root/main/trunk/greenstone2/perllib/plugins/PDFPlugin.pm @ 22953

Revision 22953, 13.2 KB (checked in by davidb, 9 years ago)

Further code tweaks to correctly support Unicode aware strings in our plugin code

  • Property svn:keywords set to Author Date Id Revision
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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 strict;
28no strict 'refs'; # so we can use a var for filehandles (e.g. STDERR)
29
30use ReadTextFile;
31use unicode;
32
33use AutoLoadConverters;
34use ConvertBinaryFile;
35
36@PDFPlugin::ISA = ('ConvertBinaryFile', 'AutoLoadConverters', 'ReadTextFile');
37
38
39my $convert_to_list =
40    [ { 'name' => "auto",
41    'desc' => "{ConvertBinaryFile.convert_to.auto}" },
42      { 'name' => "html",
43    'desc' => "{ConvertBinaryFile.convert_to.html}" },
44      { 'name' => "text",
45    'desc' => "{ConvertBinaryFile.convert_to.text}" },
46      { 'name' => "pagedimg_jpg",
47    'desc' => "{ConvertBinaryFile.convert_to.pagedimg_jpg}"},
48      { 'name' => "pagedimg_gif",
49    'desc' => "{ConvertBinaryFile.convert_to.pagedimg_gif}"},
50      { 'name' => "pagedimg_png",
51    'desc' => "{ConvertBinaryFile.convert_to.pagedimg_png}"},
52      ];
53
54
55my $arguments =
56    [
57     { 'name' => "convert_to",
58       'desc' => "{ConvertBinaryFile.convert_to}",
59       'type' => "enum",
60       'reqd' => "yes",
61       'list' => $convert_to_list,
62       'deft' => "html" },   
63     { 'name' => "process_exp",
64       'desc' => "{BasePlugin.process_exp}",
65       'type' => "regexp",
66       'deft' => &get_default_process_exp(),
67       'reqd' => "no" },
68     { 'name' => "block_exp",
69       'desc' => "{BasePlugin.block_exp}",
70       'type' => "regexp",
71       'deft' => &get_default_block_exp() },
72     { 'name' => "metadata_fields",
73       'desc' => "{HTMLPlugin.metadata_fields}",
74       'type' => "string",
75       'deft' => "" },
76      { 'name' => "metadata_field_separator",
77    'desc' => "{HTMLPlugin.metadata_field_separator}",
78    'type' => "string",
79    'deft' => "" },
80     { 'name' => "noimages",
81       'desc' => "{PDFPlugin.noimages}",
82       'type' => "flag" },
83     { 'name' => "allowimagesonly",
84       'desc' => "{PDFPlugin.allowimagesonly}",
85       'type' => "flag" },
86     { 'name' => "complex",
87       'desc' => "{PDFPlugin.complex}",
88       'type' => "flag" },
89     { 'name' => "nohidden",
90       'desc' => "{PDFPlugin.nohidden}",
91       'type' => "flag" },
92     { 'name' => "zoom",
93       'desc' => "{PDFPlugin.zoom}",
94       'deft' => "2",
95       'range' => "1,3", # actually the range is 0.5-3
96       'type' => "int" },
97     { 'name' => "use_sections",
98       'desc' => "{PDFPlugin.use_sections}",
99       'type' => "flag" },
100     { 'name' => "description_tags",
101       'desc' => "{HTMLPlugin.description_tags}",
102       'type' => "flag" }
103     ];
104
105my $options = { 'name'     => "PDFPlugin",
106        'desc'     => "{PDFPlugin.desc}",
107        'abstract' => "no",
108        'inherits' => "yes",
109        'srcreplaceable' => "yes", # Source docs in PDF can be replaced with GS-generated html     
110        'args'     => $arguments };
111
112sub new {
113    my ($class) = shift (@_);
114    my ($pluginlist,$inputargs,$hashArgOptLists) = @_;
115    push(@$pluginlist, $class);
116
117    push(@$inputargs,"-title_sub");
118    push(@$inputargs,'^(Page\s+\d+)?(\s*1\s+)?');
119
120    push(@{$hashArgOptLists->{"ArgList"}},@{$arguments});
121    push(@{$hashArgOptLists->{"OptList"}},$options);
122
123    my $auto_converter_self = new AutoLoadConverters($pluginlist,$inputargs,$hashArgOptLists,["PDFBoxConverter"],1);
124    my $cbf_self = new ConvertBinaryFile($pluginlist, $inputargs, $hashArgOptLists);
125    my $self = BasePlugin::merge_inheritance($auto_converter_self, $cbf_self);
126   
127    if ($self->{'info_only'}) {
128    # don't worry about any options etc
129    return bless $self, $class;
130    }
131   
132    $self = bless $self, $class;
133    $self->{'file_type'} = "PDF";
134
135    # these are passed through to gsConvert.pl by ConvertBinaryFile.pm
136    my $zoom = $self->{"zoom"};
137    $self->{'convert_options'} = "-pdf_zoom $zoom";
138    $self->{'convert_options'} .= " -pdf_complex" if $self->{"complex"};
139    $self->{'convert_options'} .= " -pdf_nohidden" if $self->{"nohidden"};
140    $self->{'convert_options'} .= " -pdf_ignore_images" if $self->{"noimages"};
141    $self->{'convert_options'} .= " -pdf_allow_images_only" if $self->{"allowimagesonly"};
142
143    # check convert_to
144    if ($self->{'convert_to'} eq "text" && $ENV{'GSDLOS'} =~ /^windows$/i) {
145    print STDERR "Windows does not support pdf to text. PDFs will be converted to HTML instead\n";
146    $self->{'convert_to'} = "html";
147    }
148    elsif ($self->{'convert_to'} eq "auto") {
149    # choose html ?? is this the best option
150    $self->{'convert_to'} = "html";
151    }
152    # set convert_to_plugin and convert_to_ext
153    $self->set_standard_convert_settings();
154
155    my $secondary_plugin_name = $self->{'convert_to_plugin'};
156    my $secondary_plugin_options = $self->{'secondary_plugin_options'};
157
158    if (!defined $secondary_plugin_options->{$secondary_plugin_name}) {
159    $secondary_plugin_options->{$secondary_plugin_name} = [];
160    }
161    my $specific_options = $secondary_plugin_options->{$secondary_plugin_name};
162
163    # following title_sub removes "Page 1" added by pdftohtml, and a leading
164    # "1", which is often the page number at the top of the page. Bad Luck
165    # if your document title actually starts with "1 " - is there a better way?
166    push(@$specific_options , "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
167    my $associate_tail_re = $self->{'associate_tail_re'};
168    if ((defined $associate_tail_re) && ($associate_tail_re ne "")) {
169    push(@$specific_options, "-associate_tail_re", $associate_tail_re);
170    }
171    push(@$specific_options, "-file_rename_method", "none");
172   
173    if ($secondary_plugin_name eq "HTMLPlugin") {
174    # pdftohtml always produces utf8 - What about pdfbox???
175    push(@$specific_options, "-input_encoding", "utf8");
176    push(@$specific_options, "-extract_language") if $self->{'extract_language'};
177    push(@$specific_options, "-processing_tmp_files");
178    # Instruct HTMLPlug (when eventually accessed through read_into_doc_obj)
179    # to extract these metadata fields from the HEAD META fields
180    if (defined $self->{'metadata_fields'} && $self->{'metadata_fields'} =~ /\S/) {
181        push(@$specific_options,"-metadata_fields",$self->{'metadata_fields'});
182    } else {
183        push(@$specific_options,"-metadata_fields","Title,GENERATOR,date,author<Creator>");
184    }
185    if (defined $self->{'metadata_field_separator'} && $self->{'metadata_field_separator'} =~ /\S/) {
186        push(@$specific_options,"-metadata_field_separator",$self->{'metadata_field_separator'});
187    }
188    if ($self->{'use_sections'} || $self->{'description_tags'}) {
189        $self->{'description_tags'} = 1;
190        push(@$specific_options, "-description_tags");
191    }
192    }
193    elsif ($secondary_plugin_name eq "PagedImagePlugin") {
194    push(@$specific_options, "-screenviewsize", "1000");
195    push(@$specific_options, "-enable_cache");
196    push(@$specific_options, "-processing_tmp_files");
197    }
198
199    $self = bless $self, $class;
200    $self->load_secondary_plugins($class,$secondary_plugin_options,$hashArgOptLists);
201    return $self;
202}
203
204sub get_default_process_exp {
205    my $self = shift (@_);
206
207    return q^(?i)\.pdf$^;
208}
209
210# so we don't inherit HTMLPlug's block exp...
211sub get_default_block_exp {
212    return "";
213}
214
215sub init {
216    my $self = shift (@_);
217
218    # ConvertBinaryFile init
219    $self->SUPER::init(@_);
220    $self->AutoLoadConverters::init();
221
222}
223
224sub begin {
225    my $self = shift (@_);
226
227    $self->AutoLoadConverters::begin();
228    $self->SUPER::begin(@_);
229
230}
231
232sub deinit {
233    my $self = shift (@_);
234   
235    $self->AutoLoadConverters::deinit();
236    $self->SUPER::deinit(@_);
237
238}
239 
240
241sub tmp_area_convert_file {
242
243    my $self = shift (@_);
244    return $self->AutoLoadConverters::tmp_area_convert_file(@_);
245
246}
247
248sub convert_post_process
249{
250    my $self = shift (@_);
251    my ($conv_filename) = @_;
252
253    my $outhandle=$self->{'outhandle'};
254
255    #$self->{'input_encoding'} = "utf8"; # The output is always in utf8 (is it?? it is for html, but what about other types?)
256    #my ($language, $encoding) = $self->textcat_get_language_encoding ($conv_filename);
257
258    # read in file ($text will be in utf8)
259    my $text = "";
260    # encoding will be utf8 for html files - what about other types? will we do this step for them anyway?
261    $self->read_file ($conv_filename, "utf8", "", \$text);
262
263    # Calculate number of pages based on <a ...> tags (we have a <a name=1> etc
264    # for each page).  Metadata based on this calculation not set until process()
265    #
266    # Note: this is done even if we are not breaking to document into pages as it might
267    # be useful to give an indication of document length in browser through setting
268    # num_pages as metadata.
269    my @pages = ($text =~ /\<[Aa] name=\"?\w+\"?>/ig);
270    my $num_pages = scalar(@pages);
271    $self->{'num_pages'} = $num_pages;
272
273    if ($self->{'use_sections'}
274    && $self->{'converted_to'} eq "HTML") {
275
276    print $outhandle "PDFPlugin: Calculating sections...\n";
277
278    # we have "<a name=1></a>" etc for each page
279    # it may be <A name=
280    my @sections = split('<[Aa] name=', $text);
281
282    my $top_section = "";
283
284    if (scalar (@sections) == 1) { #only one section - no split!
285        print $outhandle "PDFPlugin: warning - no sections found\n";
286    } else {
287        $top_section .= shift @sections; # keep HTML header etc as top_section
288    }
289
290    # handle first section specially for title? Or all use first 100...
291   
292    my $title = $sections[0];
293    $title =~ s/^\"?\w+\"?>//; # specific for pdftohtml...
294    $title =~ s/<\/([^>]+)><\1>//g; # (eg) </b><b> - no space
295    $title =~ s/<[^>]*>/ /g;
296    $title =~ s/(?:&nbsp;|\xc2\xa0)/ /g; # utf-8 for nbsp...
297    $title =~ s/^\s+//s;
298    $title =~ s/\s+$//;
299    $title =~ s/\s+/ /gs;
300    $title =~ s/^$self->{'title_sub'}// if ($self->{'title_sub'});
301    $title =~ s/^\s+//s; # in case title_sub introduced any...
302    $title = substr ($title, 0, 100);
303    $title =~ s/\s\S*$/.../;
304
305
306    if (scalar (@sections) == 1) { # no sections found
307        $top_section .= $sections[0];
308        @sections=();
309    } else {
310        $top_section .= "<!--<Section>\n<Metadata name=\"Title\">$title</Metadata>\n-->\n <!--</Section>-->\n";
311    }
312
313    # add metadata per section...
314    foreach my $section (@sections) {
315        # section names are not always just digits, may be like "outline"
316        $section =~ s@^\"?(\w+)\"?></a>@@; # leftover from split expression...
317
318        $title = $1; # Greenstone does magic if sections are titled digits
319        if (! defined($title) ) {
320        print STDERR "no title: $section\n";
321        $title = " "; # get rid of the undefined warning in next line
322        }
323        my $newsection = "<!-- from PDFPlugin -->\n<!-- <Section>\n";
324        $newsection .= "<Metadata name=\"Title\">" . $title
325        . "</Metadata>\n--><p>\n";
326        $newsection .= $section;
327        $newsection .= "<!--</Section>-->\n";
328        $section = $newsection;
329    }
330
331    $text=join('', ($top_section, @sections));
332    }
333
334
335    # The following should no longer be needed, now that strings
336    # read in are Unicode aware (in the Perl sense) rather than
337    # raw binary strings that just happen to be UTF-8 compliant
338
339    # turn any high bytes that aren't valid utf-8 into utf-8.
340##    unicode::ensure_utf8(\$text);
341
342    # Write it out again!
343    $self->utf8_write_file (\$text, $conv_filename);
344}
345
346
347# do plugin specific processing of doc_obj for HTML type
348sub process {
349    my $self = shift (@_);
350    my ($pluginfo, $base_dir, $file, $metadata, $doc_obj, $gli) = @_;
351
352    my $result = $self->process_type($base_dir,$file,$doc_obj);
353
354    # fix up the extracted date metadata to be in Greenstone date format,
355    # and fix the capitalisation of 'date'
356    my $cursection = $doc_obj->get_top_section();
357    foreach my $datemeta (@{$doc_obj->get_metadata($cursection, "date")}) {
358    $doc_obj->delete_metadata($cursection, "date", $datemeta);
359
360    # We're just interested in the date bit, not the time
361    # some pdf creators (eg "Acrobat 5.0 Scan Plug-in for Windows")
362    # set a /CreationDate, and set /ModDate to 000000000. pdftohtml
363    # extracts the ModDate, so it is 0...
364    $datemeta =~ /(\d+)-(\d+)-(\d+)/;
365    my ($year, $month, $day) = ($1,$2,$3);
366    if (defined($year) && defined($month) && defined($day)) {
367        if ($year == 0) {next}
368        if ($year < 100) {$year += 1900} # just to be safe
369        if ($month =~ /^\d$/) {$month="0$month"} # single digit
370        if ($day =~ /^\d$/) {$day="0$day"} # single digit
371        my $date="$year$month$day";
372        $doc_obj->add_utf8_metadata($cursection, "Date", $date);
373    }
374    }
375
376    $doc_obj->add_utf8_metadata($cursection, "NumPages", $self->{'num_pages'});
377   
378    if ($self->{'use_sections'} && $self->{'converted_to'} eq "HTML") {
379    # we explicitly make it a paged document, cos greenstone won't get it
380    # right if any section has an empty title, or one with letters in it
381    $doc_obj->set_utf8_metadata_element ($cursection, "gsdlthistype", "Paged");
382    }
383
384    return $result;
385}
386
3871;
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