Annotation of nsdl/lonsql, revision 1.3
1.1 www 1: #!/usr/bin/perl
2:
3: # The LearningOnline Network
1.2 www 4: # lonsql - LON TCP-NSDL Query Handler.
1.1 www 5: #
1.3 ! www 6: # $Id: lonsql,v 1.2 2005/11/17 22:04:47 www Exp $
1.1 www 7: #
8: # Copyright Michigan State University Board of Trustees
9: #
10: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
11: #
12: # LON-CAPA is free software; you can redistribute it and/or modify
13: # it under the terms of the GNU General Public License as published by
14: # the Free Software Foundation; either version 2 of the License, or
15: # (at your option) any later version.
16: #
17: # LON-CAPA is distributed in the hope that it will be useful,
18: # but WITHOUT ANY WARRANTY; without even the implied warranty of
19: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20: # GNU General Public License for more details.
21: #
22: # You should have received a copy of the GNU General Public License
23: # along with LON-CAPA; if not, write to the Free Software
24: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25: #
26: # /home/httpd/html/adm/gpl.txt
27: #
28: # http://www.lon-capa.org/
29: #
30:
31: =pod
32:
33: =head1 NAME
34:
35: lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
36:
37: =head1 SYNOPSIS
38:
39: This script should be run as user=www.
40: Note that a lonsql.pid file contains the pid of the parent process.
41:
42: =head1 OVERVIEW
43:
44: =head2 Purpose within LON-CAPA
45:
46: LON-CAPA is meant to distribute A LOT of educational content to A LOT
47: of people. It is ineffective to directly rely on contents within the
48: ext2 filesystem to be speedily scanned for on-the-fly searches of
49: content descriptions. (Simply put, it takes a cumbersome amount of
50: time to open, read, analyze, and close thousands of files.)
51:
52: The solution is to index various data fields that are descriptive of
53: the educational resources on a LON-CAPA server machine in a
54: database. Descriptive data fields are referred to as "metadata". The
55: question then arises as to how this metadata is handled in terms of
56: the rest of the LON-CAPA network without burdening client and daemon
57: processes.
58:
59: The obvious solution, using lonc to send a query to a lond process,
60: doesn't work so well in general as you can see in the following
61: example:
62:
63: lonc= loncapa client process A-lonc= a lonc process on Server A
64: lond= loncapa daemon process
65:
66: database command
67: A-lonc --------TCP/IP----------------> B-lond
68:
69: The problem emerges that A-lonc and B-lond are kept waiting for the
70: MySQL server to "do its stuff", or in other words, perform the
71: conceivably sophisticated, data-intensive, time-sucking database
72: transaction. By tying up a lonc and lond process, this significantly
73: cripples the capabilities of LON-CAPA servers.
74:
75: The solution is to offload the work onto another process, and use
76: lonc and lond just for requests and notifications of completed
77: processing:
78:
79: database command
80:
81: A-lonc ---------TCP/IP-----------------> B-lond =====> B-lonsql
82: <---------------------------------/ |
83: "ok, I'll get back to you..." |
84: |
85: /
86: A-lond <------------------------------- B-lonc <======
87: "Guess what? I have the result!"
88:
89: Of course, depending on success or failure, the messages may vary, but
90: the principle remains the same where a separate pool of children
91: processes (lonsql's) handle the MySQL database manipulations.
92:
93: Thus, lonc and lond spend effectively no time waiting on results from
94: the database.
95:
96: =head1 Internals
97:
98: =over 4
99:
100: =cut
101:
102: use strict;
103:
104: use lib '/home/httpd/lib/perl/';
105: use LONCAPA::Configuration;
106: use LONCAPA::lonmetadata();
107:
108: use IO::Socket;
109: use Symbol;
110: use POSIX;
111: use IO::Select;
112: use IO::File;
113: use Socket;
114: use Fcntl;
115: use Tie::RefHash;
1.3 ! www 116: use HTML::LCParser();
! 117: use LWP::UserAgent();
! 118: use HTTP::Headers;
! 119: use HTTP::Date;
1.1 www 120: use File::Find;
121: use localenroll;
122:
123: ########################################################
124: ########################################################
125:
126: =pod
127:
128: =item Variables required for forking
129:
130: =over 4
131:
132: =item $MAX_CLIENTS_PER_CHILD
133:
134: The number of clients each child should process.
135:
136: =item %children
137:
138: The keys to %children are the current child process IDs
139:
140: =item $children
141:
142: The current number of children
143:
144: =back
145:
146: =cut
147:
148: ########################################################
149: ########################################################
150: my $MAX_CLIENTS_PER_CHILD = 5; # number of clients each child should process
151: my %children = (); # keys are current child process IDs
152: my $children = 0; # current number of children
153:
154: ###################################################################
155: ###################################################################
156:
157: =pod
158:
159: =item Main body of code.
160:
161: =over 4
162:
163: =item Read data from loncapa_apache.conf and loncapa.conf.
164:
165: =item Ensure we can access the database.
166:
167: =item Determine if there are other instances of lonsql running.
168:
169: =item Read the hosts file.
170:
171: =item Create a socket for lonsql.
172:
173: =item Fork once and dissociate from parent.
174:
175: =item Write PID to disk.
176:
177: =item Prefork children and maintain the population of children.
178:
179: =back
180:
181: =cut
182:
183: ###################################################################
184: ###################################################################
185: my $childmaxattempts=10;
186: my $run =0; # running counter to generate the query-id
187: #
188: # Read loncapa_apache.conf and loncapa.conf
189: #
190: my $perlvarref=LONCAPA::Configuration::read_conf('loncapa.conf');
191: my %perlvar=%{$perlvarref};
192: #
193: # Write the /home/www/.my.cnf file
194: my $conf_file = '/home/www/.my.cnf';
195: if (! -e $conf_file) {
196: if (open MYCNF, ">$conf_file") {
197: print MYCNF <<"ENDMYCNF";
198: [client]
199: user=www
200: password=$perlvar{'lonSqlAccess'}
201: ENDMYCNF
202: close MYCNF;
203: } else {
204: warn "Unable to write $conf_file, continuing";
205: }
206: }
207:
208:
209: #
210: # Check if other instance running
211: #
212: my $pidfile="$perlvar{'lonDaemons'}/logs/lonsql.pid";
213: if (-e $pidfile) {
214: my $lfh=IO::File->new("$pidfile");
215: my $pide=<$lfh>;
216: chomp($pide);
217: if (kill 0 => $pide) { die "already running"; }
218: }
219:
220: #
221: # Read hosts file
222: #
223: my $thisserver;
224: my $PREFORK=4; # number of children to maintain, at least four spare
225: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
226: while (my $configline=<CONFIG>) {
227: my ($id,$domain,$role,$name)=split(/:/,$configline);
228: $name=~s/\s//g;
229: $thisserver=$name if ($id eq $perlvar{'lonHostID'});
230: #$PREFORK++;
231: }
232: close(CONFIG);
233: #
234: #$PREFORK=int($PREFORK/4);
235:
236: #
237: # Create a socket to talk to lond
238: #
239: my $unixsock = "mysqlsock";
240: my $localfile="$perlvar{'lonSockDir'}/$unixsock";
241: my $server;
242: unlink ($localfile);
243: unless ($server=IO::Socket::UNIX->new(Local =>"$localfile",
244: Type => SOCK_STREAM,
245: Listen => 10)) {
246: print "in socket error:$@\n";
247: }
248:
249: #
250: # Fork once and dissociate
251: #
252: my $fpid=fork;
253: exit if $fpid;
254: die "Couldn't fork: $!" unless defined ($fpid);
255: POSIX::setsid() or die "Can't start new session: $!";
256:
257: #
258: # Write our PID on disk
259: my $execdir=$perlvar{'lonDaemons'};
260: open (PIDSAVE,">$execdir/logs/lonsql.pid");
261: print PIDSAVE "$$\n";
262: close(PIDSAVE);
263: &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
264:
265: #
266: # Ignore signals generated during initial startup
267: $SIG{HUP}=$SIG{USR1}='IGNORE';
268: # Now we are on our own
269: # Fork off our children.
270: for (1 .. $PREFORK) {
271: make_new_child();
272: }
273:
274: #
275: # Install signal handlers.
276: $SIG{CHLD} = \&REAPER;
277: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
278: $SIG{HUP} = \&HUPSMAN;
279:
280: #
281: # And maintain the population.
282: while (1) {
283: sleep; # wait for a signal (i.e., child's death)
284: for (my $i = $children; $i < $PREFORK; $i++) {
285: make_new_child(); # top up the child pool
286: }
287: }
288:
289: ########################################################
290: ########################################################
291:
292: =pod
293:
294: =item &make_new_child
295:
296: Inputs: None
297:
298: Returns: None
299:
300: =cut
301:
302: ########################################################
303: ########################################################
304: sub make_new_child {
305: my $pid;
306: my $sigset;
307: #
308: # block signal for fork
309: $sigset = POSIX::SigSet->new(SIGINT);
310: sigprocmask(SIG_BLOCK, $sigset)
311: or die "Can't block SIGINT for fork: $!\n";
312: #
313: die "fork: $!" unless defined ($pid = fork);
314: #
315: if ($pid) {
316: # Parent records the child's birth and returns.
317: sigprocmask(SIG_UNBLOCK, $sigset)
318: or die "Can't unblock SIGINT for fork: $!\n";
319: $children{$pid} = 1;
320: $children++;
321: return;
322: } else {
323: # Child can *not* return from this subroutine.
324: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
325: # unblock signals
326: sigprocmask(SIG_UNBLOCK, $sigset)
327: or die "Can't unblock SIGINT for fork: $!\n";
1.2 www 328:
1.1 www 329: $SIG{TERM}=$SIG{INT}=$SIG{QUIT}=$SIG{__DIE__}=\&DISCONNECT;
330: # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
331: for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
332: my $client = $server->accept() or last;
333: # do something with the connection
334: $run = $run+1;
335: my $userinput = <$client>;
336: chomp($userinput);
337: #
338: my ($conserver,$query,
339: $arg1,$arg2,$arg3)=split(/&/,$userinput);
340: my $query=unescape($query);
341: #
342: #send query id which is pid_unixdatetime_runningcounter
343: my $queryid = $thisserver;
344: $queryid .="_".($$)."_";
345: $queryid .= time."_";
346: $queryid .= $run;
347: print $client "$queryid\n";
348: #
349: # &logthis("QUERY: $query - $arg1 - $arg2 - $arg3");
350: sleep 1;
351: #
352: my $result='';
353: #
354: # At this point, query is received, query-ID assigned and sent
355: # back, $query eq 'logquery' will mean that this is a query
356: # against log-files
357: if (($query eq 'userlog') || ($query eq 'courselog')) {
358: # beginning of log query
359: my $udom = &unescape($arg1);
360: my $uname = &unescape($arg2);
361: my $command = &unescape($arg3);
362: my $path = &propath($udom,$uname);
363: if (-e "$path/activity.log") {
364: if ($query eq 'userlog') {
365: $result=&userlog($path,$command);
366: } else {
367: $result=&courselog($path,$command);
368: }
369: } else {
370: &logthis('Unable to do log query: '.$uname.'@'.$udom);
371: $result='no_such_file';
372: }
373: # end of log query
374: } elsif ($query eq 'fetchenrollment') {
375: # retrieve institutional class lists
376: my $dom = &unescape($arg1);
377: my %affiliates = ();
378: my %replies = ();
379: my $locresult = '';
380: my $querystr = &unescape($arg3);
381: foreach (split/%%/,$querystr) {
1.2 www 382: if (/^([^=]+)=([^=]+)$/) {
1.1 www 383: @{$affiliates{$1}} = split/,/,$2;
384: }
385: }
386: $locresult = &localenroll::fetch_enrollment($dom,\%affiliates,\%replies);
387: $result = &escape($locresult.':');
388: if ($locresult) {
389: $result .= &escape(join(':',map{$_.'='.$replies{$_}} keys %replies));
390: }
391: } elsif ($query eq 'prepare activity log') {
392: my ($cid,$domain) = map {&unescape($_);} ($arg1,$arg2);
393: &logthis('preparing activity log tables for '.$cid);
394: my $command =
395: qq{$perlvar{'lonDaemons'}/parse_activity_log.pl -course=$cid -domain=$domain};
396: system($command);
397: &logthis($command);
398: my $returnvalue = $?>>8;
399: if ($returnvalue) {
400: $result = 'error: parse_activity_log.pl returned '.
401: $returnvalue;
402: } else {
403: $result = 'success';
404: }
405: } else {
406: # Do an sql query
407: $result = &do_sql_query($query,$arg1,$arg2);
408: }
409: # result does not need to be escaped because it has already been
410: # escaped.
411: #$result=&escape($result);
412: &reply("queryreply:$queryid:$result",$conserver);
413: }
414: # tidy up gracefully and finish
415: #
1.2 www 416:
1.1 www 417: # this exit is VERY important, otherwise the child will become
418: # a producer of more and more children, forking yourself into
419: # process death.
420: exit;
421: }
422: }
423:
424: ########################################################
425: ########################################################
426:
427: =pod
428:
429: =item &do_sql_query
430:
431: Runs an sql metadata table query.
432:
433: Inputs: $query, $custom, $customshow
434:
435: Returns: A string containing escaped results.
436:
437: =cut
438:
439: ########################################################
440: ########################################################
441: {
442: my @metalist;
443:
444: sub process_file {
445: if ( -e $_ && # file exists
446: -f $_ && # and is a normal file
447: /\.meta$/ && # ends in meta
448: ! /^.+\.\d+\.[^\.]+\.meta$/ # is not a previous version
449: ) {
450: push(@metalist,$File::Find::name);
451: }
452: }
453:
454: sub do_sql_query {
1.2 www 455: my ($query) = @_;
1.1 www 456: &logthis('doing query '.$query);
1.2 www 457:
1.1 www 458: my @results = ();
1.2 www 459:
1.1 www 460: #
461: if ($query) {
462: #prepare and execute the query
1.2 www 463: my $aref=&nsdl_query($query);
464: foreach my $row (@$aref) {
465: my @b=map { &escape($_); } @$row;
466: push @results,join(",", @b);
467: }
468:
1.1 www 469: }
1.2 www 470: return join("&",@results);
1.1 www 471: } # End of &do_sql_query
472:
473: } # End of scoping curly braces for &process_file and &do_sql_query
474: ########################################################
475: ########################################################
476:
477: =pod
478:
479: =item &logthis
480:
481: Inputs: $message, the message to log
482:
483: Returns: nothing
484:
485: Writes $message to the logfile.
486:
487: =cut
488:
489: ########################################################
490: ########################################################
491: sub logthis {
492: my $message=shift;
493: my $execdir=$perlvar{'lonDaemons'};
494: my $fh=IO::File->new(">>$execdir/logs/lonsql.log");
495: my $now=time;
496: my $local=localtime($now);
497: print $fh "$local ($$): $message\n";
498: }
499:
500: # -------------------------------------------------- Non-critical communication
501:
502: ########################################################
503: ########################################################
504:
505: =pod
506:
507: =item &subreply
508:
509: Sends a command to a server. Called only by &reply.
510:
511: Inputs: $cmd,$server
512:
513: Returns: The results of the message or 'con_lost' on error.
514:
515: =cut
516:
517: ########################################################
518: ########################################################
519: sub subreply {
520: my ($cmd,$server)=@_;
521: my $peerfile="$perlvar{'lonSockDir'}/$server";
522: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
523: Type => SOCK_STREAM,
524: Timeout => 10)
525: or return "con_lost";
526: print $sclient "$cmd\n";
527: my $answer=<$sclient>;
528: chomp($answer);
529: $answer="con_lost" if (!$answer);
530: return $answer;
531: }
532:
533: ########################################################
534: ########################################################
535:
536: =pod
537:
538: =item &reply
539:
540: Sends a command to a server.
541:
542: Inputs: $cmd,$server
543:
544: Returns: The results of the message or 'con_lost' on error.
545:
546: =cut
547:
548: ########################################################
549: ########################################################
550: sub reply {
551: my ($cmd,$server)=@_;
552: my $answer;
553: if ($server ne $perlvar{'lonHostID'}) {
554: $answer=subreply($cmd,$server);
555: if ($answer eq 'con_lost') {
556: $answer=subreply("ping",$server);
557: $answer=subreply($cmd,$server);
558: }
559: } else {
560: $answer='self_reply';
561: $answer=subreply($cmd,$server);
562: }
563: return $answer;
564: }
565:
566: ########################################################
567: ########################################################
568:
569: =pod
570:
571: =item &escape
572:
573: Escape special characters in a string.
574:
575: Inputs: string to escape
576:
577: Returns: The input string with special characters escaped.
578:
579: =cut
580:
581: ########################################################
582: ########################################################
583: sub escape {
584: my $str=shift;
585: $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
586: return $str;
587: }
588:
589: ########################################################
590: ########################################################
591:
592: =pod
593:
594: =item &unescape
595:
596: Unescape special characters in a string.
597:
598: Inputs: string to unescape
599:
600: Returns: The input string with special characters unescaped.
601:
602: =cut
603:
604: ########################################################
605: ########################################################
606: sub unescape {
607: my $str=shift;
608: $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
609: return $str;
610: }
611:
612: ########################################################
613: ########################################################
614:
615: =pod
616:
617: =item &ishome
618:
619: Determine if the current machine is the home server for a user.
620: The determination is made by checking the filesystem for the users information.
621:
622: Inputs: $author
623:
624: Returns: 0 - this is not the authors home server, 1 - this is.
625:
626: =cut
627:
628: ########################################################
629: ########################################################
630: sub ishome {
631: my $author=shift;
632: $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
633: my ($udom,$uname)=split(/\//,$author);
634: my $proname=propath($udom,$uname);
635: if (-e $proname) {
636: return 1;
637: } else {
638: return 0;
639: }
640: }
641:
642: ########################################################
643: ########################################################
644:
645: =pod
646:
647: =item &propath
648:
649: Inputs: user name, user domain
650:
651: Returns: The full path to the users directory.
652:
653: =cut
654:
655: ########################################################
656: ########################################################
657: sub propath {
658: my ($udom,$uname)=@_;
659: $udom=~s/\W//g;
660: $uname=~s/\W//g;
661: my $subdir=$uname.'__';
662: $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
663: my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
664: return $proname;
665: }
666:
667: ########################################################
668: ########################################################
669:
670: =pod
671:
672: =item &courselog
673:
674: Inputs: $path, $command
675:
676: Returns: unescaped string of values.
677:
678: =cut
679:
680: ########################################################
681: ########################################################
682: sub courselog {
683: my ($path,$command)=@_;
684: my %filters=();
685: foreach (split(/\:/,&unescape($command))) {
686: my ($name,$value)=split(/\=/,$_);
687: $filters{$name}=$value;
688: }
689: my @results=();
690: open(IN,$path.'/activity.log') or return ('file_error');
691: while (my $line=<IN>) {
692: chomp($line);
693: my ($timestamp,$host,$log)=split(/\:/,$line);
694: #
695: # $log has the actual log entries; currently still escaped, and
696: # %26(timestamp)%3a(url)%3a(user)%3a(domain)
697: # then additionally
698: # %3aPOST%3a(name)%3d(value)%3a(name)%3d(value)
699: # or
700: # %3aCSTORE%3a(name)%3d(value)%26(name)%3d(value)
701: #
702: # get delimiter between timestamped entries to be &&&
703: $log=~s/\%26(\d+)\%3a/\&\&\&$1\%3a/g;
704: # now go over all log entries
705: foreach (split(/\&\&\&/,&unescape($log))) {
706: my ($time,$res,$uname,$udom,$action,@values)=split(/\:/,$_);
707: my $values=&unescape(join(':',@values));
708: $values=~s/\&/\:/g;
709: $res=&unescape($res);
710: my $include=1;
711: if (($filters{'username'}) && ($uname ne $filters{'username'}))
712: { $include=0; }
713: if (($filters{'domain'}) && ($udom ne $filters{'domain'}))
714: { $include=0; }
715: if (($filters{'url'}) && ($res!~/$filters{'url'}/))
716: { $include=0; }
717: if (($filters{'start'}) && ($time<$filters{'start'}))
718: { $include=0; }
719: if (($filters{'end'}) && ($time>$filters{'end'}))
720: { $include=0; }
721: if (($filters{'action'} eq 'view') && ($action))
722: { $include=0; }
723: if (($filters{'action'} eq 'submit') && ($action ne 'POST'))
724: { $include=0; }
725: if (($filters{'action'} eq 'grade') && ($action ne 'CSTORE'))
726: { $include=0; }
727: if ($include) {
728: push(@results,($time<1000000000?'0':'').$time.':'.$res.':'.
729: $uname.':'.$udom.':'.
730: $action.':'.$values);
731: }
732: }
733: }
734: close IN;
735: return join('&',sort(@results));
736: }
737:
738: ########################################################
739: ########################################################
740:
741: =pod
742:
743: =item &userlog
744:
745: Inputs: $path, $command
746:
747: Returns: unescaped string of values.
748:
749: =cut
750:
751: ########################################################
752: ########################################################
753: sub userlog {
754: my ($path,$command)=@_;
755: my %filters=();
756: foreach (split(/\:/,&unescape($command))) {
757: my ($name,$value)=split(/\=/,$_);
758: $filters{$name}=$value;
759: }
760: my @results=();
761: open(IN,$path.'/activity.log') or return ('file_error');
762: while (my $line=<IN>) {
763: chomp($line);
764: my ($timestamp,$host,$log)=split(/\:/,$line);
765: $log=&unescape($log);
766: my $include=1;
767: if (($filters{'start'}) && ($timestamp<$filters{'start'}))
768: { $include=0; }
769: if (($filters{'end'}) && ($timestamp>$filters{'end'}))
770: { $include=0; }
771: if (($filters{'action'} eq 'log') && ($log!~/^Log/)) { $include=0; }
772: if (($filters{'action'} eq 'check') && ($log!~/^Check/))
773: { $include=0; }
774: if ($include) {
775: push(@results,$timestamp.':'.$log);
776: }
777: }
778: close IN;
779: return join('&',sort(@results));
780: }
781:
782: ########################################################
783: ########################################################
784:
785: =pod
786:
787: =item Functions required for forking
788:
789: =over 4
790:
791: =item REAPER
792:
793: REAPER takes care of dead children.
794:
795: =item HUNTSMAN
796:
797: Signal handler for SIGINT.
798:
799: =item HUPSMAN
800:
801: Signal handler for SIGHUP
802:
803: =item DISCONNECT
804:
805: Disconnects from database.
806:
807: =back
808:
809: =cut
810:
811: ########################################################
812: ########################################################
813: sub REAPER { # takes care of dead children
814: $SIG{CHLD} = \&REAPER;
815: my $pid = wait;
816: $children --;
817: &logthis("Child $pid died");
818: delete $children{$pid};
819: }
820:
821: sub HUNTSMAN { # signal handler for SIGINT
822: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
823: kill 'INT' => keys %children;
824: my $execdir=$perlvar{'lonDaemons'};
825: unlink("$execdir/logs/lonsql.pid");
826: &logthis("<font color='red'>CRITICAL: Shutting down</font>");
827: $unixsock = "mysqlsock";
828: my $port="$perlvar{'lonSockDir'}/$unixsock";
829: unlink($port);
830: exit; # clean up with dignity
831: }
832:
833: sub HUPSMAN { # signal handler for SIGHUP
834: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
835: kill 'INT' => keys %children;
836: close($server); # free up socket
837: &logthis("<font color='red'>CRITICAL: Restarting</font>");
838: my $execdir=$perlvar{'lonDaemons'};
839: $unixsock = "mysqlsock";
840: my $port="$perlvar{'lonSockDir'}/$unixsock";
841: unlink($port);
842: exec("$execdir/lonsql"); # here we go again
843: }
844:
1.2 www 845: #
846: # Takes SQL query
847: # sends it to NSDL
848: # has to return array reference
849: #
1.1 www 850:
1.2 www 851: sub nsdl_query {
852: my $query=shift;
1.3 ! www 853: my ($keyword)=($query=~/\"\%([^\%]+)\%\"/);
! 854: $keyword=&escape($keyword);
! 855: &logthis('Doing '.$keyword);
! 856: my $url='http://search.nsdl.org?verb=Search&s=0&n=500&q='.$keyword;
! 857: my $ua=new LWP::UserAgent;
! 858: my $response=$ua->get($url);
! 859:
! 860: return [];
! 861: }
1.1 www 862:
863: =pod
864:
865: =back
866:
867: =cut
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