[LON-CAPA-cvs] cvs: rat / lonuserstate.pm
foxr
foxr at source.lon-capa.org
Tue Jul 26 06:40:23 EDT 2011
foxr Tue Jul 26 10:40:23 2011 EDT
Modified files:
/rat lonuserstate.pm
Log:
1. Centralize tempdir location in unlink_tmpfiles.
2. Get rid of >dirty< next in parse_resource ... returning
undef instead for zombie resources and checking in the
loop that calls it.
-------------- next part --------------
Index: rat/lonuserstate.pm
diff -u rat/lonuserstate.pm:1.137 rat/lonuserstate.pm:1.138
--- rat/lonuserstate.pm:1.137 Thu Apr 21 13:28:50 2011
+++ rat/lonuserstate.pm Tue Jul 26 10:40:23 2011
@@ -1,7 +1,7 @@
# The LearningOnline Network with CAPA
# Construct and maintain state and binary representation of course for user
#
-# $Id: lonuserstate.pm,v 1.137 2011/04/21 13:28:50 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 Apache::lonenc;
use Fcntl qw(:flock);
use LONCAPA;
+use File::Basename;
+
# ---------------------------------------------------- Globals for this package
-my $pc; # Package counter
+my $pc; # Package counter is this what 'Guts' calls the map counter?
my %hash; # The big tied hash
my %parmhash;# The hash with the parameters
my @cond; # Array with all of the conditions
@@ -112,20 +114,30 @@
}
}
-# --------------------------------------------------------- Loads map from disk
+# --------------------------------------------------------- Loads from disk
sub loadmap {
my ($uri,$parent_rid)=@_;
+
+ # Is the map already included?
+
if ($hash{'map_pc_'.$uri}) {
$errtext.='<p class="LC_error">'.
&mt('Multiple use of sequence/page [_1]! The course will not function properly.','<tt>'.$uri.'</tt>').
'</p>';
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}=$uri;
+
+ # If the parent is of the form n.m hang this map underneath it in the
+ # map hierarchy.
+
if ($parent_rid =~ /^(\d+)\.\d+$/) {
my $parent_pc = $1;
if (defined($hash{'map_hierarchy_'.$parent_pc})) {
@@ -136,17 +148,21 @@
}
}
-# Determine and check filename
+# 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) {
$errtext.=&mt("<br />Invalid map: <tt>[_1]</tt>",$fn);
return;
}
+ # Read the XML that constitutes the file.
+
my $instr=&Apache::lonnet::getfile($fn);
if ($instr eq -1) {
@@ -154,18 +170,29 @@
return;
}
-# Successfully got file, parse it
+ # Successfully got file, parse it
+
+ # parse for parameter processing.
+ # Note that these are <param... / > 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);
@@ -177,21 +204,40 @@
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;
@@ -205,7 +251,10 @@
$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);
@@ -241,9 +290,52 @@
# -------------------------------------------------------------------- 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).
+# $uri - URI of the enclosing resource.
+# Returns:
+#
+# Note:
+# The token is an array that contains the following elements:
+# [0] => 'S' indicating this is a start token
+# [1] => 'resource' indicating this tag is a <resource> tag.
+# [2] => Hash of attribute =>value pairs.
+# [3] => @(keys [2]).
+# [4] => unused.
+#
+# The attributes of the resourcde tag include:
+#
+# id - The resource id.
+# src - The URI of the resource.
+# type - The resource type (e.g. start and finish).
+# title - The resource title.
+
+
sub parse_resource {
my ($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';
@@ -373,36 +465,77 @@
}
# ------------------------------------------------------------------- Parameter
+# Parse a <parameter> 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;
@@ -657,7 +790,11 @@
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;
$short=~s/\//\_/g;
@@ -669,27 +806,40 @@
@cond=('true:normal');
unless (open(LOCKFILE,">$fn.db.lock")) {
+ #
+ # Most likely a permissions problem on the lockfile or its directory.
+ #
$errtext.='<br />'.&mt('Map not loaded - Lock file could not be opened when reading map:').' <tt>'.$fn.'</tt>.';
$retfurl = '';
return ($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,
+ $short,
+ \%cenv); # TODO: Need to provide requested user at dom
unless ($gotstate) {
&Apache::lonnet::logthis('Failed to write statemap at first attempt '.$fn.' for '.$uri.'.</font>');
}
@@ -705,7 +855,10 @@
'Could not untie coursemap hash '.$fn.' for '.$uri.'.</font>');
}
}
- 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 && $tiedparmhash) {
# if we are here it is likely because we are already trying to
@@ -713,6 +866,13 @@
# tie the hashes for the next 90 seconds, if we succeed forward
# them on to navmaps, if we fail, throw up the Could not init
# course screen
+ #
+ # RF: I'm not seeing the case where the ties/unties can fail in a way
+ # that can be remedied by this. Since we owned the lock seems
+ # Tie/untie failures are a result of something like a permissions problem instead?
+ #
+
+ # In any vent, undo what we did manage to do above first:
if ($lock) {
# Got the lock but not the DB files
flock(LOCKFILE,LOCK_UN);
@@ -728,15 +888,25 @@
untie(%parmhash);
}
}
+ # Log our failure:
+
&Apache::lonnet::logthis('<font color="blue">WARNING: '.
"Could not tie coursemap $fn for $uri.</font>");
$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;
@@ -744,6 +914,11 @@
$tiedparmhash = 1;
if (-e "$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.uri" => $uri});
@@ -775,6 +950,11 @@
}
}
}
+ # I think this branch of code is all about what happens if we just did the stuff above,
+ # but found that the state file did not exist...again if we'd just held the lock
+ # would that have made this logic simpler..as generating all the files would be
+ # an atomic operation with respect to the lock.
+ #
unless ($gotstate) {
$lock = 0;
&Apache::lonnet::logthis('<font color="blue">WARNING: '.
@@ -787,10 +967,13 @@
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 ($gotstate) {
&Apache::lonnet::logthis('<font color="blue">WARNING: '.
'Failed to write statemap at second attempt '.$fn.' for '.$uri.'.</font>');
@@ -814,6 +997,8 @@
flock(LOCKFILE,LOCK_UN);
$lock = 0;
} else {
+ # Failed to get the immediate lock.
+
&Apache::lonnet::logthis('<font color="blue">WARNING: '.
'Could not obtain lock to tie coursemap hash '.$fn.'.db for '.$uri.'.</font>');
}
@@ -821,10 +1006,13 @@
close(LOCKFILE);
unless (($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]) {
@@ -835,20 +1023,39 @@
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';
@@ -906,7 +1113,9 @@
sub unlink_tmpfiles {
my ($fn) = @_;
- if ($fn =~ m{^\Q$Apache::lonnet::perlvar{'lonDaemons'}\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) {
@@ -960,6 +1169,9 @@
return $state;
}
+# This block seems to have code to manage/detect doubly defined
+# aliases in maps.
+
{
my %mapalias_cache;
sub count_mapalias {
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