# The LearningOnline Network with CAPA # # Page flip handler # # (Page Handler # # (TeX Content Handler # # 05/29/00,05/30 Gerd Kortemeyer) # 08/30,08/31,09/06,09/14,09/15,09/16,09/19,09/20,09/21,09/23, # 10/02 Gerd Kortemeyer) # # 10/03,10/05,10/06,10/07,10/09,10/10,10/11 Gerd Kortemeyer package Apache::lonpageflip; use strict; use Apache::Constants qw(:common :http REDIRECT); use Apache::lonnet(); use HTML::TokeParser; use GDBM_File; # ========================================================== Module Global Hash my %hash; sub addrid { my ($current,$new,$condid)=@_; unless ($condid) { $condid=0; } if (&Apache::lonnet::allowed('bre',$hash{'src_'.$new})) { if ($current) { $current.=','.$new; } else { $current=''.$new; } } return $current; } # ================================================================ Main Handler sub handler { my $r=shift; # ------------------------------------------- Set document type for header only if ($r->header_only) { $r->content_type('text/html'); $r->send_http_header; return OK; } my %cachehash=(); my $multichoice=0; my %multichoicehash=(); my $redirecturl=''; my $next=''; my @possibilities=(); if (($ENV{'form.postdata'})&&($ENV{'request.course.fn'})) { $ENV{'form.postdata'}=~/(\w+)\:(.*)/; my $direction=$1; my $currenturl=$2; $currenturl=~s/^http\:\/\///; $currenturl=~s/^[^\/]+//; # ------------------------------------------- Do we have any idea where we are? my $position; if ($position=Apache::lonnet::symbread($currenturl)) { # ------------------------------------------------------------------------- Yes my ($mapurl,$mapnum,$thisurl)=split(/\_\_\_/,$position); $cachehash{$thisurl}=$mapnum; # ============================================================ Tie the big hash if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db', &GDBM_READER,0640)) { my $rid=$hash{'map_pc_/res/'.$mapurl}.'.'.$mapnum; my $next=''; my $mincond=1; my $posnext=''; if ($direction eq 'forward') { # --------------------------------------------------------------------- Forward map { my $thiscond= &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}}); if ($thiscond>=$mincond) { if ($posnext) { $posnext.=','.$_.':'.$thiscond; } else { $posnext=$_.':'.$thiscond; } if ($thiscond>$mincond) { $mincond=$thiscond; } } } split(/\,/,$hash{'to_'.$rid}); map { my ($linkid,$condval)=split(/\:/,$_); if ($condval>=$mincond) { $next=&addrid($next,$hash{'goesto_'.$linkid}, $hash{'condid_'.$hash{'undercond_'.$linkid}}); } } split(/\,/,$posnext); } elsif ($direction eq 'back') { # ------------------------------------------------------------------- Backwards map { my $thiscond= &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}}); if ($thiscond>=$mincond) { if ($posnext) { $posnext.=','.$_.':'.$thiscond; } else { $posnext=$_.':'.$thiscond; } if ($thiscond>$mincond) { $mincond=$thiscond; } } } split(/\,/,$hash{'from_'.$rid}); map { my ($linkid,$condval)=split(/\:/,$_); if ($condval>=$mincond) { $next=&addrid($next,$hash{'comesfrom_'.$linkid}, $hash{'condid_'.$hash{'undercond_'.$linkid}}); } } split(/\,/,$posnext); } elsif ($direction eq 'up') { # -------------------------------------------------------------------------- Up } elsif ($direction eq 'down') { # ------------------------------------------------------------------------ Down } # ----------------------------------------------------- Check out possibilities if ($next) { @possibilities=split(/\,/,$next); if ($#possibilities==0) { # ---------------------------------------------- Only one possibility, redirect $redirecturl=$hash{'src_'.$next}; $cachehash{&Apache::lonnet::declutter($redirecturl)} =(split(/\./,$next))[1]; } else { # ------------------------ There are multiple possibilities for a next resource $multichoice=1; map { $multichoicehash{'src_'.$_}=$hash{'src_'.$_}; $multichoicehash{'title_'.$_}=$hash{'title_'.$_}; $cachehash {&Apache::lonnet::declutter( $multichoicehash {'src_'.$_} )} =(split(/\./,$_))[1]; } @possibilities; } } else { # -------------------------------------------------------------- No place to go $multichoice=-1; } # ----------------- The program must come past this point to untie the big hash untie(%hash); # --------------------------------------------------------- Store position info $cachehash{'last_direction'}=$direction; &Apache::lonnet::symblist($mapurl,%cachehash); # ============================================== Do not return before this line if ($redirecturl) { # ----------------------------------------------------- There is a URL to go to $r->content_type('text/html'); $r->header_out(Location => 'http://'.$ENV{'HTTP_HOST'}.$redirecturl); return REDIRECT; } else { # --------------------------------------------------------- There was a problem } } else { # ------------------------------------------------- Problem, could not tie hash $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing"; return HTTP_NOT_ACCEPTABLE; } } else { # ---------------------------------------- No, could not determine where we are } } else { # -------------------------- Class was not initialized or page fliped strangely $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course"; return HTTP_NOT_ACCEPTABLE; } } 1; __END__