source: gsdl/trunk/perllib/plugins/PDFPlugin.pm@ 17739

Last change on this file since 17739 was 15963, checked in by kjdon, 16 years ago

commented out the textcat stuff in post_process - need to think about whether we need it or not - does the conversion always produce utf8?

  • Property svn:keywords set to Author Date Id Revision
File size: 12.2 KB
Line 
1###########################################################################
2#
3# PDFPlugin.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 PDFPlugin;
26
27use ConvertBinaryFile;
28use ReadTextFile;
29use unicode;
30use strict;
31no strict 'refs'; # so we can use a var for filehandles (eg STDERR)
32
33sub BEGIN {
34 @PDFPlugin::ISA = ('ConvertBinaryFile', 'ReadTextFile');
35}
36
37my $convert_to_list =
38 [ { 'name' => "auto",
39 'desc' => "{ConvertBinaryFile.convert_to.auto}" },
40 { 'name' => "html",
41 'desc' => "{ConvertBinaryFile.convert_to.html}" },
42 { 'name' => "text",
43 'desc' => "{ConvertBinaryFile.convert_to.text}" },
44 { 'name' => "pagedimg_jpg",
45 'desc' => "{ConvertBinaryFile.convert_to.pagedimg_jpg}"},
46 { 'name' => "pagedimg_gif",
47 'desc' => "{ConvertBinaryFile.convert_to.pagedimg_gif}"},
48 { 'name' => "pagedimg_png",
49 'desc' => "{ConvertBinaryFile.convert_to.pagedimg_png}"},
50 ];
51
52
53my $arguments =
54 [
55 { 'name' => "convert_to",
56 'desc' => "{ConvertBinaryFile.convert_to}",
57 'type' => "enum",
58 'reqd' => "yes",
59 'list' => $convert_to_list,
60 'deft' => "html" },
61 { 'name' => "process_exp",
62 'desc' => "{BasePlugin.process_exp}",
63 'type' => "regexp",
64 'deft' => &get_default_process_exp(),
65 'reqd' => "no" },
66 { 'name' => "block_exp",
67 'desc' => "{BasePlugin.block_exp}",
68 'type' => "regexp",
69 'deft' => &get_default_block_exp() },
70 { 'name' => "metadata_fields",
71 'desc' => "{HTMLPlugin.metadata_fields}",
72 'type' => "string",
73 'deft' => "" },
74 { 'name' => "noimages",
75 'desc' => "{PDFPlugin.noimages}",
76 'type' => "flag" },
77 { 'name' => "allowimagesonly",
78 'desc' => "{PDFPlugin.allowimagesonly}",
79 'type' => "flag" },
80 { 'name' => "complex",
81 'desc' => "{PDFPlugin.complex}",
82 'type' => "flag" },
83 { 'name' => "nohidden",
84 'desc' => "{PDFPlugin.nohidden}",
85 'type' => "flag" },
86 { 'name' => "zoom",
87 'desc' => "{PDFPlugin.zoom}",
88 'deft' => "2",
89 'range' => "1,3", # actually the range is 0.5-3
90 'type' => "int" },
91 { 'name' => "use_sections",
92 'desc' => "{PDFPlugin.use_sections}",
93 'type' => "flag" },
94 { 'name' => "description_tags",
95 'desc' => "{HTMLPlugin.description_tags}",
96 'type' => "flag" }
97 ];
98
99my $options = { 'name' => "PDFPlugin",
100 'desc' => "{PDFPlugin.desc}",
101 'abstract' => "no",
102 'inherits' => "yes",
103 'srcreplaceable' => "yes", # Source docs in PDF can be replaced with GS-generated html
104 'args' => $arguments };
105
106sub new {
107 my ($class) = shift (@_);
108 my ($pluginlist,$inputargs,$hashArgOptLists) = @_;
109 push(@$pluginlist, $class);
110
111 push(@$inputargs,"-title_sub");
112 push(@$inputargs,'^(Page\s+\d+)?(\s*1\s+)?');
113
114 push(@{$hashArgOptLists->{"ArgList"}},@{$arguments});
115 push(@{$hashArgOptLists->{"OptList"}},$options);
116
117 my @arg_array = @$inputargs;
118 my $self = new ConvertBinaryFile($pluginlist, $inputargs, $hashArgOptLists);
119
120 if ($self->{'info_only'}) {
121 # don't worry about any options etc
122 return bless $self, $class;
123 }
124
125 $self->{'filename_extension'} = "pdf";
126 $self->{'file_type'} = "PDF";
127
128 # these are passed through to gsConvert.pl by ConvertBinaryFile.pm
129 my $zoom = $self->{"zoom"};
130 $self->{'convert_options'} = "-pdf_zoom $zoom";
131 $self->{'convert_options'} .= " -pdf_complex" if $self->{"complex"};
132 $self->{'convert_options'} .= " -pdf_nohidden" if $self->{"nohidden"};
133 $self->{'convert_options'} .= " -pdf_ignore_images" if $self->{"noimages"};
134 $self->{'convert_options'} .= " -pdf_allow_images_only" if $self->{"allowimagesonly"};
135
136 my $secondary_plugin_options = $self->{'secondary_plugin_options'};
137
138 if (!defined $secondary_plugin_options->{'HTMLPlugin'}) {
139 $secondary_plugin_options->{'HTMLPlugin'} = [];
140 }
141 if (!defined $secondary_plugin_options->{'TextPlugin'}) {
142 $secondary_plugin_options->{'TextPlugin'} = [];
143 }
144 if (defined $self->{'convert_to'} && $self->{'convert_to'} =~ /pagedimg.*/i) {
145 if (!defined $secondary_plugin_options->{'PagedImagePlugin'}){
146 $secondary_plugin_options->{'PagedImagePlugin'} = [];
147 my $pagedimg_options = $secondary_plugin_options->{'PagedImagePlugin'};
148 push(@$pagedimg_options, "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
149 }
150 }
151 my $html_options = $secondary_plugin_options->{'HTMLPlugin'};
152 my $text_options = $secondary_plugin_options->{'TextPlugin'};
153 my $pagedimg_options = $secondary_plugin_options->{'PagedImagePlugin'};
154
155# if ($self->{'input_encoding'} eq "auto") {
156# $self->{'input_encoding'} = "utf8";
157# }
158
159 # if pdftohtml is always producing utf8, then htmlplug always needs this option
160 push(@$html_options,"-input_encoding", "utf8");
161 push(@$html_options,"-extract_language") if $self->{'extract_language'};
162 # Instruct HTMLPlug (when eventually accessed through read_into_doc_obj)
163 # to extract these metadata fields from the HEAD META fields
164 my $required_metadata;
165 if (defined $self->{'metadata_fields'} && $self->{'metadata_fields'} =~ /\S/) {
166 push(@$html_options,"-metadata_fields",$self->{'metadata_fields'});
167 } else {
168 push(@$html_options,"-metadata_fields","Title,GENERATOR,date,author<Creator>");
169 }
170 #push(@$html_options,"-metadata_fields","Title,GENERATOR,date,author<Creator>");
171
172 if ($self->{'use_sections'} || $self->{'description_tags'}) {
173 $self->{'description_tags'} = 1;
174 push(@$html_options,"-description_tags");
175 }
176
177 # following title_sub removes "Page 1" added by pdftohtml, and a leading
178 # "1", which is often the page number at the top of the page. Bad Luck
179 # if your document title actually starts with "1 " - is there a better way?
180 push(@$html_options , "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
181 push(@$text_options , "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
182
183 my $associate_tail_re = $self->{'associate_tail_re'};
184 if ((defined $associate_tail_re) && ($associate_tail_re ne "")) {
185 push(@$html_options, "-associate_tail_re", $associate_tail_re);
186 push(@$text_options, "-associate_tail_re", $associate_tail_re);
187 push(@$pagedimg_options, "-associate_tail_re", $associate_tail_re);
188 }
189
190
191 $self = bless $self, $class;
192 $self->load_secondary_plugins($class,$secondary_plugin_options,$hashArgOptLists);
193 return $self;
194}
195
196sub get_default_process_exp {
197 my $self = shift (@_);
198
199 return q^(?i)\.pdf$^;
200}
201
202# so we don't inherit HTMLPlug's block exp...
203sub get_default_block_exp {
204 return "";
205}
206
207sub convert_post_process
208{
209 my $self = shift (@_);
210 my ($conv_filename) = @_;
211
212 my $outhandle=$self->{'outhandle'};
213
214 #$self->{'input_encoding'} = "utf8"; # The output is always in utf8 (is it?? it is for html, but what about other types?)
215 #my ($language, $encoding) = $self->textcat_get_language_encoding ($conv_filename);
216
217 # read in file ($text will be in utf8)
218 my $text = "";
219 # encoding will be utf8 for html files - what about other types? will we do this step for them anyway?
220 $self->read_file ($conv_filename, "utf8", "", \$text);
221
222 # Calculate number of pages based on <a ...> tags (we have a <a name=1> etc
223 # for each page). Metadata based on this calculation not set until process()
224 #
225 # Note: this is done even if we are not breaking to document into pages as it might
226 # be useful to give an indication of document length in browser through setting
227 # num_pages as metadata.
228 my @pages = ($text =~ /\<[Aa] name=\"?\w+\"?>/ig);
229 my $num_pages = scalar(@pages);
230 $self->{'num_pages'} = $num_pages;
231
232 if ($self->{'use_sections'}
233 && $self->{'converted_to'} eq "HTML") {
234
235 print $outhandle "PDFPlugin: Calculating sections...\n";
236
237 # we have "<a name=1></a>" etc for each page
238 # it may be <A name=
239 my @sections = split('<[Aa] name=', $text);
240
241 my $top_section = "";
242
243 if (scalar (@sections) == 1) { #only one section - no split!
244 print $outhandle "PDFPlugin: warning - no sections found\n";
245 } else {
246 $top_section .= shift @sections; # keep HTML header etc as top_section
247 }
248
249 # handle first section specially for title? Or all use first 100...
250
251 my $title = $sections[0];
252 $title =~ s/^\"?\w+\"?>//; # specific for pdftohtml...
253 $title =~ s/<\/([^>]+)><\1>//g; # (eg) </b><b> - no space
254 $title =~ s/<[^>]*>/ /g;
255 $title =~ s/(?:&nbsp;|\xc2\xa0)/ /g; # utf-8 for nbsp...
256 $title =~ s/^\s+//s;
257 $title =~ s/\s+$//;
258 $title =~ s/\s+/ /gs;
259 $title =~ s/^$self->{'title_sub'}// if ($self->{'title_sub'});
260 $title =~ s/^\s+//s; # in case title_sub introduced any...
261 $title = substr ($title, 0, 100);
262 $title =~ s/\s\S*$/.../;
263
264
265 if (scalar (@sections) == 1) { # no sections found
266 $top_section .= $sections[0];
267 @sections=();
268 } else {
269 $top_section .= "<!--<Section>\n<Metadata name=\"Title\">$title</Metadata>\n-->\n <!--</Section>-->\n";
270 }
271
272 # add metadata per section...
273 foreach my $section (@sections) {
274 # section names are not always just digits, may be like "outline"
275 $section =~ s@^\"?(\w+)\"?></a>@@; # leftover from split expression...
276
277 $title = $1; # Greenstone does magic if sections are titled digits
278 if (! defined($title) ) {
279 print STDERR "no title: $section\n";
280 $title = " "; # get rid of the undefined warning in next line
281 }
282 my $newsection = "<!-- from PDFPlugin -->\n<!-- <Section>\n";
283 $newsection .= "<Metadata name=\"Title\">" . $title
284 . "</Metadata>\n--><p>\n";
285 $newsection .= $section;
286 $newsection .= "<!--</Section>-->\n";
287 $section = $newsection;
288 }
289
290 $text=join('', ($top_section, @sections));
291 }
292
293 # turn any high bytes that aren't valid utf-8 into utf-8.
294 unicode::ensure_utf8(\$text);
295
296 # Write it out again!
297 $self->utf8_write_file (\$text, $conv_filename);
298}
299
300
301# do plugin specific processing of doc_obj for HTML type
302sub process {
303 my $self = shift (@_);
304 my ($pluginfo, $base_dir, $file, $metadata, $doc_obj, $gli) = @_;
305
306 my $result = $self->process_type($base_dir,$file,$doc_obj);
307
308 # fix up the extracted date metadata to be in Greenstone date format,
309 # and fix the capitalisation of 'date'
310 my $cursection = $doc_obj->get_top_section();
311 foreach my $datemeta (@{$doc_obj->get_metadata($cursection, "date")}) {
312 $doc_obj->delete_metadata($cursection, "date", $datemeta);
313
314 # We're just interested in the date bit, not the time
315 # some pdf creators (eg "Acrobat 5.0 Scan Plug-in for Windows")
316 # set a /CreationDate, and set /ModDate to 000000000. pdftohtml
317 # extracts the ModDate, so it is 0...
318 $datemeta =~ /(\d+)-(\d+)-(\d+)/;
319 my ($year, $month, $day) = ($1,$2,$3);
320 if (defined($year) && defined($month) && defined($day)) {
321 if ($year == 0) {next}
322 if ($year < 100) {$year += 1900} # just to be safe
323 if ($month =~ /^\d$/) {$month="0$month"} # single digit
324 if ($day =~ /^\d$/) {$day="0$day"} # single digit
325 my $date="$year$month$day";
326 $doc_obj->add_utf8_metadata($cursection, "Date", $date);
327 }
328 }
329
330 $doc_obj->add_utf8_metadata($cursection, "NumPages", $self->{'num_pages'});
331
332 if ($self->{'use_sections'} && $self->{'converted_to'} eq "HTML") {
333 # we explicitly make it a paged document, cos greenstone won't get it
334 # right if any section has an empty title, or one with letters in it
335 $doc_obj->set_utf8_metadata_element ($cursection, "gsdlthistype", "Paged");
336 }
337
338 return $result;
339}
340
3411;
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