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    1: # The LearningOnline Network with CAPA
    2: #
    3: # Page flip handler
    4: #
    5: # $Id: lonpageflip.pm,v 1.46 2003/10/29 22:09:17 www Exp $
    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: # (Page Handler
   30: #
   31: # (TeX Content Handler
   32: #
   33: # 05/29/00,05/30 Gerd Kortemeyer)
   34: # 08/30,08/31,09/06,09/14,09/15,09/16,09/19,09/20,09/21,09/23,
   35: # 10/02 Gerd Kortemeyer)
   36: #
   37: # 10/03,10/05,10/06,10/07,10/09,10/10,10/11,10/16,10/17,
   38: # 11/14,11/16,
   39: # 10/01/01,05/01,05/28,07/05 Gerd Kortemeyer
   40: 
   41: package Apache::lonpageflip;
   42: 
   43: use strict;
   44: use Apache::Constants qw(:common :http REDIRECT);
   45: use Apache::lonnet();
   46: use HTML::TokeParser;
   47: use GDBM_File;
   48: 
   49: # ========================================================== Module Global Hash
   50:   
   51: my %hash;
   52: 
   53: sub cleanup {
   54:     if (tied(%hash)){
   55: 	&Apache::lonnet::logthis('Cleanup pageflip: hash');
   56:         unless (untie(%hash)) {
   57: 	    &Apache::lonnet::logthis('Failed cleanup pageflip: hash');
   58:         }
   59:     }
   60: }
   61: 
   62: sub addrid {
   63:     my ($current,$new,$condid)=@_;
   64:     unless ($condid) { $condid=0; }
   65: 
   66: 	if ($current) {
   67: 	    $current.=','.$new;
   68:         } else {
   69:             $current=''.$new;
   70:         }
   71: 
   72:     return $current;
   73: }
   74: 
   75: sub fullmove {
   76:     my ($rid,$mapurl,$direction)=@_;
   77:     if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
   78:                         &GDBM_READER(),0640)) {
   79: 	($rid,$mapurl)=&move($rid,$mapurl,$direction);
   80:         untie(%hash);
   81:     }
   82:     return($rid,$mapurl);
   83: }
   84: 
   85: sub move {
   86:     my ($rid,$mapurl,$direction)=@_;
   87:     my $startoutrid=$rid;
   88: 
   89:     my $next='';
   90: 
   91:               my $mincond=1;
   92:               my $posnext='';
   93:               if ($direction eq 'forward') {
   94: # --------------------------------------------------------------------- Forward
   95:                   while ($hash{'type_'.$rid} eq 'finish') {
   96: 	             $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
   97:                   }
   98:                   map {
   99:                       my $thiscond=
  100:       &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
  101:                       if ($thiscond>=$mincond) {
  102: 		          if ($posnext) {
  103: 		             $posnext.=','.$_.':'.$thiscond;
  104:                           } else {
  105:                              $posnext=$_.':'.$thiscond;
  106: 		          }
  107:                           if ($thiscond>$mincond) { $mincond=$thiscond; }
  108: 	              }
  109:                   } split(/\,/,$hash{'to_'.$rid});
  110:                   map {
  111:                       my ($linkid,$condval)=split(/\:/,$_);
  112:                       if ($condval>=$mincond) {
  113: 		          $next=&addrid($next,$hash{'goesto_'.$linkid},
  114:                                 $hash{'condid_'.$hash{'undercond_'.$linkid}});
  115:                       }
  116:                   } split(/\,/,$posnext);
  117:                   if ($hash{'is_map_'.$next}) {
  118: # This jumps to the beginning of a new map (going down level)
  119:                       if (
  120:       $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
  121: 			  $mapurl=$hash{'src_'.$next};
  122: 			  $next=$hash{'map_start_'.$hash{'src_'.$next}};
  123:                      }
  124:                   } elsif 
  125:                     ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
  126: # This comes up from a map (coming up one level);
  127: 		      $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
  128:                   }
  129:               } elsif ($direction eq 'back') {
  130: # ------------------------------------------------------------------- Backwards
  131:                  while ($hash{'type_'.$rid} eq 'start') {
  132: 	             $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
  133: 		 }
  134:                   map {
  135:                       my $thiscond=
  136:       &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
  137:                       if ($thiscond>=$mincond) {
  138: 		          if ($posnext) {
  139: 		             $posnext.=','.$_.':'.$thiscond;
  140:                           } else {
  141:                              $posnext=$_.':'.$thiscond;
  142: 		          }
  143:                           if ($thiscond>$mincond) { $mincond=$thiscond; }
  144: 	              }
  145:                   } split(/\,/,$hash{'from_'.$rid});
  146:                   map {
  147:                       my ($linkid,$condval)=split(/\:/,$_);
  148:                       if ($condval>=$mincond) {
  149: 		          $next=&addrid($next,$hash{'comesfrom_'.$linkid},
  150:                                 $hash{'condid_'.$hash{'undercond_'.$linkid}});
  151:                       }
  152:                   } split(/\,/,$posnext);
  153:                   if ($hash{'is_map_'.$next}) {
  154: # This jumps to the end of a new map (going down one level)
  155:                       if (
  156:       $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
  157: 			  $mapurl=$hash{'src_'.$next};
  158: 			  $next=$hash{'map_finish_'.$hash{'src_'.$next}};
  159:                      }
  160:                   } elsif 
  161:                     ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
  162: # This comes back up from a map (going up one level);
  163: 		      $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
  164:                   }
  165: 	      }
  166:               return ($next,$mapurl);
  167: }
  168: 
  169: # ================================================================ Main Handler
  170: 
  171: sub handler {
  172:    my $r=shift;
  173: 
  174: # ------------------------------------------- Set document type for header only
  175: 
  176:   if ($r->header_only) {
  177:      $r->content_type('text/html');
  178:      $r->send_http_header;
  179:      return OK;
  180:   }
  181: 
  182:   my %cachehash=(); 
  183:   my $multichoice=0;
  184:   my %multichoicehash=();
  185:   my $redirecturl='';
  186:   my $next='';
  187:   my @possibilities=();
  188:    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
  189:   if (($ENV{'form.postdata'})&&($ENV{'request.course.fn'})) {
  190:       $ENV{'form.postdata'}=~/(\w+)\:(.*)/;
  191:       my $direction=$1;
  192:       my $currenturl=$2;
  193:       $currenturl=~s/\.\d+\.(\w+)$/\.$1/;
  194:       if ($direction eq 'return') {
  195: # -------------------------------------------------------- Return to last known
  196:          my $last;
  197:          if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
  198:                     &GDBM_READER(),0640)) {
  199: 	     $last=$hash{'last_known'};
  200:              untie(%hash);
  201:          }
  202:          my $newloc;
  203:          if (($last) && (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
  204:                         &GDBM_READER(),0640))) {
  205:             my ($murl,$fn)=&Apache::lonnet::decode_symb($last);
  206:             my $id;
  207:             ($murl,$id,$fn)=&Apache::lonnet::decode_symb(&Apache::lonnet::symbread($fn));
  208: 	    $newloc=$hash{'src_'.
  209:                 $hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id};
  210:             unless ($newloc) { $newloc='/adm/noidea.html'; }
  211:             untie %hash;
  212:          } else {
  213: 	    $newloc='/adm/noidea.html';
  214:          }  
  215: 	 $r->content_type('text/html');
  216:          $r->header_out(Location => 
  217: 			'http://'.$ENV{'HTTP_HOST'}.$newloc);
  218:                                
  219:          return REDIRECT;
  220:       }
  221:       $currenturl=~s/^http\:\/\///;
  222:       $currenturl=~s/^[^\/]+//;
  223: #
  224: # Is the current URL on the map? If not, start with last known URL
  225: #
  226:       unless (&Apache::lonnet::is_on_map($currenturl)) {
  227: 	 my $last;
  228:          if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
  229:                     &GDBM_READER(),0640)) {
  230: 	     $last=$hash{'last_known'};
  231:              untie(%hash);
  232:          }
  233:          if ($last) {
  234: 	     $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[1]);
  235: 	 } else {
  236: 	     $r->content_type('text/html');
  237:              $r->header_out(Location => 
  238:                                'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
  239:              return REDIRECT;
  240:          }
  241:       }
  242: # ------------------------------------------- Do we have any idea where we are?
  243:       my $position;
  244:       if ($position=Apache::lonnet::symbread($currenturl)) {
  245: # ------------------------------------------------------------------------- Yes
  246: 	  my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
  247:           $cachehash{$startoutmap}{$thisurl}=$mapnum;
  248:           $cachehash{$startoutmap}{'last_known'}=
  249:                                        &Apache::lonnet::declutter($currenturl);
  250: 
  251: # ============================================================ Tie the big hash
  252:           if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
  253:                         &GDBM_READER(),0640)) {
  254:               my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
  255:                       '.'.$mapnum;
  256: 
  257: # ------------------------------------------------- Move forward, backward, etc
  258:               my $endupmap;
  259:               ($next,$endupmap)=&move($rid,$startoutmap,$direction);
  260: # -------------------------------------- Do we have one and only one empty URL?
  261:               my $safecount=0;
  262:               while (($next) && ($next!~/\,/) && 
  263:                      ((!$hash{'src_'.$next}) || ($hash{'randomout_'.$next}))
  264:                      && ($safecount<10000)) {
  265:                   ($next,$endupmap)=&move($next,$endupmap,$direction);
  266:                   $safecount++;
  267:               }
  268: # We are now at at least one non-empty URL
  269: # ----------------------------------------------------- Check out possibilities
  270:               if ($next) {
  271:                   @possibilities=split(/\,/,$next);
  272:                   if ($#possibilities==0) {
  273: # ---------------------------------------------- Only one possibility, redirect
  274: 	              $redirecturl=$hash{'src_'.$next};
  275:                       $cachehash{$endupmap}
  276:                                 {&Apache::lonnet::declutter($redirecturl)}
  277: 		                                 =(split(/\./,$next))[1];
  278:                   } else {
  279: # ------------------------ There are multiple possibilities for a next resource
  280:                       $multichoice=1;
  281:                       map {
  282: 			  $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
  283:                           $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
  284:                           $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
  285:                           (my $first, my $second) = $_ =~ /(\d+).(\d+)/;
  286:                           my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$_});
  287:                           $multichoicehash{'symb_'.$_} = 
  288:                               Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
  289:                                                         $second.'___'.$symbSrc);
  290:                                                          
  291:                           my ($choicemap,$choiceres)=split(/\./,$_);
  292:                           $cachehash
  293: 			 {&Apache::lonnet::declutter($hash{'src_'.$choicemap})}
  294:                          {&Apache::lonnet::declutter(
  295: 						      $multichoicehash
  296:                                                          {'src_'.$_}
  297:                                                        )}
  298: 		                                 =$choiceres;
  299:                       } @possibilities;
  300:                   }
  301: 	      } else {
  302: # -------------------------------------------------------------- No place to go
  303:                   $multichoice=-1;
  304:               }
  305: # ----------------- The program must come past this point to untie the big hash
  306: 	      untie(%hash);
  307: # --------------------------------------------------------- Store position info
  308:               $cachehash{$startoutmap}{'last_direction'}=$direction;
  309:               foreach my $thismap (keys %cachehash) {
  310:                  &Apache::lonnet::symblist($thismap,%{$cachehash{$thismap}});
  311: 	      }
  312: # ============================================== Do not return before this line
  313:               if ($redirecturl) {
  314: # ----------------------------------------------------- There is a URL to go to
  315: 		  if ($direction eq 'forward') {
  316:                      &Apache::lonnet::linklog($currenturl,$redirecturl);
  317: 		  }
  318: 		  if ($direction eq 'back') {
  319:                      &Apache::lonnet::linklog($redirecturl,$currenturl);
  320: 		  }
  321: # ------------------------------------------------- Check for critical messages
  322: 		  if ((time-$ENV{'user.criticalcheck.time'})>300) {
  323:                      my @what=&Apache::lonnet::dump
  324:                                   ('critical',$ENV{'user.domain'},
  325:                                               $ENV{'user.name'});
  326:                      if ($what[0]) {
  327: 	                if (($what[0] ne 'con_lost') && 
  328:                             ($what[0]!~/^error\:/)) {
  329: 	                   $redirecturl='/adm/email?critical=display';
  330:                         }
  331:                      }
  332:                      &Apache::lonnet::appenv('user.criticalcheck.time'=>time);
  333: 		  }
  334: 
  335: 		  $r->content_type('text/html');
  336:                   $r->header_out(Location => 
  337:                                 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
  338:                   return REDIRECT;
  339: 	      } else {
  340: # --------------------------------------------------------- There was a problem
  341:                   $r->content_type('text/html');
  342:                   $r->send_http_header;
  343:                   if ($#possibilities>0) {
  344: 		      my $bodytag=
  345:                              &Apache::loncommon::bodytag('Multiple Resources');
  346:                      $r->print(<<ENDSTART);
  347: <head><title>Choose Next Location</title></head>
  348: $bodytag
  349: <h3>There are several possibilities of where to go next</h3>
  350: <p>
  351: Please click on the the resource you intend to access:
  352: <p>
  353: <table border=2>
  354: <tr><th>Title</th><th>Type</th></tr>
  355: ENDSTART
  356:                      foreach (@possibilities) {
  357:                         $r->print(
  358:                               '<tr><td><a href="'.
  359:                               $multichoicehash{'src_'.$_}.'?symb=' .
  360:                                   Apache::lonnet::escape($multichoicehash{'symb_'.$_}).'">'.
  361:                               $multichoicehash{'title_'.$_}.
  362:                               '</a></td><td>'.$multichoicehash{'type_'.$_}.
  363: 			      '</td></tr>');
  364:                      }
  365:                      $r->print('</table></body></html>');
  366: 		     return OK;
  367:                   } else {
  368: 		      my $bodytag=&Apache::loncommon::bodytag('No Resource');
  369:                      $r->print(<<ENDNONE);
  370: <head><title>No Resource</title></head>
  371: $bodytag
  372: <h3>Next resource could not be identified.</h3>
  373: <p>You probably are at the <b>beginning</b> or the <b>end</b> of the 
  374: course.</p>
  375: <ul>
  376: <li><a href="/adm/flip?postdata=return:">Go Back</a></li>
  377: <li><a href="/adm/navmaps">Navigate Course Content</a></li>
  378: </ul>
  379: </body>
  380: </html>
  381: ENDNONE
  382:                      return OK;
  383: 	         }
  384: 	     }
  385: 	  } else {
  386: # ------------------------------------------------- Problem, could not tie hash
  387:               $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
  388:               return HTTP_NOT_ACCEPTABLE; 
  389:           }
  390:       } else {
  391: # ---------------------------------------- No, could not determine where we are
  392: 	  if ( &Apache::lonnet::mod_perl_version() == 2 ) {
  393: 	      &Apache::lonnet::cleanenv();
  394: 	  }
  395: 	  $r->internal_redirect('/adm/ambiguous');
  396:       }
  397:   } else {
  398: # -------------------------- Class was not initialized or page fliped strangely
  399:       $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
  400:       return HTTP_NOT_ACCEPTABLE; 
  401:   } 
  402: }
  403: 
  404: 1;
  405: __END__
  406: 
  407: 
  408: 
  409: 
  410: 
  411: 
  412: