$major) || (($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'}).'
'. &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'}).'
'.&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.'&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 $output = &start_page('Selected course unavailable on this server').
+ '';
+ if ($switchwarning) {
+ $output .= $switchwarning.'
';
+ if (&show_course()) {
+ $output .= &mt('Display courses');
+ } else {
+ $output .= &mt('Display roles');
+ }
+ $output .= '';
+ } elsif ($switchserver) {
+ $output .= &mt('This course requires a newer version of LON-CAPA than is installed on this server.').
+ '
'.
+ ''.
+ &mt('Switch Server').
+ '';
+ }
+ $output .= '
'.&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) = @_;