Commit | Line | Data |
d80786d0 |
1 | package HTML::Zoom; |
2 | |
1cf03540 |
3 | use strictures 1; |
d80786d0 |
4 | |
5 | use HTML::Zoom::ZConfig; |
bf5a23d0 |
6 | use HTML::Zoom::ReadFH; |
655965b3 |
7 | use HTML::Zoom::Transform; |
eeeb0921 |
8 | use HTML::Zoom::TransformBuilder; |
b9c27a5a |
9 | use Scalar::Util (); |
d80786d0 |
10 | |
f107bef7 |
11 | our $VERSION = '0.009004'; |
7af7362d |
12 | |
13 | $VERSION = eval $VERSION; |
14 | |
d80786d0 |
15 | sub new { |
16 | my ($class, $args) = @_; |
17 | my $new = {}; |
18 | $new->{zconfig} = HTML::Zoom::ZConfig->new($args->{zconfig}||{}); |
19 | bless($new, $class); |
20 | } |
21 | |
22 | sub zconfig { shift->_self_or_new->{zconfig} } |
23 | |
24 | sub _self_or_new { |
25 | ref($_[0]) ? $_[0] : $_[0]->new |
26 | } |
27 | |
28 | sub _with { |
29 | bless({ %{$_[0]}, %{$_[1]} }, ref($_[0])); |
30 | } |
31 | |
7567494d |
32 | sub from_events { |
d80786d0 |
33 | my $self = shift->_self_or_new; |
34 | $self->_with({ |
7567494d |
35 | initial_events => shift, |
d80786d0 |
36 | }); |
37 | } |
38 | |
7567494d |
39 | sub from_html { |
40 | my $self = shift->_self_or_new; |
41 | $self->from_events($self->zconfig->parser->html_to_events($_[0])) |
42 | } |
43 | |
bf5a23d0 |
44 | sub from_file { |
45 | my $self = shift->_self_or_new; |
46 | my $filename = shift; |
47 | $self->from_html(do { local (@ARGV, $/) = ($filename); <> }); |
48 | } |
49 | |
d80786d0 |
50 | sub to_stream { |
51 | my $self = shift; |
52 | die "No events to build from - forgot to call from_html?" |
53 | unless $self->{initial_events}; |
54 | my $sutils = $self->zconfig->stream_utils; |
55 | my $stream = $sutils->stream_from_array(@{$self->{initial_events}}); |
2f0c6a86 |
56 | $stream = $_->apply_to_stream($stream) for @{$self->{transforms}||[]}; |
d80786d0 |
57 | $stream |
58 | } |
59 | |
bf5a23d0 |
60 | sub to_fh { |
61 | HTML::Zoom::ReadFH->from_zoom(shift); |
62 | } |
63 | |
7567494d |
64 | sub to_events { |
65 | my $self = shift; |
66 | [ $self->zconfig->stream_utils->stream_to_array($self->to_stream) ]; |
67 | } |
68 | |
bf5a23d0 |
69 | sub run { |
70 | my $self = shift; |
7567494d |
71 | $self->to_events; |
bf5a23d0 |
72 | return |
73 | } |
74 | |
75 | sub apply { |
76 | my ($self, $code) = @_; |
77 | local $_ = $self; |
78 | $self->$code; |
79 | } |
80 | |
fdb039c6 |
81 | sub apply_if { |
82 | my ($self, $predicate, $code) = @_; |
83 | if($predicate) { |
84 | local $_ = $self; |
85 | $self->$code; |
86 | } |
87 | else { |
88 | $self; |
89 | } |
90 | } |
91 | |
d80786d0 |
92 | sub to_html { |
93 | my $self = shift; |
94 | $self->zconfig->producer->html_from_stream($self->to_stream); |
95 | } |
96 | |
97 | sub memoize { |
98 | my $self = shift; |
99 | ref($self)->new($self)->from_html($self->to_html); |
100 | } |
101 | |
eeeb0921 |
102 | sub with_transform { |
1c4455ae |
103 | my $self = shift->_self_or_new; |
eeeb0921 |
104 | my ($transform) = @_; |
d80786d0 |
105 | $self->_with({ |
2f0c6a86 |
106 | transforms => [ |
107 | @{$self->{transforms}||[]}, |
eeeb0921 |
108 | $transform |
2f0c6a86 |
109 | ] |
d80786d0 |
110 | }); |
111 | } |
eeeb0921 |
112 | |
113 | sub with_filter { |
114 | my $self = shift->_self_or_new; |
115 | my ($selector, $filter) = @_; |
116 | $self->with_transform( |
117 | HTML::Zoom::Transform->new({ |
118 | zconfig => $self->zconfig, |
119 | selector => $selector, |
120 | filters => [ $filter ] |
121 | }) |
122 | ); |
123 | } |
d80786d0 |
124 | |
125 | sub select { |
1c4455ae |
126 | my $self = shift->_self_or_new; |
127 | my ($selector) = @_; |
eeeb0921 |
128 | return HTML::Zoom::TransformBuilder->new({ |
129 | zconfig => $self->zconfig, |
130 | selector => $selector, |
131 | proto => $self |
132 | }); |
d80786d0 |
133 | } |
134 | |
135 | # There's a bug waiting to happen here: if you do something like |
136 | # |
137 | # $zoom->select('.foo') |
1c4455ae |
138 | # ->remove_attribute(class => 'foo') |
d80786d0 |
139 | # ->then |
140 | # ->well_anything_really |
141 | # |
142 | # the second action won't execute because it doesn't match anymore. |
143 | # Ideally instead we'd merge the match subs but that's more complex to |
144 | # implement so I'm deferring it for the moment. |
145 | |
146 | sub then { |
147 | my $self = shift; |
2f0c6a86 |
148 | die "Can't call ->then without a previous transform" |
149 | unless $self->{transforms}; |
150 | $self->select($self->{transforms}->[-1]->selector); |
d80786d0 |
151 | } |
152 | |
c877066a |
153 | sub AUTOLOAD { |
b9c27a5a |
154 | my ($self, $selector, @args) = @_; |
c877066a |
155 | my $meth = our $AUTOLOAD; |
156 | $meth =~ s/.*:://; |
b9c27a5a |
157 | return $self = $self->select($selector)->$meth(@args); |
c877066a |
158 | } |
c2d0669e |
159 | |
160 | ## mst: I've been thinking |
161 | ## mst: $zoom->fill($selector => $text) -> $zoom->select($selector)->replace_content($text) |
162 | ## mst: same for \$html |
163 | ## mst: then if it's an object or an arrayref we assume repeat_content |
164 | |
165 | =head2 fill |
166 | |
167 | @args = ($selector => $text||\$text) ## $zoom->select($selector)->replace_content($text) |
b9c27a5a |
168 | @args = ($selector => \@arrayref||$coderef) ## $zoom->select($selector)->repeat_content(\@arrayref) |
169 | @args = [qw/a b c/] => {}, $object |
c2d0669e |
170 | |
171 | =cut |
172 | |
173 | sub fill { |
174 | my $self = shift; |
b9c27a5a |
175 | while(@_) { |
176 | my $selector = shift; |
177 | my $args = shift; |
178 | my $type = Scalar::Util::reftype($args) ? Scalar::Util::reftype($args) : 'SCALAR'; |
c2d0669e |
179 | if($type eq 'ARRAY' || $type eq 'CODE') { |
180 | $self = $self->select($selector)->repeat_content($args); |
181 | } elsif($type eq 'SCALAR') { |
c2d0669e |
182 | $self = $self->select($selector)->replace_content($args); |
b9c27a5a |
183 | } elsif($type eq 'HASH') { |
184 | die "Selector must be ArrayRef" |
185 | unless ref($selector) eq 'ARRAY'; |
186 | foreach my $attr (@$selector) { |
187 | my $val = Scalar::Util::blessed($args) ? $args->$attr : $args->{$attr}; |
188 | next unless defined($val); |
189 | $self = $self->select(".$attr")->replace_content($val); |
190 | } |
c2d0669e |
191 | } else { |
192 | die "I don't know what to do with args of type $type"; |
193 | } |
194 | } |
195 | return $self; |
196 | } |
197 | |
198 | =head2 wrap_with |
199 | |
200 | my $layout = HTML::Zoom->from_html(<<HTML); |
201 | <html> |
202 | <head> |
203 | <title>Default Title</title> |
204 | <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> |
205 | <meta name="keywords" content="my special website" /> |
206 | <link rel="shortcut icon" href="/favicon.ico" /> |
207 | <link rel="stylesheet" href="/css/core.css" type="text/css" /> |
208 | </head> |
209 | </body id="content-area"> |
210 | <div>Default Content</div> |
211 | </body> |
212 | </html> |
213 | HTML |
214 | |
215 | my $content = HTML::Zoom->from_html(<<HTML); |
216 | <html> |
217 | <head> |
218 | <title>My Awesome Page</title> |
219 | </head> |
220 | </body> |
221 | <h1>Special Page</h1> |
222 | <p>Here is some content</p> |
223 | </body> |
224 | </html> |
225 | HTML |
226 | |
227 | $content |
228 | ->template($layout) ## is a wrap object of some sort |
229 | ->match('title') |
230 | ->match('body') |
3f03e15a |
231 | ->apply |
c2d0669e |
232 | |
233 | ## ^^ would be similar to: |
234 | |
235 | my (@title, @body); |
236 | $content |
237 | ->select('title') |
238 | ->collect_content({into => \@title}) |
239 | ->select('body') |
240 | ->collect_content({into => \@body}) |
241 | ->run; |
242 | |
243 | $layout |
244 | ->select('title') |
245 | ->replace_content(\@title); |
246 | ->select('body') |
247 | ->replace_content(\@body); |
248 | ->... |
249 | |
250 | =cut |
251 | |
d80786d0 |
252 | 1; |
253 | |
254 | =head1 NAME |
255 | |
256 | HTML::Zoom - selector based streaming template engine |
257 | |
258 | =head1 SYNOPSIS |
259 | |
260 | use HTML::Zoom; |
261 | |
262 | my $template = <<HTML; |
263 | <html> |
264 | <head> |
265 | <title>Hello people</title> |
266 | </head> |
267 | <body> |
268 | <h1 id="greeting">Placeholder</h1> |
269 | <div id="list"> |
270 | <span> |
271 | <p>Name: <span class="name">Bob</span></p> |
272 | <p>Age: <span class="age">23</span></p> |
273 | </span> |
274 | <hr class="between" /> |
275 | </div> |
276 | </body> |
277 | </html> |
278 | HTML |
279 | |
280 | my $output = HTML::Zoom |
281 | ->from_html($template) |
282 | ->select('title, #greeting')->replace_content('Hello world & dog!') |
283 | ->select('#list')->repeat_content( |
284 | [ |
285 | sub { |
286 | $_->select('.name')->replace_content('Matt') |
287 | ->select('.age')->replace_content('26') |
288 | }, |
289 | sub { |
290 | $_->select('.name')->replace_content('Mark') |
291 | ->select('.age')->replace_content('0x29') |
292 | }, |
293 | sub { |
294 | $_->select('.name')->replace_content('Epitaph') |
295 | ->select('.age')->replace_content('<redacted>') |
296 | }, |
297 | ], |
298 | { repeat_between => '.between' } |
299 | ) |
300 | ->to_html; |
301 | |
302 | will produce: |
303 | |
304 | =begin testinfo |
305 | |
306 | my $expect = <<HTML; |
307 | |
308 | =end testinfo |
309 | |
310 | <html> |
311 | <head> |
312 | <title>Hello world & dog!</title> |
313 | </head> |
314 | <body> |
315 | <h1 id="greeting">Hello world & dog!</h1> |
316 | <div id="list"> |
317 | <span> |
318 | <p>Name: <span class="name">Matt</span></p> |
319 | <p>Age: <span class="age">26</span></p> |
320 | </span> |
321 | <hr class="between" /> |
322 | <span> |
323 | <p>Name: <span class="name">Mark</span></p> |
324 | <p>Age: <span class="age">0x29</span></p> |
325 | </span> |
326 | <hr class="between" /> |
327 | <span> |
328 | <p>Name: <span class="name">Epitaph</span></p> |
329 | <p>Age: <span class="age"><redacted></span></p> |
330 | </span> |
331 | |
332 | </div> |
333 | </body> |
334 | </html> |
335 | |
336 | =begin testinfo |
337 | |
338 | HTML |
339 | is($output, $expect, 'Synopsis code works ok'); |
340 | |
341 | =end testinfo |
342 | |
1c4455ae |
343 | =head1 DANGER WILL ROBINSON |
344 | |
345 | This is a 0.9 release. That means that I'm fairly happy the API isn't going |
346 | to change in surprising and upsetting ways before 1.0 and a real compatibility |
347 | freeze. But it also means that if it turns out there's a mistake the size of |
348 | a politician's ego in the API design that I haven't spotted yet there may be |
349 | a bit of breakage between here and 1.0. Hopefully not though. Appendages |
350 | crossed and all that. |
351 | |
352 | Worse still, the rest of the distribution isn't documented yet. I'm sorry. |
353 | I suck. But lots of people have been asking me to ship this, docs or no, so |
354 | having got this class itself at least somewhat documented I figured now was |
355 | a good time to cut a first real release. |
356 | |
357 | =head1 DESCRIPTION |
358 | |
359 | HTML::Zoom is a lazy, stream oriented, streaming capable, mostly functional, |
360 | CSS selector based semantic templating engine for HTML and HTML-like |
361 | document formats. |
362 | |
363 | Which is, on the whole, a bit of a mouthful. So let me step back a moment |
364 | and explain why you care enough to understand what I mean: |
365 | |
366 | =head2 JQUERY ENVY |
367 | |
368 | HTML::Zoom is the cure for JQuery envy. When your javascript guy pushes a |
369 | piece of data into a document by doing: |
370 | |
371 | $('.username').replaceAll(username); |
372 | |
373 | In HTML::Zoom one can write |
374 | |
375 | $zoom->select('.username')->replace_content($username); |
376 | |
377 | which is, I hope, almost as clear, hampered only by the fact that Zoom can't |
378 | assume a global document and therefore has nothing quite so simple as the |
379 | $() function to get the initial selection. |
380 | |
381 | L<HTML::Zoom::SelectorParser> implements a subset of the JQuery selector |
382 | specification, and will continue to track that rather than the W3C standards |
383 | for the forseeable future on grounds of pragmatism. Also on grounds of their |
384 | spec is written in EN_US rather than EN_W3C, and I read the former much better. |
385 | |
386 | I am happy to admit that it's very, very much a subset at the moment - see the |
387 | L<HTML::Zoom::SelectorParser> POD for what's currently there, and expect more |
388 | and more to be supported over time as we need it and patch it in. |
389 | |
390 | =head2 CLEAN TEMPLATES |
391 | |
392 | HTML::Zoom is the cure for messy templates. How many times have you looked at |
393 | templates like this: |
394 | |
395 | <form action="/somewhere"> |
396 | [% FOREACH field IN fields %] |
397 | <label for="[% field.id %]">[% field.label %]</label> |
398 | <input name="[% field.name %]" type="[% field.type %]" value="[% field.value %]" /> |
399 | [% END %] |
400 | </form> |
401 | |
402 | and despaired of the fact that neither the HTML structure nor the logic are |
403 | remotely easy to read? Fortunately, with HTML::Zoom we can separate the two |
404 | cleanly: |
405 | |
406 | <form class="myform" action="/somewhere"> |
407 | <label /> |
408 | <input /> |
409 | </form> |
410 | |
411 | $zoom->select('.myform')->repeat_content([ |
412 | map { my $field = $_; sub { |
413 | |
414 | $_->select('label') |
2daa653a |
415 | ->add_to_attribute( for => $field->{id} ) |
1c4455ae |
416 | ->then |
417 | ->replace_content( $field->{label} ) |
418 | |
419 | ->select('input') |
2daa653a |
420 | ->add_to_attribute( name => $field->{name} ) |
1c4455ae |
421 | ->then |
2daa653a |
422 | ->add_to_attribute( type => $field->{type} ) |
1c4455ae |
423 | ->then |
2daa653a |
424 | ->add_to_attribute( value => $field->{value} ) |
1c4455ae |
425 | |
426 | } } @fields |
427 | ]); |
428 | |
429 | This is, admittedly, very much not shorter. However, it makes it extremely |
430 | clear what's happening and therefore less hassle to maintain. Especially |
431 | because it allows the designer to fiddle with the HTML without cutting |
432 | himself on sharp ELSE clauses, and the developer to add available data to |
433 | the template without getting angle bracket cuts on sensitive parts. |
434 | |
435 | Better still, HTML::Zoom knows that it's inserting content into HTML and |
436 | can escape it for you - the example template should really have been: |
437 | |
438 | <form action="/somewhere"> |
439 | [% FOREACH field IN fields %] |
440 | <label for="[% field.id | html %]">[% field.label | html %]</label> |
441 | <input name="[% field.name | html %]" type="[% field.type | html %]" value="[% field.value | html %]" /> |
442 | [% END %] |
443 | </form> |
444 | |
445 | and frankly I'll take slightly more code any day over *that* crawling horror. |
446 | |
447 | (addendum: I pick on L<Template Toolkit|Template> here specifically because |
448 | it's the template system I hate the least - for text templating, I don't |
449 | honestly think I'll ever like anything except the next version of Template |
450 | Toolkit better - but HTML isn't text. Zoom knows that. Do you?) |
451 | |
452 | =head2 PUTTING THE FUN INTO FUNCTIONAL |
453 | |
454 | The principle of HTML::Zoom is to provide a reusable, functional container |
455 | object that lets you build up a set of transforms to be applied; every method |
456 | call you make on a zoom object returns a new object, so it's safe to do so |
457 | on one somebody else gave you without worrying about altering state (with |
458 | the notable exception of ->next for stream objects, which I'll come to later). |
459 | |
460 | So: |
461 | |
462 | my $z2 = $z1->select('.name')->replace_content($name); |
463 | |
464 | my $z3 = $z2->select('.title')->replace_content('Ms.'); |
465 | |
466 | each time produces a new Zoom object. If you want to package up a set of |
467 | transforms to re-use, HTML::Zoom provides an 'apply' method: |
468 | |
469 | my $add_name = sub { $_->select('.name')->replace_content($name) }; |
470 | |
471 | my $same_as_z2 = $z1->apply($add_name); |
472 | |
473 | =head2 LAZINESS IS A VIRTUE |
474 | |
475 | HTML::Zoom does its best to defer doing anything until it's absolutely |
476 | required. The only point at which it descends into state is when you force |
477 | it to create a stream, directly by: |
478 | |
c9e76777 |
479 | my $stream = $zoom->to_stream; |
1c4455ae |
480 | |
481 | while (my $evt = $stream->next) { |
482 | # handle zoom event here |
483 | } |
484 | |
485 | or indirectly via: |
486 | |
487 | my $final_html = $zoom->to_html; |
488 | |
489 | my $fh = $zoom->to_fh; |
490 | |
491 | while (my $chunk = $fh->getline) { |
492 | ... |
493 | } |
494 | |
495 | Better still, the $fh returned doesn't create its stream until the first |
496 | call to getline, which means that until you call that and force it to be |
497 | stateful you can get back to the original stateless Zoom object via: |
498 | |
499 | my $zoom = $fh->to_zoom; |
500 | |
501 | which is exceedingly handy for filtering L<Plack> PSGI responses, among other |
502 | things. |
503 | |
504 | Because HTML::Zoom doesn't try and evaluate everything up front, you can |
505 | generally put things together in whatever order is most appropriate. This |
506 | means that: |
507 | |
508 | my $start = HTML::Zoom->from_html($html); |
509 | |
510 | my $zoom = $start->select('div')->replace_content('THIS IS A DIV!'); |
511 | |
512 | and: |
513 | |
514 | my $start = HTML::Zoom->select('div')->replace_content('THIS IS A DIV!'); |
515 | |
516 | my $zoom = $start->from_html($html); |
517 | |
518 | will produce equivalent final $zoom objects, thus proving that there can be |
519 | more than one way to do it without one of them being a |
520 | L<bait and switch|Switch>. |
521 | |
522 | =head2 STOCKTON TO DARLINGTON UNDER STREAM POWER |
523 | |
524 | HTML::Zoom's execution always happens in terms of streams under the hood |
525 | - that is, the basic pattern for doing anything is - |
526 | |
527 | my $stream = get_stream_from_somewhere |
528 | |
529 | while (my ($evt) = $stream->next) { |
530 | # do something with the event |
531 | } |
532 | |
533 | More importantly, all selectors and filters are also built as stream |
534 | operations, so a selector and filter pair is effectively: |
535 | |
536 | sub next { |
537 | my ($self) = @_; |
538 | my $next_evt = $self->parent_stream->next; |
539 | if ($self->selector_matches($next_evt)) { |
540 | return $self->apply_filter_to($next_evt); |
541 | } else { |
542 | return $next_evt; |
543 | } |
544 | } |
545 | |
546 | Internally, things are marginally more complicated than that, but not enough |
547 | that you as a user should normally need to care. |
548 | |
549 | In fact, an HTML::Zoom object is mostly just a container for the relevant |
550 | information from which to build the final stream that does the real work. A |
551 | stream built from a Zoom object is a stream of events from parsing the |
552 | initial HTML, wrapped in a filter stream per selector/filter pair provided |
553 | as described above. |
554 | |
555 | The upshot of this is that the application of filters works just as well on |
556 | streams as on the original Zoom object - in fact, when you run a |
557 | L</repeat_content> operation your subroutines are applied to the stream for |
558 | that element of the repeat, rather than constructing a new zoom per repeat |
559 | element as well. |
560 | |
561 | More concretely: |
562 | |
563 | $_->select('div')->replace_content('I AM A DIV!'); |
564 | |
565 | works on both HTML::Zoom objects themselves and HTML::Zoom stream objects and |
566 | shares sufficient of the implementation that you can generally forget the |
567 | difference - barring the fact that a stream already has state attached so |
568 | things like to_fh are no longer available. |
569 | |
570 | =head2 POP! GOES THE WEASEL |
571 | |
572 | ... and by Weasel, I mean layout. |
573 | |
574 | HTML::Zoom's filehandle object supports an additional event key, 'flush', |
575 | that is transparent to the rest of the system but indicates to the filehandle |
576 | object to end a getline operation at that point and return the HTML so far. |
577 | |
578 | This means that in an environment where streaming output is available, such |
579 | as a number of the L<Plack> PSGI handlers, you can add the flush key to an |
580 | event in order to ensure that the HTML generated so far is flushed through |
581 | to the browser right now. This can be especially useful if you know you're |
582 | about to call a web service or a potentially slow database query or similar |
583 | to ensure that at least the header/layout of your page renders now, improving |
584 | perceived user responsiveness while your application waits around for the |
585 | data it needs. |
586 | |
587 | This is currently exposed by the 'flush_before' option to the collect filter, |
588 | which incidentally also underlies the replace and repeat filters, so to |
589 | indicate we want this behaviour to happen before a query is executed we can |
590 | write something like: |
591 | |
592 | $zoom->select('.item')->repeat(sub { |
593 | if (my $row = $db_thing->next) { |
594 | return sub { $_->select('.item-name')->replace_content($row->name) } |
595 | } else { |
596 | return |
597 | } |
598 | }, { flush_before => 1 }); |
599 | |
600 | which should have the desired effect given a sufficiently lazy $db_thing (for |
601 | example a L<DBIx::Class::ResultSet> object). |
602 | |
603 | =head2 A FISTFUL OF OBJECTS |
604 | |
605 | At the core of an HTML::Zoom system lurks an L<HTML::Zoom::ZConfig> object, |
606 | whose purpose is to hang on to the various bits and pieces that things need |
607 | so that there's a common way of accessing shared functionality. |
608 | |
609 | Were I a computer scientist I would probably call this an "Inversion of |
610 | Control" object - which you'd be welcome to google to learn more about, or |
611 | you can just imagine a computer scientist being suspended upside down over |
612 | a pit. Either way works for me, I'm a pure maths grad. |
613 | |
614 | The ZConfig object hangs on to one each of the following for you: |
615 | |
616 | =over 4 |
617 | |
618 | =item * An HTML parser, normally L<HTML::Zoom::Parser::BuiltIn> |
619 | |
620 | =item * An HTML producer (emitter), normally L<HTML::Zoom::Producer::BuiltIn> |
621 | |
622 | =item * An object to build event filters, normally L<HTML::Zoom::FilterBuilder> |
623 | |
624 | =item * An object to parse CSS selectors, normally L<HTML::Zoom::SelectorParser> |
625 | |
626 | =item * An object to build streams, normally L<HTML::Zoom::StreamUtils> |
627 | |
628 | =back |
629 | |
630 | In theory you could replace any of these with anything you like, but in |
631 | practice you're probably best restricting yourself to subclasses, or at |
632 | least things that manage to look like the original if you squint a bit. |
633 | |
634 | If you do something more clever than that, or find yourself overriding things |
635 | in your ZConfig a lot, please please tell us about it via one of the means |
636 | mentioned under L</SUPPORT>. |
637 | |
638 | =head2 SEMANTIC DIDACTIC |
639 | |
640 | Some will argue that overloading CSS selectors to do data stuff is a terrible |
641 | idea, and possibly even a step towards the "Concrete Javascript" pattern |
642 | (which I abhor) or Smalltalk's Morphic (which I ignore, except for the part |
643 | where it keeps reminding me of the late, great Tony Hart's plasticine friend). |
644 | |
645 | To which I say, "eh", "meh", and possibly also "feh". If it really upsets |
646 | you, either use extra classes for this (and remove them afterwards) or |
647 | use special fake elements or, well, honestly, just use something different. |
648 | L<Template::Semantic> provides a similar idea to zoom except using XPath |
649 | and XML::LibXML transforms rather than a lightweight streaming approach - |
650 | maybe you'd like that better. Or maybe you really did want |
651 | L<Template Toolkit|Template> after all. It is still damn good at what it does, |
652 | after all. |
653 | |
654 | So far, however, I've found that for new sites the designers I'm working with |
655 | generally want to produce nice semantic HTML with classes that represent the |
656 | nature of the data rather than the structure of the layout, so sharing them |
657 | as a common interface works really well for us. |
658 | |
659 | In the absence of any evidence that overloading CSS selectors has killed |
660 | children or unexpectedly set fire to grandmothers - and given microformats |
661 | have been around for a while there's been plenty of opportunity for |
662 | octagenarian combustion - I'd suggest you give it a try and see if you like it. |
663 | |
664 | =head2 GET THEE TO A SUMMARY! |
665 | |
666 | Erm. Well. |
667 | |
668 | HTML::Zoom is a lazy, stream oriented, streaming capable, mostly functional, |
669 | CSS selector based semantic templating engine for HTML and HTML-like |
670 | document formats. |
671 | |
672 | But I said that already. Although hopefully by now you have some idea what I |
673 | meant when I said it. If you didn't have any idea the first time. I mean, I'm |
674 | not trying to call you stupid or anything. Just saying that maybe it wasn't |
675 | totally obvious without the explanation. Or something. |
676 | |
677 | Er. |
678 | |
679 | Maybe we should just move on to the method docs. |
680 | |
681 | =head1 METHODS |
682 | |
683 | =head2 new |
684 | |
685 | my $zoom = HTML::Zoom->new; |
686 | |
687 | my $zoom = HTML::Zoom->new({ zconfig => $zconfig }); |
688 | |
689 | Create a new empty Zoom object. You can optionally pass an |
690 | L<HTML::Zoom::ZConfig> instance if you're trying to override one or more of |
691 | the default components. |
692 | |
693 | This method isn't often used directly since several other methods can also |
694 | act as constructors, notable L</select> and L</from_html> |
695 | |
696 | =head2 zconfig |
697 | |
698 | my $zconfig = $zoom->zconfig; |
699 | |
700 | Retrieve the L<HTML::Zoom::ZConfig> instance used by this Zoom object. You |
701 | shouldn't usually need to call this yourself. |
702 | |
703 | =head2 from_html |
704 | |
705 | my $zoom = HTML::Zoom->from_html($html); |
706 | |
707 | my $z2 = $z1->from_html($html); |
708 | |
709 | Parses the HTML using the current zconfig's parser object and returns a new |
710 | zoom instance with that as the source HTML to be transformed. |
711 | |
712 | =head2 from_file |
713 | |
714 | my $zoom = HTML::Zoom->from_file($file); |
715 | |
716 | my $z2 = $z1->from_file($file); |
717 | |
718 | Convenience method - slurps the contents of $file and calls from_html with it. |
719 | |
720 | =head2 to_stream |
721 | |
722 | my $stream = $zoom->to_stream; |
723 | |
724 | while (my ($evt) = $stream->next) { |
725 | ... |
726 | |
727 | Creates a stream, starting with a stream of the events from the HTML supplied |
728 | via L</from_html> and then wrapping it in turn with each selector+filter pair |
729 | that have been applied to the zoom object. |
730 | |
731 | =head2 to_fh |
732 | |
733 | my $fh = $zoom->to_fh; |
734 | |
735 | call_something_expecting_a_filehandle($fh); |
736 | |
737 | Returns an L<HTML::Zoom::ReadFH> instance that will create a stream the first |
738 | time its getline method is called and then return all HTML up to the next |
739 | event with 'flush' set. |
740 | |
741 | You can pass this filehandle to compliant PSGI handlers (and probably most |
742 | web frameworks). |
743 | |
744 | =head2 run |
745 | |
746 | $zoom->run; |
747 | |
748 | Runs the zoom object's transforms without doing anything with the results. |
749 | |
750 | Normally used to get side effects of a zoom run - for example when using |
751 | L<HTML::Zoom::FilterBuilder/collect> to slurp events for scraping or layout. |
752 | |
753 | =head2 apply |
754 | |
755 | my $z2 = $z1->apply(sub { |
756 | $_->select('div')->replace_content('I AM A DIV!') }) |
757 | }); |
758 | |
759 | Sets $_ to the zoom object and then runs the provided code. Basically syntax |
760 | sugar, the following is entirely equivalent: |
761 | |
762 | my $sub = sub { |
763 | shift->select('div')->replace_content('I AM A DIV!') }) |
764 | }; |
765 | |
766 | my $z2 = $sub->($z1); |
767 | |
768 | =head2 to_html |
769 | |
770 | my $html = $zoom->to_html; |
771 | |
772 | Runs the zoom processing and returns the resulting HTML. |
773 | |
774 | =head2 memoize |
775 | |
776 | my $z2 = $z1->memoize; |
777 | |
778 | Creates a new zoom whose source HTML is the results of the original zoom's |
779 | processing. Effectively syntax sugar for: |
780 | |
781 | my $z2 = HTML::Zoom->from_html($z1->to_html); |
782 | |
783 | but preserves your L<HTML::Zoom::ZConfig> object. |
784 | |
785 | =head2 with_filter |
786 | |
787 | my $zoom = HTML::Zoom->with_filter( |
788 | 'div', $filter_builder->replace_content('I AM A DIV!') |
789 | ); |
790 | |
791 | my $z2 = $z1->with_filter( |
792 | 'div', $filter_builder->replace_content('I AM A DIV!') |
793 | ); |
794 | |
795 | Lower level interface than L</select> to adding filters to your zoom object. |
796 | |
797 | In normal usage, you probably don't need to call this yourself. |
798 | |
799 | =head2 select |
800 | |
801 | my $zoom = HTML::Zoom->select('div')->replace_content('I AM A DIV!'); |
802 | |
803 | my $z2 = $z1->select('div')->replace_content('I AM A DIV!'); |
804 | |
97192b02 |
805 | Returns an intermediary object of the class L<HTML::Zoom::TransformBuilder> |
1c4455ae |
806 | on which methods of your L<HTML::Zoom::FilterBuilder> object can be called. |
807 | |
808 | In normal usage you should generally always put the pair of method calls |
809 | together; the intermediary object isn't designed or expected to stick around. |
810 | |
811 | =head2 then |
812 | |
2daa653a |
813 | my $z2 = $z1->select('div')->add_to_attribute(class => 'spoon') |
1c4455ae |
814 | ->then |
815 | ->replace_content('I AM A DIV!'); |
816 | |
817 | Re-runs the previous select to allow you to chain actions together on the |
818 | same selector. |
819 | |
b9c27a5a |
820 | =head1 AUTOLOAD METHODS |
821 | |
822 | L<HTML::Zoom> AUTOLOADS methods against L</select> so that you can reduce a |
823 | certain amount of boilerplate typing. This allows you to replace: |
824 | |
825 | $z->select('div')->replace_content("Hello World"); |
826 | |
827 | With: |
828 | |
829 | $z->replace_content(div => "Hello World"); |
830 | |
831 | Besides saving a few keys per invocations, you may feel this looks neater |
832 | in your code and increases understanding. |
833 | |
f107bef7 |
834 | =head1 AUTHOR |
45b4cea1 |
835 | |
f107bef7 |
836 | mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk> |
45b4cea1 |
837 | |
f107bef7 |
838 | =head1 CONTRIBUTORS |
45b4cea1 |
839 | |
f107bef7 |
840 | Oliver Charles |
841 | |
842 | Jakub Nareski |
843 | |
844 | Simon Elliot |
845 | |
846 | Joe Highton |
847 | |
848 | John Napiorkowski |
849 | |
850 | =head1 COPYRIGHT |
851 | |
852 | Copyright (c) 2010-2011 the HTML::Zoom L</AUTHOR> and L</CONTRIBUTORS> |
853 | as listed above. |
45b4cea1 |
854 | |
855 | =head1 LICENSE |
856 | |
857 | This library is free software, you can redistribute it and/or modify |
858 | it under the same terms as Perl itself. |
859 | |
d80786d0 |
860 | =cut |
45b4cea1 |
861 | |