/[webpac2]/trunk/lib/WebPAC/Input.pm
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Revision 760 - (show annotations)
Wed Oct 25 15:56:44 2006 UTC (17 years, 6 months ago) by dpavlin
File size: 17026 byte(s)
Turn on option low_mem (which need rewrite to use db/row) if there
are more than 10000 rows (hardcoded, but should go away).

This prevents webpac from running out of memory with databases
of about 300000 records on 4Gb of (virtual) memory.

1 package WebPAC::Input;
2
3 use warnings;
4 use strict;
5
6 use blib;
7
8 use WebPAC::Common;
9 use base qw/WebPAC::Common/;
10 use Data::Dumper;
11 use Encode qw/from_to/;
12
13 =head1 NAME
14
15 WebPAC::Input - read different file formats into WebPAC
16
17 =head1 VERSION
18
19 Version 0.13
20
21 =cut
22
23 our $VERSION = '0.13';
24
25 =head1 SYNOPSIS
26
27 This module implements input as database which have fixed and known
28 I<size> while indexing and single unique numeric identifier for database
29 position ranging from 1 to I<size>.
30
31 Simply, something that is indexed by unmber from 1 .. I<size>.
32
33 Examples of such databases are CDS/ISIS files, MARC files, lines in
34 text file, and so on.
35
36 Specific file formats are implemented using low-level interface modules,
37 located in C<WebPAC::Input::*> namespace which export C<open_db>,
38 C<fetch_rec> and optional C<init> functions.
39
40 Perhaps a little code snippet.
41
42 use WebPAC::Input;
43
44 my $db = WebPAC::Input->new(
45 module => 'WebPAC::Input::ISIS',
46 low_mem => 1,
47 );
48
49 $db->open( path => '/path/to/database' );
50 print "database size: ",$db->size,"\n";
51 while (my $rec = $db->fetch) {
52 # do something with $rec
53 }
54
55
56
57 =head1 FUNCTIONS
58
59 =head2 new
60
61 Create new input database object.
62
63 my $db = new WebPAC::Input(
64 module => 'WebPAC::Input::MARC',
65 encoding => 'ISO-8859-2',
66 low_mem => 1,
67 recode => 'char pairs',
68 no_progress_bar => 1,
69 );
70
71 C<module> is low-level file format module. See L<WebPAC::Input::ISIS> and
72 L<WebPAC::Input::MARC>.
73
74 Optional parametar C<encoding> specify application code page (which will be
75 used internally). This should probably be your terminal encoding, and by
76 default, it C<ISO-8859-2>.
77
78 Default is not to use C<low_mem> options (see L<MEMORY USAGE> below).
79
80 C<recode> is optional string constisting of character or words pairs that
81 should be replaced in input stream.
82
83 C<no_progress_bar> disables progress bar output on C<STDOUT>
84
85 This function will also call low-level C<init> if it exists with same
86 parametars.
87
88 =cut
89
90 sub new {
91 my $class = shift;
92 my $self = {@_};
93 bless($self, $class);
94
95 my $log = $self->_get_logger;
96
97 $log->logconfess("code_page argument is not suppored any more. change it to encoding") if ($self->{lookup});
98 $log->logconfess("lookup argument is not suppored any more. rewrite call to lookup_ref") if ($self->{lookup});
99
100 $log->logconfess("specify low-level file format module") unless ($self->{module});
101 my $module_path = $self->{module};
102 $module_path =~ s#::#/#g;
103 $module_path .= '.pm';
104 $log->debug("require low-level module $self->{module} from $module_path");
105
106 require $module_path;
107
108 # check if required subclasses are implemented
109 foreach my $subclass (qw/open_db fetch_rec init dump_rec/) {
110 # FIXME
111 }
112
113 $self->{'encoding'} ||= 'ISO-8859-2';
114
115 $self ? return $self : return undef;
116 }
117
118 =head2 open
119
120 This function will read whole database in memory and produce lookups.
121
122 $input->open(
123 path => '/path/to/database/file',
124 code_page => 'cp852',
125 limit => 500,
126 offset => 6000,
127 stats => 1,
128 lookup_coderef => sub {
129 my $rec = shift;
130 # store lookups
131 },
132 modify_records => {
133 900 => { '^a' => { ' : ' => '^b' } },
134 901 => { '*' => { '^b' => ' ; ' } },
135 },
136 modify_file => 'conf/modify/mapping.map',
137 );
138
139 By default, C<code_page> is assumed to be C<cp852>.
140
141 C<offset> is optional parametar to position at some offset before reading from database.
142
143 C<limit> is optional parametar to read just C<limit> records from database
144
145 C<stats> create optional report about usage of fields and subfields
146
147 C<lookup_coderef> is closure to called to save data into lookups
148
149 C<modify_records> specify mapping from subfields to delimiters or from
150 delimiters to subfields, as well as oprations on fields (if subfield is
151 defined as C<*>.
152
153 C<modify_file> is alternative for C<modify_records> above which preserves order and offers
154 (hopefully) simplier sintax than YAML or perl (see L</modify_file_regex>). This option
155 overrides C<modify_records> if both exists for same input.
156
157 Returns size of database, regardless of C<offset> and C<limit>
158 parametars, see also C<size>.
159
160 =cut
161
162 sub open {
163 my $self = shift;
164 my $arg = {@_};
165
166 my $log = $self->_get_logger();
167
168 $log->logconfess("lookup argument is not suppored any more. rewrite call to lookup_coderef") if ($arg->{lookup});
169 $log->logconfess("lookup_coderef must be CODE, not ",ref($arg->{lookup_coderef}))
170 if ($arg->{lookup_coderef} && ref($arg->{lookup_coderef}) ne 'CODE');
171
172 $log->debug( $arg->{lookup_coderef} ? '' : 'not ', "using lookup_coderef");
173
174 $log->logcroak("need path") if (! $arg->{'path'});
175 my $code_page = $arg->{'code_page'} || 'cp852';
176
177 # store data in object
178 $self->{'input_code_page'} = $code_page;
179 foreach my $v (qw/path offset limit/) {
180 $self->{$v} = $arg->{$v} if ($arg->{$v});
181 }
182
183 my $filter_ref;
184 my $recode_regex;
185 my $recode_map;
186
187 if ($self->{recode}) {
188 my @r = split(/\s/, $self->{recode});
189 if ($#r % 2 != 1) {
190 $log->logwarn("recode needs even number of elements (some number of valid pairs)");
191 } else {
192 while (@r) {
193 my $from = shift @r;
194 my $to = shift @r;
195 $recode_map->{$from} = $to;
196 }
197
198 $recode_regex = join '|' => keys %{ $recode_map };
199
200 $log->debug("using recode regex: $recode_regex");
201 }
202
203 }
204
205 my $rec_regex;
206 if (my $p = $arg->{modify_file}) {
207 $log->debug("using modify_file $p");
208 $rec_regex = $self->modify_file_regexps( $p );
209 } elsif (my $h = $arg->{modify_records}) {
210 $log->debug("using modify_records ", Dumper( $h ));
211 $rec_regex = $self->modify_record_regexps(%{ $h });
212 }
213 $log->debug("rec_regex: ", Dumper($rec_regex)) if ($rec_regex);
214
215 my $class = $self->{module} || $log->logconfess("can't get low-level module name!");
216
217 my $ll_db = $class->new(
218 path => $arg->{path},
219 # filter => sub {
220 # my ($l,$f_nr) = @_;
221 # return unless defined($l);
222 # from_to($l, $code_page, $self->{'encoding'});
223 # $l =~ s/($recode_regex)/$recode_map->{$1}/g if ($recode_regex && $recode_map);
224 # return $l;
225 # },
226 %{ $arg },
227 );
228
229 unless (defined($ll_db)) {
230 $log->logwarn("can't open database $arg->{path}, skipping...");
231 return;
232 }
233
234 my $size = $ll_db->size;
235
236 unless ($size) {
237 $log->logwarn("no records in database $arg->{path}, skipping...");
238 return;
239 }
240
241 my $from_rec = 1;
242 my $to_rec = $size;
243
244 if (my $s = $self->{offset}) {
245 $log->debug("skipping to MFN $s");
246 $from_rec = $s;
247 } else {
248 $self->{offset} = $from_rec;
249 }
250
251 if ($self->{limit}) {
252 $log->debug("limiting to ",$self->{limit}," records");
253 $to_rec = $from_rec + $self->{limit} - 1;
254 $to_rec = $size if ($to_rec > $size);
255 }
256
257 # store size for later
258 $self->{size} = ($to_rec - $from_rec) ? ($to_rec - $from_rec + 1) : 0;
259
260 $log->info("processing $self->{size}/$size records [$from_rec-$to_rec] convert $code_page -> $self->{encoding}", $self->{stats} ? ' [stats]' : '');
261
262 # turn on low_mem for databases with more than 100000 records!
263 if (! $self->{low_mem} && $size > 100000) {
264 $log->warn("Using on-disk storage instead of memory for input data. This will affect performance.");
265 $self->{low_mem}++;
266 }
267
268 # running with low_mem flag? well, use DBM::Deep then.
269 if ($self->{'low_mem'}) {
270 $log->info("running with low_mem which impacts performance (<32 Mb memory usage)");
271
272 my $db_file = "data.db";
273
274 if (-e $db_file) {
275 unlink $db_file or $log->logdie("can't remove '$db_file' from last run");
276 $log->debug("removed '$db_file' from last run");
277 }
278
279 require DBM::Deep;
280
281 my $db = new DBM::Deep $db_file;
282
283 $log->logdie("DBM::Deep error: $!") unless ($db);
284
285 if ($db->error()) {
286 $log->logdie("can't open '$db_file' under low_mem: ",$db->error());
287 } else {
288 $log->debug("using file '$db_file' for DBM::Deep");
289 }
290
291 $self->{'db'} = $db;
292 }
293
294 # read database
295 for (my $pos = $from_rec; $pos <= $to_rec; $pos++) {
296
297 $log->debug("position: $pos\n");
298
299 my $rec = $ll_db->fetch_rec($pos, sub {
300 my ($l,$f_nr) = @_;
301 # return unless defined($l);
302 # return $l unless ($rec_regex && $f_nr);
303
304 $log->debug("-=> $f_nr ## $l");
305
306 # codepage conversion and recode_regex
307 from_to($l, $code_page, $self->{'encoding'});
308 $l =~ s/($recode_regex)/$recode_map->{$1}/g if ($recode_regex && $recode_map);
309
310 # apply regexps
311 if ($rec_regex && defined($rec_regex->{$f_nr})) {
312 $log->logconfess("regexps->{$f_nr} must be ARRAY") if (ref($rec_regex->{$f_nr}) ne 'ARRAY');
313 my $c = 0;
314 foreach my $r (@{ $rec_regex->{$f_nr} }) {
315 my $old_l = $l;
316 eval '$l =~ ' . $r;
317 if ($old_l ne $l) {
318 $log->debug("REGEX on $f_nr eval \$l =~ $r\n## old l: [$old_l]\n## new l: [$l]");
319 }
320 $log->error("error applying regex: $r") if ($@);
321 }
322 }
323
324 $log->debug("<=- $f_nr ## $l");
325 return $l;
326 });
327
328 $log->debug(sub { Dumper($rec) });
329
330 if (! $rec) {
331 $log->warn("record $pos empty? skipping...");
332 next;
333 }
334
335 # store
336 if ($self->{low_mem}) {
337 $self->{db}->put($pos, $rec);
338 } else {
339 $self->{data}->{$pos} = $rec;
340 }
341
342 # create lookup
343 $arg->{'lookup_coderef'}->( $rec ) if ($rec && $arg->{'lookup_coderef'});
344
345 # update counters for statistics
346 if ($self->{stats}) {
347
348 # fetch clean record with regexpes applied for statistics
349 my $rec = $ll_db->fetch_rec($pos);
350
351 foreach my $fld (keys %{ $rec }) {
352 $self->{_stats}->{fld}->{ $fld }++;
353
354 $log->logdie("invalid record fild $fld, not ARRAY")
355 unless (ref($rec->{ $fld }) eq 'ARRAY');
356
357 foreach my $row (@{ $rec->{$fld} }) {
358
359 if (ref($row) eq 'HASH') {
360
361 foreach my $sf (keys %{ $row }) {
362 next if ($sf eq 'subfields');
363 $self->{_stats}->{sf}->{ $fld }->{ $sf }->{count}++;
364 $self->{_stats}->{sf}->{ $fld }->{ $sf }->{repeatable}++
365 if (ref($row->{$sf}) eq 'ARRAY');
366 }
367
368 } else {
369 $self->{_stats}->{repeatable}->{ $fld }++;
370 }
371 }
372 }
373 }
374
375 $self->progress_bar($pos,$to_rec) unless ($self->{no_progress_bar});
376
377 }
378
379 $self->{pos} = -1;
380 $self->{last_pcnt} = 0;
381
382 # store max mfn and return it.
383 $self->{max_pos} = $to_rec;
384 $log->debug("max_pos: $to_rec");
385
386 # save for dump
387 $self->{ll_db} = $ll_db;
388
389 return $size;
390 }
391
392 =head2 fetch
393
394 Fetch next record from database. It will also displays progress bar.
395
396 my $rec = $isis->fetch;
397
398 Record from this function should probably go to C<data_structure> for
399 normalisation.
400
401 =cut
402
403 sub fetch {
404 my $self = shift;
405
406 my $log = $self->_get_logger();
407
408 $log->logconfess("it seems that you didn't load database!") unless ($self->{pos});
409
410 if ($self->{pos} == -1) {
411 $self->{pos} = $self->{offset};
412 } else {
413 $self->{pos}++;
414 }
415
416 my $mfn = $self->{pos};
417
418 if ($mfn > $self->{max_pos}) {
419 $self->{pos} = $self->{max_pos};
420 $log->debug("at EOF");
421 return;
422 }
423
424 $self->progress_bar($mfn,$self->{max_pos}) unless ($self->{no_progress_bar});
425
426 my $rec;
427
428 if ($self->{low_mem}) {
429 $rec = $self->{db}->get($mfn);
430 } else {
431 $rec = $self->{data}->{$mfn};
432 }
433
434 $rec ||= 0E0;
435 }
436
437 =head2 pos
438
439 Returns current record number (MFN).
440
441 print $isis->pos;
442
443 First record in database has position 1.
444
445 =cut
446
447 sub pos {
448 my $self = shift;
449 return $self->{pos};
450 }
451
452
453 =head2 size
454
455 Returns number of records in database
456
457 print $isis->size;
458
459 Result from this function can be used to loop through all records
460
461 foreach my $mfn ( 1 ... $isis->size ) { ... }
462
463 because it takes into account C<offset> and C<limit>.
464
465 =cut
466
467 sub size {
468 my $self = shift;
469 return $self->{size};
470 }
471
472 =head2 seek
473
474 Seek to specified MFN in file.
475
476 $isis->seek(42);
477
478 First record in database has position 1.
479
480 =cut
481
482 sub seek {
483 my $self = shift;
484 my $pos = shift || return;
485
486 my $log = $self->_get_logger();
487
488 if ($pos < 1) {
489 $log->warn("seek before first record");
490 $pos = 1;
491 } elsif ($pos > $self->{max_pos}) {
492 $log->warn("seek beyond last record");
493 $pos = $self->{max_pos};
494 }
495
496 return $self->{pos} = (($pos - 1) || -1);
497 }
498
499 =head2 stats
500
501 Dump statistics about field and subfield usage
502
503 print $input->stats;
504
505 =cut
506
507 sub stats {
508 my $self = shift;
509
510 my $log = $self->_get_logger();
511
512 my $s = $self->{_stats};
513 if (! $s) {
514 $log->warn("called stats, but there is no statistics collected");
515 return;
516 }
517
518 my $max_fld = 0;
519
520 my $out = join("\n",
521 map {
522 my $f = $_ || die "no field";
523 my $v = $s->{fld}->{$f} || die "no s->{fld}->{$f}";
524 $max_fld = $v if ($v > $max_fld);
525
526 my $o = sprintf("%4s %d ~", $f, $v);
527
528 if (defined($s->{sf}->{$f})) {
529 map {
530 $o .= sprintf(" %s:%d%s", $_,
531 $s->{sf}->{$f}->{$_}->{count},
532 $s->{sf}->{$f}->{$_}->{repeatable} ? '*' : '',
533 );
534 } sort keys %{ $s->{sf}->{$f} };
535 }
536
537 if (my $v_r = $s->{repeatable}->{$f}) {
538 $o .= " ($v_r)" if ($v_r != $v);
539 }
540
541 $o;
542 } sort { $a cmp $b } keys %{ $s->{fld} }
543 );
544
545 $log->debug( sub { Dumper($s) } );
546
547 return $out;
548 }
549
550 =head2 dump
551
552 Display humanly readable dump of record
553
554 =cut
555
556 sub dump {
557 my $self = shift;
558
559 return $self->{ll_db}->dump_rec( $self->{pos} );
560
561 }
562
563 =head2 modify_record_regexps
564
565 Generate hash with regexpes to be applied using l<filter>.
566
567 my $regexpes = $input->modify_record_regexps(
568 900 => { '^a' => { ' : ' => '^b' } },
569 901 => { '*' => { '^b' => ' ; ' } },
570 );
571
572 =cut
573
574 sub _get_regex {
575 my ($sf,$from,$to) = @_;
576 if ($sf =~ /^\^/) {
577 return
578 's/\Q'. $sf .'\E([^\^]*?)\Q'. $from .'\E([^\^]*?)/'. $sf .'$1'. $to .'$2/';
579 } else {
580 return
581 's/\Q'. $from .'\E/'. $to .'/g';
582 }
583 }
584
585 sub modify_record_regexps {
586 my $self = shift;
587 my $modify_record = {@_};
588
589 my $regexpes;
590
591 my $log = $self->_get_logger();
592
593 foreach my $f (keys %$modify_record) {
594 $log->debug("field: $f");
595
596 foreach my $sf (keys %{ $modify_record->{$f} }) {
597 $log->debug("subfield: $sf");
598
599 foreach my $from (keys %{ $modify_record->{$f}->{$sf} }) {
600 my $to = $modify_record->{$f}->{$sf}->{$from};
601 #die "no field?" unless defined($to);
602 $log->debug("transform: |$from| -> |$to|");
603
604 my $regex = _get_regex($sf,$from,$to);
605 push @{ $regexpes->{$f} }, $regex;
606 $log->debug("regex: $regex");
607 }
608 }
609 }
610
611 return $regexpes;
612 }
613
614 =head2 modify_file_regexps
615
616 Generate hash with regexpes to be applied using l<filter> from
617 pseudo hash/yaml format for regex mappings.
618
619 It should be obvious:
620
621 200
622 '^a'
623 ' : ' => '^e'
624 ' = ' => '^d'
625
626 In field I<200> find C<'^a'> and then C<' : '>, and replace it with C<'^e'>.
627 In field I<200> find C<'^a'> and then C<' = '>, and replace it with C<'^d'>.
628
629 my $regexpes = $input->modify_file_regexps( 'conf/modify/common.pl' );
630
631 On undef path it will just return.
632
633 =cut
634
635 sub modify_file_regexps {
636 my $self = shift;
637
638 my $modify_path = shift || return;
639
640 my $log = $self->_get_logger();
641
642 my $regexpes;
643
644 CORE::open(my $fh, $modify_path) || $log->logdie("can't open modify file $modify_path: $!");
645
646 my ($f,$sf);
647
648 while(<$fh>) {
649 chomp;
650 next if (/^#/ || /^\s*$/);
651
652 if (/^\s*(\d+)\s*$/) {
653 $f = $1;
654 $log->debug("field: $f");
655 next;
656 } elsif (/^\s*'([^']*)'\s*$/) {
657 $sf = $1;
658 $log->die("can't define subfiled before field in: $_") unless ($f);
659 $log->debug("subfield: $sf");
660 } elsif (/^\s*'([^']*)'\s*=>\s*'([^']*)'\s*$/) {
661 my ($from,$to) = ($1, $2);
662
663 $log->debug("transform: |$from| -> |$to|");
664
665 my $regex = _get_regex($sf,$from,$to);
666 push @{ $regexpes->{$f} }, $regex;
667 $log->debug("regex: $regex");
668 }
669 }
670
671 return $regexpes;
672 }
673
674 =head1 MEMORY USAGE
675
676 C<low_mem> options is double-edged sword. If enabled, WebPAC
677 will run on memory constraint machines (which doesn't have enough
678 physical RAM to create memory structure for whole source database).
679
680 If your machine has 512Mb or more of RAM and database is around 10000 records,
681 memory shouldn't be an issue. If you don't have enough physical RAM, you
682 might consider using virtual memory (if your operating system is handling it
683 well, like on FreeBSD or Linux) instead of dropping to L<DBM::Deep> to handle
684 parsed structure of ISIS database (this is what C<low_mem> option does).
685
686 Hitting swap at end of reading source database is probably o.k. However,
687 hitting swap before 90% will dramatically decrease performance and you will
688 be better off with C<low_mem> and using rest of availble memory for
689 operating system disk cache (Linux is particuallary good about this).
690 However, every access to database record will require disk access, so
691 generation phase will be slower 10-100 times.
692
693 Parsed structures are essential - you just have option to trade RAM memory
694 (which is fast) for disk space (which is slow). Be sure to have planty of
695 disk space if you are using C<low_mem> and thus L<DBM::Deep>.
696
697 However, when WebPAC is running on desktop machines (or laptops :-), it's
698 highly undesireable for system to start swapping. Using C<low_mem> option can
699 reduce WecPAC memory usage to around 64Mb for same database with lookup
700 fields and sorted indexes which stay in RAM. Performance will suffer, but
701 memory usage will really be minimal. It might be also more confortable to
702 run WebPAC reniced on those machines.
703
704
705 =head1 AUTHOR
706
707 Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>
708
709 =head1 COPYRIGHT & LICENSE
710
711 Copyright 2005-2006 Dobrica Pavlinusic, All Rights Reserved.
712
713 This program is free software; you can redistribute it and/or modify it
714 under the same terms as Perl itself.
715
716 =cut
717
718 1; # End of WebPAC::Input

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