/[webpac2]/trunk/lib/WebPAC/Input.pm
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Contents of /trunk/lib/WebPAC/Input.pm

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Revision 757 - (show annotations)
Tue Oct 10 10:57:59 2006 UTC (17 years, 6 months ago) by dpavlin
File size: 16788 byte(s)
fix dump (ugly, needs re-visiting)

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

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