source: gsdl/trunk/perllib/plugins/ReadTextFile.pm@ 16667

Last change on this file since 16667 was 16667, checked in by kjdon, 13 years ago

get_language_encoding was setting ->input_encoding, which means its wrong for all the next files. Changed this.

  • Property svn:executable set to *
File size: 14.6 KB
Line 
1###########################################################################
2#
3# ReadTxtFile.pm -- base class for import plugins that have plain text files
4# A component of the Greenstone digital library software
5# from the New Zealand Digital Library Project at the
6# University of Waikato, New Zealand.
7#
8# Copyright (C) 1999-2005 New Zealand Digital Library Project
9#
10# This program is free software; you can redistribute it and/or modify
11# it under the terms of the GNU General Public License as published by
12# the Free Software Foundation; either version 2 of the License, or
13# (at your option) any later version.
14#
15# This program is distributed in the hope that it will be useful,
16# but WITHOUT ANY WARRANTY; without even the implied warranty of
17# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18# GNU General Public License for more details.
19#
20# You should have received a copy of the GNU General Public License
21# along with this program; if not, write to the Free Software
22# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23#
24###########################################################################
25
26package ReadTextFile;
27
28use strict;
29no strict 'subs';
30no strict 'refs'; # allow filehandles to be variables and viceversa
31
32
33use multiread;
34use encodings;
35use unicode;
36use textcat;
37use doc;
38use ghtml;
39use gsprintf 'gsprintf';
40
41use AutoExtractMetadata;
42
43sub BEGIN {
44 @ReadTextFile::ISA = ( 'AutoExtractMetadata' );
45}
46
47my $encoding_plus_auto_list =
48 [ { 'name' => "auto",
49 'desc' => "{ReadTextFile.input_encoding.auto}" } ];
50push(@{$encoding_plus_auto_list},@{$BasePlugin::encoding_list});
51
52my $arguments =
53 [ { 'name' => "input_encoding",
54 'desc' => "{ReadTextFile.input_encoding}",
55 'type' => "enum",
56 'list' => $encoding_plus_auto_list,
57 'reqd' => "no" ,
58 'deft' => "auto" } ,
59 { 'name' => "default_encoding",
60 'desc' => "{ReadTextFile.default_encoding}",
61 'type' => "enum",
62 'list' => $BasePlugin::encoding_list,
63 'reqd' => "no",
64 'deft' => "utf8" },
65 { 'name' => "extract_language",
66 'desc' => "{ReadTextFile.extract_language}",
67 'type' => "flag",
68 'reqd' => "no" },
69 { 'name' => "default_language",
70 'desc' => "{ReadTextFile.default_language}",
71 'type' => "string",
72 'deft' => "en",
73 'reqd' => "no" }
74 ];
75
76
77my $options = { 'name' => "ReadTextFile",
78 'desc' => "{ReadTextFile.desc}",
79 'abstract' => "yes",
80 'inherits' => "no",
81 'args' => $arguments };
82
83
84
85sub new {
86 my $class = shift (@_);
87 my ($pluginlist,$inputargs,$hashArgOptLists) = @_;
88 push(@$pluginlist, $class);
89
90 push(@{$hashArgOptLists->{"ArgList"}},@{$arguments});
91 push(@{$hashArgOptLists->{"OptList"}},$options);
92
93 my $self = new AutoExtractMetadata($pluginlist, $inputargs, $hashArgOptLists);
94
95 return bless $self, $class;
96
97}
98
99
100
101# The ReadTextFile read_into_doc_obj() function. This function does all the
102# right things to make general options work for a given plugin. It reads in
103# a file and sets up a slew of metadata all saved in doc_obj, which
104# it then returns as part of a tuple (process_status,doc_obj)
105#
106# Much of this functionality used to reside in read, but it was broken
107# down into a supporting routine to make the code more flexible.
108#
109# recursive plugins (e.g. RecPlug) and specialized plugins like those
110# capable of processing many documents within a single file (e.g.
111# GMLPlug) will normally want to implement their own version of
112# read_into_doc_obj()
113#
114# Note that $base_dir might be "" and that $file might
115# include directories
116sub read_into_doc_obj {
117 my $self = shift (@_);
118 my ($pluginfo, $base_dir, $file, $block_hash, $metadata, $processor, $maxdocs, $total_count, $gli) = @_;
119
120 my $outhandle = $self->{'outhandle'};
121 # should we move this to read? What about secondary plugins?
122 print STDERR "<Processing n='$file' p='$self->{'plugin_type'}'>\n" if ($gli);
123 print $outhandle "$self->{'plugin_type'} processing $file\n"
124 if $self->{'verbosity'} > 1;
125
126 my ($filename_full_path, $filename_no_path) = &util::get_full_filenames($base_dir, $file);
127
128 # Do encoding stuff
129 my ($language, $encoding) = $self->textcat_get_language_encoding ($filename_full_path);
130 if ($self->{'verbosity'} > 2) {
131 print $outhandle "ReadTextFile: reading $file as ($encoding,$language)\n";
132 }
133
134 # create a new document
135 my $doc_obj = new doc ($filename_full_path, "indexed_doc");
136 my $top_section = $doc_obj->get_top_section();
137
138 # this should look at the plugin option too...
139 $doc_obj->set_OIDtype ($processor->{'OIDtype'}, $processor->{'OIDmetadata'});
140 $doc_obj->add_utf8_metadata($top_section, "Plugin", "$self->{'plugin_type'}");
141 $doc_obj->add_utf8_metadata($top_section, "FileSize", (-s $filename_full_path));
142 $self->set_Source_metadata($doc_obj, $filename_no_path, $encoding);
143
144 $doc_obj->add_utf8_metadata($top_section, "Language", $language);
145 $doc_obj->add_utf8_metadata($top_section, "Encoding", $encoding);
146
147 # read in file ($text will be in utf8)
148 my $text = "";
149 $self->read_file ($filename_full_path, $encoding, $language, \$text);
150
151 if (!length ($text)) {
152 if ($gli) {
153 print STDERR "<ProcessingError n='$file' r='File contains no text'>\n";
154 }
155 gsprintf($outhandle, "$self->{'plugin_type'}: {ReadTextFile.file_has_no_text}\n", $filename_full_path) if $self->{'verbosity'};
156
157 my $failhandle = $self->{'failhandle'};
158 gsprintf($failhandle, "$file: " . ref($self) . ": {ReadTextFile.empty_file}\n");
159 # print $failhandle "$file: " . ref($self) . ": file contains no text\n";
160 $self->{'num_not_processed'} ++;
161
162 return (0,undef); # what should we return here?? error but don't want to pass it on
163 }
164
165 # do plugin specific processing of doc_obj
166 unless (defined ($self->process (\$text, $pluginfo, $base_dir, $file, $metadata, $doc_obj, $gli))) {
167 $text = '';
168 undef $text;
169 print STDERR "<ProcessingError n='$file'>\n" if ($gli);
170 return (-1,undef);
171 }
172 $text='';
173 undef $text;
174
175 # include any metadata passed in from previous plugins
176 # note that this metadata is associated with the top level section
177 $self->add_associated_files($doc_obj, $filename_full_path);
178 $self->extra_metadata ($doc_obj, $top_section, $metadata);
179
180 # do any automatic metadata extraction
181 $self->auto_extract_metadata ($doc_obj);
182
183
184 # if we haven't found any Title so far, assign one
185 $self->title_fallback($doc_obj,$top_section,$filename_no_path);
186
187 $self->add_OID($doc_obj);
188
189 return (1,$doc_obj);
190}
191
192# uses the multiread package to read in the entire file pointed to
193# by filename and loads the resulting text into $$textref. Input text
194# may be in any of the encodings handled by multiread, output text
195# will be in utf8
196sub read_file {
197 my $self = shift (@_);
198 my ($filename, $encoding, $language, $textref) = @_;
199
200 if (!-r $filename)
201 {
202 my $outhandle = $self->{'outhandle'};
203 gsprintf($outhandle, "{ReadTextFile.read_denied}\n", $filename) if $self->{'verbosity'};
204 # print $outhandle "Read permission denied for $filename\n" if $self->{'verbosity'};
205 return;
206 }
207 $$textref = "";
208 if (!open (FILE, $filename)) {
209 gsprintf(STDERR, "ReadTextFile::read_file {ReadTextFile.could_not_open_for_reading} ($!)\n", $filename);
210 die "\n";
211 }
212
213 if ($encoding eq "ascii") {
214 undef $/;
215 $$textref = <FILE>;
216 $/ = "\n";
217 } else {
218 my $reader = new multiread();
219 $reader->set_handle ('ReadTextFile::FILE');
220 $reader->set_encoding ($encoding);
221 $reader->read_file ($textref);
222 }
223 close FILE;
224}
225
226
227sub textcat_get_language_encoding {
228 my $self = shift (@_);
229 my ($filename) = @_;
230
231
232 my ($language, $encoding, $extracted_encoding);
233 if ($self->{'input_encoding'} eq "auto") {
234 # use textcat to automatically work out the input encoding and language
235 ($language, $encoding) = $self->get_language_encoding ($filename);
236 } elsif ($self->{'extract_language'}) {
237 # use textcat to get language metadata
238 ($language, $extracted_encoding) = $self->get_language_encoding ($filename);
239 $encoding = $self->{'input_encoding'};
240 # don't print this message for english... english in utf8 is identical
241 # to english in iso-8859-1 (except for some punctuation). We don't have
242 # a language model for en_utf8, so textcat always says iso-8859-1!
243 if ($extracted_encoding ne $encoding && $language ne "en"
244 && $self->{'verbosity'}) {
245 my $plugin_name = ref ($self);
246 my $outhandle = $self->{'outhandle'};
247 gsprintf($outhandle, "$plugin_name: {ReadTextFile.wrong_encoding}\n", $filename, $encoding, $extracted_encoding);
248 }
249 } else {
250 $language = $self->{'default_language'};
251 $encoding = $self->{'input_encoding'};
252 }
253
254 return ($language, $encoding);
255}
256
257# Uses textcat to work out the encoding and language of the text in
258# $filename. All html tags are removed before processing.
259# returns an array containing "language" and "encoding"
260sub get_language_encoding {
261 my $self = shift (@_);
262 my ($filename) = @_;
263 my $outhandle = $self->{'outhandle'};
264 my $unicode_format = "";
265 my $best_language = "";
266 my $best_encoding = "";
267
268 # read in file
269 if (!open (FILE, $filename)) {
270 gsprintf(STDERR, "ReadTextFile::get_language_encoding {ReadTextFile.could_not_open_for_reading} ($!)\n", $filename);
271 # this is a pretty bad error, but try to continue anyway
272 return ($self->{'default_language'}, $self->{'input_encoding'});
273 }
274 undef $/;
275 my $text = <FILE>;
276 $/ = "\n";
277 close FILE;
278
279 # check if first few bytes have a Byte Order Marker
280 my $bom=substr($text,0,2); # check 16bit unicode
281 if ($bom eq "\xff\xfe") { # little endian 16bit unicode
282 $unicode_format="unicode";
283 } elsif ($bom eq "\xfe\xff") { # big endian 16bit unicode
284 $unicode_format="unicode";
285 } else {
286 $bom=substr($text,0,3); # check utf-8
287 if ($bom eq "\xef\xbb\xbf") { # utf-8 coded FEFF bom
288 $unicode_format="utf8";
289# } elsif ($bom eq "\xef\xbf\xbe") { # utf-8 coded FFFE bom. Error!?
290# $unicode_format="utf8";
291 }
292 }
293
294 my $found_html_encoding = 0;
295 # handle html files specially
296 # XXX this doesn't match plugins derived from HTMLPlug (except ConvertTo)
297 if (ref($self) eq 'HTMLPlugin' ||
298 (exists $self->{'converted_to'} && $self->{'converted_to'} eq 'HTML')){
299
300 # remove <title>stuff</title> -- as titles tend often to be in English
301 # for foreign language documents
302 $text =~ s!<title>.*?</title>!!si;
303
304 # see if this html file specifies its encoding
305 if ($text =~ /^<\?xml.*encoding="(.+?)"/) {
306 $best_encoding = $1;
307 } elsif ($text =~ /<meta http-equiv.*content-type.*charset=(.+?)"/i) {#"
308 $best_encoding = $1;
309 }
310 if ($best_encoding) { # we extracted an encoding
311 $best_encoding =~ s/-+/_/g;
312 $best_encoding = lc($best_encoding); # lowercase
313 if ($best_encoding eq "utf_8") { $best_encoding = "utf8" }
314 $found_html_encoding = 1;
315 # We shouldn't be modifying this here!!
316 #$self->{'input_encoding'} = $best_encoding;
317 }
318
319 # remove all HTML tags
320 $text =~ s/<[^>]*>//sg;
321 }
322
323 # get the language/encoding
324 $self->{'textcat'} = new textcat() if (!defined($self->{'textcat'}));
325 my $results = $self->{'textcat'}->classify(\$text);
326
327 # if textcat returns 3 or less possibilities we'll use the
328 # first one in the list - otherwise use the defaults
329 if (scalar @$results > 3) {
330 if ($unicode_format) { # in case the first had a BOM
331 $best_encoding=$unicode_format;
332 } else {
333 my %guessed_encodings = ();
334 foreach my $result (@$results) {
335 $result =~ /([^\-]+)$/;
336 my $enc=$1;
337 if (!defined($guessed_encodings{$enc})) {
338 $guessed_encodings{$enc}=0;
339 }
340 $guessed_encodings{$enc}++;
341 }
342
343 $guessed_encodings{""}=-1; # for default best_encoding of ""
344 foreach my $enc (keys %guessed_encodings) {
345 if ($guessed_encodings{$enc} >
346 $guessed_encodings{$best_encoding}){
347 $best_encoding=$enc;
348 }
349 }
350 }
351
352 if ($self->{'input_encoding'} ne 'auto') {
353 if ($self->{'extract_language'} && ($self->{'verbosity'}>2)) {
354 gsprintf($outhandle,
355 "ReadTextFile: {ReadTextFile.could_not_extract_language}\n",
356 $filename, $self->{'default_language'});
357 }
358 $best_language = $self->{'default_language'};
359 if (!$found_html_encoding) {
360 $best_encoding = $self->{'input_encoding'};
361 }
362
363 } else {
364 if ($self->{'verbosity'}>2) {
365 gsprintf($outhandle,
366 "ReadTextFile: {ReadTextFile.could_not_extract_language}\n",
367 $filename, $self->{'default_language'});
368 }
369 $best_language = $self->{'default_language'};
370 }
371 } else { # <= 3 suggestions
372 my ($language, $encoding) = $results->[0] =~ /^([^-]*)(?:-(.*))?$/;
373 if (!defined $language) {
374 if ($self->{'verbosity'}>2) {
375 gsprintf($outhandle,
376 "ReadTextFile: {ReadTextFile.could_not_extract_language}\n",
377 $filename, $self->{'default_language'});
378 }
379 $language = $self->{'default_language'};
380 }
381 if (!defined $encoding) {
382 if ($self->{'verbosity'}>2) {
383 gsprintf($outhandle,
384 "ReadTextFile: {ReadTextFile.could_not_extract_encoding}\n",
385 $filename, $self->{'default_encoding'});
386 }
387 $encoding = $self->{'default_encoding'};
388 }
389 $best_language = $language;
390 if (! $best_encoding ) { # may already be set... eg from html meta tag
391 $best_encoding = $encoding;
392 }
393 }
394
395 if ($best_encoding =~ /^iso_8859/ && &unicode::check_is_utf8($text)) {
396 # the text is valid utf8, so assume that's the real encoding
397 # (since textcat is based on probabilities)
398 $best_encoding = 'utf8';
399 }
400
401 # check for equivalents where textcat doesn't have some encodings...
402 # eg MS versions of standard encodings
403 if ($best_encoding =~ /^iso_8859_(\d+)/) {
404 my $iso = $1; # which variant of the iso standard?
405 # iso-8859 sets don't use chars 0x80-0x9f, windows codepages do
406 if ($text =~ /[\x80-\x9f]/) {
407 # Western Europe
408 if ($iso == 1 or $iso == 15) { $best_encoding = 'windows_1252' }
409 elsif ($iso == 2) {$best_encoding = 'windows_1250'} # Central Europe
410 elsif ($iso == 5) {$best_encoding = 'windows_1251'} # Cyrillic
411 elsif ($iso == 6) {$best_encoding = 'windows_1256'} # Arabic
412 elsif ($iso == 7) {$best_encoding = 'windows_1253'} # Greek
413 elsif ($iso == 8) {$best_encoding = 'windows_1255'} # Hebrew
414 elsif ($iso == 9) {$best_encoding = 'windows_1254'} # Turkish
415 }
416 }
417
418 if ($best_encoding !~ /^(ascii|utf8|unicode)$/ &&
419 !defined $encodings::encodings->{$best_encoding}) {
420 if ($self->{'verbosity'}) {
421 gsprintf($outhandle, "ReadTextFile: {ReadTextFile.unsupported_encoding}\n",
422 $filename, $best_encoding, $self->{'default_encoding'});
423 }
424 $best_encoding = $self->{'default_encoding'};
425 }
426
427 return ($best_language, $best_encoding);
428}
429
430
431
432# Overridden by exploding plugins (eg. ISISPlug)
433sub clean_up_after_exploding
434{
435 my $self = shift(@_);
436}
437
438
4391;
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