1HTML::TokeParser::SimplUes(e3r)Contributed Perl DocumentHaTtMiLo:n:TokeParser::Simple(3)
2
6 HTML::TokeParser::Simple - Easy to use "HTML::TokeParser" interface
7
9 use HTML::TokeParser::Simple;
10 my $p = HTML::TokeParser::Simple->new( $somefile );
11 while ( my $token = $p->get_token ) {
13 # This prints all text in an HTML doc (i.e., it strips the HTML)
14 next unless $token->is_text;
15 print $token->as_is;
16 }
17
19 "HTML::TokeParser" is an excellent module that's often used for parsing
20 HTML. However, the tokens returned are not exactly intuitive to parse:
21 ["S", $tag, $attr, $attrseq, $text]
23 ["E", $tag, $text]
24 ["T", $text, $is_data]
25 ["C", $text]
26 ["D", $text]
27 ["PI", $token0, $text]
28 To simplify this, "HTML::TokeParser::Simple" allows the user ask more
30 intuitive (read: more self-documenting) questions about the tokens
31 returned.
32 You can also rebuild some tags on the fly. Frequently, the attributes
34 associated with start tags need to be altered, added to, or deleted.
35 This functionality is built in.
36 Since this is a subclass of "HTML::TokeParser", all "HTML::TokeParser"
38 methods are available. To truly appreciate the power of this module,
39 please read the documentation for "HTML::TokeParser" and
40 "HTML::Parser".
41
43 new($source)
44 The constructor for "HTML::TokeParser::Simple" can be used just like
45 "HTML::TokeParser"'s constructor:
46 my $parser = HTML::TokeParser::Simple->new($filename);
48 # or
49 my $parser = HTML::TokeParser::Simple->new($filehandle);
50 # or
51 my $parser = HTML::TokeParser::Simple->new(\$html_string);
52 "new($source_type, $source)"
54 If you wish to be more explicit, there is a new style of constructor
55 available.
56 my $parser = HTML::TokeParser::Simple->new(file => $filename);
58 # or
59 my $parser = HTML::TokeParser::Simple->new(handle => $filehandle);
60 # or
61 my $parser = HTML::TokeParser::Simple->new(string => $html_string);
62 Note that you do not have to provide a reference for the string if
64 using the string constructor.
65 As a convenience, you can also attempt to fetch the HTML directly from
67 a URL.
68 my $parser = HTML::TokeParser::Simple->new(url => 'http://some.url');
70 This method relies on "LWP::Simple". If this module is not found or
72 the page cannot be fetched, the constructor will croak().
73
75 get_token
76 This method will return the next token that
77 HTML::TokeParser::get_token() method would return. However, it will be
78 blessed into a class appropriate which represents the token type.
79 get_tag
81 This method will return the next token that HTML::TokeParser::get_tag()
82 method would return. However, it will be blessed into either the
83 HTML::TokeParser::Simple::Token::Tag::Start or
84 HTML::TokeParser::Simple::Token::Tag::End class.
85 peek
87 As of version 3.14, you can now peek() at the upcomings tokens without
88 affecting the state of the parser. By default, peek() will return the
89 text of the next token, but specifying an integer $count will return
90 the text of the next $count tokens.
91 This is useful when you're trying to debug where you are in a document.
93 warn $parser->peek(3); # show the next 3 tokens
95
97 The following methods may be called on the token object which is
98 returned, not on the parser object.
99 Boolean Accessors
101 These accessors return true or false.
102 • is_tag([$tag])
104 Use this to determine if you have any tag. An optional "tag type"
106 may be passed. This will allow you to match if it's a particular
107 tag. The supplied tag is case-insensitive.
108 if ( $token->is_tag ) { ... }
110 Optionally, you may pass a regular expression as an argument.
112 • is_start_tag([$tag])
114 Use this to determine if you have a start tag. An optional "tag
116 type" may be passed. This will allow you to match if it's a
117 particular start tag. The supplied tag is case-insensitive.
118 if ( $token->is_start_tag ) { ... }
120 if ( $token->is_start_tag( 'font' ) ) { ... }
121 Optionally, you may pass a regular expression as an argument. To
123 match all header (h1, h2, ... h6) tags:
124 if ( $token->is_start_tag( qr/^h[123456]$/ ) ) { ... }
126 • is_end_tag([$tag])
128 Use this to determine if you have an end tag. An optional "tag
130 type" may be passed. This will allow you to match if it's a
131 particular end tag. The supplied tag is case-insensitive.
132 When testing for an end tag, the forward slash on the tag is
134 optional.
135 while ( $token = $p->get_token ) {
137 if ( $token->is_end_tag( 'form' ) ) { ... }
138 }
139 Or:
141 while ( $token = $p->get_token ) {
143 if ( $token->is_end_tag( '/form' ) ) { ... }
144 }
145 Optionally, you may pass a regular expression as an argument.
147 • is_text()
149 Use this to determine if you have text. Note that this is not to
151 be confused with the "return_text" (deprecated) method described
152 below! "is_text" will identify text that the user typically sees
153 display in the Web browser.
154 • is_comment()
156 Are you still reading this? Nobody reads POD. Don't you know
158 you're supposed to go to CLPM, ask a question that's answered in
159 the POD and get flamed? It's a rite of passage.
160 Really.
162 "is_comment" is used to identify comments. See the HTML::Parser
164 documentation for more information about comments. There's more
165 than you might think.
166 • is_declaration()
168 This will match the DTD at the top of your HTML. (You do use DTD's,
170 don't you?)
171 • is_process_instruction()
173 Process Instructions are from XML. This is very handy if you need
175 to parse out PHP and similar things with a parser.
176 Currently, there appear to be some problems with process
178 instructions. You can override
179 "HTML::TokeParser::Simple::Token::ProcessInstruction" if you need
180 to.
181 • is_pi()
183 This is a shorthand for is_process_instruction().
185 Data Accessors
187 Some of these were originally "return_" methods, but that name was not
188 only unwieldy, but also went against reasonable conventions. The
189 "get_" methods listed below still have "return_" methods available for
190 backwards compatibility reasons, but they merely call their "get_"
191 counterpart. For example, calling return_tag() actually calls
192 get_tag() internally.
193 • get_tag()
195 Do you have a start tag or end tag? This will return the type
197 (lower case). Note that this is not the same as the get_tag()
198 method on the actual parser object.
199 • get_attr([$attribute])
201 If you have a start tag, this will return a hash ref with the
203 attribute names as keys and the values as the values.
204 If you pass in an attribute name, it will return the value for just
206 that attribute.
207 Returns false if the token is not a start tag.
209 • get_attrseq()
211 For a start tag, this is an array reference with the sequence of
213 the attributes, if any.
214 Returns false if the token is not a start tag.
216 • return_text()
218 This method has been heavily deprecated (for a couple of years) in
220 favor of "as_is". Programmers were getting confused over the
221 difference between "is_text", "return_text", and some parser
222 methods such as "HTML::TokeParser::get_text" and friends.
223 Using this method still succeeds, but will now carp and will be
225 removed in the next major release of this module.
226 • as_is()
228 This is the exact text of whatever the token is representing.
230 • get_token0()
232 For processing instructions, this will return the token found
234 immediately after the opening tag. Example: For <?php, "php" will
235 be the start of the returned string.
236 Note that process instruction handling appears to be incomplete in
238 "HTML::TokeParser".
239 Returns false if the token is not a process instruction.
241
243 The delete_attr() and set_attr() methods allow the programmer to
244 rewrite start tag attributes on the fly. It should be noted that bad
245 HTML will be "corrected" by this. Specifically, the new tag will have
246 all attributes lower-cased with the values properly quoted.
247 Self-closing tags (e.g. <hr />) are also handled correctly. Some older
249 browsers require a space prior to the final slash in a self-closed tag.
250 If such a space is detected in the original HTML, it will be preserved.
251 Calling a mutator on an token type that does not support that property
253 is a no-op. For example:
254 if ($token->is_comment) {
256 $token->set_attr(foo => 'bar'); # does nothing
257 }
258 • delete_attr($name)
260 This method attempts to delete the attribute specified. It will
262 silently fail if called on anything other than a start tag. The
263 argument is case-insensitive, but must otherwise be an exact match
264 of the attribute you are attempting to delete. If the attribute is
265 not found, the method will return without changing the tag.
266 # <body bgcolor="#FFFFFF">
268 $token->delete_attr('bgcolor');
269 print $token->as_is;
270 # <body>
271 After this method is called, if successful, the as_is(), get_attr()
273 and get_attrseq() methods will all return updated results.
274 • "set_attr($name,$value)"
276 This method will set the value of an attribute. If the attribute
278 is not found, then get_attrseq() will have the new attribute listed
279 at the end.
280 # <p>
282 $token->set_attr(class => 'some_class');
283 print $token->as_is;
284 # <p class="some_class">
285 # <body bgcolor="#FFFFFF">
287 $token->set_attr('bgcolor','red');
288 print $token->as_is;
289 # <body bgcolor="red">
290 After this method is called, if successful, the as_is(), get_attr()
292 and get_attrseq() methods will all return updated results.
293 • set_attr($hashref)
295 Under the premise that "set_" methods should accept what their
297 corresponding "get_" methods emit, the following works:
298 $tag->set_attr($tag->get_attr);
300 Theoretically that's a no-op and for purposes of rendering HTML, it
302 should be. However, internally this calls "$tag->rewrite_tag", so
303 see that method to understand how this may affect you.
304 Of course, this is useless if you want to actually change the
306 attributes, so you can do this:
307 my $attrs = {
309 class => 'headline',
310 valign => 'top'
311 };
312 $token->set_attr($attrs)
313 if $token->is_start_tag('td') && $token->get_attr('class') eq 'stories';
314 • rewrite_tag()
316 This method rewrites the tag. The tag name and the name of all
318 attributes will be lower-cased. Values that are not quoted with
319 double quotes will be. This may be called on both start or end
320 tags. Note that both set_attr() and delete_attr() call this method
321 prior to returning.
322 If called on a token that is not a tag, it simply returns.
324 Regardless of how it is called, it returns the token.
325 # <body alink=#0000ff BGCOLOR=#ffffff class='none'>
327 $token->rewrite_tag;
328 print $token->as_is;
329 # <body alink="#0000ff" bgcolor="#ffffff" class="none">
330 A quick cleanup of sloppy HTML is now the following:
332 my $parser = HTML::TokeParser::Simple->new( string => $ugly_html );
334 while (my $token = $parser->get_token) {
335 $token->rewrite_tag;
336 print $token->as_is;
337 }
338
340 The parser returns tokens that are blessed into appropriate classes.
341 Some people get confused and try to call parser methods on tokens and
342 token methods on the parser. To prevent this,
343 "HTML::TokeParser::Simple" versions 1.4 and above now bless all tokens
344 into appropriate token classes. Please keep this in mind while using
345 this module (and many thanks to PodMaster
346 <http://www.perlmonks.org/index.pl?node_id=107642> for pointing out
347 this issue to me.)
348
350 Finding comments
351 For some strange reason, your Pointy-Haired Boss (PHB) is convinced
352 that the graphics department is making fun of him by embedding rude
353 things about him in HTML comments. You need to get all HTML comments
354 from the HTML.
355 use strict;
357 use HTML::TokeParser::Simple;
358 my @html_docs = glob( "*.html" );
360 open PHB, "> phbreport.txt" or die "Cannot open phbreport for writing: $!";
362 foreach my $doc ( @html_docs ) {
364 print "Processing $doc\n";
365 my $p = HTML::TokeParser::Simple->new( file => $doc );
366 while ( my $token = $p->get_token ) {
367 next unless $token->is_comment;
368 print PHB $token->as_is, "\n";
369 }
370 }
371 close PHB;
373 Stripping Comments
375 Uh oh. Turns out that your PHB was right for a change. Many of the
376 comments in the HTML weren't very polite. Since your entire graphics
377 department was just fired, it falls on you need to strip those comments
378 from the HTML.
379 use strict;
381 use HTML::TokeParser::Simple;
382 my $new_folder = 'no_comment/';
384 my @html_docs = glob( "*.html" );
385 foreach my $doc ( @html_docs ) {
387 print "Processing $doc\n";
388 my $new_file = "$new_folder$doc";
389 open PHB, "> $new_file" or die "Cannot open $new_file for writing: $!";
391 my $p = HTML::TokeParser::Simple->new( $file => doc );
393 while ( my $token = $p->get_token ) {
394 next if $token->is_comment;
395 print PHB $token->as_is;
396 }
397 close PHB;
398 }
399 Changing form tags
401 Your company was foo.com and now is bar.com. Unfortunately, whoever
402 wrote your HTML decided to hardcode "http://www.foo.com/" into the
403 "action" attribute of the form tags. You need to change it to
404 "http://www.bar.com/".
405 use strict;
407 use HTML::TokeParser::Simple;
408 my $new_folder = 'new_html/';
410 my @html_docs = glob( "*.html" );
411 foreach my $doc ( @html_docs ) {
413 print "Processing $doc\n";
414 my $new_file = "$new_folder$doc";
415 open FILE, "> $new_file" or die "Cannot open $new_file for writing: $!";
417 my $p = HTML::TokeParser::Simple->new( file => $doc );
419 while ( my $token = $p->get_token ) {
420 if ( $token->is_start_tag('form') ) {
421 my $action = $token->get_attr(action);
422 $action =~ s/www\.foo\.com/www.bar.com/;
423 $token->set_attr('action', $action);
424 }
425 print FILE $token->as_is;
426 }
427 close FILE;
428 }
429
431 For compatibility reasons with "HTML::TokeParser", methods that return
432 references are violating encapsulation and altering the references
433 directly will alter the state of the object. Subsequent calls to
434 rewrite_tag() can thus have unexpected results. Do not alter these
435 references directly unless you are following behavior described in
436 these docs. In the future, certain methods such as "get_attr",
437 "get_attrseq" and others may return a copy of the reference rather than
438 the original reference. This behavior has not yet been changed in
439 order to maintain compatibility with previous versions of this module.
440 At the present time, your author is not aware of anyone taking
441 advantage of this "feature," but it's better to be safe than sorry.
442 Use of $HTML::Parser::VERSION which is less than 3.25 may result in
444 incorrect behavior as older versions do not always handle XHTML
445 correctly. It is the programmer's responsibility to verify that the
446 behavior of this code matches the programmer's needs.
447 Note that "HTML::Parser" processes text in 512 byte chunks. This
449 sometimes will cause strange behavior and cause text to be broken into
450 more than one token. You can suppress this behavior with the following
451 command:
452 $p->unbroken_text( [$bool] );
454 See the "HTML::Parser" documentation and
456 http://www.perlmonks.org/index.pl?node_id=230667 for more information.
457
459 There are no known bugs, but that's no guarantee.
460 Address bug reports and comments to: <eop_divo_sitruc@yahoo.com>. When
462 sending bug reports, please provide the version of "HTML::Parser",
463 "HTML::TokeParser", "HTML::TokeParser::Simple", the version of Perl,
464 and the version of the operating system you are using.
465 Reverse the name to email the author.
467
469 You may wish to change the behavior of this module. You probably do
470 not want to subclass "HTML::TokeParser::Simple". Instead, you'll want
471 to subclass one of the token classes.
472 "HTML::TokeParser::Simple::Token" is the base class for all tokens.
473 Global behavioral changes should go there. Otherwise, see the
474 appropriate token class for the behavior you wish to alter.
475
477 HTML::TokeParser::Simple::Token
478 HTML::TokeParser::Simple::Token::Tag
480 HTML::TokeParser::Simple::Token::Text
482 HTML::TokeParser::Simple::Token::Comment
484 HTML::TokeParser::Simple::Token::Declaration
486 HTML::TokeParser::Simple::Token::ProcessInstruction
488
490 Copyright (c) 2004 by Curtis "Ovid" Poe. All rights reserved. This
491 program is free software; you may redistribute it and/or modify it
492 under the same terms as Perl itself
493
495 Curtis "Ovid" Poe <eop_divo_sitruc@yahoo.com>
496 Reverse the name to email the author.
498perl v5.36.0 2023-01-20 HTML::TokeParser::Simple(3)