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lonpageflip.pm
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Sat Mar 14 21:56:13 2015 UTC (9 years, 5 months ago) by
raeburn
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- When LON-CAPA navigation arrows are used to move between resources check
if > 10 minutes since last check for content change.
If course changed after "Big Hash" last tied for current user's session,
course is re-initialized or Switch Server link is displayed, as needed.
# The LearningOnline Network with CAPA
#
# Page flip handler
#
# $Id: lonpageflip.pm,v 1.87 2015/03/14 21:56:13 raeburn Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
package Apache::lonpageflip;
use strict;
use LONCAPA;
use Apache::Constants qw(:common :http REDIRECT);
use Apache::lonnet;
use Apache::loncommon();
use Apache::lonuserstate;
use Apache::lonlocal;
use HTML::TokeParser;
use GDBM_File;
# ========================================================== Module Global Hash
my %hash;
sub cleanup {
if (tied(%hash)){
&Apache::lonnet::logthis('Cleanup pageflip: hash');
unless (untie(%hash)) {
&Apache::lonnet::logthis('Failed cleanup pageflip: hash');
}
}
return OK;
}
sub addrid {
my ($current,$new,$condid)=@_;
unless ($condid) { $condid=0; }
if ($current) {
$current.=','.$new;
} else {
$current=''.$new;
}
return $current;
}
sub fullmove {
my ($rid,$mapurl,$direction)=@_;
if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
&GDBM_READER(),0640)) {
($rid,$mapurl)=&move($rid,$mapurl,$direction);
untie(%hash);
}
return($rid,$mapurl);
}
sub hash_src {
my ($id)=@_;
my ($mapid,$resid)=split(/\./,$id);
my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
$resid,$hash{'src_'.$id});
if ($hash{'encrypted_'.$id}) {
return (&Apache::lonenc::encrypted($hash{'src_'.$id}),
&Apache::lonenc::encrypted($symb));
}
return ($hash{'src_'.$id},$symb);
}
sub move {
my ($next,$endupmap,$direction) = @_;
my $safecount=0;
my $allowed=0;
do {
($next,$endupmap)=&get_next_possible_move($next,$endupmap,$direction);
my $url = $hash{'src_'.$next};
my ($mapid,$resid)=split(/\./,$next);
my $symb = &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
$resid,$url);
if ($url eq '' || $symb eq '') {
$allowed = 0;
} else {
my $priv = &Apache::lonnet::allowed('bre',$url,$symb);
$allowed = (($priv eq 'F') || ($priv eq '2'));
}
$safecount++;
} while ( ($next)
&& ($next!~/\,/)
&& (
(!$hash{'src_'.$next})
|| (
(!$env{'request.role.adv'})
&& $hash{'randomout_'.$next}
)
|| (!$allowed)
)
&& ($safecount<10000));
return ($next,$endupmap);
}
sub get_next_possible_move {
my ($rid,$mapurl,$direction)=@_;
my $startoutrid=$rid;
my $next='';
my $mincond=1;
my $posnext='';
if ($direction eq 'forward') {
# --------------------------------------------------------------------- Forward
while ($hash{'type_'.$rid} eq 'finish') {
$rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
}
foreach my $id (split(/\,/,$hash{'to_'.$rid})) {
my $condition= $hash{'conditions_'.$hash{'goesto_'.$id}};
my $rescond = &Apache::lonnet::docondval($condition);
my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
if ($thiscond>=$mincond) {
if ($posnext) {
$posnext.=','.$id.':'.$thiscond;
} else {
$posnext=$id.':'.$thiscond;
}
if ($thiscond>$mincond) { $mincond=$thiscond; }
}
}
foreach my $id (split(/\,/,$posnext)) {
my ($linkid,$condval)=split(/\:/,$id);
if ($condval>=$mincond) {
$next=&addrid($next,$hash{'goesto_'.$linkid},
$hash{'condid_'.$hash{'undercond_'.$linkid}});
}
}
if ($hash{'is_map_'.$next}) {
# This jumps to the beginning of a new map (going down level)
if (
$hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
$mapurl=$hash{'src_'.$next};
$next=$hash{'map_start_'.$hash{'src_'.$next}};
} elsif (
# This jumps back up from an empty sequence, to a page up one level
$hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
$mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
}
} elsif
((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
# This comes up from a map (coming up one level);
$mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
}
} elsif ($direction eq 'back') {
# ------------------------------------------------------------------- Backwards
while ($hash{'type_'.$rid} eq 'start') {
$rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
}
foreach my $id (split(/\,/,$hash{'from_'.$rid})) {
my $condition= $hash{'conditions_'.$hash{'comesfrom_'.$id}};
my $rescond = &Apache::lonnet::docondval($condition);
my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
if ($thiscond>=$mincond) {
if ($posnext) {
$posnext.=','.$id.':'.$thiscond;
} else {
$posnext=$id.':'.$thiscond;
}
if ($thiscond>$mincond) { $mincond=$thiscond; }
}
}
foreach my $id (split(/\,/,$posnext)) {
my ($linkid,$condval)=split(/\:/,$id);
if ($condval>=$mincond) {
$next=&addrid($next,$hash{'comesfrom_'.$linkid},
$hash{'condid_'.$hash{'undercond_'.$linkid}});
}
}
if ($hash{'is_map_'.$next}) {
# This jumps to the end of a new map (going down one level)
if (
$hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
$mapurl=$hash{'src_'.$next};
$next=$hash{'map_finish_'.$hash{'src_'.$next}};
} elsif (
$hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
# This jumps back up from an empty sequence, to a page up one level
$mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
}
} elsif
((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
# This comes back up from a map (going up one level);
$mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
}
}
return ($next,$mapurl);
}
sub first_accessible_resource {
my $furl;
if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
&GDBM_READER(),0640)) {
$furl=$hash{'first_url'};
my %args;
my ($url,$args) = split(/\?/,$furl);
foreach my $pair (split(/\&/,$args)) {
my ($name,$value) = split(/=/,$pair);
$args{&unescape($name)} = &unescape($value);
}
if (!&Apache::lonnet::allowed('bre',$url,$args{'symb'})) {
# Wow, we cannot see this ... move forward to the next one that we can see
my ($newrid,$newmap)=&move($hash{'first_rid'},$hash{'first_mapurl'},'forward');
# Build the new URL
my ($newmapid,$newresid)=split(/\./,$newrid);
my $symb=&Apache::lonnet::encode_symb($newmap,$newresid,$hash{'src_'.$newrid});
$furl=&add_get_param($hash{'src_'.$newrid},{ 'symb' => $symb });
if ($hash{'encrypted_'.$newrid}) {
$furl=&Apache::lonenc::encrypted($furl);
}
}
untie(%hash);
return $furl;
} else {
return '/adm/navmaps';
}
}
# ================================================================ Main Handler
sub handler {
my $r=shift;
# ------------------------------------------- Set document type for header only
if ($r->header_only) {
&Apache::loncommon::content_type($r,'text/html');
$r->send_http_header;
return OK;
}
my %cachehash=();
my $multichoice=0;
my %multichoicehash=();
my ($redirecturl,$redirectsymb);
my $next='';
my @possibilities=();
&Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
if (($env{'form.postdata'})&&($env{'request.course.fn'})) {
$env{'form.postdata'}=~/(\w+)\:(.*)/;
if ($env{'request.course.id'}) {
# Check if course needs to be re-initialized
my $loncaparev = $r->dir_config('lonVersion');
my ($result,@reinit) = &Apache::loncommon::needs_coursereinit($loncaparev);
if ($result eq 'switch') {
&Apache::loncommon::content_type($r,'text/html');
$r->send_http_header;
$r->print(&Apache::loncommon::check_release_result(@reinit));
return OK;
} elsif ($result eq 'update') {
my $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
my $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
my ($furl,$ferr) = &Apache::lonuserstate::readmap("$cdom/$cnum");
if ($ferr) {
my $requrl = $r->uri;
$env{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
$env{'user.reinit'} = 1;
return HTTP_NOT_ACCEPTABLE;
}
}
}
my $direction=$1;
my $currenturl=$2;
if ($currenturl=~m|^/enc/|) {
$currenturl=&Apache::lonenc::unencrypted($currenturl);
}
$currenturl=~s/\.\d+\.(\w+)$/\.$1/;
if ($direction eq 'firstres') {
my $furl=&first_accessible_resource();
&Apache::loncommon::content_type($r,'text/html');
$r->header_out(Location =>
&Apache::lonnet::absolute_url().$furl);
return REDIRECT;
}
if ($direction eq 'return') {
# -------------------------------------------------------- Return to last known
my $last;
if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
&GDBM_READER(),0640)) {
$last=$hash{'last_known'};
untie(%hash);
}
my $newloc;
if (($last) && (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
&GDBM_READER(),0640))) {
my ($murl,$id,$fn)=&Apache::lonnet::decode_symb($last);
$id=$hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id;
$newloc=$hash{'src_'.$id};
if ($newloc) {
if ($hash{'encrypted_'.$id}) { $newloc=&Apache::lonenc::encrypted($newloc); }
} else {
$newloc='/adm/navmaps';
}
untie %hash;
} else {
$newloc='/adm/navmaps';
}
&Apache::loncommon::content_type($r,'text/html');
$r->header_out(Location =>
&Apache::lonnet::absolute_url().$newloc);
return REDIRECT;
}
$currenturl=~s/^https?\:\/\///;
$currenturl=~s/^[^\/]+//;
#
# Is the current URL on the map? If not, start with last known URL
#
unless (&Apache::lonnet::is_on_map($currenturl)) {
my $last;
if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
&GDBM_READER(),0640)) {
$last=$hash{'last_known'};
untie(%hash);
}
if ($last) {
$currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[2]);
} else {
&Apache::loncommon::content_type($r,'text/html');
$r->header_out(Location =>
&Apache::lonnet::absolute_url().
'/adm/noidea.html');
return REDIRECT;
}
}
# ------------------------------------------- Do we have any idea where we are?
my $position;
if ($position=Apache::lonnet::symbread($currenturl)) {
# ------------------------------------------------------------------------- Yes
my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
$cachehash{$startoutmap}{$thisurl}=[$thisurl,$mapnum];
$cachehash{$startoutmap}{'last_known'}=
[&Apache::lonnet::declutter($currenturl),$mapnum];
# ============================================================ Tie the big hash
if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
&GDBM_READER(),0640)) {
my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
'.'.$mapnum;
# ------------------------------------------------- Move forward, backward, etc
my $endupmap;
($next,$endupmap)=&move($rid,$startoutmap,$direction);
# -------------------------------------- Do we have one and only one empty URL?
# We are now at at least one non-empty URL
# ----------------------------------------------------- Check out possibilities
if ($next) {
@possibilities=split(/\,/,$next);
if ($#possibilities==0) {
# ---------------------------------------------- Only one possibility, redirect
($redirecturl,$redirectsymb)=&hash_src($next);
$cachehash{$endupmap}{$redirecturl}=
[$redirecturl,(split(/\./,$next))[1]];
} else {
# ------------------------ There are multiple possibilities for a next resource
$multichoice=1;
foreach my $id (@possibilities) {
$multichoicehash{'src_'.$id}=$hash{'src_'.$id};
$multichoicehash{'title_'.$id}=$hash{'title_'.$id};
$multichoicehash{'type_'.$id}=$hash{'type_'.$id};
(my $first, my $second) = $id =~ /(\d+).(\d+)/;
my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$id});
$multichoicehash{'symb_'.$id} =
Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
$second.'___'.$symbSrc);
my ($choicemap,$choiceres)=split(/\./,$id);
my $map=&Apache::lonnet::declutter($hash{'src_'.$choicemap});
my $url=$multichoicehash{'src_'.$id};
$cachehash{$map}{$url}=[$url,$choiceres];
}
}
} else {
# -------------------------------------------------------------- No place to go
$multichoice=-1;
}
# ----------------- The program must come past this point to untie the big hash
untie(%hash);
# --------------------------------------------------------- Store position info
$cachehash{$startoutmap}{'last_direction'}=[$direction,'notasymb'];
foreach my $thismap (keys(%cachehash)) {
my $mapnum=$cachehash{$thismap}->{'mapnum'};
delete($cachehash{$thismap}->{'mapnum'});
&Apache::lonnet::symblist($thismap,
%{$cachehash{$thismap}});
}
# ============================================== Do not return before this line
if ($redirecturl) {
# ----------------------------------------------------- There is a URL to go to
if ($direction eq 'forward') {
&Apache::lonnet::linklog($currenturl,$redirecturl);
}
if ($direction eq 'back') {
&Apache::lonnet::linklog($redirecturl,$currenturl);
}
# ------------------------------------- Check for and display critical messages
my ($redirect, $url) = &Apache::loncommon::critical_redirect(300);
unless ($redirect) {
$url=&Apache::lonnet::absolute_url().$redirecturl;
$url = &add_get_param($url, { 'symb' => $redirectsymb});
}
&Apache::loncommon::content_type($r,'text/html');
$r->header_out(Location => $url);
return REDIRECT;
} else {
# --------------------------------------------------------- There was a problem
&Apache::loncommon::content_type($r,'text/html');
$r->send_http_header;
my %lt=&Apache::lonlocal::texthash('title' => 'End of Sequence',
'explain' =>
'You have reached the end of the sequence of materials.',
'back' => 'Go Back',
'nav' => 'Course Contents',
'wherenext' =>
'There are several possibilities of where to go next',
'pick' =>
'Please click on the the resource you intend to access',
'titleheader' => 'Title',
'type' => 'Type');
if (&Apache::loncommon::course_type() eq 'Community') {
$lt{'nav'} = &mt('Community Contents');
}
if ($#possibilities>0) {
my $start_page=
&Apache::loncommon::start_page('Multiple Resources');
$r->print(<<ENDSTART);
$start_page
<h3>$lt{'wherenext'}</h3>
<p>
$lt{'pick'}:
<p>
<table border="2">
<tr><th>$lt{'titleheader'}</th><th>$lt{'type'}</th></tr>
ENDSTART
foreach my $id (@possibilities) {
$r->print(
'<tr><td><a href="'.
&add_get_param($multichoicehash{'src_'.$id},
{'symb' =>
$multichoicehash{'symb_'.$id},
}).'">'.
$multichoicehash{'title_'.$id}.
'</a></td><td>'.$multichoicehash{'type_'.$id}.
'</td></tr>');
}
$r->print('</table>');
} else {
$r->print(
&Apache::loncommon::start_page('No Resource')
.'<h2>'.$lt{'title'}.'</h2>'
.'<p>'.$lt{'explain'}.'</p>');
}
$r->print(
&Apache::lonhtmlcommon::actionbox(
['<a href="/adm/flip?postdata=return:">'.$lt{'back'}.'</a></li>',
'<a href="/adm/navmaps">'.$lt{'nav'}.'</a></li>'
])
.&Apache::loncommon::end_page());
return OK;
}
} 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
$r->internal_redirect('/adm/ambiguous');
return OK;
}
} 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__
=pod
=head1 NAME
Apache::lonpageflip
=head1 SYNOPSIS
Deals with forward, backward, and other page flips.
This is part of the LearningOnline Network with CAPA project
described at http://www.lon-capa.org.
=head1 OVERVIEW
(empty)
=head1 SUBROUTINES
=over cleanup()
=item addrid()
=item fullmove()
=item hash_src()
=item move()
=item get_next_possible_move()
=item first_accessible_resource()
=item handler()
=back
=cut
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