/[webpac2]/trunk/lib/WebPAC/Input.pm
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Revision 707 - (show annotations)
Mon Sep 25 15:26:12 2006 UTC (17 years, 7 months ago) by dpavlin
File size: 16992 byte(s)
 r1008@llin:  dpavlin | 2006-09-25 17:23:42 +0200
 lookup creation somewhat works

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

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