--- rat/lonuserstate.pm 2009/11/16 20:26:04 1.128.2.3 +++ rat/lonuserstate.pm 2011/07/26 10:40:23 1.138 @@ -1,7 +1,7 @@ # The LearningOnline Network with CAPA # Construct and maintain state and binary representation of course for user # -# $Id: lonuserstate.pm,v 1.128.2.3 2009/11/16 20:26:04 raeburn Exp $ +# $Id: lonuserstate.pm,v 1.138 2011/07/26 10:40:23 foxr Exp $ # # Copyright Michigan State University Board of Trustees # @@ -43,11 +43,13 @@ use Opcode; use Apache::lonenc; use Fcntl qw(:flock); use LONCAPA; +use File::Basename; + # ---------------------------------------------------- Globals for this package -my $pc; # Package counter +my $pc; # Package counter is this what 'Guts' calls the map counter? my %hash; # The big tied hash my %parmhash;# The hash with the parameters my @cond; # Array with all of the conditions @@ -62,6 +64,12 @@ my %hiddenurl; # this URL (or complete f # ----------------------------------- Remove version from URL and store in hash +sub versionerror { + my ($uri,$usedversion,$unusedversion)=@_; + return '
'.&mt('Version discrepancy: resource [_1] included in both version [_2] and version [_3]. Using version [_2].', + $uri,$usedversion,$unusedversion).'
'; +} + sub versiontrack { my $uri=shift; if ($uri=~/\.(\d+)\.\w+$/) { @@ -69,7 +77,9 @@ sub versiontrack { $uri=~s/\.\d+\.(\w+)$/\.$1/; unless ($hash{'version_'.$uri}) { $hash{'version_'.$uri}=$version; - } + } elsif ($version!=$hash{'version_'.$uri}) { + $errtext.=&versionerror($uri,$hash{'version_'.$uri},$version); + } } return $uri; } @@ -104,32 +114,55 @@ sub processversionfile { } } -# --------------------------------------------------------- Loads map from disk +# --------------------------------------------------------- Loads from disk sub loadmap { my ($uri,$parent_rid)=@_; + + # Is the map already included? + if ($hash{'map_pc_'.$uri}) { $errtext.='

'. &mt('Multiple use of sequence/page [_1]! The course will not function properly.',''.$uri.''). '

'; return; } + # Register the resource in it's map_pc_ [for the URL] + # map_id.nnn is the nesting level -> to the URI. + $pc++; my $lpc=$pc; $hash{'map_pc_'.$uri}=$lpc; $hash{'map_id_'.$lpc}=$uri; -# Determine and check filename + # If the parent is of the form n.m hang this map underneath it in the + # map hierarchy. + + if ($parent_rid =~ /^(\d+)\.\d+$/) { + my $parent_pc = $1; + if (defined($hash{'map_hierarchy_'.$parent_pc})) { + $hash{'map_hierarchy_'.$lpc}=$hash{'map_hierarchy_'.$parent_pc}.','. + $parent_pc; + } else { + $hash{'map_hierarchy_'.$lpc}=$parent_pc; + } + } + +# Determine and check filename of the sequence we need to read: + my $fn=&Apache::lonnet::filelocation('',&putinversion($uri)); my $ispage=($fn=~/\.page$/); - unless (($fn=~/\.sequence$/) || - ($fn=~/\.page$/)) { + # We can only nest sequences or pages. Anything else is an illegal nest. + + unless (($fn=~/\.sequence$/) || $ispage) { $errtext.=&mt("
Invalid map: [_1]",$fn); return; } + # Read the XML that constitutes the file. + my $instr=&Apache::lonnet::getfile($fn); if ($instr eq -1) { @@ -137,18 +170,29 @@ sub loadmap { return; } -# Successfully got file, parse it + # Successfully got file, parse it + + # parse for parameter processing. + # Note that these are tags + # so we only care about 'S' (tag start) nodes. + my $parser = HTML::TokeParser->new(\$instr); $parser->attr_encoded(1); + # first get all parameters + + while (my $token = $parser->get_token) { next if ($token->[0] ne 'S'); if ($token->[1] eq 'param') { &parse_param($token,$lpc); } } - #reset parser + + # Get set to take another pass through the XML: + # for resources and links. + $parser = HTML::TokeParser->new(\$instr); $parser->attr_encoded(1); @@ -160,21 +204,40 @@ sub loadmap { my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i); + # Parse the resources, link and condition tags. + # Note that if randomorder or random select is chosen the links and + # conditions are meaningless but are determined by the randomization. + # This is handled in the next chunk of code. + my @map_ids; while (my $token = $parser->get_token) { next if ($token->[0] ne 'S'); + + # Resource + if ($token->[1] eq 'resource') { - push(@map_ids,&parse_resource($token,$lpc,$ispage,$uri)); + my $resource_id = &parse_resource($token,$lpc,$ispage,$uri); + if (defined $resource_id) { + push(@map_ids, $resource_id); + } + + # Link + } elsif ($token->[1] eq 'link' && !$randomize) { -# ----------------------------------------------------------------------- Links &make_link(++$linkpc,$lpc,$token->[2]->{'to'}, $token->[2]->{'from'}, $token->[2]->{'condition'}); + + # condition + } elsif ($token->[1] eq 'condition' && !$randomize) { &parse_condition($token,$lpc); } } + + # Handle randomization and random selection + if ($randomize) { if (!$env{'request.role.adv'}) { my $seed; @@ -188,7 +251,10 @@ sub loadmap { $seed = $symb; } - + + # Here for sure we need to pass along the username/domain + # so that we can impersonate users in lonprintout e.g. + my $rndseed=&Apache::lonnet::rndseed($seed); &Apache::lonnet::setup_random_from_rndseed($rndseed); @map_ids=&Math::Random::random_permutation(@map_ids); @@ -224,9 +290,52 @@ sub loadmap { # -------------------------------------------------------------------- Resource +# +# Parses a resource tag to produce the value to push into the +# map_ids array. +# +# +# Information about the actual type of resource is provided by the file extension +# of the uri (e.g. .problem, .sequence etc. etc.). +# +# Parameters: +# $token - A token from HTML::TokeParser +# This is an array that describes the most recently parsed HTML item. +# $lpc - Map nesting level (?) +# $ispage - True if this resource is encapsulated in a .page (assembled resourcde). +# $uri - URI of the enclosing resource. +# Returns: +# +# Note: +# The token is an array that contains the following elements: +# [0] => 'S' indicating this is a start token +# [1] => 'resource' indicating this tag is a tag. +# [2] => Hash of attribute =>value pairs. +# [3] => @(keys [2]). +# [4] => unused. +# +# The attributes of the resourcde tag include: +# +# id - The resource id. +# src - The URI of the resource. +# type - The resource type (e.g. start and finish). +# title - The resource title. + + sub parse_resource { my ($token,$lpc,$ispage,$uri) = @_; - if ($token->[2]->{'type'} eq 'zombie') { next; } + + # I refuse to coutenance code like this that has + # such a dirty side effect (and forcing this sub to be called within a loop). + # + # if ($token->[2]->{'type'} eq 'zombie') { next; } + + # Zombie resources don't produce anything useful. + + if ($token->[2]->{'type'} eq 'zombie') { + return undef; + } + my $rid=$lpc.'.'.$token->[2]->{'id'}; $hash{'kind_'.$rid}='res'; @@ -278,7 +387,7 @@ sub parse_resource { $hash{'ids_'.$idsuri}=''.$rid; } - if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard)$/) { + if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard|viewclasslist)$/) { $turi.='?register=1'; } @@ -356,36 +465,77 @@ sub parse_condition { } # ------------------------------------------------------------------- Parameter +# Parse a tag in the map. +# Parmameters: +# $token Token array for a start tag from HTML::TokeParser +# [0] = 'S' +# [1] = tagname ("param") +# [2] = Hash of {attribute} = values. +# [3] = Array of the keys in [2]. +# [4] = unused. +# $lpc Current map nesting level.a +# +# Typical attributes: +# to=n - Number of the resource the parameter applies to. +# type=xx - Type of parameter value (e.g. string_yesno or int_pos). +# name=xxx - Name ofr parameter (e.g. parameter_randompick or parameter_randomorder). +# value=xxx - value of the parameter. sub parse_param { my ($token,$lpc) = @_; - my $referid=$lpc.'.'.$token->[2]->{'to'}; - my $name=$token->[2]->{'name'}; + my $referid=$lpc.'.'.$token->[2]->{'to'}; # Resource param applies to. + my $name=$token->[2]->{'name'}; # Name of parameter my $part; - if ($name=~/^parameter_(.*)_/) { + + + if ($name=~/^parameter_(.*)_/) { $part=$1; } else { $part=0; } + + # Peel the parameter_ off the parameter name. + $name=~s/^.*_([^_]*)$/$1/; + + # The value is: + # type.part.name.value + my $newparam= &escape($token->[2]->{'type'}).':'. &escape($part.'.'.$name).'='. &escape($token->[2]->{'value'}); + + # The hash key is param_resourceid. + # Multiple parameters for a single resource are & separated in the hash. + + if (defined($hash{'param_'.$referid})) { $hash{'param_'.$referid}.='&'.$newparam; } else { $hash{'param_'.$referid}=''.$newparam; } - if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { + # + # These parameters have to do with randomly selecting + # resources, therefore a separate hash is also created to + # make it easy to locate them when actually computing the resource set later on + # See the code conditionalized by ($randomize) in loadmap(). + + if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { # Random selection turned on $randompick{$referid}=$token->[2]->{'value'}; } - if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { + if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { # Randomseed provided. $randompickseed{$referid}=$token->[2]->{'value'}; } - if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { + if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { # Random order turned on. $randomorder{$referid}=$token->[2]->{'value'}; } + + # These parameters have to do with how the URLs of resources are presented to + # course members(?). encrypturl presents encypted url's while + # hiddenresource hides the URL. + # + if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) { if ($token->[2]->{'value'}=~/^yes$/i) { $encurl{$referid}=1; @@ -640,7 +790,11 @@ sub hiddenurls { sub readmap { my $short=shift; $short=~s/^\///; - my %cenv=&Apache::lonnet::coursedescription($short,{'freshen_cache'=>1}); + + # TODO: Hidden dependency on current user: + + my %cenv=&Apache::lonnet::coursedescription($short,{'freshen_cache'=>1}); + my $fn=$cenv{'fn'}; my $uri; $short=~s/\//\_/g; @@ -652,27 +806,40 @@ sub readmap { @cond=('true:normal'); unless (open(LOCKFILE,">$fn.db.lock")) { + # + # Most likely a permissions problem on the lockfile or its directory. + # $errtext.='
'.&mt('Map not loaded - Lock file could not be opened when reading map:').' '.$fn.'.'; $retfurl = ''; return ($retfurl,$errtext); } my $lock=0; my $gotstate=0; - if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) { - $lock=1; + + # If we can get the lock without delay any files there are idle + # and from some prior request. We'll kill them off and regenerate them: + + if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) { + $lock=1; # Remember that we hold the lock. &unlink_tmpfiles($fn); } undef %randompick; undef %hiddenurl; undef %encurl; $retfrid=''; - my ($untiedhash,$untiedparmhash,$tiedhash,$tiedparmhash); + my ($untiedhash,$untiedparmhash,$tiedhash,$tiedparmhash); # More state flags. + + # if we got the lock, regenerate course regnerate empty files and tie them. + if ($lock) { if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) { $tiedhash = 1; if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640)) { $tiedparmhash = 1; - $gotstate = &build_tmp_hashes($uri,$fn,$short,\%cenv); + $gotstate = &build_tmp_hashes($uri, + $fn, + $short, + \%cenv); # TODO: Need to provide requested user@dom unless ($gotstate) { &Apache::lonnet::logthis('Failed to write statemap at first attempt '.$fn.' for '.$uri.'.'); } @@ -688,14 +855,24 @@ sub readmap { 'Could not untie coursemap hash '.$fn.' for '.$uri.'.'); } } - flock(LOCKFILE,LOCK_UN); + flock(LOCKFILE,LOCK_UN); # RF: this is what I don't get unless there are other + # unlocked places the remainder happens..seems like if we + # just kept the lock here the rest of the code would have + # been much easier? } - unless ($lock && $tiedhash && $tiedparmhash) { + unless ($lock && $tiedhash && $tiedparmhash) { # if we are here it is likely because we are already trying to # initialize the course in another child, busy wait trying to # tie the hashes for the next 90 seconds, if we succeed forward # them on to navmaps, if we fail, throw up the Could not init # course screen + # + # RF: I'm not seeing the case where the ties/unties can fail in a way + # that can be remedied by this. Since we owned the lock seems + # Tie/untie failures are a result of something like a permissions problem instead? + # + + # In any vent, undo what we did manage to do above first: if ($lock) { # Got the lock but not the DB files flock(LOCKFILE,LOCK_UN); @@ -703,7 +880,7 @@ sub readmap { } if ($tiedhash) { unless($untiedhash) { - untie(%hash); + untie(%hash); } } if ($tiedparmhash) { @@ -711,15 +888,25 @@ sub readmap { untie(%parmhash); } } - &Apache::lonnet::logthis('WARNING: '. - "Could not tie coursemap $fn for $uri."); + # Log our failure: + + &Apache::lonnet::logthis('WARNING: '. + "Could not tie coursemap $fn for $uri."); $tiedhash = ''; $tiedparmhash = ''; my $i=0; + + # Keep on retrying the lock for 90 sec until we succeed. + while($i<90) { $i++; sleep(1); if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) { + + # Got the lock, tie the hashes...the assumption in this code is + # that some other worker thread has created the db files quite recently + # so no load is needed: + $lock = 1; if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640)) { $tiedhash = 1; @@ -727,19 +914,24 @@ sub readmap { $tiedparmhash = 1; if (-e "$fn.state") { $retfurl='/adm/navmaps'; + + # BUG BUG: Side effect! + # Should conditionalize on something so that we can use this + # to load maps for courses that are not current? + # &Apache::lonnet::appenv({"request.course.id" => $short, - "request.course.fn" => $fn, + "request.course.fn" => $fn, "request.course.uri" => $uri}); - $untiedhash = untie(%hash); - $untiedparmhash = untie(%parmhash); + $untiedhash = untie(%hash); + $untiedparmhash = untie(%parmhash); $gotstate = 1; last; - } + } $untiedparmhash = untie(%parmhash); - } - $untiedhash = untie(%hash); - } - } + } + $untiedhash = untie(%hash); + } + } } if ($lock) { flock(LOCKFILE,LOCK_UN); @@ -758,6 +950,11 @@ sub readmap { } } } + # I think this branch of code is all about what happens if we just did the stuff above, + # but found that the state file did not exist...again if we'd just held the lock + # would that have made this logic simpler..as generating all the files would be + # an atomic operation with respect to the lock. + # unless ($gotstate) { $lock = 0; &Apache::lonnet::logthis('WARNING: '. @@ -770,10 +967,13 @@ sub readmap { undef %hiddenurl; undef %encurl; $retfrid=''; + # + # Once more through the routine of tying and loading and so on. + # if ($lock) { if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) { if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640)) { - $gotstate = &build_tmp_hashes($uri,$fn,$short,\%cenv); + $gotstate = &build_tmp_hashes($uri,$fn,$short,\%cenv); # TODO: User dependent? unless ($gotstate) { &Apache::lonnet::logthis('WARNING: '. 'Failed to write statemap at second attempt '.$fn.' for '.$uri.'.'); @@ -797,6 +997,8 @@ sub readmap { flock(LOCKFILE,LOCK_UN); $lock = 0; } else { + # Failed to get the immediate lock. + &Apache::lonnet::logthis('WARNING: '. 'Could not obtain lock to tie coursemap hash '.$fn.'.db for '.$uri.'.'); } @@ -804,10 +1006,13 @@ sub readmap { close(LOCKFILE); unless (($errtext eq '') || ($env{'request.course.uri'} =~ m{^/uploaded/})) { &Apache::lonmsg::author_res_msg($env{'request.course.uri'}, - $errtext); + $errtext); # TODO: User dependent? } # ------------------------------------------------- Check for critical messages +# Depends on user must parameterize this as well..or separate as this is: +# more part of determining what someone sees on entering a course? + my @what=&Apache::lonnet::dump('critical',$env{'user.domain'}, $env{'user.name'}); if ($what[0]) { @@ -818,20 +1023,39 @@ sub readmap { return ($retfurl,$errtext); } +# +# This sub is called when the course hash and the param hash have been tied and +# their lock file is held. +# Parameters: +# $uri - URI that identifies the course. +# $fn - The base path/filename of the files that make up the context +# being built. +# $short - Short course name. +# $cenvref - Reference to the course environment hash returned by +# Apache::lonnet::coursedescription +# +# Assumptions: +# The globals +# %hash, %paramhash are tied to their gdbm files and we hold the lock on them. +# sub build_tmp_hashes { my ($uri,$fn,$short,$cenvref) = @_; + unless(ref($cenvref) eq 'HASH') { return; } my %cenv = %{$cenvref}; my $gotstate = 0; - %hash=(); + %hash=(); # empty the global course and parameter hashes. %parmhash=(); - $errtext=''; + $errtext=''; # No error messages yet. $pc=0; &clear_mapalias_count(); &processversionfile(%cenv); my $furi=&Apache::lonnet::clutter($uri); + # + # the map staring points. + # $hash{'src_0.0'}=&versiontrack($furi); $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title'); $hash{'ids_'.$furi}='0.0'; @@ -889,7 +1113,9 @@ sub build_tmp_hashes { sub unlink_tmpfiles { my ($fn) = @_; - if ($fn =~ m{^\Q$Apache::lonnet::perlvar{'lonUsersDir'}\E/tmp/}) { + my $file_dir = dirname($fn); + + if ($fn eq LONCAPA::tempdir()) { my @files = qw (.db _symb.db .state _parms.db); foreach my $file (@files) { if (-e $fn.$file) { @@ -943,6 +1169,9 @@ sub evalstate { return $state; } +# This block seems to have code to manage/detect doubly defined +# aliases in maps. + { my %mapalias_cache; sub count_mapalias { @@ -1002,37 +1231,33 @@ of course for user. This is part of the LearningOnline Network with CAPA project described at http://www.lon-capa.org. -=head1 HANDLER SUBROUTINE - -There is no handler subroutine. - -=head1 OTHER SUBROUTINES +=head1 SUBROUTINES -=over 4 +=over -=item * +=item loadmap() -loadmap() : Loads map from disk +Loads map from disk -=item * +=item simplify() -simplify() : Simplify expression +Simplify expression -=item * +=item traceroute() -traceroute() : Build condition hash +Build condition hash -=item * +=item accinit() -accinit() : Cascading conditions, quick access, parameters +Cascading conditions, quick access, parameters -=item * +=item readmap() -readmap() : Read map and all submaps +Read map and all submaps -=item * +=item evalstate() -evalstate() : Evaluate state string +Evaluate state string =back