Annotation of loncom/LONCAPA.pm, revision 1.7
1.1 albertel 1: # The LearningOnline Network
2: # Base routines
3: #
1.7 ! albertel 4: # $Id: LONCAPA.pm,v 1.6 2006/06/19 09:35:08 www Exp $
1.1 albertel 5: #
6: # Copyright Michigan State University Board of Trustees
7: #
8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
9: #
10: # LON-CAPA is free software; you can redistribute it and/or modify
11: # it under the terms of the GNU General Public License as published by
12: # the Free Software Foundation; either version 2 of the License, or
13: # (at your option) any later version.
14: #
15: # LON-CAPA is distributed in the hope that it will be useful,
16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18: # GNU General Public License for more details.
19: #
20: # You should have received a copy of the GNU General Public License
21: # along with LON-CAPA; if not, write to the Free Software
22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23: #
24: # /home/httpd/html/adm/gpl.txt
25: #
26: # http://www.lon-capa.org/
27: #
28: ###
29:
30: package LONCAPA;
31:
32: use strict;
1.2 www 33: use lib '/home/httpd/lib/perl/';
34: use LONCAPA::Configuration;
35: use Fcntl qw(:flock);
36: use GDBM_File;
37: use POSIX;
38:
39: my $loncapa_max_wait_time = 13;
40:
1.1 albertel 41: require Exporter;
42: our @ISA = qw (Exporter);
1.2 www 43: our @EXPORT = qw(&add_get_param &escape &unescape &tie_domain_hash &untie_domain_hash &tie_user_hash &untie_user_hash &propath);
44: my %perlvar;
1.1 albertel 45:
1.2 www 46: # Inputs are a url, and a hash ref of
1.1 albertel 47: # form name => value pairs
48: # takes care of properly adding the form name elements and values to the
49: # the url doing proper escaping of the values and joining with ? or & as
50: # needed
51:
52: sub add_get_param {
53: my ($url,$form_data) = @_;
54: my $needs_question_mark = ($url !~ /\?/);
55:
56: while (my ($name,$value) = each(%$form_data)) {
57: if ($needs_question_mark) {
58: $url.='?';
59: $needs_question_mark = 0;
60: } else {
61: $url.='&';
62: }
63: $url.=$name.'='.&escape($form_data->{$name});
64: }
65: return $url;
66: }
67:
68: # -------------------------------------------------------- Escape Special Chars
69:
70: sub escape {
71: my $str=shift;
72: $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
73: return $str;
74: }
75:
76: # ----------------------------------------------------- Un-Escape Special Chars
77:
78: sub unescape {
79: my $str=shift;
80: $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
81: return $str;
82: }
83:
1.2 www 84: # -------------------------------------------- Return path to profile directory
85:
86: sub propath {
87: my ($udom,$uname)=@_;
88: $udom=~s/\W//g;
89: $uname=~s/\W//g;
90: my $subdir=$uname.'__';
91: $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
92: my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
93: return $proname;
94: }
95:
96:
97: #---------------------------------------------------------------
98: #
99: # Manipulation of hash based databases (factoring out common code
100: # for later use as we refactor.
101: #
102: # Ties a domain level resource file to a hash.
103: # If requested a history entry is created in the associated hist file.
104: #
105: # Parameters:
106: # domain - Name of the domain in which the resource file lives.
107: # namespace - Name of the hash within that domain.
108: # how - How to tie the hash (e.g. GDBM_WRCREAT()).
109: # loghead - Optional parameter, if present a log entry is created
110: # in the associated history file and this is the first part
111: # of that entry.
112: # logtail - Goes along with loghead, The actual logentry is of the
113: # form $loghead:<timestamp>:logtail.
114: # Returns:
115: # Reference to a hash bound to the db file or alternatively undef
116: # if the tie failed.
117: #
118: sub tie_domain_hash {
119: my ($domain,$namespace,$how,$loghead,$logtail) = @_;
120:
121: # Filter out any whitespace in the domain name:
122:
123: $domain =~ s/\W//g;
124:
125: # We have enough to go on to tie the hash:
126:
127: my $user_top_dir = $perlvar{'lonUsersDir'};
128: my $domain_dir = $user_top_dir."/$domain";
129: my $resource_file = $domain_dir."/$namespace";
130: return &_locking_hash_tie($resource_file,$namespace,$how,$loghead,$logtail);
131: }
132:
133: sub untie_domain_hash {
134: return &_locking_hash_untie(@_);
135: }
136: #
137: # Ties a user's resource file to a hash.
138: # If necessary, an appropriate history
139: # log file entry is made as well.
140: # This sub factors out common code from the subs that manipulate
141: # the various gdbm files that keep keyword value pairs.
142: # Parameters:
143: # domain - Name of the domain the user is in.
144: # user - Name of the 'current user'.
145: # namespace - Namespace representing the file to tie.
146: # how - What the tie is done to (e.g. GDBM_WRCREAT().
147: # loghead - Optional first part of log entry if there may be a
148: # history file.
149: # what - Optional tail of log entry if there may be a history
150: # file.
151: # Returns:
152: # hash to which the database is tied. It's up to the caller to untie.
153: # undef if the has could not be tied.
154: #
155: sub tie_user_hash {
156: my ($domain,$user,$namespace,$how,$loghead,$what) = @_;
157:
158: $namespace=~s/\//\_/g; # / -> _
159: $namespace=~s/\W//g; # whitespace eliminated.
160: my $proname = &propath($domain, $user);
161:
162: my $file_prefix="$proname/$namespace";
163: return &_locking_hash_tie($file_prefix,$namespace,$how,$loghead,$what);
164: }
165:
166: sub untie_user_hash {
167: return &_locking_hash_untie(@_);
168: }
169:
1.6 www 170: # routines if you just have a filename
171: # return tied hashref or undef
172:
173: sub locking_hash_tie {
174: my ($filename,$how)=@_;
175: my ($file_prefix,$namespace)=&db_filename_parts($filename);
1.7 ! albertel 176: if ($namespace eq '') { return undef; }
1.6 www 177: return &_locking_hash_tie($file_prefix,$namespace,$how);
178: }
179:
180: sub locking_hash_untie {
181: return &_locking_hash_untie(@_);
182: }
183:
184: sub db_filename_parts {
185: my ($filename)=@_;
186: my ($file_path,$namespace)=($filename=~/^(.*)\/([^\/]+)\.db$/);
1.7 ! albertel 187: if ($namespace eq '') { return undef; }
1.6 www 188: return ($file_path.'/'.$namespace,$namespace);
189: }
190:
1.2 www 191: # internal routines that handle the actual tieing and untieing process
192:
193: sub _do_hash_tie {
194: my ($file_prefix,$namespace,$how,$loghead,$what) = @_;
195: my %hash;
196: if(tie(%hash, 'GDBM_File', "$file_prefix.db", $how, 0640)) {
197: # If this is a namespace for which a history is kept,
198: # make the history log entry:
199: if (($namespace !~/^nohist\_/) && (defined($loghead))) {
200: my $hfh = IO::File->new(">>$file_prefix.hist");
201: if($hfh) {
1.5 albertel 202: my $now = time();
203: print $hfh ("$loghead:$now:$what\n");
1.2 www 204: }
205: $hfh->close;
206: }
207: return \%hash;
208: } else {
209: return undef;
210: }
211: }
212:
213: sub _do_hash_untie {
214: my ($hashref) = @_;
215: my $result = untie(%$hashref);
216: return $result;
217: }
218:
219: {
220: my $sym;
221:
222: sub _locking_hash_tie {
223: my ($file_prefix,$namespace,$how,$loghead,$what) = @_;
224: my $lock_type=LOCK_SH;
225: # Are we reading or writing?
226: if ($how eq &GDBM_READER()) {
227: # We are reading
228: if (!open($sym,"$file_prefix.db.lock")) {
229: # We don't have a lock file. This could mean
230: # - that there is no such db-file
231: # - that it does not have a lock file yet
232: if ((! -e "$file_prefix.db") && (! -e "$file_prefix.db.gz")) {
233: # No such file. Forget it.
234: $! = 2;
235: return undef;
236: }
237: # Apparently just no lock file yet. Make one
238: open($sym,">>$file_prefix.db.lock");
239: }
240: # Do a shared lock
241: if (!&flock_sym(LOCK_SH)) { return undef; }
242: # If this is compressed, we will actually need an exclusive lock
243: if (-e "$file_prefix.db.gz") {
244: if (!&flock_sym(LOCK_EX)) { return undef; }
245: }
246: } elsif ($how eq &GDBM_WRCREAT()) {
247: # We are writing
248: open($sym,">>$file_prefix.db.lock");
249: # Writing needs exclusive lock
250: if (!&flock_sym(LOCK_EX)) { return undef; }
251: } else {
1.5 albertel 252: die("Unknown method $how for $file_prefix");
1.2 www 253: }
254: # The file is ours!
255: # If it is archived, un-archive it now
256: if (-e "$file_prefix.db.gz") {
257: system("gunzip $file_prefix.db.gz");
258: if (-e "$file_prefix.hist.gz") {
259: system("gunzip $file_prefix.hist.gz");
260: }
261: }
262: # Change access mode to non-blocking
263: $how=$how|&GDBM_NOLOCK();
264: # Go ahead and tie the hash
265: return &_do_hash_tie($file_prefix,$namespace,$how,$loghead,$what);
266: }
267:
268: sub flock_sym {
269: my ($lock_type)=@_;
270: my $failed=0;
271: eval {
272: local $SIG{__DIE__}='DEFAULT';
273: local $SIG{ALRM}=sub {
274: $failed=1;
275: die("failed lock");
276: };
277: alarm($loncapa_max_wait_time);
278: flock($sym,$lock_type);
279: alarm(0);
280: };
281: if ($failed) {
282: $! = 100; # throwing error # 100
283: return undef;
284: } else {
285: return 1;
286: }
287: }
288:
289: sub _locking_hash_untie {
290: my ($hashref) = @_;
291: my $result = untie(%$hashref);
292: flock($sym,LOCK_UN);
293: close($sym);
294: undef($sym);
295: return $result;
296: }
297: }
298:
299: BEGIN {
1.4 albertel 300: %perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')};
1.2 www 301: }
302:
1.1 albertel 303: 1;
304:
305: __END__
306:
307: =pod
308:
309: =head1 NAME
310:
311: LONCAPA - Basic routines
312:
313: =head1 SYNOPSIS
314:
315: Generally useful routines
316:
317: =head1 EXPORTED SUBROUTINES
318:
319: =over 4
320:
321: =item *
322:
323: escape() : unpack non-word characters into CGI-compatible hex codes
324:
325: =item *
326:
327: unescape() : pack CGI-compatible hex codes into actual non-word ASCII character
328:
329: =item *
330:
331: add_get_param() :
332: Inputs: url (with or without exit GET from parameters), hash ref of
333: form name => value pairs
334:
335: Return: url with properly added the form name elements and values to the
336: the url doing proper escaping of the values and joining with ? or &
337: as needed
338:
339: =back
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