root/main/trunk/greenstone2/perllib/plugins/PDFPlugin.pm @ 30492

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Fix for previous commit.

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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' => "Title,Author,Subject,Keywords" },
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      { 'name' => "use_realistic_book",
104        'desc' => "{PDFPlugin.use_realistic_book}",
105    'type' => "flag"}
106     ];
107
108my $options = { 'name'     => "PDFPlugin",
109        'desc'     => "{PDFPlugin.desc}",
110        'abstract' => "no",
111        'inherits' => "yes",
112        'srcreplaceable' => "yes", # Source docs in PDF can be replaced with GS-generated html     
113        'args'     => $arguments };
114
115sub new {
116    my ($class) = shift (@_);
117    my ($pluginlist,$inputargs,$hashArgOptLists) = @_;
118    push(@$pluginlist, $class);
119
120    push(@$inputargs,"-title_sub");
121    push(@$inputargs,'^(Page\s+\d+)?(\s*1\s+)?');
122
123    push(@{$hashArgOptLists->{"ArgList"}},@{$arguments});
124    push(@{$hashArgOptLists->{"OptList"}},$options);
125
126    my $auto_converter_self = new AutoLoadConverters($pluginlist,$inputargs,$hashArgOptLists,["PDFBoxConverter"],1);
127    my $cbf_self = new ConvertBinaryFile($pluginlist, $inputargs, $hashArgOptLists);
128    my $self = BasePlugin::merge_inheritance($auto_converter_self, $cbf_self);
129   
130    if ($self->{'info_only'}) {
131    # don't worry about any options etc
132    return bless $self, $class;
133    }
134   
135    $self = bless $self, $class;
136    $self->{'file_type'} = "PDF";
137
138    # these are passed through to gsConvert.pl by ConvertBinaryFile.pm
139    my $zoom = $self->{"zoom"};
140    $self->{'convert_options'} = "-pdf_zoom $zoom";
141    $self->{'convert_options'} .= " -pdf_complex" if $self->{"complex"};
142    $self->{'convert_options'} .= " -pdf_nohidden" if $self->{"nohidden"};
143    $self->{'convert_options'} .= " -pdf_ignore_images" if $self->{"noimages"};
144    $self->{'convert_options'} .= " -pdf_allow_images_only" if $self->{"allowimagesonly"};
145
146    # check convert_to
147    if ($self->{'convert_to'} eq "text" && $ENV{'GSDLOS'} =~ /^windows$/i) {
148    print STDERR "Windows does not support pdf to text. PDFs will be converted to HTML instead\n";
149    $self->{'convert_to'} = "html";
150    }
151    elsif ($self->{'convert_to'} eq "auto") {
152    # choose html ?? is this the best option
153    $self->{'convert_to'} = "html";
154    }
155    if ($self->{'use_realistic_book'}) {
156    if ($self->{'convert_to'} ne "html") {
157        print STDERR "PDFs will be converted to HTML for realistic book functionality\n";
158        $self->{'convert_to'} = "html";
159    }
160    }
161    # set convert_to_plugin and convert_to_ext
162    $self->set_standard_convert_settings();
163
164    my $secondary_plugin_name = $self->{'convert_to_plugin'};
165    my $secondary_plugin_options = $self->{'secondary_plugin_options'};
166
167    if (!defined $secondary_plugin_options->{$secondary_plugin_name}) {
168    $secondary_plugin_options->{$secondary_plugin_name} = [];
169    }
170    my $specific_options = $secondary_plugin_options->{$secondary_plugin_name};
171
172    # following title_sub removes "Page 1" added by pdftohtml, and a leading
173    # "1", which is often the page number at the top of the page. Bad Luck
174    # if your document title actually starts with "1 " - is there a better way?
175    push(@$specific_options , "-title_sub", '^(Page\s+\d+)?(\s*1\s+)?');
176    my $associate_tail_re = $self->{'associate_tail_re'};
177    if ((defined $associate_tail_re) && ($associate_tail_re ne "")) {
178    push(@$specific_options, "-associate_tail_re", $associate_tail_re);
179    }
180    push(@$specific_options, "-file_rename_method", "none");
181   
182    if ($secondary_plugin_name eq "HTMLPlugin") {
183    # pdftohtml always produces utf8 - What about pdfbox???
184    # push(@$specific_options, "-input_encoding", "utf8");
185    push(@$specific_options, "-extract_language") if $self->{'extract_language'};
186    push(@$specific_options, "-processing_tmp_files");
187    # Instruct HTMLPlug (when eventually accessed through read_into_doc_obj)
188    # to extract these metadata fields from the HEAD META fields
189    if (defined $self->{'metadata_fields'} && $self->{'metadata_fields'} =~ /\S/) {
190        push(@$specific_options,"-metadata_fields",$self->{'metadata_fields'});
191    } else {
192        push(@$specific_options,"-metadata_fields","Title,GENERATOR,date,author<Creator>");
193    }
194    if (defined $self->{'metadata_field_separator'} && $self->{'metadata_field_separator'} =~ /\S/) {
195        push(@$specific_options,"-metadata_field_separator",$self->{'metadata_field_separator'});
196    }
197    if ($self->{'use_sections'} || $self->{'description_tags'}) {
198        $self->{'description_tags'} = 1;
199        push(@$specific_options, "-description_tags");
200    }
201    if ($self->{'use_realistic_book'}) {
202        push(@$specific_options, "-use_realistic_book");
203    }
204    }
205    elsif ($secondary_plugin_name eq "PagedImagePlugin") {
206    push(@$specific_options, "-screenviewsize", "1000");
207    push(@$specific_options, "-enable_cache");
208    push(@$specific_options, "-processing_tmp_files");
209    }
210
211    $self = bless $self, $class;
212    $self->load_secondary_plugins($class,$secondary_plugin_options,$hashArgOptLists);
213    return $self;
214}
215
216sub get_default_process_exp {
217    my $self = shift (@_);
218
219    return q^(?i)\.pdf$^;
220}
221
222# so we don't inherit HTMLPlug's block exp...
223sub get_default_block_exp {
224    return "";
225}
226
227sub init {
228    my $self = shift (@_);
229
230    # ConvertBinaryFile init
231    $self->SUPER::init(@_);
232    $self->AutoLoadConverters::init(@_);
233
234}
235
236sub begin {
237    my $self = shift (@_);
238
239    $self->AutoLoadConverters::begin(@_);
240    $self->SUPER::begin(@_);
241
242}
243
244sub deinit {
245    my $self = shift (@_);
246   
247    $self->AutoLoadConverters::deinit(@_);
248    $self->SUPER::deinit(@_);
249
250}
251 
252# By setting hashing to be on ga xml this ensures that two
253# PDF files that are identical except for the metadata
254# to hash to different values. Without this, when each PDF
255# file is converted to HTML there is a chance that they
256# will both be *identical* if the conversion utility does
257# not embed the metadata in the generated HTML. This is
258# certainly the case when PDFBOX is being used.
259
260# This change makes this convert to based plugin more
261# consistent with the original vision that the same document
262# with different metadata should
263# be seen as different.
264
265sub get_oid_hash_type {
266    my $self = shift (@_);
267    return "hash_on_ga_xml";
268}
269 
270 
271sub tmp_area_convert_file {
272
273    my $self = shift (@_);
274    return $self->AutoLoadConverters::tmp_area_convert_file(@_);
275
276}
277
278sub convert_post_process
279{
280    my $self = shift (@_);
281    my ($conv_filename) = @_;
282
283    my $outhandle=$self->{'outhandle'};
284
285    #$self->{'input_encoding'} = "utf8"; # The output is always in utf8 (is it?? it is for html, but what about other types?)
286    #my ($language, $encoding) = $self->textcat_get_language_encoding ($conv_filename);
287
288    # read in file ($text will be in utf8)
289    my $text = "";
290    # encoding will be utf8 for html files - what about other types? will we do this step for them anyway?
291    $self->read_file ($conv_filename, "utf8", "", \$text);
292
293    # To support the use_sections option with PDFBox: Greenstone splits PDFs into pages for
294    # sections. The PDFPlugin code wants each new page to be prefixed with <a name=pagenum></a>,
295    # which it then splits on to generate page-based sections. However, that's not what PDFBox
296    # generates in its HTML output. Fortunately, PDFBox does have its own page-separator: it
297    # embeds each page in an extra div. The div opener is:
298    # <div style=\"page-break-before:always; page-break-after:always\">
299    # The PDFPlugin now looks for this and prefixes <a name=0></a> to each such div. (The
300    # pagenumber is fixed at 0 since I'm unable to work out how to increment the pagenum during
301    # a regex substitution even with regex extensions on.) Later, when we process each section
302    # to get the pagenum, PDFBox's output for this is pre-processed by having a loopcounter
303    # that increments the pagenum for each subsequent section.
304
305    #$pdfbox_pageheader="\<div style=\"page-break-before:always; page-break-after:always\">";
306    my $loopcounter = 0; # used later on!
307    $text =~ s@\<div style=\"page-break-before:always; page-break-after:always\">@<a name=$loopcounter></a><div style=\"page-break-before:always; page-break-after:always\">@g;
308
309
310    # Calculate number of pages based on <a ...> tags (we have a <a name=1> etc
311    # for each page).  Metadata based on this calculation not set until process()
312    #
313    # Note: this is done even if we are not breaking the document into pages as it might
314    # be useful to give an indication of document length in browser through setting
315    # num_pages as metadata.
316    # Clean html from low and hight surrogates D800–DFFF
317    $text =~ s@[\N{U+D800}-\N{U+DFFF}]@\ @g;
318    my @pages = ($text =~ m/\<[Aa] name=\"?\w+\"?>/ig); #<div style=\"?page-break-before:always; page-break-after:always\"?>
319    my $num_pages = scalar(@pages);
320    $self->{'num_pages'} = $num_pages;
321
322    if ($self->{'use_sections'}
323    && $self->{'converted_to'} eq "HTML") {
324
325    print $outhandle "PDFPlugin: Calculating sections...\n";
326
327    # we have "<a name=1></a>" etc for each page
328    # it may be <A name=
329    my @sections = split('<[Aa] name=', $text);
330
331    my $top_section = "";
332
333    if (scalar (@sections) == 1) { #only one section - no split!
334        print $outhandle "PDFPlugin: warning - no sections found\n";
335    } else {
336        $top_section .= shift @sections; # keep HTML header etc as top_section
337    }
338
339    # handle first section specially for title? Or all use first 100...
340   
341    my $title = $sections[0];
342    $title =~ s/^\"?\w+\"?>//; # specific for pdftohtml...
343    $title =~ s/<\/([^>]+)><\1>//g; # (eg) </b><b> - no space
344    $title =~ s/<[^>]*>/ /g;
345    $title =~ s/(?:&nbsp;|\xc2\xa0)/ /g; # utf-8 for nbsp...
346    $title =~ s/^\s+//s;
347    $title =~ s/\s+$//;
348    $title =~ s/\s+/ /gs;
349    $title =~ s/^$self->{'title_sub'}// if ($self->{'title_sub'});
350    $title =~ s/^\s+//s; # in case title_sub introduced any...
351    $title = substr ($title, 0, 100);
352    $title =~ s/\s\S*$/.../;
353
354
355    if (scalar (@sections) == 1) { # no sections found
356        $top_section .= $sections[0];
357        @sections=();
358    } else {
359        $top_section .= "<!--<Section>\n<Metadata name=\"Title\">$title</Metadata>\n-->\n <!--</Section>-->\n";
360    }
361
362    # add metadata per section...
363    foreach my $section (@sections) {
364        # section names are not always just digits, may be like "outline"
365        $section =~ s@^\"?(\w+)\"?></a>@@; # leftover from split expression...
366
367        $title = $1; # Greenstone does magic if sections are titled digits
368
369        # A title of pagenum=0 means use_sections is being applied on output from PDFBox,
370        # which didn't originally have a <a name=incremented pagenumber></a> to split each page.
371        # Our Perl code then prefixed <a name=0></a> to it. Now need to increment the pagenum here:
372        if($loopcounter > 0 || ($title eq 0 && $loopcounter == 0)) { # implies use_sections with PDFBox
373        $title = ++$loopcounter;
374        }
375
376        if (! defined($title) ) {
377        print STDERR "no title: $section\n";
378        $title = " "; # get rid of the undefined warning in next line
379        }
380        my $newsection = "<!-- from PDFPlugin -->\n<!-- <Section>\n";
381        $newsection .= "<Metadata name=\"Title\">" . $title
382        . "</Metadata>\n--><br />\n";
383        $newsection .= $section;
384        $newsection .= "<!--</Section>-->\n";
385        $section = $newsection;
386    }
387
388    $text=join('', ($top_section, @sections));
389    }
390
391    if ($self->{'use_sections'}
392    && $self->{'converted_to'} eq "text") {
393    print STDERR "**** When converting PDF to text, cannot apply use_sections\n";
394    }
395
396
397    # The following should no longer be needed, now that strings
398    # read in are Unicode aware (in the Perl sense) rather than
399    # raw binary strings that just happen to be UTF-8 compliant
400
401    # turn any high bytes that aren't valid utf-8 into utf-8.
402##    unicode::ensure_utf8(\$text);
403
404    # Write it out again!
405    $self->utf8_write_file (\$text, $conv_filename);
406}
407
408
409# do plugin specific processing of doc_obj for HTML type
410sub process {
411    my $self = shift (@_);
412    my ($pluginfo, $base_dir, $file, $metadata, $doc_obj, $gli) = @_;
413
414    my $result = $self->process_type($base_dir,$file,$doc_obj);
415
416    # fix up the extracted date metadata to be in Greenstone date format,
417    # and fix the capitalisation of 'date'
418    my $cursection = $doc_obj->get_top_section();
419    foreach my $datemeta (@{$doc_obj->get_metadata($cursection, "date")}) {
420    $doc_obj->delete_metadata($cursection, "date", $datemeta);
421
422    # We're just interested in the date bit, not the time
423    # some pdf creators (eg "Acrobat 5.0 Scan Plug-in for Windows")
424    # set a /CreationDate, and set /ModDate to 000000000. pdftohtml
425    # extracts the ModDate, so it is 0...
426    $datemeta =~ /(\d+)-(\d+)-(\d+)/;
427    my ($year, $month, $day) = ($1,$2,$3);
428    if (defined($year) && defined($month) && defined($day)) {
429        if ($year == 0) {next}
430        if ($year < 100) {$year += 1900} # just to be safe
431        if ($month =~ /^\d$/) {$month="0$month"} # single digit
432        if ($day =~ /^\d$/) {$day="0$day"} # single digit
433        my $date="$year$month$day";
434        $doc_obj->add_utf8_metadata($cursection, "Date", $date);
435    }
436    }
437
438    $doc_obj->add_utf8_metadata($cursection, "NumPages", $self->{'num_pages'}) if defined $self->{'num_pages'};
439   
440    if ($self->{'use_sections'} && $self->{'converted_to'} eq "HTML") {
441    # we explicitly make it a paged document, cos greenstone won't get it
442    # right if any section has an empty title, or one with letters in it
443    $doc_obj->set_utf8_metadata_element ($cursection, "gsdlthistype", "Paged");
444    }
445
446    return $result;
447}
448
4491;
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