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

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Revision 598 - (show annotations)
Thu Jul 13 13:55:15 2006 UTC (17 years, 9 months ago) by dpavlin
File size: 14523 byte(s)
 r834@llin:  dpavlin | 2006-07-13 14:49:23 +0200
 fix pod

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 Text::Iconv;
11 use Data::Dumper;
12
13 =head1 NAME
14
15 WebPAC::Input - read different file formats into WebPAC
16
17 =head1 VERSION
18
19 Version 0.08
20
21 =cut
22
23 our $VERSION = '0.08';
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/) {
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 => '852',
163 limit => 500,
164 offset => 6000,
165 lookup => $lookup_obj,
166 stats => 1,
167 lookup_ref => sub {
168 my ($k,$v) = @_;
169 # store lookup $k => $v
170 },
171 modify_records => {
172 900 => { '^a' => { ' : ' => '^b' } },
173 901 => { '*' => { '^b' => ' ; ' } },
174 },
175 );
176
177 By default, C<code_page> is assumed to be C<852>.
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 call when adding C<< key => 'value' >> combinations to
186 lookup.
187
188 C<modify_records> specify mapping from subfields to delimiters or from
189 delimiters to subfields, as well as oprations on fields (if subfield is
190 defined as C<*>.
191
192 Returns size of database, regardless of C<offset> and C<limit>
193 parametars, see also C<size>.
194
195 =cut
196
197 sub open {
198 my $self = shift;
199 my $arg = {@_};
200
201 my $log = $self->_get_logger();
202
203 $log->logconfess("lookup argument is not suppored any more. rewrite call to lookup_coderef") if ($arg->{lookup});
204 $log->logconfess("lookup_coderef must be CODE, not ",ref($arg->{lookup_coderef}))
205 if ($arg->{lookup_coderef} && ref($arg->{lookup_coderef}) ne 'CODE');
206
207 $log->logcroak("need path") if (! $arg->{'path'});
208 my $code_page = $arg->{'code_page'} || '852';
209
210 # store data in object
211 $self->{'input_code_page'} = $code_page;
212 foreach my $v (qw/path offset limit/) {
213 $self->{$v} = $arg->{$v} if ($arg->{$v});
214 }
215
216 # create Text::Iconv object
217 $self->{iconv} = Text::Iconv->new($code_page,$self->{'encoding'}); ## FIXME remove!
218
219 my $filter_ref;
220 my $recode_regex;
221 my $recode_map;
222
223 if ($self->{recode}) {
224 my @r = split(/\s/, $self->{recode});
225 if ($#r % 2 != 1) {
226 $log->logwarn("recode needs even number of elements (some number of valid pairs)");
227 } else {
228 while (@r) {
229 my $from = shift @r;
230 my $to = shift @r;
231 $recode_map->{$from} = $to;
232 }
233
234 $recode_regex = join '|' => keys %{ $recode_map };
235
236 $log->debug("using recode regex: $recode_regex");
237 }
238
239 }
240
241 my $rec_regex = $self->modify_record_regexps(%{ $arg->{modify_records} });
242 $log->debug("rec_regex: ", Dumper($rec_regex));
243
244 my ($db, $size) = $self->{open_db}->( $self,
245 path => $arg->{path},
246 filter => sub {
247 my ($l,$f_nr) = @_;
248 return unless defined($l);
249
250 ## FIXME remove iconv!
251 $l = $self->{iconv}->convert($l) if ($self->{iconv});
252
253 $l =~ s/($recode_regex)/$recode_map->{$1}/g if ($recode_regex && $recode_map);
254
255 return $l unless ($rec_regex);
256
257 # apply regexps
258 if ($rec_regex && defined($rec_regex->{$f_nr})) {
259 $log->logconfess("regexps->{$f_nr} must be ARRAY") if (ref($rec_regex->{$f_nr}) ne 'ARRAY');
260 my $c = 0;
261 foreach my $r (@{ $rec_regex->{$f_nr} }) {
262 while ( eval '$l =~ ' . $r ) { $c++ };
263 }
264 warn "## field $f_nr triggered $c regexpes\n" if ($c && $self->{debug});
265 }
266
267 return $l;
268 },
269 %{ $arg },
270 );
271
272 unless (defined($db)) {
273 $log->logwarn("can't open database $arg->{path}, skipping...");
274 return;
275 }
276
277 unless ($size) {
278 $log->logwarn("no records in database $arg->{path}, skipping...");
279 return;
280 }
281
282 my $from_rec = 1;
283 my $to_rec = $size;
284
285 if (my $s = $self->{offset}) {
286 $log->debug("skipping to MFN $s");
287 $from_rec = $s;
288 } else {
289 $self->{offset} = $from_rec;
290 }
291
292 if ($self->{limit}) {
293 $log->debug("limiting to ",$self->{limit}," records");
294 $to_rec = $from_rec + $self->{limit} - 1;
295 $to_rec = $size if ($to_rec > $size);
296 }
297
298 # store size for later
299 $self->{size} = ($to_rec - $from_rec) ? ($to_rec - $from_rec + 1) : 0;
300
301 $log->info("processing $self->{size}/$size records [$from_rec-$to_rec] convert $code_page -> $self->{encoding}", $self->{stats} ? ' [stats]' : '');
302
303 # read database
304 for (my $pos = $from_rec; $pos <= $to_rec; $pos++) {
305
306 $log->debug("position: $pos\n");
307
308 my $rec = $self->{fetch_rec}->($self, $db, $pos );
309
310 $log->debug(sub { Dumper($rec) });
311
312 if (! $rec) {
313 $log->warn("record $pos empty? skipping...");
314 next;
315 }
316
317 # store
318 if ($self->{low_mem}) {
319 $self->{db}->put($pos, $rec);
320 } else {
321 $self->{data}->{$pos} = $rec;
322 }
323
324 # create lookup
325 $arg->{'lookup_coderef'}->( $rec ) if ($rec && $arg->{'lookup_coderef'});
326
327 # update counters for statistics
328 if ($self->{stats}) {
329
330 foreach my $fld (keys %{ $rec }) {
331 $self->{_stats}->{fld}->{ $fld }++;
332
333 $log->logdie("invalid record fild $fld, not ARRAY")
334 unless (ref($rec->{ $fld }) eq 'ARRAY');
335
336 foreach my $row (@{ $rec->{$fld} }) {
337
338 if (ref($row) eq 'HASH') {
339
340 foreach my $sf (keys %{ $row }) {
341 $self->{_stats}->{sf}->{ $fld }->{ $sf }->{count}++;
342 $self->{_stats}->{sf}->{ $fld }->{ $sf }->{repeatable}++
343 if (ref($row->{$sf}) eq 'ARRAY');
344 }
345
346 } else {
347 $self->{_stats}->{repeatable}->{ $fld }++;
348 }
349 }
350 }
351 }
352
353 $self->progress_bar($pos,$to_rec) unless ($self->{no_progress_bar});
354
355 }
356
357 $self->{pos} = -1;
358 $self->{last_pcnt} = 0;
359
360 # store max mfn and return it.
361 $self->{max_pos} = $to_rec;
362 $log->debug("max_pos: $to_rec");
363
364 return $size;
365 }
366
367 =head2 fetch
368
369 Fetch next record from database. It will also displays progress bar.
370
371 my $rec = $isis->fetch;
372
373 Record from this function should probably go to C<data_structure> for
374 normalisation.
375
376 =cut
377
378 sub fetch {
379 my $self = shift;
380
381 my $log = $self->_get_logger();
382
383 $log->logconfess("it seems that you didn't load database!") unless ($self->{pos});
384
385 if ($self->{pos} == -1) {
386 $self->{pos} = $self->{offset};
387 } else {
388 $self->{pos}++;
389 }
390
391 my $mfn = $self->{pos};
392
393 if ($mfn > $self->{max_pos}) {
394 $self->{pos} = $self->{max_pos};
395 $log->debug("at EOF");
396 return;
397 }
398
399 $self->progress_bar($mfn,$self->{max_pos}) unless ($self->{no_progress_bar});
400
401 my $rec;
402
403 if ($self->{low_mem}) {
404 $rec = $self->{db}->get($mfn);
405 } else {
406 $rec = $self->{data}->{$mfn};
407 }
408
409 $rec ||= 0E0;
410 }
411
412 =head2 pos
413
414 Returns current record number (MFN).
415
416 print $isis->pos;
417
418 First record in database has position 1.
419
420 =cut
421
422 sub pos {
423 my $self = shift;
424 return $self->{pos};
425 }
426
427
428 =head2 size
429
430 Returns number of records in database
431
432 print $isis->size;
433
434 Result from this function can be used to loop through all records
435
436 foreach my $mfn ( 1 ... $isis->size ) { ... }
437
438 because it takes into account C<offset> and C<limit>.
439
440 =cut
441
442 sub size {
443 my $self = shift;
444 return $self->{size};
445 }
446
447 =head2 seek
448
449 Seek to specified MFN in file.
450
451 $isis->seek(42);
452
453 First record in database has position 1.
454
455 =cut
456
457 sub seek {
458 my $self = shift;
459 my $pos = shift || return;
460
461 my $log = $self->_get_logger();
462
463 if ($pos < 1) {
464 $log->warn("seek before first record");
465 $pos = 1;
466 } elsif ($pos > $self->{max_pos}) {
467 $log->warn("seek beyond last record");
468 $pos = $self->{max_pos};
469 }
470
471 return $self->{pos} = (($pos - 1) || -1);
472 }
473
474 =head2 stats
475
476 Dump statistics about field and subfield usage
477
478 print $input->stats;
479
480 =cut
481
482 sub stats {
483 my $self = shift;
484
485 my $log = $self->_get_logger();
486
487 my $s = $self->{_stats};
488 if (! $s) {
489 $log->warn("called stats, but there is no statistics collected");
490 return;
491 }
492
493 my $max_fld = 0;
494
495 my $out = join("\n",
496 map {
497 my $f = $_ || die "no field";
498 my $v = $s->{fld}->{$f} || die "no s->{fld}->{$f}";
499 $max_fld = $v if ($v > $max_fld);
500
501 my $o = sprintf("%4s %d ~", $f, $v);
502
503 if (defined($s->{sf}->{$f})) {
504 map {
505 $o .= sprintf(" %s:%d%s", $_,
506 $s->{sf}->{$f}->{$_}->{count},
507 $s->{sf}->{$f}->{$_}->{repeatable} ? '*' : '',
508 );
509 } sort keys %{ $s->{sf}->{$f} };
510 }
511
512 if (my $v_r = $s->{repeatable}->{$f}) {
513 $o .= " ($v_r)" if ($v_r != $v);
514 }
515
516 $o;
517 } sort { $a cmp $b } keys %{ $s->{fld} }
518 );
519
520 $log->debug( sub { Dumper($s) } );
521
522 return $out;
523 }
524
525 =head2 modify_record_regexps
526
527 Generate hash with regexpes to be applied using L<filter>.
528
529 my $regexpes = $input->modify_record_regexps(
530 900 => { '^a' => { ' : ' => '^b' } },
531 901 => { '*' => { '^b' => ' ; ' } },
532 );
533
534 =cut
535
536 sub modify_record_regexps {
537 my $self = shift;
538 my $modify_record = {@_};
539
540 my $regexpes;
541
542 foreach my $f (keys %$modify_record) {
543 warn "--- f: $f\n";
544 foreach my $sf (keys %{ $modify_record->{$f} }) {
545 warn "---- sf: $sf\n";
546 foreach my $from (keys %{ $modify_record->{$f}->{$sf} }) {
547 my $to = $modify_record->{$f}->{$sf}->{$from};
548 #die "no field?" unless defined($to);
549 warn "----- transform: |$from| -> |$to|\n";
550
551 if ($sf =~ /^\^/) {
552 my $regex =
553 's/\Q'. $sf .'\E([^\^]+)\Q'. $from .'\E([^\^]+)/'. $sf .'$1'. $to .'$2/g';
554 push @{ $regexpes->{$f} }, $regex;
555 warn ">>>>> $regex [sf]\n";
556 } else {
557 my $regex =
558 's/\Q'. $from .'\E/'. $to .'/g';
559 push @{ $regexpes->{$f} }, $regex;
560 warn ">>>>> $regex [global]\n";
561 }
562
563 }
564 }
565 }
566
567 return $regexpes;
568 }
569
570 =head1 MEMORY USAGE
571
572 C<low_mem> options is double-edged sword. If enabled, WebPAC
573 will run on memory constraint machines (which doesn't have enough
574 physical RAM to create memory structure for whole source database).
575
576 If your machine has 512Mb or more of RAM and database is around 10000 records,
577 memory shouldn't be an issue. If you don't have enough physical RAM, you
578 might consider using virtual memory (if your operating system is handling it
579 well, like on FreeBSD or Linux) instead of dropping to L<DBM::Deep> to handle
580 parsed structure of ISIS database (this is what C<low_mem> option does).
581
582 Hitting swap at end of reading source database is probably o.k. However,
583 hitting swap before 90% will dramatically decrease performance and you will
584 be better off with C<low_mem> and using rest of availble memory for
585 operating system disk cache (Linux is particuallary good about this).
586 However, every access to database record will require disk access, so
587 generation phase will be slower 10-100 times.
588
589 Parsed structures are essential - you just have option to trade RAM memory
590 (which is fast) for disk space (which is slow). Be sure to have planty of
591 disk space if you are using C<low_mem> and thus L<DBM::Deep>.
592
593 However, when WebPAC is running on desktop machines (or laptops :-), it's
594 highly undesireable for system to start swapping. Using C<low_mem> option can
595 reduce WecPAC memory usage to around 64Mb for same database with lookup
596 fields and sorted indexes which stay in RAM. Performance will suffer, but
597 memory usage will really be minimal. It might be also more confortable to
598 run WebPAC reniced on those machines.
599
600
601 =head1 AUTHOR
602
603 Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>
604
605 =head1 COPYRIGHT & LICENSE
606
607 Copyright 2005 Dobrica Pavlinusic, All Rights Reserved.
608
609 This program is free software; you can redistribute it and/or modify it
610 under the same terms as Perl itself.
611
612 =cut
613
614 1; # End of WebPAC::Input

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