1212:     }
                   1213: 
                   1214:     $filename =~ /\.(\w+)$/;
                   1215: 
1.2       foxr     1216:     $hash->{'map_type_'.$lmap_no}=$1;
1.1       foxr     1217: 
                   1218:     # Repcopy the file and get its contents...report errors if we can't
                   1219:    
1.3     ! foxr     1220:     my $contents = &Apache::lonnet::getfile($filename);
1.1       foxr     1221:     if($contents eq -1) {
                   1222:         throw Error::Simple(&mt('<br />Map not loaded: The file <tt>[_1]</tt> does not exist.',
                   1223: 				$filename));
                   1224:     }
                   1225:     # Now that we succesfully retrieved the file we can make our parsing passes over it:
                   1226:     # parsing is done in passes:
                   1227:     # 1. Parameters are parsed.
                   1228:     # 2. Resource, links and conditions are parsed.
                   1229:     #
                   1230:     # post processing takes care of the case where the sequence is random ordered
                   1231:     # or randomselected.
                   1232: 
                   1233:     # Parse the parameters,  This pass only cares about start tags for <param>
                   1234:     # tags.. this is because there is no body to a <param> tag.
                   1235:     #
                   1236: 
1.2       foxr     1237:     my $parser  = HTML::TokeParser->new(\$contents);
1.1       foxr     1238:     $parser->attr_encoded(1);	# Don't interpret entities in attributes (leave &xyz; alone).
                   1239: 
                   1240:     while (my $token = $parser->get_token()) {
                   1241: 	if (($token->[0] eq 'S') && ($token->[1] eq 'param')) { 
                   1242: 	    &parse_param($token, $map_number, $hash);
                   1243: 	}
                   1244:     }
                   1245: 
                   1246:     # ready for pass 2: Resource links and conditions.
                   1247:     # Note that if the map is random-ordered link tags are computed by randomizing
                   1248:     # resource order.  Furthermore, since conditions are set on links rather than
                   1249:     # resources, they are also not processed if random order is turned on.
                   1250:     #
                   1251: 
1.2       foxr     1252:     $parser = HTML::TokeParser->new(\$contents); # no way to reset the existing parser
1.1       foxr     1253:     $parser->attr_encoded(1);
                   1254: 
                   1255:     my $linkpc=0;
                   1256:     my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i);
                   1257: 
                   1258:     my @map_ids;
                   1259:     while (my $token = $parser->get_token) {
                   1260: 	next if ($token->[0] ne 'S');
                   1261: 
                   1262: 	# Resource
                   1263: 
                   1264: 	if ($token->[1] eq 'resource') {
1.2       foxr     1265: 	    my $resource_id = &parse_resource($token,$lmap_no,$ispage,$uri, $hash);
1.1       foxr     1266: 	    if (defined $resource_id) {
                   1267: 		push(@map_ids, $resource_id); 
                   1268: 	    }
                   1269: 
                   1270:        # Link
                   1271: 
                   1272: 	} elsif ($token->[1] eq 'link' && !$randomize) {
1.2       foxr     1273: 	    &make_link(++$linkpc,$lmap_no,$token->[2]->{'to'},
1.1       foxr     1274: 		       $token->[2]->{'from'},
                   1275: 		       $token->[2]->{'condition'}, $hash); # note ..condition may be undefined.
                   1276: 
                   1277: 	# condition
                   1278: 
                   1279: 	} elsif ($token->[1] eq 'condition' && !$randomize) {
1.2       foxr     1280: 	    &parse_condition($token,$lmap_no, $hash);
1.1       foxr     1281: 	}
                   1282:     }
                   1283: 
                   1284:     #  This section handles random ordering by permuting the 
                   1285:     # IDs of the map according to the user's random seed.
                   1286:     # 
                   1287: 
                   1288:     if ($randomize) {
                   1289: 	if (!$env{'request.role.adv'}) {
                   1290: 	    my $seed;
                   1291: 
                   1292: 	    # In the advanced role, the map's random seed
                   1293: 	    # parameter is used as the basis for computing the
                   1294: 	    # seed ... if it has been specified:
                   1295: 
                   1296: 	    if (defined($randompickseed{$parent_rid})) {
                   1297: 		$seed = $randompickseed{$parent_rid};
                   1298: 	    } else {
                   1299: 
                   1300: 		# Otherwise the parent's fully encoded symb is used.
                   1301: 
                   1302: 		my ($mapid,$resid)=split(/\./,$parent_rid);
                   1303: 		my $symb=
                   1304: 		    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},
                   1305: 						 $resid,$hash->{'src_'.$parent_rid});
                   1306: 		
                   1307: 		$seed = $symb;
                   1308: 	    }
                   1309: 
                   1310: 
                   1311: 	    my $rndseed=&Apache::lonnet::rndseed($seed, $username, $userdomain);
                   1312: 	    &Apache::lonnet::setup_random_from_rndseed($rndseed);
                   1313: 
                   1314: 	    # Take the set of map ids we have decoded and permute them to a
                   1315: 	    # random order based on the seed set above. All of this is
                   1316: 	    # processing the randomorder parameter if it is set, not
                   1317: 	    # randompick.
                   1318: 
                   1319: 	    @map_ids=&math::Random::random_permutation(@map_ids); 
                   1320: 	}
                   1321: 
                   1322: 
                   1323: 	my $from = shift(@map_ids);
1.2       foxr     1324: 	my $from_rid = $lmap_no.'.'.$from;
1.1       foxr     1325: 	$hash->{'map_start_'.$uri} = $from_rid;
                   1326: 	$hash->{'type_'.$from_rid}='start';
                   1327: 
                   1328: 	# Create links to reflect the random re-ordering done above.
                   1329: 	# In the code to process the map XML, we did not process links or conditions
                   1330: 	# if randomorder was set.  This means that for an instructor to choose
                   1331: 
                   1332: 	while (my $to = shift(@map_ids)) {
1.3     ! foxr     1333: 	    &make_link(++$linkpc,$lmap_no,$to,$from, 0, $hash);
1.2       foxr     1334: 	    my $to_rid =  $lmap_no.'.'.$to;
1.1       foxr     1335: 	    $hash->{'type_'.$to_rid}='normal';
                   1336: 	    $from = $to;
                   1337: 	    $from_rid = $to_rid;
                   1338: 	}
                   1339: 
                   1340: 	$hash->{'map_finish_'.$uri}= $from_rid;
                   1341: 	$hash->{'type_'.$from_rid}='finish';
                   1342:     }
                   1343: 
                   1344:     #  The last parsing pass parses the <mapalias> tags that associate a name
                   1345:     #  with resource ids.
                   1346: 
                   1347:     $parser = HTML::TokeParser->new(\$contents);
                   1348:     $parser->attr_encoded(1);
                   1349: 
                   1350:     while (my $token = $parser->get_token) {
                   1351: 	next if ($token->[0] ne 'S');
                   1352: 	if ($token->[1] eq 'param') {
1.2       foxr     1353: 	    &parse_mapalias_param($token,$lmap_no, $hash);  
1.1       foxr     1354: 	} 
                   1355:     }
                   1356: 
                   1357: }
                   1358: 
                   1359: 
                   1360: #
                   1361: #  Load a map from file into a target hash.  This is done by first parsing the 
                   1362: #  map file into local hashes and then unrolling those hashes into the big hash.
                   1363: # 
                   1364: # Parameters:
                   1365: #
                   1366: #    $cnum       - number of course being read.
                   1367: #    $cdom       - Domain in which the course is evaluated.
                   1368: #    $uname      - Name of the user for whom the course is being read
                   1369: #    $udom       - Name of the domain of the user for whom the course is being read.
                   1370: #    $target_hash- Reference to the target hash into which all of this is read.
                   1371: #                  Note tht some of the hash entries we need to build require knowledge of the
                   1372: #                  course URI.. these are expected to be filled in by the caller.
                   1373: #
                   1374: # Errors are logged to lonnet and are managed via the Perl structured exception package.
                   1375: #
                   1376: #  
                   1377: sub loadmap {
1.3     ! foxr     1378:     my ($cnum, $cdom, $uname, $udom,  $target_hash) = @_;
        !          1379: 
        !          1380: 
1.1       foxr     1381: 
                   1382:     # Clear the auxillary hashes and the cond array.
                   1383: 
                   1384: 
                   1385:     %randompick     = ();
                   1386:     %randompickseed = ();
                   1387:     %encurl         = ();
                   1388:     %hiddenurl      = ();
1.2       foxr     1389:     %parmhash       = ();
1.1       foxr     1390:     @cond           = ();
1.2       foxr     1391:     $retfrid        = '';
1.3     ! foxr     1392:     $username       = '';
        !          1393:     $userdomain     = '';
        !          1394:     %mapalias_cache = ();
        !          1395:     %cenv           = ();
1.1       foxr     1396: 
1.2       foxr     1397:     
1.1       foxr     1398:     # 
                   1399: 
                   1400:     $username   = $uname;
                   1401:     $userdomain = $udom;
                   1402: 
1.3     ! foxr     1403:     my $short_name = $cdom .'/' . $cnum;
        !          1404:     my $retfurl;
1.1       foxr     1405: 
                   1406:     try {
                   1407: 
                   1408: 	
                   1409: 	# Get the information we need about the course.
                   1410: 	# Return without filling in anything if we can't get any info:
                   1411: 	
1.3     ! foxr     1412: 	%cenv = &Apache::lonnet::coursedescription($short_name,
1.1       foxr     1413: 						     {'freshen_cache' => 1,
                   1414: 						      'user'          => $uname}); 
1.3     ! foxr     1415: 
1.1       foxr     1416: 	unless ($cenv{'url'}) { 
                   1417: 	    &Apache::lonnet::logthis("lonmap::loadmap failed: $cnum/$cdom - did not get url");
                   1418: 	    return; 
                   1419: 	}
1.3     ! foxr     1420: 	&Apache::lonnet::logthis("Course environment: \n" . Dumper(\%cenv));
        !          1421: 
        !          1422: 	$course_id = $cdom . '_' . $cnum; # Long course id.
1.1       foxr     1423: 
                   1424: 	# Load the version information into the hash
                   1425: 
                   1426: 	
                   1427: 	&process_versions(\%cenv, $target_hash);
                   1428: 	
                   1429: 	
                   1430: 	# Figure out the map filename's URI, and set up some starting points for the map.
                   1431: 	
1.2       foxr     1432: 	my $course_uri = $cenv{'url'};
                   1433: 	my $map_uri    = &Apache::lonnet::clutter($course_uri);
1.1       foxr     1434: 	
                   1435: 	$target_hash->{'src_0.0'}            = &versiontrack($map_uri, $target_hash); 
                   1436: 	$target_hash->{'title_0.0'}          = &Apache::lonnet::metadata($course_uri, 'title');
1.3     ! foxr     1437: 	if(!defined $target_hash->{'title_0.0'}) {
        !          1438: 	    $target_hash->{'title_0.0'} = '';
        !          1439: 	}
1.2       foxr     1440: 	$target_hash->{'ids_'.$map_uri} = '0.0';
1.3     ! foxr     1441: 	$target_hash->{'is_map_0.0'}         = '1';
        !          1442: 
        !          1443: 	# In some places we need a username a domain and the courseid...store that
        !          1444: 	# in the target hash in the context.xxxx keys:
        !          1445: 
        !          1446: 	$target_hash->{'context.username'} = $username;
        !          1447: 	$target_hash->{'context.userdom'}  = $userdomain;
        !          1448: 	$target_hash->{'context.courseid'} = $course_id;
        !          1449: 
        !          1450:         &read_map($course_uri, '0.0', $target_hash);
1.1       foxr     1451: 
                   1452: 	# 
                   1453: 
1.2       foxr     1454: 	if (defined($target_hash->{'map_start_'.$map_uri})) {
1.1       foxr     1455: 
1.3     ! foxr     1456: 	    &traceroute('0',$target_hash->{'map_start_'.$course_uri},'&', 0, 0, $target_hash);
        !          1457: 	    &accinit($course_uri, $short_name,  $target_hash);
1.2       foxr     1458: 	    &hiddenurls($target_hash);
                   1459: 	}
                   1460: 	my $errors = &get_mapalias_errors($target_hash);
                   1461: 	if ($errors ne "") {
                   1462: 	    throw Error::Simple("Map alias errors: ", $errors);
                   1463: 	}
                   1464: 
                   1465: 	# Put the versions in to src:
                   1466: 
                   1467: 	foreach my $key (keys(%$target_hash)) {
                   1468: 	    if ($key =~ /^src_/) {
                   1469: 		$target_hash->{$key} = 
                   1470: 		    &putinversion($target_hash->{$key}, $target_hash, $short_name);
                   1471: 	    } elsif ($key =~ /^(map_(?:start|finish|pc)_)(.*)/) {
                   1472: 		my ($type, $url) = ($1,$2);
                   1473: 		my $value = $target_hash->{$key};
                   1474: 		$target_hash->{$type.&putinversion($url, $target_hash, $short_name)}=$value;
                   1475: 	    }
1.1       foxr     1476: 	}
1.3     ! foxr     1477: 	#  Mark necrypted URLS.
        !          1478: 
        !          1479: 	foreach my $id (keys(%encurl)) {
        !          1480: 	    $target_hash->{'encrypted_'.$id}=1;
        !          1481: 	}
        !          1482: 
        !          1483: 	# Store first keys.
        !          1484: 
        !          1485: 	$target_hash->{'first_rid'}=$retfrid;
        !          1486: 	my ($mapid,$resid)=split(/\./,$retfrid);
        !          1487: 	$target_hash->{'first_mapurl'}=$target_hash->{'map_id_'.$mapid};
        !          1488: 	my $symb=&Apache::lonnet::encode_symb($target_hash->{'map_id_'.$mapid},
        !          1489: 					      $resid,
        !          1490: 					      $target_hash->{'src_'.$retfrid});
        !          1491: 	$retfurl=&add_get_param($target_hash->{'src_'.$retfrid},{ 'symb' => $symb });
        !          1492: 	if ($target_hash->{'encrypted_'.$retfrid}) {
        !          1493: 	    $retfurl=&Apache::lonenc::encrypted($retfurl,
        !          1494: 						(&Apache::lonnet::allowed('adv') ne 'F'));
        !          1495: 	}
        !          1496: 	$target_hash->{'first_url'}=$retfurl;	
1.1       foxr     1497: 
                   1498: 	# Merge in the child hashes in case the caller wants that information as well.
                   1499: 
                   1500: 
1.2       foxr     1501: 	&merge_hash($target_hash, 'randompick', \%randompick);
                   1502: 	&merge_hash($target_hash, 'randompickseed', \%randompick);
                   1503: 	&merge_hash($target_hash, 'randomorder', \%randomorder);
                   1504: 	&merge_hash($target_hash, 'encurl', \%encurl);
                   1505: 	&merge_hash($target_hash, 'hiddenurl', \%hiddenurl);
                   1506: 	&merge_hash($target_hash, 'param', \%parmhash);
                   1507: 	&merge_conditions($target_hash);
1.1       foxr     1508:     }
                   1509:     otherwise {
                   1510: 	my $e = shift;
                   1511: 	&Apache::lonnet::logthis("lonmap::loadmap failed: " . $e->stringify());
                   1512:     }
                   1513: 
                   1514: }
                   1515: 
                   1516: 
                   1517: 1;
                   1518: 
                   1519: #
                   1520: #  Module initialization code:
1.3     ! foxr     1521: #  TODO:  Fix the pod docs below.
1.1       foxr     1522: 
                   1523: 1;
                   1524: __END__
                   1525: 
                   1526: =head1 NAME
                   1527: 
                   1528: Apache::lonmap - Construct a hash that represents a course (Big Hash).
                   1529: 
                   1530: =head1 SYNOPSIS
                   1531: 
                   1532: &Apache::lonmap::loadmap($filepath, \%target_hash);
                   1533: 
                   1534: =head1 INTRODUCTION
                   1535: 
                   1536: This module reads a course filename into a hash reference.  It's up to the caller
                   1537: to to things like decide the has should be tied to some external file and handle the locking
                   1538: if this file should be shared amongst several Apache children.
                   1539: 
                   1540: =head1 SUBROUTINES
                   1541: 
                   1542: =over
                   1543: 
                   1544: =item loadmap($filepath, $targethash)
                   1545: 
                   1546: 
                   1547: Reads the map file into a target hash.
                   1548: 
                   1549: =over
                   1550: 
                   1551: =item $filepath - The path to the map file to read.
                   1552: 
                   1553: =item $targethash - A reference to hash into which the course is read.
                   1554: 
                   1555: =back
                   1556: 
                   1557: =item process_versions($cenv, $hash)
                   1558: 
                   1559: Makes hash entries for each version of a course described by a course environment
                   1560: returned from Apache::lonnet::coursedescription.
                   1561: 
                   1562: =over
                   1563: 
                   1564: =item $cenv - Reference to the environment hash returned by Apache::lonnet::coursedescription
                   1565: 
                   1566: =item $hash - Hash to be filled in with 'version_xxx' entries as per the big hash.
                   1567: 
                   1568: =back
                   1569: 
                   1570: =back
                   1571:  
                   1572: 
                   1573: =cut

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