--- loncom/lond	2012/02/28 15:54:07	1.486
+++ loncom/lond	2012/04/11 21:32:28	1.490
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # lond "LON Daemon" Server (port "LOND" 5663)
 #
-# $Id: lond,v 1.486 2012/02/28 15:54:07 raeburn Exp $
+# $Id: lond,v 1.490 2012/04/11 21:32:28 droeschl Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -34,6 +34,7 @@ use strict;
 use lib '/home/httpd/lib/perl/';
 use LONCAPA;
 use LONCAPA::Configuration;
+use LONCAPA::Lond;
 
 use IO::Socket;
 use IO::File;
@@ -60,7 +61,7 @@ my $DEBUG = 0;		       # Non zero to ena
 my $status='';
 my $lastlog='';
 
-my $VERSION='$Revision: 1.486 $'; #' stupid emacs
+my $VERSION='$Revision: 1.490 $'; #' stupid emacs
 my $remoteVERSION;
 my $currenthostid="default";
 my $currentdomainid;
@@ -3245,6 +3246,12 @@ sub dump_profile_database {
 #                                             that is matched against
 #                                             database keywords to do
 #                                             selective dumps.
+#                               range       - optional range of entries
+#                                             e.g., 10-20 would return the
+#                                             10th to 19th items, etc.  
+#                               extra       - optional ref to hash of
+#                                             additional args. currently
+#                                             skipcheck is only key used.   
 #   $client                   - Channel open on the client.
 # Returns:
 #    1    - Continue processing.
@@ -3254,6 +3261,15 @@ sub dump_profile_database {
 sub dump_with_regexp {
     my ($cmd, $tail, $client) = @_;
 
+    #TODO encapsulate $clientname and $clientversion in a object.
+    my $res = LONCAPA::Lond::dump_with_regexp($cmd, $tail, $clientname, $clientversion);
+    
+    if ($res =~ /^error:/) {
+        Failure($client, \$res, "$cmd:$tail");
+    } else {
+        Reply($client, \$res, "$cmd:$tail");
+    }
+    return 1;
 
     my $userinput = "$cmd:$tail";
 
@@ -3279,12 +3295,26 @@ sub dump_with_regexp {
     if ($hashref) {
         my $qresult='';
 	my $count=0;
+#
+# When dump is for roles.db, determine if LON-CAPA version checking is needed.
+# Sessions on 2.10 and later will include skipcheck => 1 in extra args ref,
+# to indicate no version checking is needed (in this case, checking occurs
+# on the server hosting the user session, when constructing the roles/courses 
+# screen).
+# 
         if ($extra ne '') {
             $extra = &Apache::lonnet::thaw_unescape($extra);
             $skipcheck = $extra->{'skipcheck'};
         }
         my @ids = &Apache::lonnet::current_machine_ids();
         my (%homecourses,$major,$minor,$now);
+# 
+# If dump is for roles.db from a pre-2.10 server, determine the LON-CAPA   
+# version on the server which requested the data. For LON-CAPA 2.9, the  
+# client session will have sent its LON-CAPA version when initiating the
+# connection. For LON-CAPA 2.8 and older, the version is retrieved from
+# the global %loncaparevs in lonnet.pm.
+# 
         if (($namespace eq 'roles') && (!$skipcheck)) {
             my $loncaparev = $clientversion;
             if ($loncaparev eq '') {
@@ -3302,8 +3332,18 @@ sub dump_with_regexp {
                     my $cdom = $1;
                     my $cnum = $2;
                     unless ($skipcheck) {
-                        my ($role,$end,$start) = split(/\_/,$value);
-                        if (!$end || $end > $now) {
+                        my ($role,$roleend,$rolestart) = split(/\_/,$value);
+                        if (!$roleend || $roleend > $now) {
+#
+# For active course roles, check that requesting server is running a LON-CAPA
+# version which meets any version requirements for the course. Do not include
+# the role amongst the results returned if the requesting server's version is
+# too old.
+#
+# This determination is handled differently depending on whether the course's 
+# homeserver is the current server, or whether it is a different server.
+# In both cases, the course's version requirement needs to be retrieved.
+# 
                             next unless (&releasereqd_check($cnum,$cdom,$key,$value,$major,
                                                             $minor,\%homecourses,\@ids));
                         }
@@ -3326,9 +3366,16 @@ sub dump_with_regexp {
 	    }
 	}
 	if (&untie_user_hash($hashref)) {
+#
+# If dump is for roles.db from a pre-2.10 server, check if the LON-CAPA
+# version requirements for courses for which the current server is the home
+# server permit course roles to be usable on the client server hosting the
+# user's session. If so, include those role results in the data returned to  
+# the client server.
+#
             if (($namespace eq 'roles') && (!$skipcheck)) {
                 if (keys(%homecourses) > 0) {
-                    $qresult .= &check_homecourses(\%homecourses,$udom,$regexp,$count,
+                    $qresult .= &check_homecourses(\%homecourses,$regexp,$count,
                                                    $range,$start,$end,$major,$minor);
                 }
             }
@@ -6282,6 +6329,9 @@ sub Debug {
 #     reply   - Text to send to client.
 #     request - Original request from client.
 #
+#NOTE $reply must be terminated by exactly *one* \n. If $reply is a reference
+#this is done automatically ($$reply must not contain any \n in this case). 
+#If $reply is a string the caller has to ensure this.
 sub Reply {
     my ($fd, $reply, $request) = @_;
     if (ref($reply)) {
@@ -6717,14 +6767,22 @@ sub is_author {
 
     #  Author role should show up as a key /domain/_au
 
-    my $key    = "/$domain/_au";
     my $value;
-    if (defined($hashref)) {
-	$value = $hashref->{$key};
-    }
+    if ($hashref) {
 
-    if(defined($value)) {
-	&Debug("$user @ $domain is an author");
+	my $key    = "/$domain/_au";
+	if (defined($hashref)) {
+	    $value = $hashref->{$key};
+	    if(!untie_user_hash($hashref)) {
+		return 'error: ' .  ($!+0)." untie (GDBM) Failed";
+	    }
+	}
+	
+	if(defined($value)) {
+	    &Debug("$user @ $domain is an author");
+	}
+    } else {
+	return 'error: '.($!+0)." tie (GDBM) Failed";
     }
 
     return defined($value);
@@ -7429,6 +7487,20 @@ sub get_usersession_config {
     return;
 }
 
+#
+# releasereqd_check() will determine if a LON-CAPA version (defined in the
+# $major,$minor args passed) is not too old to allow use of a role in a 
+# course ($cnum,$cdom args passed), if at least one of the following applies: 
+# (a) the course is a Community, (b) the course's home server is *not* the
+# current server, or (c) cached course information is not stale. 
+#
+# For the case where none of these apply, the course is added to the 
+# $homecourse hash ref (keys = courseIDs, values = array of a hash of roles).
+# The $homecourse hash ref is for courses for which the current server is the 
+# home server.  LON-CAPA version requirements are checked elsewhere for the
+# items in $homecourse.
+#
+
 sub releasereqd_check {
     my ($cnum,$cdom,$key,$value,$major,$minor,$homecourses,$ids) = @_;
     my $home = &Apache::lonnet::homeserver($cnum,$cdom);
@@ -7458,10 +7530,18 @@ sub releasereqd_check {
         if (ref($ids) eq 'ARRAY') {
             if (grep(/^\Q$home\E$/,@{$ids})) {
                 if (ref($homecourses) eq 'HASH') {
-                    if (ref($homecourses->{$hashid}) eq 'ARRAY') {
-                        push(@{$homecourses->{$hashid}},{$key=>$value});
+                    if (ref($homecourses->{$cdom}) eq 'HASH') {
+                        if (ref($homecourses->{$cdom}{$cnum}) eq 'HASH') {
+                            if (ref($homecourses->{$cdom}{$cnum}) eq 'ARRAY') {
+                                push(@{$homecourses->{$cdom}{$cnum}},{$key=>$value});
+                            } else {
+                                $homecourses->{$cdom}{$cnum} = [{$key=>$value}];
+                            }
+                        } else {
+                            $homecourses->{$cdom}{$cnum} = [{$key=>$value}];
+                        }
                     } else {
-                        $homecourses->{$hashid} = [{$key=>$value}];
+                        $homecourses->{$cdom}{$cnum} = [{$key=>$value}];
                     }
                 }
                 return;
@@ -7480,6 +7560,17 @@ sub releasereqd_check {
     return 1;
 }
 
+# 
+# get_courseinfo_hash() is used to retrieve course information from the db
+# file: nohist_courseids.db for a course for which the current server is *not*
+# the home server.
+#
+# A hash of a hash will be retrieved. The outer hash contains a single key --
+# courseID -- for the course for which the data are being requested.
+# The contents of the inner hash, for that single item in the outer hash
+# are returned (and cached in memcache for 10 minutes).
+# 
+
 sub get_courseinfo_hash {
     my ($cnum,$cdom,$home) = @_;
     my %info;
@@ -7505,43 +7596,64 @@ sub get_courseinfo_hash {
     return;
 }
 
+#
+# check_homecourses() will retrieve course information for those courses which
+# are keys of the $homecourses hash ref (first arg). The nohist_courseids.db 
+# GDBM file is tied and course information for each course retrieved. Last   
+# visit (lasttime key) is also retrieved for each, and cached values updated  
+# for any courses last visited less than 24 hours ago. Cached values are also
+# updated for any courses included in the $homecourses hash ref.
+#
+# The reason for the 24 hours constraint is that the cron entry in 
+# /etc/cron.d/loncapa for /home/httpd/perl/refresh_courseids_db.pl causes 
+# cached course information to be updated nightly for courses with activity
+# within the past 24 hours.
+#
+# Role information for the user (included in a ref to an array of hashes as the
+# value for each key in $homecourses) is appended to the result returned by the
+# routine, which will in turn be appended to the string returned to the client
+# hosting the user's session.
+# 
+
 sub check_homecourses {
-    my ($homecourses,$udom,$regexp,$count,$range,$start,$end,$major,$minor) = @_;
+    my ($homecourses,$regexp,$count,$range,$start,$end,$major,$minor) = @_;
     my ($result,%addtocache);
     my $yesterday = time - 24*3600; 
     if (ref($homecourses) eq 'HASH') {
         my (%okcourses,%courseinfo,%recent);
-        my $hashref = &tie_domain_hash($udom, "nohist_courseids", &GDBM_WRCREAT());
-        if ($hashref) {
-            while (my ($key,$value) = each(%$hashref)) {
-                my $unesc_key = &unescape($key);
-                if ($unesc_key =~ /^lasttime:(\w+)$/) {
-                    my $cid = $1;
-                    $cid =~ s/_/:/;
-                    if ($value > $yesterday ) {
-                        $recent{$cid} = 1;
+        foreach my $domain (keys(%{$homecourses})) {
+            my $hashref = 
+                &tie_domain_hash($domain, "nohist_courseids", &GDBM_WRCREAT());
+            if (ref($hashref) eq 'HASH') {
+                while (my ($key,$value) = each(%$hashref)) {
+                    my $unesc_key = &unescape($key);
+                    if ($unesc_key =~ /^lasttime:(\w+)$/) {
+                        my $cid = $1;
+                        $cid =~ s/_/:/;
+                        if ($value > $yesterday ) {
+                            $recent{$cid} = 1;
+                        }
+                        next;
                     }
-                    next;
-                }
-                my $items = &Apache::lonnet::thaw_unescape($value);
-                if (ref($items) eq 'HASH') {
-                    my $hashid = $unesc_key;
-                    $hashid =~ s/_/:/;
-                    $courseinfo{$hashid} = $items;
-                    if (ref($homecourses->{$hashid}) eq 'ARRAY') {
-                        my ($reqdmajor,$reqdminor) = split(/\./,$items->{'releaserequired'});
-                        if (&useable_role($reqdmajor,$reqdminor,$major,$minor)) {
-                            $okcourses{$hashid} = 1;
+                    my $items = &Apache::lonnet::thaw_unescape($value);
+                    if (ref($items) eq 'HASH') {
+                        my ($cdom,$cnum) = split(/_/,$unesc_key);
+                        my $hashid = $cdom.':'.$cnum; 
+                        $courseinfo{$hashid} = $items;
+                        if (ref($homecourses->{$cdom}{$cnum}) eq 'ARRAY') {
+                            my ($reqdmajor,$reqdminor) = split(/\./,$items->{'releaserequired'});
+                            if (&useable_role($reqdmajor,$reqdminor,$major,$minor)) {
+                               $okcourses{$hashid} = 1;
+                            }
                         }
                     }
                 }
+                unless (&untie_domain_hash($hashref)) {
+                    &logthis("Failed to untie tied hash for nohist_courseids.db for $domain");
+                }
+            } else {
+                &logthis("Failed to tie hash for nohist_courseids.db for $domain");
             }
-            unless (&untie_domain_hash($hashref)) {
-                &logthis('Failed to untie tied hash for nohist_courseids.db');
-            }
-        } else {
-            &logthis('Failed to tie hash for nohist_courseids.db');
-            return;
         }
         foreach my $hashid (keys(%recent)) {
             my ($result,$cached)=&Apache::lonnet::is_cached_new('courseinfo',$hashid);
@@ -7549,13 +7661,20 @@ sub check_homecourses {
                 &Apache::lonnet::do_cache_new('courseinfo',$hashid,$courseinfo{$hashid},600);
             }
         }
-        foreach my $hashid (keys(%{$homecourses})) {
-            next if ($recent{$hashid});
-            &Apache::lonnet::do_cache_new('courseinfo',$hashid,$courseinfo{$hashid},600);
+        foreach my $cdom (keys(%{$homecourses})) {
+            if (ref($homecourses->{$cdom}) eq 'HASH') {
+                foreach my $cnum (keys(%{$homecourses->{$cdom}})) {
+                    my $hashid = $cdom.':'.$cnum;
+                    next if ($recent{$hashid});
+                    &Apache::lonnet::do_cache_new('courseinfo',$hashid,$courseinfo{$hashid},600);
+                }
+            }
         }
         foreach my $hashid (keys(%okcourses)) {
-            if (ref($homecourses->{$hashid}) eq 'ARRAY') {
-                foreach my $role (@{$homecourses->{$hashid}}) {
+            my ($cdom,$cnum) = split(/:/,$hashid);
+            if ((ref($homecourses->{$cdom}) eq 'HASH') &&  
+                (ref($homecourses->{$cdom}{$cnum}) eq 'ARRAY')) {
+                foreach my $role (@{$homecourses->{$cdom}{$cnum}}) {
                     if (ref($role) eq 'HASH') {
                         while (my ($key,$value) = each(%{$role})) {
                             if ($regexp eq '.') {
@@ -7581,6 +7700,12 @@ sub check_homecourses {
     return $result;
 }
 
+#
+# useable_role() will compare the LON-CAPA version required by a course with 
+# the version available on the client server.  If the client server's version
+# is compatible, 1 will be returned.
+#
+
 sub useable_role {
     my ($reqdmajor,$reqdminor,$major,$minor) = @_; 
     if ($reqdmajor ne '' && $reqdminor ne '') {
@@ -7919,6 +8044,8 @@ Authen::Krb5
 
 =head1 COREQUISITES
 
+none
+
 =head1 OSNAMES
 
 linux
@@ -8006,9 +8133,9 @@ or the CA's certificate in the call to l
 <error> is the textual reason this failed.  Usual reasons:
 
 =over 2
-       
+
 =item Apache config file for loncapa  incorrect:
- 
+
 one of the variables 
 lonCertificateDirectory, lonnetCertificateAuthority, or lonnetCertificate
 undefined or incorrect
@@ -8127,7 +8254,7 @@ Could not rewrite the
 internal password file for a user
 
 =item Result of password change for <user> : <result>
-                                                                     
+
 A unix password change for <user> was attempted 
 and the pipe returned <result>  
 
@@ -8156,7 +8283,7 @@ lond has been asked to exit by its clien
 client systemand <input> is the full exit command sent to the server.
 
 =item Red CRITICAL: ABNORMAL EXIT. child <pid> for server <hostname> died through a crass with this error->[<message>].
-                                                 
+
 A lond child terminated.  NOte that this termination can also occur when the
 child receives the QUIT or DIE signals.  <pid> is the process id of the child,
 <hostname> the host lond is working for, and <message> the reason the child died
@@ -8240,7 +8367,7 @@ file when sent it's USR1 signal.  That p
 assumed to be hung in some un-fixable way.
 
 =item Finished checking children                   
- 
+
 Master processs's USR1 processing is cojmplete.
 
 =item (Red) CRITICAL: ------- Starting ------            
@@ -8254,7 +8381,7 @@ Started a new child process for <client>
 connected to the child.  This was as a result of a TCP/IP connection from a client.
 
 =item Unable to determine who caller was, getpeername returned nothing
-                                                  
+
 In child process initialization.  either getpeername returned undef or
 a zero sized object was returned.  Processing continues, but in my opinion,
 this should be cause for the child to exit.
@@ -8265,7 +8392,7 @@ In child process initialization.  The pe
 The client address is stored as "Unavailable" and processing continues.
 
 =item (Yellow) INFO: Connection <ip> <name> connection type = <type>
-                                                  
+
 In child initialization.  A good connectionw as received from <ip>.
 
 =over 2
@@ -8315,7 +8442,7 @@ The client (<client> is the peer's name
 negotiated an SSL connection with this child process.
 
 =item (Green) Successful insecure authentication with <client>
-                                                   
+
 
 The client has successfully negotiated an  insecure connection withthe child process.