--- loncom/interface/loncommon.pm	2014/06/24 00:31:38	1.1075.2.80
+++ loncom/interface/loncommon.pm	2015/04/06 19:06:45	1.1075.2.91
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # a pile of common routines
 #
-# $Id: loncommon.pm,v 1.1075.2.80 2014/06/24 00:31:38 raeburn Exp $
+# $Id: loncommon.pm,v 1.1075.2.91 2015/04/06 19:06:45 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -3677,7 +3677,7 @@ sub user_lang {
 =over 4
 
 =item * &get_previous_attempt($symb, $username, $domain, $course,
-    $getattempt, $regexp, $gradesub)
+    $getattempt, $regexp, $gradesub, $usec, $identifier)
 
 Return string with previous attempt on problem. Arguments:
 
@@ -3699,6 +3699,11 @@ Return string with previous attempt on p
 
 =item * $gradesub: routine that processes the string if it matches $regexp
 
+=item * $usec: section of the desired student
+
+=item * $identifier: counter for student (multiple students one problem) or
+    problem (one student; whole sequence).
+
 =back
 
 The output string is a table containing all desired attempts, if any.
@@ -3706,7 +3711,7 @@ The output string is a table containing
 =cut
 
 sub get_previous_attempt {
-  my ($symb,$username,$domain,$course,$getattempt,$regexp,$gradesub)=@_;
+  my ($symb,$username,$domain,$course,$getattempt,$regexp,$gradesub,$usec,$identifier)=@_;
   my $prevattempts='';
   no strict 'refs';
   if ($symb) {
@@ -3716,13 +3721,18 @@ sub get_previous_attempt {
       my %lasthash=();
       my $version;
       for ($version=1;$version<=$returnhash{'version'};$version++) {
-        foreach my $key (sort(split(/\:/,$returnhash{$version.':keys'}))) {
-	  $lasthash{$key}=$returnhash{$version.':'.$key};
+        foreach my $key (reverse(sort(split(/\:/,$returnhash{$version.':keys'})))) {
+            if ($key =~ /\.rawrndseed$/) {
+                my ($id) = ($key =~ /^(.+)\.rawrndseed$/);
+                $lasthash{$id.'.rndseed'} = $returnhash{$version.':'.$key};
+            } else {
+                $lasthash{$key}=$returnhash{$version.':'.$key};
+            }
         }
       }
       $prevattempts=&start_data_table().&start_data_table_header_row();
       $prevattempts.='<th>'.&mt('History').'</th>';
-      my (%typeparts,%lasthidden);
+      my (%typeparts,%lasthidden,%regraded,%hidestatus);
       my $showsurv=&Apache::lonnet::allowed('vas',$env{'request.course.id'});
       foreach my $key (sort(keys(%lasthash))) {
 	my ($ign,@parts) = split(/\./,$key);
@@ -3739,6 +3749,18 @@ sub get_previous_attempt {
                       $lasthidden{$ign.'.'.$id} = 1;
                   }
               }
+              if ($identifier ne '') {
+                  my $id = join(',',@parts);
+                  if (&Apache::lonnet::EXT("resource.$id.problemstatus",$symb,
+                                               $domain,$username,$usec,undef,$course) =~ /^no/) {
+                      $hidestatus{$ign.'.'.$id} = 1;
+                  }
+              }
+          } elsif ($data eq 'regrader') {
+              if (($identifier ne '') && (@parts)) {
+                  my $id = join(',',@parts);
+                  $regraded{$ign.'.'.$id} = 1;
+              }
           } 
 	} else {
 	  if ($#parts == 0) {
@@ -3750,17 +3772,60 @@ sub get_previous_attempt {
       }
       $prevattempts.=&end_data_table_header_row();
       if ($getattempt eq '') {
+        my (%solved,%resets,%probstatus);
+        if (($identifier ne '') && (keys(%regraded) > 0)) {
+            for ($version=1;$version<=$returnhash{'version'};$version++) {
+                foreach my $id (keys(%regraded)) {
+                    if (($returnhash{$version.':'.$id.'.regrader'}) &&
+                        ($returnhash{$version.':'.$id.'.tries'} eq '') &&
+                        ($returnhash{$version.':'.$id.'.award'} eq '')) {
+                        push(@{$resets{$id}},$version);
+                    }
+                }
+            }
+        }
 	for ($version=1;$version<=$returnhash{'version'};$version++) {
-            my @hidden;
+            my (@hidden,@unsolved);
             if (%typeparts) {
                 foreach my $id (keys(%typeparts)) {
-                    if (($returnhash{$version.':'.$id.'.type'} eq 'anonsurvey') || ($returnhash{$version.':'.$id.'.type'} eq 'anonsurveycred')) {
+                    if (($returnhash{$version.':'.$id.'.type'} eq 'anonsurvey') ||
+                        ($returnhash{$version.':'.$id.'.type'} eq 'anonsurveycred')) {
                         push(@hidden,$id);
+                    } elsif ($identifier ne '') {
+                        unless (($returnhash{$version.':'.$id.'.type'} eq 'survey') ||
+                                ($returnhash{$version.':'.$id.'.type'} eq 'surveycred') ||
+                                ($hidestatus{$id})) {
+                            next if ((ref($resets{$id}) eq 'ARRAY') && grep(/^\Q$version\E$/,@{$resets{$id}}));
+                            if ($returnhash{$version.':'.$id.'.solved'} eq 'correct_by_student') {
+                                push(@{$solved{$id}},$version);
+                            } elsif (($returnhash{$version.':'.$id.'.solved'} ne '') &&
+                                     (ref($solved{$id}) eq 'ARRAY')) {
+                                my $skip;
+                                if (ref($resets{$id}) eq 'ARRAY') {
+                                    foreach my $reset (@{$resets{$id}}) {
+                                        if ($reset > $solved{$id}[-1]) {
+                                            $skip=1;
+                                            last;
+                                        }
+                                    }
+                                }
+                                unless ($skip) {
+                                    my ($ign,$partslist) = split(/\./,$id,2);
+                                    push(@unsolved,$partslist);
+                                }
+                            }
+                        }
                     }
                 }
             }
             $prevattempts.=&start_data_table_row().
-                           '<td>'.&mt('Transaction [_1]',$version).'</td>';
+                           '<td>'.&mt('Transaction [_1]',$version);
+            if (@unsolved) {
+                $prevattempts .= '<span class="LC_nobreak"><label>'.
+                                 '<input type="checkbox" name="HIDE'.$identifier.'" value="'.$version.':'.join('_',@unsolved).'" />'.
+                                 &mt('Hide').'</label></span>';
+            }
+            $prevattempts .= '</td>';
             if (@hidden) {
                 foreach my $key (sort(keys(%lasthash))) {
                     next if ($key =~ /\.foilorder$/);
@@ -3782,9 +3847,15 @@ sub get_previous_attempt {
                         }
                     } else {
                         if ($key =~ /\./) {
-                            my $value = &format_previous_attempt_value($key,
-                                              $returnhash{$version.':'.$key});
-                            $prevattempts.='<td>'.$value.'&nbsp;</td>';
+                            my $value = $returnhash{$version.':'.$key};
+                            if ($key =~ /\.rndseed$/) {
+                                my ($id) = ($key =~ /^(.+)\.rndseed$/);
+                                if (exists($returnhash{$version.':'.$id.'.rawrndseed'})) {
+                                    $value = $returnhash{$version.':'.$id.'.rawrndseed'};
+                                }
+                            }
+                            $prevattempts.='<td>'.&format_previous_attempt_value($key,$value).
+                                           '&nbsp;</td>';
                         } else {
                             $prevattempts.='<td>&nbsp;</td>';
                         }
@@ -3793,9 +3864,15 @@ sub get_previous_attempt {
             } else {
 	        foreach my $key (sort(keys(%lasthash))) {
                     next if ($key =~ /\.foilorder$/);
-		    my $value = &format_previous_attempt_value($key,
-			            $returnhash{$version.':'.$key});
-		    $prevattempts.='<td>'.$value.'&nbsp;</td>';
+                    my $value = $returnhash{$version.':'.$key};
+                    if ($key =~ /\.rndseed$/) {
+                        my ($id) = ($key =~ /^(.+)\.rndseed$/);
+                        if (exists($returnhash{$version.':'.$id.'.rawrndseed'})) {
+                            $value = $returnhash{$version.':'.$id.'.rawrndseed'};
+                        }
+                    }
+                    $prevattempts.='<td>'.&format_previous_attempt_value($key,$value).
+                                   '&nbsp;</td>';
 	        }
             }
 	    $prevattempts.=&end_data_table_row();
@@ -4695,23 +4772,28 @@ sub get_domainconf {
             if (keys(%{$domconfig{'login'}})) {
                 foreach my $key (keys(%{$domconfig{'login'}})) {
                     if (ref($domconfig{'login'}{$key}) eq 'HASH') {
-                        if ($key eq 'loginvia') {
-                            if (ref($domconfig{'login'}{'loginvia'}) eq 'HASH') {
-                                foreach my $hostname (keys(%{$domconfig{'login'}{'loginvia'}})) {
-                                    if (ref($domconfig{'login'}{'loginvia'}{$hostname}) eq 'HASH') {
-                                        if ($domconfig{'login'}{'loginvia'}{$hostname}{'server'}) {
-                                            my $server = $domconfig{'login'}{'loginvia'}{$hostname}{'server'};
-                                            $designhash{$udom.'.login.loginvia'} = $server;
-                                            if ($domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'} eq 'custom') {
-
-                                                $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'custompath'};
-                                            } else {
-                                                $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'};
+                        if (($key eq 'loginvia') || ($key eq 'headtag')) {
+                            if (ref($domconfig{'login'}{$key}) eq 'HASH') {
+                                foreach my $hostname (keys(%{$domconfig{'login'}{$key}})) {
+                                    if (ref($domconfig{'login'}{$key}{$hostname}) eq 'HASH') {
+                                        if ($key eq 'loginvia') {
+                                            if ($domconfig{'login'}{'loginvia'}{$hostname}{'server'}) {
+                                                my $server = $domconfig{'login'}{'loginvia'}{$hostname}{'server'};
+                                                $designhash{$udom.'.login.loginvia'} = $server;
+                                                if ($domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'} eq 'custom') {
+                                                    $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'custompath'};
+                                                } else {
+                                                    $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'};
+                                                }
                                             }
-                                            if ($domconfig{'login'}{'loginvia'}{$hostname}{'exempt'}) {
-                                                $designhash{$udom.'.login.loginvia_exempt_'.$hostname} = $domconfig{'login'}{'loginvia'}{$hostname}{'exempt'};
+                                        } elsif ($key eq 'headtag') {
+                                            if ($domconfig{'login'}{'headtag'}{$hostname}{'url'}) {
+                                                $designhash{$udom.'.login.headtag_'.$hostname} = $domconfig{'login'}{'headtag'}{$hostname}{'url'};
                                             }
                                         }
+                                        if ($domconfig{'login'}{$key}{$hostname}{'exempt'}) {
+                                            $designhash{$udom.'.login.'.$key.'_exempt_'.$hostname} = $domconfig{'login'}{$key}{$hostname}{'exempt'};
+                                        }
                                     }
                                 }
                             }
@@ -6611,6 +6693,10 @@ fieldset {
   /* overflow: hidden; */
 }
 
+article.geogebraweb div {
+    margin: 0;
+}
+
 fieldset > legend {
   font-weight: bold;
   padding: 0 5px 0 5px;
@@ -7346,6 +7432,79 @@ sub headtag {
 <meta http-equiv="pragma" content="no-cache" />
 <meta http-equiv="Refresh" content="$time; url=$url" />
 ADDMETA
+    } else {
+        unless (($args->{'frameset'}) || ($args->{'js_ready'}) || ($args->{'only_body'}) || ($args->{'no_nav_bar'})) {
+            my $requrl = $env{'request.uri'};
+            if ($requrl eq '') {
+                $requrl = $ENV{'REQUEST_URI'};
+                $requrl =~ s/\?.+$//;
+            }
+            unless (($requrl =~ m{^/adm/(?:switchserver|login|authenticate|logout|groupsort|cleanup|helper|slotrequest|grades)(\?|$)}) ||
+                    (($requrl =~ m{^/res/}) && (($env{'form.submitted'} eq 'scantron') ||
+                     ($env{'form.grade_symb'}) || ($Apache::lonhomework::scantronmode)))) {
+                my $dom_in_use = $Apache::lonnet::perlvar{'lonDefDomain'};
+                unless (&Apache::lonnet::allowed('mau',$dom_in_use)) {
+                    my %domdefs = &Apache::lonnet::get_domain_defaults($dom_in_use);
+                    if (ref($domdefs{'offloadnow'}) eq 'HASH') {
+                        my $lonhost = $Apache::lonnet::perlvar{'lonHostID'};
+                        if ($domdefs{'offloadnow'}{$lonhost}) {
+                            my $newserver = &Apache::lonnet::spareserver(30000,undef,1,$dom_in_use);
+                            if (($newserver) && ($newserver ne $lonhost)) {
+                                my $numsec = 5;
+                                my $timeout = $numsec * 1000;
+                                my ($newurl,$locknum,%locks,$msg);
+                                if ($env{'request.role.adv'}) {
+                                    ($locknum,%locks) = &Apache::lonnet::get_locks();
+                                }
+                                my $disable_submit = 0;
+                                if ($requrl =~ /$LONCAPA::assess_re/) {
+                                    $disable_submit = 1;
+                                }
+                                if ($locknum) {
+                                    my @lockinfo = sort(values(%locks));
+                                    $msg = &mt('Once the following tasks are complete: ')."\\n".
+                                           join(", ",sort(values(%locks)))."\\n".
+                                           &mt('your session will be transferred to a different server, after you click "Roles".');
+                                } else {
+                                    if (($requrl =~ m{^/res/}) && ($env{'form.submitted'} =~ /^part_/)) {
+                                        $msg = &mt('Your LON-CAPA submission has been recorded')."\\n";
+                                    }
+                                    $msg .= &mt('Your current LON-CAPA session will be transferred to a different server in [quant,_1,second].',$numsec);
+                                    $newurl = '/adm/switchserver?otherserver='.$newserver;
+                                    if (($env{'request.role'}) && ($env{'request.role'} ne 'cm')) {
+                                        $newurl .= '&role='.$env{'request.role'};
+                                    }
+                                    if ($env{'request.symb'}) {
+                                        $newurl .= '&symb='.$env{'request.symb'};
+                                    } else {
+                                        $newurl .= '&origurl='.$requrl;
+                                    }
+                                }
+                                $result.=<<OFFLOAD
+<meta http-equiv="pragma" content="no-cache" />
+<script type="text/javascript">
+function LC_Offload_Now() {
+    var dest = "$newurl";
+    if (dest != '') {
+        window.location.href="$newurl";
+    }
+}
+window.alert('$msg');
+if ($disable_submit) {
+    \$(document).ready(function () {
+        \$(".LC_hwk_submit").prop("disabled", true);
+        \$( ".LC_textline" ).prop( "readonly", "readonly");
+    });
+}
+setTimeout('LC_Offload_Now()', $timeout);
+</script>
+OFFLOAD
+                            }
+                        }
+                    }
+                }
+            }
+        }
     }
     if (!defined($title)) {
 	$title = 'The LearningOnline Network with CAPA';
@@ -7672,10 +7831,12 @@ function set_wishlistlink(title, path) {
         title = title.replace(/^LON-CAPA /,'');
     }
     title = encodeURIComponent(title);
+    title = title.replace("'","\\\'");
     if (!path) {
         path = location.pathname;
     }
     path = encodeURIComponent(path);
+    path = path.replace("'","\\\'");
     Win = window.open('/adm/wishlist?mode=newLink&setTitle='+title+'&setPath='+path,
                       'wishlistNewLink','width=560,height=350,scrollbars=0');
 }
@@ -7718,12 +7879,13 @@ var modalWindow = {
 };
 	var openMyModal = function(source,width,height,scrolling,transparency,style)
 	{
+                source = source.replace("'","&#39;");
 		modalWindow.windowId = "myModal";
 		modalWindow.width = width;
 		modalWindow.height = height;
 		modalWindow.content = "<iframe width='"+width+"' height='"+height+"' frameborder='0' scrolling='"+scrolling+"' allowtransparency='"+transparency+"' src='" + source + "' style='"+style+"'></iframe>";
 		modalWindow.open();
-	};	
+	};
 // END LON-CAPA Internal -->
 // ]]>
 </script>
@@ -8325,7 +8487,7 @@ role status: active, previous or future.
 sub check_user_status {
     my ($udom,$uname,$cdom,$crs,$role,$sec) = @_;
     my %userinfo = &Apache::lonnet::dump('roles',$udom,$uname);
-    my @uroles = keys %userinfo;
+    my @uroles = keys(%userinfo);
     my $srchstr;
     my $active_chk = 'none';
     my $now = time;
@@ -11070,7 +11232,7 @@ sub decompress_form {
                         "$topdir/media/player.swf",
                         "$topdir/media/swfobject.js",
                         "$topdir/media/expressInstall.swf");
-        my @camtasia8 = ("$topdir/","$topdir/$topdir.html",
+        my @camtasia8_1 = ("$topdir/","$topdir/$topdir.html",
                          "$topdir/$topdir.mp4",
                          "$topdir/$topdir\_config.xml",
                          "$topdir/$topdir\_controller.swf",
@@ -11092,13 +11254,36 @@ sub decompress_form {
                          "$topdir/skins/express_show/",
                          "$topdir/skins/express_show/player-min.css",
                          "$topdir/skins/express_show/spritesheet.png");
+        my @camtasia8_4 = ("$topdir/","$topdir/$topdir.html",
+                         "$topdir/$topdir.mp4",
+                         "$topdir/$topdir\_config.xml",
+                         "$topdir/$topdir\_controller.swf",
+                         "$topdir/$topdir\_embed.css",
+                         "$topdir/$topdir\_First_Frame.png",
+                         "$topdir/$topdir\_player.html",
+                         "$topdir/$topdir\_Thumbnails.png",
+                         "$topdir/playerProductInstall.swf",
+                         "$topdir/scripts/",
+                         "$topdir/scripts/config_xml.js",
+                         "$topdir/scripts/techsmith-smart-player.min.js",
+                         "$topdir/skins/",
+                         "$topdir/skins/configuration_express.xml",
+                         "$topdir/skins/express_show/",
+                         "$topdir/skins/express_show/spritesheet.min.css",
+                         "$topdir/skins/express_show/spritesheet.png",
+                         "$topdir/skins/express_show/techsmith-smart-player.min.css");
         my @diffs = &compare_arrays(\@paths,\@camtasia6);
         if (@diffs == 0) {
             $is_camtasia = 6;
         } else {
-            @diffs = &compare_arrays(\@paths,\@camtasia8);
+            @diffs = &compare_arrays(\@paths,\@camtasia8_1);
             if (@diffs == 0) {
                 $is_camtasia = 8;
+            } else {
+                @diffs = &compare_arrays(\@paths,\@camtasia8_4);
+                if (@diffs == 0) {
+                    $is_camtasia = 8;
+                }
             }
         }
     }
@@ -14465,7 +14650,7 @@ sub escape_url {
     my ($url)   = @_;
     my @urlslices = split(/\//, $url,-1);
     my $lastitem = &escape(pop(@urlslices));
-    return join('/',@urlslices).'/'.$lastitem;
+    return &HTML::Entities::encode(join('/',@urlslices),"'").'/'.$lastitem;
 }
 
 sub compare_arrays {
@@ -14523,6 +14708,17 @@ sub init_user_environment {
 		}
 	    }
 	    closedir(DIR);
+# If there is a undeleted lockfile for the user's paste buffer remove it.
+            my $namespace = 'nohist_courseeditor';
+            my $lockingkey = 'paste'."\0".'locked_num';
+            my %lockhash = &Apache::lonnet::get($namespace,[$lockingkey],
+                                                $domain,$username);
+            if (exists($lockhash{$lockingkey})) {
+                my $delresult = &Apache::lonnet::del($namespace,[$lockingkey],$domain,$username);
+                unless ($delresult eq 'ok') {
+                    &Apache::lonnet::logthis("Failed to delete paste buffer locking key in $namespace for ".$username.":".$domain." Result was: $delresult");
+                }
+            }
 	}
 # Give them a new cookie
 	my $id = ($args->{'robot'} ? 'robot'.$args->{'robot'}
@@ -14941,7 +15137,12 @@ sub build_filters {
         $output .= '<input type="hidden" name="phase" value="courselist" />'."\n".
                    '<input type="hidden" name="prevphase" value="'.
                    $prevphase.'" />'."\n";
-    } elsif ($formname ne 'quotacheck') {
+    } elsif ($formname eq 'quotacheck') {
+        $output .= qq|
+<input type="hidden" name="sortby" value="" />
+<input type="hidden" name="sortorder" value="" />
+|;
+    } else {
         my $name_input;
         if ($cnameelement ne '') {
             $name_input = '<input type="hidden" name="cnameelement" value="'.
@@ -15234,13 +15435,210 @@ sub search_courses {
     return %courses;
 }
 
+=pod
+
+=back
+
+=head1 Routines for version requirements for current course.
+
+=over 4
+
+=item * &check_release_required()
+
+Compares required LON-CAPA version with version on server, and
+if required version is newer looks for a server with the required version.
+
+Looks first at servers in user's owen domain; if none suitable, looks at
+servers in course's domain are permitted to host sessions for user's domain.
+
+Inputs:
+
+$loncaparev - Version on current server (format: Major.Minor.Subrelease-datestamp)
+
+$courseid - Course ID of current course
+
+$rolecode - User's current role in course (for switchserver query string).
+
+$required - LON-CAPA version needed by course (format: Major.Minor).
+
+
+Returns:
+
+$switchserver - query string tp append to /adm/switchserver call (if
+                current server's LON-CAPA version is too old.
+
+$warning - Message is displayed if no suitable server could be found.
+
+=cut
+
+sub check_release_required {
+    my ($loncaparev,$courseid,$rolecode,$required) = @_;
+    my ($switchserver,$warning);
+    if ($required ne '') {
+        my ($reqdmajor,$reqdminor) = ($required =~ /^(\d+)\.(\d+)$/);
+        my ($major,$minor) = ($loncaparev =~ /^\'?(\d+)\.(\d+)\.[\w.\-]+\'?$/);
+        if ($reqdmajor ne '' && $reqdminor ne '') {
+            my $otherserver;
+            if (($major eq '' && $minor eq '') ||
+                (($reqdmajor > $major) || (($reqdmajor == $major) && ($reqdminor > $minor)))) {
+                my ($userdomserver) = &Apache::lonnet::choose_server($env{'user.domain'},undef,$required,1);
+                my $switchlcrev =
+                    &Apache::lonnet::get_server_loncaparev($env{'user.domain'},
+                                                           $userdomserver);
+                my ($swmajor,$swminor) = ($switchlcrev =~ /^\'?(\d+)\.(\d+)\.[\w.\-]+\'?$/);
+                if (($swmajor eq '' && $swminor eq '') || ($reqdmajor > $swmajor) ||
+                    (($reqdmajor == $swmajor) && ($reqdminor > $swminor))) {
+                    my $cdom = $env{'course.'.$courseid.'.domain'};
+                    if ($cdom ne $env{'user.domain'}) {
+                        my ($coursedomserver,$coursehostname) = &Apache::lonnet::choose_server($cdom,undef,$required,1);
+                        my $serverhomeID = &Apache::lonnet::get_server_homeID($coursehostname);
+                        my $serverhomedom = &Apache::lonnet::host_domain($serverhomeID);
+                        my %defdomdefaults = &Apache::lonnet::get_domain_defaults($serverhomedom);
+                        my %udomdefaults = &Apache::lonnet::get_domain_defaults($env{'user.domain'});
+                        my $remoterev = &Apache::lonnet::get_server_loncaparev($serverhomedom,$coursedomserver);
+                        my $canhost =
+                            &Apache::lonnet::can_host_session($env{'user.domain'},
+                                                              $coursedomserver,
+                                                              $remoterev,
+                                                              $udomdefaults{'remotesessions'},
+                                                              $defdomdefaults{'hostedsessions'});
+
+                        if ($canhost) {
+                            $otherserver = $coursedomserver;
+                        } else {
+                            $warning = &mt('Requires LON-CAPA version [_1].',$env{'course.'.$courseid.'.internal.releaserequired'}).'<br />'. &mt("No suitable server could be found amongst servers in either your own domain or in the course's domain.");
+                        }
+                    } else {
+                        $warning = &mt('Requires LON-CAPA version [_1].',$env{'course.'.$courseid.'.internal.releaserequired'}).'<br />'.&mt("No suitable server could be found amongst servers in your own domain (which is also the course's domain).");
+                    }
+                } else {
+                    $otherserver = $userdomserver;
+                }
+            }
+            if ($otherserver ne '') {
+                $switchserver = 'otherserver='.$otherserver.'&amp;role='.$rolecode;
+            }
+        }
+    }
+    return ($switchserver,$warning);
+}
+
+=pod
+
+=item * &check_release_result()
+
+Inputs:
+
+$switchwarning - Warning message if no suitable server found to host session.
+
+$switchserver - query string to append to /adm/switchserver containing lonHostID
+                and current role.
+
+Returns: HTML to display with information about requirement to switch server.
+         Either displaying warning with link to Roles/Courses screen or
+         display link to switchserver.
+
+=cut
+
+sub check_release_result {
+    my ($switchwarning,$switchserver) = @_;
+    my $output = &start_page('Selected course unavailable on this server').
+                 '<p class="LC_warning">';
+    if ($switchwarning) {
+        $output .= $switchwarning.'<br /><a href="/adm/roles">';
+        if (&show_course()) {
+            $output .= &mt('Display courses');
+        } else {
+            $output .= &mt('Display roles');
+        }
+        $output .= '</a>';
+    } elsif ($switchserver) {
+        $output .= &mt('This course requires a newer version of LON-CAPA than is installed on this server.').
+                   '<br />'.
+                   '<a href="/adm/switchserver?'.$switchserver.'">'.
+                   &mt('Switch Server').
+                   '</a>';
+    }
+    $output .= '</p>'.&end_page();
+    return $output;
+}
 
 =pod
 
+=item * &needs_coursereinit()
+
+Determine if course contents stored for user's session needs to be
+refreshed, because content has changed since "Big Hash" last tied.
+
+Check for change is made if time last checked is more than 10 minutes ago
+(by default).
+
+Inputs:
+
+$loncaparev - Version on current server (format: Major.Minor.Subrelease-datestamp)
+
+$interval (optional) - Time which may elapse (in s) between last check for content
+                       change in current course. (default: 600 s).
+
+Returns: an array; first element is:
+
+=over 4
+
+'switch' - if content updates mean user's session
+           needs to be switched to a server running a newer LON-CAPA version
+
+'update' - if course session needs to be refreshed (i.e., Big Hash needs to be reloaded)
+           on current server hosting user's session
+
+''       - if no action required.
+
+=back
+
+If first item element is 'switch':
+
+second item is $switchwarning - Warning message if no suitable server found to host session.
+
+third item is $switchserver - query string to append to /adm/switchserver containing lonHostID
+                              and current role.
+
+otherwise: no other elements returned.
+
 =back
 
 =cut
 
+sub needs_coursereinit {
+    my ($loncaparev,$interval) = @_;
+    return() unless ($env{'request.course.id'} && $env{'request.course.tied'});
+    my $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
+    my $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
+    my $now = time;
+    if ($interval eq '') {
+        $interval = 600;
+    }
+    if (($now-$env{'request.course.timechecked'})>$interval) {
+        my $lastchange = &Apache::lonnet::get_coursechange($cdom,$cnum);
+        &Apache::lonnet::appenv({'request.course.timechecked'=>$now});
+        if ($lastchange > $env{'request.course.tied'}) {
+            my %curr_reqd_hash = &Apache::lonnet::userenvironment($cdom,$cnum,'internal.releaserequired');
+            if ($curr_reqd_hash{'internal.releaserequired'} ne '') {
+                my $required = $env{'course.'.$cdom.'_'.$cnum.'.internal.releaserequired'};
+                if ($curr_reqd_hash{'internal.releaserequired'} ne $required) {
+                    &Apache::lonnet::appenv({'course.'.$cdom.'_'.$cnum.'.internal.releaserequired' =>
+                                             $curr_reqd_hash{'internal.releaserequired'}});
+                    my ($switchserver,$switchwarning) =
+                        &check_release_required($loncaparev,$cdom.'_'.$cnum,$env{'request.role'},
+                                                $curr_reqd_hash{'internal.releaserequired'});
+                    if ($switchwarning ne '' || $switchserver ne '') {
+                        return ('switch',$switchwarning,$switchserver);
+                    }
+                }
+            }
+            return ('update');
+        }
+    }
+    return ();
+}
 
 sub update_content_constraints {
     my ($cdom,$cnum,$chome,$cid) = @_;