source: trunk/gsdl/perllib/plugins/PDFPlug.pm@ 10724

Last change on this file since 10724 was 10724, checked in by chi, 19 years ago

Add an option-metadata_fields to allow user-specified metadata fields to be extracted from PDF document.

  • Property svn:keywords set to Author Date Id Revision
File size: 11.2 KB
Line 
1###########################################################################
2#
3# PDFPlug.pm -- reasonably with-it pdf plugin
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) 1999-2001 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###########################################################################
25package PDFPlug;
26
27use ConvertToPlug;
28use unicode;
29use strict;
30no strict 'refs'; # so we can use a var for filehandles (eg STDERR)
31
32sub BEGIN {
33 @PDFPlug::ISA = ('ConvertToPlug');
34}
35
36my $convert_to_list =
37 [ { 'name' => "auto",
38 'desc' => "{ConvertToPlug.convert_to.auto}" },
39 { 'name' => "html",
40 'desc' => "{ConvertToPlug.convert_to.html}" },
41 { 'name' => "text",
42 'desc' => "{ConvertToPlug.convert_to.text}" },
43 { 'name' => "pagedimg_jpg",
44 'desc' => "{ConvertToPlug.convert_to.pagedimg_jpg}"},
45 { 'name' => "pagedimg_gif",
46 'desc' => "{ConvertToPlug.convert_to.pagedimg_gif}"},
47 { 'name' => "pagedimg_png",
48 'desc' => "{ConvertToPlug.convert_to.pagedimg_png}"},
49 ];
50
51
52my $arguments =
53 [
54 { 'name' => "convert_to",
55 'desc' => "{ConvertToPlug.convert_to}",
56 'type' => "enum",
57 'reqd' => "yes",
58 'list' => $convert_to_list,
59 'deft' => "html" },
60 { 'name' => "process_exp",
61 'desc' => "{BasPlug.process_exp}",
62 'type' => "regexp",
63 'deft' => &get_default_process_exp(),
64 'reqd' => "no" },
65 { 'name' => "block_exp",
66 'desc' => "{BasPlug.block_exp}",
67 'type' => "regexp",
68 'deft' => &get_default_block_exp() },
69 { 'name' => "metadata_fields",
70 'type' => "string",
71 'deft' => "" },
72 { 'name' => "noimages",
73 'desc' => "{PDFPlug.noimages}",
74 'type' => "flag" },
75 { 'name' => "allowimagesonly",
76 'desc' => "{PDFPlug.allowimagesonly}",
77 'type' => "flag" },
78 { 'name' => "complex",
79 'desc' => "{PDFPlug.complex}",
80 'type' => "flag" },
81 { 'name' => "nohidden",
82 'desc' => "{PDFPlug.nohidden}",
83 'type' => "flag" },
84 { 'name' => "zoom",
85 'desc' => "{PDFPlug.zoom}",
86 'deft' => "2",
87 'range' => "1,3", # actually the range is 0.5-3
88 'type' => "int" },
89 { 'name' => "use_sections",
90 'desc' => "{PDFPlug.use_sections}",
91 'type' => "flag" },
92 { 'name' => "description_tags",
93 'desc' => "{HTMLPlug.description_tags}",
94 'type' => "flag" }
95];
96
97my $options = { 'name' => "PDFPlug",
98 'desc' => "{PDFPlug.desc}",
99 'abstract' => "no",
100 'inherits' => "yes",
101 'args' => $arguments };
102
103sub new {
104 my ($class) = shift (@_);
105 my ($pluginlist,$inputargs,$hashArgOptLists) = @_;
106 push(@$pluginlist, $class);
107
108 push(@$inputargs,"-title_sub");
109 push(@$inputargs,'^(Page\s+\d+)?(\s*1\s+)?');
110
111 if(defined $arguments){ push(@{$hashArgOptLists->{"ArgList"}},@{$arguments});}
112 if(defined $options) { push(@{$hashArgOptLists->{"OptList"}},$options)};
113
114 my @arg_array = @$inputargs;
115 my $self = (defined $hashArgOptLists)? new ConvertToPlug($pluginlist,$inputargs,$hashArgOptLists): new ConvertToPlug($pluginlist,$inputargs);
116
117 if ($self->{'info_only'}) {
118 # don't worry about any options etc
119 return bless $self, $class;
120 }
121
122 # these are passed through to gsConvert.pl by ConvertToPlug.pm
123 my $zoom = $self->{"zoom"};
124 $self->{'convert_options'} = "-pdf_zoom $zoom";
125 $self->{'convert_options'} .= " -pdf_complex" if $self->{"complex"};
126 $self->{'convert_options'} .= " -pdf_nohidden" if $self->{"nohidden"};
127 $self->{'convert_options'} .= " -pdf_ignore_images" if $self->{"noimages"};
128 $self->{'convert_options'} .= " -pdf_allow_images_only" if $self->{"allowimagesonly"};
129
130 my $secondary_plugin_options = $self->{'secondary_plugin_options'};
131
132 if (!defined $secondary_plugin_options->{'HTMLPlug'}) {
133 $secondary_plugin_options->{'HTMLPlug'} = [];
134 }
135 if (!defined $secondary_plugin_options->{'TEXTPlug'}) {
136 $secondary_plugin_options->{'TEXTPlug'} = [];
137 }
138 if (defined $self->{'convert_to'} && $self->{'convert_to'} =~ /pagedimg.*/i) {
139 if (!defined $secondary_plugin_options->{'PagedImgPlug'}){
140 $secondary_plugin_options->{'PagedImgPlug'} = [];
141 my $pagedimg_options = $secondary_plugin_options->{'PagedImgPlug'};
142 push(@$pagedimg_options, "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
143 }
144 }
145 my $html_options = $secondary_plugin_options->{'HTMLPlug'};
146 my $text_options = $secondary_plugin_options->{'TEXTPlug'};
147
148 if ($self->{'input_encoding'} eq "auto") {
149 # pdftohtml will always produce html files encoded as utf-8
150 # => restrict primary PDFPlug and secondary HTML plugin to use
151 # utf8 and extract language.
152 $self->{'input_encoding'} = "utf8";
153 $self->{'extract_language'} = 1;
154
155 push(@$html_options,"-input_encoding", "utf8");
156 push(@$html_options,"-extract_language");
157 }
158
159 # Instruct HTMLPlug (when eventually accessed through read_into_doc_obj)
160 # to extract these metadata fields from the HEAD META fields
161 my $required_metadata;
162 if (defined $self->{'metadata_fields'} && $self->{'metadata_fields'} =~ /\S/) {
163 push(@$html_options,"-metadata_fields",$self->{'metadata_fields'});
164 } else {
165 push(@$html_options,"-metadata_fields","Title,GENERATOR,date,author<Creator>");
166 }
167 #push(@$html_options,"-metadata_fields","Title,GENERATOR,date,author<Creator>");
168
169 if ($self->{'use_sections'} || $self->{'description_tags'}) {
170 $self->{'description_tags'} = 1;
171 push(@$html_options,"-description_tags");
172 }
173
174 # following title_sub removes "Page 1" added by pdftohtml, and a leading
175 # "1", which is often the page number at the top of the page. Bad Luck
176 # if your document title actually starts with "1 " - is there a better way?
177 push(@$html_options , "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
178 push(@$text_options , "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
179
180 $self = bless $self, $class;
181 $self->load_secondary_plugins($class,$secondary_plugin_options,$hashArgOptLists);
182 return $self;
183}
184
185sub get_default_process_exp {
186 my $self = shift (@_);
187
188 return q^(?i)\.pdf$^;
189}
190
191# so we don't inherit HTMLPlug's block exp...
192sub get_default_block_exp {
193 return "";
194}
195
196sub convert_post_process
197{
198 my $self = shift (@_);
199 my ($conv_filename) = @_;
200
201 my $outhandle=$self->{'outhandle'};
202
203 my ($language, $encoding) = $self->textcat_get_language_encoding ($conv_filename);
204
205 # read in file ($text will be in utf8)
206 my $text = "";
207 $self->read_file ($conv_filename, $encoding, $language, \$text);
208
209 # Calculate number of pages based on <a ...> tags (we have a <a name=1> etc
210 # for each page). Metadata based on this calculation not set until process()
211 #
212 # Note: this is done even if we are not breaking to document into pages as it might
213 # be useful to give an indication of document length in browser through setting
214 # num_pages as metadata.
215 my @pages = ($text =~ /\<[Aa] name=\"?\w+\"?>/ig);
216 my $num_pages = scalar(@pages);
217 $self->{'num_pages'} = $num_pages;
218
219 if ($self->{'use_sections'}
220 && $self->{'converted_to'} eq "HTML") {
221
222 print $outhandle "PDFPlug: Calculating sections...\n";
223
224 # we have "<a name=1></a>" etc for each page
225 # it may be <A name=
226 my @sections = split('<[Aa] name=', $text);
227
228 my $top_section = "";
229
230 if (scalar (@sections) == 1) { #only one section - no split!
231 print $outhandle "PDFPlug: warning - no sections found\n";
232 } else {
233 $top_section .= shift @sections; # keep HTML header etc as top_section
234 }
235
236 # handle first section specially for title? Or all use first 100...
237
238 my $title = $sections[0];
239 $title =~ s/^\"?\w+\"?>//; # specific for pdftohtml...
240 $title =~ s/<\/([^>]+)><\1>//g; # (eg) </b><b> - no space
241 $title =~ s/<[^>]*>/ /g;
242 $title =~ s/(?:&nbsp;|\xc2\xa0)/ /g; # utf-8 for nbsp...
243 $title =~ s/^\s+//s;
244 $title =~ s/\s+$//;
245 $title =~ s/\s+/ /gs;
246 $title =~ s/^$self->{'title_sub'}// if ($self->{'title_sub'});
247 $title =~ s/^\s+//s; # in case title_sub introduced any...
248 $title = substr ($title, 0, 100);
249 $title =~ s/\s\S*$/.../;
250
251
252 if (scalar (@sections) == 1) { # no sections found
253 $top_section .= $sections[0];
254 @sections=();
255 } else {
256 $top_section .= "<!--<Section>\n<Metadata name=\"Title\">$title</Metadata>\n-->\n <!--</Section>-->\n";
257 }
258
259 # add metadata per section...
260 foreach my $section (@sections) {
261 # section names are not always just digits, may be like "outline"
262 $section =~ s@^\"?(\w+)\"?></a>@@; # leftover from split expression...
263
264 $title = $1; # Greenstone does magic if sections are titled digits
265 if (! defined($title) ) {
266 print STDERR "no title: $section\n";
267 $title = " "; # get rid of the undefined warning in next line
268 }
269 my $newsection = "<!-- from PDFPlug -->\n<!-- <Section>\n";
270 $newsection .= "<Metadata name=\"Title\">" . $title
271 . "</Metadata>\n--><p>\n";
272 $newsection .= $section;
273 $newsection .= "<!--</Section>-->\n";
274 $section = $newsection;
275 }
276
277 $text=join('', ($top_section, @sections));
278 }
279
280 # turn any high bytes that aren't valid utf-8 into utf-8.
281 unicode::ensure_utf8(\$text);
282
283 # Write it out again!
284 $self->utf8_write_file (\$text, $conv_filename);
285}
286
287
288# do plugin specific processing of doc_obj for HTML type
289sub process {
290 my $self = shift (@_);
291 my ($textref, $pluginfo, $base_dir, $file, $metadata, $doc_obj, $gli) = @_;
292
293 my $result = $self->process_type("pdf",$base_dir,$file,$doc_obj);
294
295 # fix up the extracted date metadata to be in Greenstone date format,
296 # and fix the capitalisation of 'date'
297 my $cursection = $doc_obj->get_top_section();
298 foreach my $datemeta (@{$doc_obj->get_metadata($cursection, "date")}) {
299 $doc_obj->delete_metadata($cursection, "date", $datemeta);
300
301 # We're just interested in the date bit, not the time
302 # some pdf creators (eg "Acrobat 5.0 Scan Plug-in for Windows")
303 # set a /CreationDate, and set /ModDate to 000000000. pdftohtml
304 # extracts the ModDate, so it is 0...
305 $datemeta =~ /(\d+)-(\d+)-(\d+)/;
306 my ($year, $month, $day) = ($1,$2,$3);
307 if (defined($year) && defined($month) && defined($day)) {
308 if ($year == 0) {next}
309 if ($year < 100) {$year += 1900} # just to be safe
310 if ($month =~ /^\d$/) {$month="0$month"} # single digit
311 if ($day =~ /^\d$/) {$day="0$day"} # single digit
312 my $date="$year$month$day";
313 $doc_obj->add_utf8_metadata($cursection, "Date", $date);
314 }
315 }
316
317 $doc_obj->add_utf8_metadata($cursection, "NumPages", $self->{'num_pages'});
318
319 if ($self->{'use_sections'} && $self->{'converted_to'} eq "HTML") {
320 # we explicitly make it a paged document, cos greenstone won't get it
321 # right if any section has an empty title, or one with letters in it
322 $doc_obj->set_utf8_metadata_element ($cursection, "gsdlthistype", "Paged");
323 }
324
325 return $result;
326}
327
3281;
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