Annotation of loncom/Lond.pm, revision 1.3

1.1       droeschl    1: # The LearningOnline Network
                      2: #
1.3     ! droeschl    3: # $Id: Lond.pm,v 1.2 2012/04/26 19:51:40 droeschl Exp $
1.1       droeschl    4: #
                      5: # Copyright Michigan State University Board of Trustees
                      6: #
                      7: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
                      8: #
                      9: # LON-CAPA is free software; you can redistribute it and/or modify
                     10: # it under the terms of the GNU General Public License as published by
                     11: # the Free Software Foundation; either version 2 of the License, or
                     12: # (at your option) any later version.
                     13: #
                     14: # LON-CAPA is distributed in the hope that it will be useful,
                     15: # but WITHOUT ANY WARRANTY; without even the implied warranty of
                     16: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     17: # GNU General Public License for more details.
                     18: #
                     19: # You should have received a copy of the GNU General Public License
                     20: # along with LON-CAPA; if not, write to the Free Software
                     21: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     22: #
                     23: # /home/httpd/html/adm/gpl.txt
                     24: #
                     25: # http://www.lon-capa.org/
                     26: #
                     27: ###
                     28: 
                     29: #NOTE perldoc at the end of file
                     30: 
                     31: package LONCAPA::Lond;
                     32: 
                     33: use strict;
                     34: use lib '/home/httpd/lib/perl/';
                     35: 
                     36: use LONCAPA;
                     37: use Apache::lonnet;
                     38: use GDBM_File;
                     39: 
                     40: 
                     41: sub dump_with_regexp {
1.2       droeschl   42:     my ( $tail, $clientname, $clientversion ) = @_;
                     43:     my ( $udom, $uname, $namespace, $regexp, $range ) = 
                     44:         split /:/, $tail;
1.1       droeschl   45: 
1.2       droeschl   46:     $regexp = defined $regexp ? unescape($regexp) : '.';
1.1       droeschl   47: 
                     48:     my ($start,$end);
1.2       droeschl   49: 
1.1       droeschl   50:     if (defined($range)) {
1.2       droeschl   51:         if ($range =~ /^(\d+)\-(\d+)$/) {
                     52:             ($start,$end) = ($1,$2);
                     53:         } elsif ($range =~/^(\d+)$/) {
                     54:             ($start,$end) = (0,$1);
                     55:         } else {
                     56:             undef($range);
                     57:         }
                     58:     }
                     59: 
                     60:     my $hashref = &tie_user_hash($udom, $uname, $namespace, &GDBM_READER()) or 
                     61:         return "error: ".($!+0)." tie(GDBM) Failed while attempting dump";
                     62: 
                     63:     my $qresult = '';
                     64:     my $count = 0;
1.1       droeschl   65: #
                     66: # When dump is for roles.db, determine if LON-CAPA version checking is needed.
1.2       droeschl   67: # Sessions on 2.10 and later do not require version checking, as that occurs
1.1       droeschl   68: # on the server hosting the user session, when constructing the roles/courses 
                     69: # screen).
                     70: # 
1.2       droeschl   71:     my $skipcheck;
                     72:     my @ids = &Apache::lonnet::current_machine_ids();
                     73:     my (%homecourses, $major, $minor, $now);
1.1       droeschl   74: # 
                     75: # If dump is for roles.db from a pre-2.10 server, determine the LON-CAPA   
1.2       droeschl   76: # version on the server which requested the data. 
1.1       droeschl   77: # 
1.2       droeschl   78:     if ($namespace eq 'roles') {
                     79:         if ($clientversion =~ /^\'?(\d+)\.(\d+)\.[\w.\-]+\'?/) {
                     80:             $major = $1;
                     81:             $minor = $2;
                     82:         }
                     83:         if (($major > 2) || (($major == 2) && ($minor > 9))) {
                     84:             $skipcheck = 1;
1.1       droeschl   85:         }
1.2       droeschl   86:         $now = time;
                     87:     }
                     88:     while (my ($key,$value) = each(%$hashref)) {
                     89:             if ($namespace eq 'roles' && (!$skipcheck)) {
1.1       droeschl   90:                 if ($key =~ m{^/($LONCAPA::match_domain)/($LONCAPA::match_courseid)(/?[^_]*)_(cc|co|in|ta|ep|ad|st|cr)$}) {
                     91:                     my $cdom = $1;
                     92:                     my $cnum = $2;
1.2       droeschl   93:                     my ($role,$roleend,$rolestart) = split(/\_/,$value);
                     94:                     if (!$roleend || $roleend > $now) {
1.1       droeschl   95: #
                     96: # For active course roles, check that requesting server is running a LON-CAPA
                     97: # version which meets any version requirements for the course. Do not include
                     98: # the role amongst the results returned if the requesting server's version is
                     99: # too old.
                    100: #
                    101: # This determination is handled differently depending on whether the course's 
                    102: # homeserver is the current server, or whether it is a different server.
                    103: # In both cases, the course's version requirement needs to be retrieved.
                    104: # 
1.2       droeschl  105:                         next unless (&releasereqd_check($cnum,$cdom,$key,$value,$major,
                    106:                                                         $minor,\%homecourses,\@ids));
1.1       droeschl  107:                     }
                    108:                 }
                    109:             }
1.2       droeschl  110:         if ($regexp eq '.') {
                    111:             $count++;
                    112:             if (defined($range) && $count >= $end)   { last; }
                    113:             if (defined($range) && $count <  $start) { next; }
                    114:             $qresult.=$key.'='.$value.'&';
                    115:         } else {
                    116:             my $unescapeKey = &unescape($key);
                    117:             if (eval('$unescapeKey=~/$regexp/')) {
                    118:                 $count++;
                    119:                 if (defined($range) && $count >= $end)   { last; }
                    120:                 if (defined($range) && $count <  $start) { next; }
                    121:                 $qresult.="$key=$value&";
                    122:             }
                    123:         }
                    124:     }
                    125: 
                    126:     &untie_user_hash($hashref) or 
                    127:         return "error: ".($!+0)." untie(GDBM) Failed while attempting dump";
1.1       droeschl  128: #
                    129: # If dump is for roles.db from a pre-2.10 server, check if the LON-CAPA
                    130: # version requirements for courses for which the current server is the home
                    131: # server permit course roles to be usable on the client server hosting the
                    132: # user's session. If so, include those role results in the data returned to  
                    133: # the client server.
                    134: #
1.2       droeschl  135:     if (($namespace eq 'roles') && (!$skipcheck)) {
                    136:         if (keys(%homecourses) > 0) {
                    137:             $qresult .= &check_homecourses(\%homecourses,$regexp,$count,
                    138:                                            $range,$start,$end,$major,$minor);
                    139:         }
                    140:     }
                    141:     chop($qresult);
                    142:     return $qresult;
                    143: }
                    144: 
                    145: 
                    146: sub releasereqd_check {
                    147:     my ($cnum,$cdom,$key,$value,$major,$minor,$homecourses,$ids) = @_;
                    148:     my $home = &Apache::lonnet::homeserver($cnum,$cdom);
                    149:     return if ($home eq 'no_host');
                    150:     my ($reqdmajor,$reqdminor,$displayrole);
                    151:     if ($cnum =~ /$LONCAPA::match_community/) {
                    152:         if ($major eq '' && $minor eq '') {
                    153:             return unless ((ref($ids) eq 'ARRAY') && 
                    154:                            (grep(/^\Q$home\E$/,@{$ids})));
                    155:         } else {
                    156:             $reqdmajor = 2;
                    157:             $reqdminor = 9;
                    158:             return unless (&useable_role($reqdmajor,$reqdminor,$major,$minor));
                    159:         }
                    160:     }
                    161:     my $hashid = $cdom.':'.$cnum;
                    162:     my ($courseinfo,$cached) =
                    163:         &Apache::lonnet::is_cached_new('courseinfo',$hashid);
                    164:     if (defined($cached)) {
                    165:         if (ref($courseinfo) eq 'HASH') {
                    166:             if (exists($courseinfo->{'releaserequired'})) {
                    167:                 my ($reqdmajor,$reqdminor) = split(/\./,$courseinfo->{'releaserequired'});
                    168:                 return unless (&useable_role($reqdmajor,$reqdminor,$major,$minor));
                    169:             }
                    170:         }
                    171:     } else {
                    172:         if (ref($ids) eq 'ARRAY') {
                    173:             if (grep(/^\Q$home\E$/,@{$ids})) {
                    174:                 if (ref($homecourses) eq 'HASH') {
                    175:                     if (ref($homecourses->{$cdom}) eq 'HASH') {
                    176:                         if (ref($homecourses->{$cdom}{$cnum}) eq 'HASH') {
                    177:                             if (ref($homecourses->{$cdom}{$cnum}) eq 'ARRAY') {
                    178:                                 push(@{$homecourses->{$cdom}{$cnum}},{$key=>$value});
                    179:                             } else {
                    180:                                 $homecourses->{$cdom}{$cnum} = [{$key=>$value}];
                    181:                             }
                    182:                         } else {
                    183:                             $homecourses->{$cdom}{$cnum} = [{$key=>$value}];
                    184:                         }
                    185:                     } else {
                    186:                         $homecourses->{$cdom}{$cnum} = [{$key=>$value}];
                    187:                     }
                    188:                 }
                    189:                 return;
                    190:             }
                    191:         }
                    192:         my $courseinfo = &get_courseinfo_hash($cnum,$cdom,$home);
                    193:         if (ref($courseinfo) eq 'HASH') {
                    194:             if (exists($courseinfo->{'releaserequired'})) {
                    195:                 my ($reqdmajor,$reqdminor) = split(/\./,$courseinfo->{'releaserequired'});
                    196:                 return unless (&useable_role($reqdmajor,$reqdminor,$major,$minor));
                    197:             }
                    198:         } else {
                    199:             return;
                    200:         }
                    201:     }
                    202:     return 1;
                    203: }
                    204: 
                    205: 
                    206: sub check_homecourses {
                    207:     my ($homecourses,$regexp,$count,$range,$start,$end,$major,$minor) = @_;
                    208:     my ($result,%addtocache);
                    209:     my $yesterday = time - 24*3600; 
                    210:     if (ref($homecourses) eq 'HASH') {
                    211:         my (%okcourses,%courseinfo,%recent);
                    212:         foreach my $domain (keys(%{$homecourses})) {
                    213:             my $hashref = 
                    214:                 &tie_domain_hash($domain, "nohist_courseids", &GDBM_WRCREAT());
                    215:             if (ref($hashref) eq 'HASH') {
                    216:                 while (my ($key,$value) = each(%$hashref)) {
                    217:                     my $unesc_key = &unescape($key);
                    218:                     if ($unesc_key =~ /^lasttime:(\w+)$/) {
                    219:                         my $cid = $1;
                    220:                         $cid =~ s/_/:/;
                    221:                         if ($value > $yesterday ) {
                    222:                             $recent{$cid} = 1;
                    223:                         }
                    224:                         next;
                    225:                     }
                    226:                     my $items = &Apache::lonnet::thaw_unescape($value);
                    227:                     if (ref($items) eq 'HASH') {
                    228:                         my ($cdom,$cnum) = split(/_/,$unesc_key);
                    229:                         my $hashid = $cdom.':'.$cnum; 
                    230:                         $courseinfo{$hashid} = $items;
                    231:                         if (ref($homecourses->{$cdom}{$cnum}) eq 'ARRAY') {
                    232:                             my ($reqdmajor,$reqdminor) = split(/\./,$items->{'releaserequired'});
                    233:                             if (&useable_role($reqdmajor,$reqdminor,$major,$minor)) {
                    234:                                $okcourses{$hashid} = 1;
                    235:                             }
                    236:                         }
                    237:                     }
                    238:                 }
                    239:                 unless (&untie_domain_hash($hashref)) {
                    240:                     &logthis("Failed to untie tied hash for nohist_courseids.db for $domain");
                    241:                 }
                    242:             } else {
                    243:                 &logthis("Failed to tie hash for nohist_courseids.db for $domain");
                    244:             }
                    245:         }
                    246:         foreach my $hashid (keys(%recent)) {
                    247:             my ($result,$cached)=&Apache::lonnet::is_cached_new('courseinfo',$hashid);
                    248:             unless ($cached) {
                    249:                 &Apache::lonnet::do_cache_new('courseinfo',$hashid,$courseinfo{$hashid},600);
                    250:             }
                    251:         }
                    252:         foreach my $cdom (keys(%{$homecourses})) {
                    253:             if (ref($homecourses->{$cdom}) eq 'HASH') {
                    254:                 foreach my $cnum (keys(%{$homecourses->{$cdom}})) {
                    255:                     my $hashid = $cdom.':'.$cnum;
                    256:                     next if ($recent{$hashid});
                    257:                     &Apache::lonnet::do_cache_new('courseinfo',$hashid,$courseinfo{$hashid},600);
                    258:                 }
                    259:             }
                    260:         }
                    261:         foreach my $hashid (keys(%okcourses)) {
                    262:             my ($cdom,$cnum) = split(/:/,$hashid);
                    263:             if ((ref($homecourses->{$cdom}) eq 'HASH') &&  
                    264:                 (ref($homecourses->{$cdom}{$cnum}) eq 'ARRAY')) {
                    265:                 foreach my $role (@{$homecourses->{$cdom}{$cnum}}) {
                    266:                     if (ref($role) eq 'HASH') {
                    267:                         while (my ($key,$value) = each(%{$role})) {
                    268:                             if ($regexp eq '.') {
                    269:                                 $count++;
                    270:                                 if (defined($range) && $count >= $end)   { last; }
                    271:                                 if (defined($range) && $count <  $start) { next; }
                    272:                                 $result.=$key.'='.$value.'&';
                    273:                             } else {
                    274:                                 my $unescapeKey = &unescape($key);
                    275:                                 if (eval('$unescapeKey=~/$regexp/')) {
                    276:                                     $count++;
                    277:                                     if (defined($range) && $count >= $end)   { last; }
                    278:                                     if (defined($range) && $count <  $start) { next; }
                    279:                                     $result.="$key=$value&";
                    280:                                 }
                    281:                             }
                    282:                         }
                    283:                     }
1.1       droeschl  284:                 }
                    285:             }
1.2       droeschl  286:         }
1.1       droeschl  287:     }
1.2       droeschl  288:     return $result;
                    289: }
                    290: 
1.1       droeschl  291: 
1.2       droeschl  292: sub useable_role {
                    293:     my ($reqdmajor,$reqdminor,$major,$minor) = @_; 
                    294:     if ($reqdmajor ne '' && $reqdminor ne '') {
                    295:         return if (($major eq '' && $minor eq '') ||
                    296:                    ($major < $reqdmajor) ||
                    297:                    (($major == $reqdmajor) && ($minor < $reqdminor)));
                    298:     }
1.1       droeschl  299:     return 1;
                    300: }
                    301: 
1.2       droeschl  302: 
1.3     ! droeschl  303: sub get_courseinfo_hash {
        !           304:     my ($cnum,$cdom,$home) = @_;
        !           305:     my %info;
        !           306:     eval {
        !           307:         local($SIG{ALRM}) = sub { die "timeout\n"; };
        !           308:         local($SIG{__DIE__})='DEFAULT';
        !           309:         alarm(3);
        !           310:         %info = &Apache::lonnet::courseiddump($cdom,'.',1,'.','.',$cnum,1,[$home],'.');
        !           311:         alarm(0);
        !           312:     };
        !           313:     if ($@) {
        !           314:         if ($@ eq "timeout\n") {
        !           315:             &logthis("<font color='blue'>WARNING courseiddump for $cnum:$cdom from $home timedout</font>");
        !           316:         } else {
        !           317:             &logthis("<font color='yellow'>WARNING unexpected error during eval of call for courseiddump from $home</font>");
        !           318:         }
        !           319:     } else {
        !           320:         if (ref($info{$cdom.'_'.$cnum}) eq 'HASH') {
        !           321:             my $hashid = $cdom.':'.$cnum;
        !           322:             return &Apache::lonnet::do_cache_new('courseinfo',$hashid,$info{$cdom.'_'.$cnum},600);
        !           323:         }
        !           324:     }
        !           325:     return;
        !           326: }
1.2       droeschl  327: 
                    328: 
                    329: 
                    330: 
1.1       droeschl  331: 1;
                    332: 
                    333: __END__
                    334: 
                    335: =head1 NAME
                    336: 
                    337: LONCAPA::Lond.pm
                    338: 
                    339: =head1 SYNOPSIS
                    340: 
                    341: #TODO
                    342: 
                    343: =head1 DESCRIPTION
                    344: 
                    345: #TODO
                    346: 
                    347: =head1 METHODS
                    348: 
                    349: =over 4
                    350: 
1.2       droeschl  351: =item dump_with_regexp( $tail, $client )
1.1       droeschl  352: 
                    353: Dump a profile database with an optional regular expression to match against
                    354: the keys.  In this dump, no effort is made to separate symb from version
                    355: information. Presumably the databases that are dumped by this command are of a
                    356: different structure.  Need to look at this and improve the documentation of
                    357: both this and the currentdump handler.
                    358: 
                    359: $tail a colon separated list containing
                    360: 
                    361: =over 
                    362: 
                    363: =item domain
                    364: 
                    365: =item user 
                    366: 
                    367: identifying the user.
                    368: 
                    369: =item namespace    
                    370: 
                    371: identifying the database.
                    372: 
                    373: =item regexp     
                    374: 
                    375: optional regular expression that is matched against database keywords to do
                    376: selective dumps.
                    377: 
                    378: =item range       
                    379: 
                    380: optional range of entries e.g., 10-20 would return the 10th to 19th items, etc.  
                    381: 
                    382: =back
                    383: 
                    384: $client is the channel open on the client.
                    385: 
                    386: Returns: 1 (Continue processing).
                    387: 
                    388: Side effects: response is written to $client.  
                    389: 
1.2       droeschl  390: 
                    391: =item releasereqd_check( $cnum, $cdom, $key, $value, $major, $minor, 
                    392:         $homecourses, $ids )
                    393: 
                    394: releasereqd_check() will determine if a LON-CAPA version (defined in the
                    395: $major,$minor args passed) is not too old to allow use of a role in a 
                    396: course ($cnum,$cdom args passed), if at least one of the following applies: 
                    397: (a) the course is a Community, (b) the course's home server is *not* the
                    398: current server, or (c) cached course information is not stale. 
                    399: 
                    400: For the case where none of these apply, the course is added to the 
                    401: $homecourse hash ref (keys = courseIDs, values = array of a hash of roles).
                    402: The $homecourse hash ref is for courses for which the current server is the 
                    403: home server.  LON-CAPA version requirements are checked elsewhere for the
                    404: items in $homecourse.
                    405: 
                    406: 
                    407: =item check_homecourses( $homecourses, $regexp, $count, $range, $start, $end, 
                    408:         $major, $minor )
                    409: 
                    410: check_homecourses() will retrieve course information for those courses which
                    411: are keys of the $homecourses hash ref (first arg). The nohist_courseids.db 
                    412: GDBM file is tied and course information for each course retrieved. Last   
                    413: visit (lasttime key) is also retrieved for each, and cached values updated  
                    414: for any courses last visited less than 24 hours ago. Cached values are also
                    415: updated for any courses included in the $homecourses hash ref.
                    416: 
                    417: The reason for the 24 hours constraint is that the cron entry in 
                    418: /etc/cron.d/loncapa for /home/httpd/perl/refresh_courseids_db.pl causes 
                    419: cached course information to be updated nightly for courses with activity
                    420: within the past 24 hours.
                    421: 
                    422: Role information for the user (included in a ref to an array of hashes as the
                    423: value for each key in $homecourses) is appended to the result returned by the
                    424: routine, which will in turn be appended to the string returned to the client
                    425: hosting the user's session.
                    426: 
                    427: 
                    428: =item useable_role( $reqdmajor, $reqdminor, $major, $minor )
                    429: 
                    430: useable_role() will compare the LON-CAPA version required by a course with 
                    431: the version available on the client server.  If the client server's version
                    432: is compatible, 1 will be returned.
                    433: 
                    434: 
1.3     ! droeschl  435: =item get_courseinfo_hash( $cnum, $cdom, $home )
        !           436: 
        !           437: get_courseinfo_hash() is used to retrieve course information from the db
        !           438: file: nohist_courseids.db for a course for which the current server is *not*
        !           439: the home server.
        !           440: 
        !           441: A hash of a hash will be retrieved. The outer hash contains a single key --
        !           442: courseID -- for the course for which the data are being requested.
        !           443: The contents of the inner hash, for that single item in the outer hash
        !           444: are returned (and cached in memcache for 10 minutes).
        !           445: 
        !           446: 
        !           447: 
1.1       droeschl  448: =back
                    449: 
                    450: =head1 BUGS
                    451: 
                    452: No known bugs at this time.
                    453: 
                    454: =head1 SEE ALSO
                    455: 
                    456: L<Apache::lonnet>, L<lond>
                    457: 
                    458: =cut  

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