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1 | =encoding utf-8 | |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | HTML::Element::Library - HTML::Element convenience functions | |
6 | ||
7 | =head1 SYNOPSIS | |
8 | ||
9 | use HTML::Element::Library; | |
10 | use HTML::TreeBuilder; | |
11 | ||
12 | =head1 DESCRIPTION | |
13 | ||
14 | This method provides API calls for common actions on trees when using | |
15 | L<HTML::Tree>. | |
16 | ||
17 | =head1 METHODS | |
18 | ||
19 | The test suite contains examples of each of these methods in a file | |
20 | C<t/$method.t> | |
21 | ||
22 | =head2 Positional Querying Methods | |
23 | ||
24 | =head3 $elem->siblings | |
25 | ||
26 | Return a list of all nodes under the same parent. | |
27 | ||
28 | =head3 $elem->sibdex | |
29 | ||
30 | Return the index of C<$elem> into the array of siblings of which it is | |
31 | a part. L<HTML::ElementSuper> calls this method C<addr> but I don't | |
32 | think that is a descriptive name. And such naming is deceptively close | |
33 | to the C<address> function of C<HTML::Element>. HOWEVER, in the | |
34 | interest of backwards compatibility, both methods are available. | |
35 | ||
36 | =head3 $elem->addr | |
37 | ||
38 | Same as sibdex | |
39 | ||
40 | =head3 $elem->position() | |
41 | ||
42 | Returns the coordinates of this element in the tree it inhabits. This | |
43 | is accomplished by succesively calling addr() on ancestor elements | |
44 | until either a) an element that does not support these methods is | |
45 | found, or b) there are no more parents. The resulting list is the | |
46 | n-dimensional coordinates of the element in the tree. | |
47 | ||
48 | =head2 Element Decoration Methods | |
49 | ||
50 | =head3 HTML::Element::Library::super_literal($text) | |
51 | ||
52 | In L<HTML::Element>, Sean Burke discusses super-literals. They are | |
53 | text which does not get escaped. Great for includng Javascript in | |
54 | HTML. Also great for including foreign language into a document. | |
55 | ||
56 | So, you basically toss C<super_literal> your text and back comes your | |
57 | text wrapped in a C<~literal> element. | |
58 | ||
59 | One of these days, I'll around to writing a nice C<EXPORT> section. | |
60 | ||
61 | =head2 Tree Rewriting Methods | |
62 | ||
63 | =head3 "de-prepping" HTML | |
64 | ||
65 | Oftentimes, the HTML to be worked with will have multiple sample rows: | |
66 | ||
67 | <OL> | |
68 | <LI>bread | |
69 | <LI>butter | |
70 | <LI>beer | |
71 | <LI>bacon | |
72 | </OL> | |
73 | ||
74 | But, before you begin to rewrite the HTML with your model data, you | |
75 | typically only want 1 or 2 sample rows. | |
76 | ||
77 | Thus, you want to "crunch" the multiple sample rows to a specified | |
78 | amount. Hence the C<crunch> method: | |
79 | ||
80 | $tree->crunch(look_down => [ '_tag' => 'li' ], leave => 2) ; | |
81 | ||
82 | The C<leave> argument defaults to 1 if not given. The call above would | |
83 | "crunch" the above 4 sample rows to: | |
84 | ||
85 | <OL> | |
86 | <LI>bread | |
87 | <LI>butter | |
88 | </OL> | |
89 | ||
90 | =head3 Simplifying calls to HTML::FillInForm | |
91 | ||
92 | Since HTML::FillInForm gets and returns strings, using HTML::Element | |
93 | instances becomes tedious: | |
94 | ||
95 | 1. Seamstress has an HTML tree that it wants the form filled in on | |
96 | 2. Seamstress converts this tree to a string | |
97 | 3. FillInForm parses the string into an HTML tree and then fills in the form | |
98 | 4. FillInForm converts the HTML tree to a string | |
99 | 5. Seamstress re-parses the HTML for additional processing | |
100 | ||
101 | I've filed a bug about this: | |
102 | L<https://rt.cpan.org/Ticket/Display.html?id=44105> | |
103 | ||
104 | This function, fillinform, allows you to pass a tree to fillinform | |
105 | (along with your data structure) and get back a tree: | |
106 | ||
107 | my $new_tree = $html_tree->fillinform($data_structure); | |
108 | ||
109 | =head3 Mapping a hashref to HTML elements | |
110 | ||
111 | It is very common to get a hashref of data from some external source - | |
112 | flat file, database, XML, etc. Therefore, it is important to have a | |
113 | convenient way of mapping this data to HTML. | |
114 | ||
115 | As it turns out, there are 3 ways to do this in | |
116 | HTML::Element::Library. The most strict and structured way to do this | |
117 | is with C<content_handler>. Two other methods, C<hashmap> and | |
118 | C<datamap> require less manual mapping and may prove even more easy to | |
119 | use in certain cases. | |
120 | ||
121 | As is usual with Perl, a practical example is always best. So let's | |
122 | take some sample HTML: | |
123 | ||
124 | <h1>user data</h1> | |
125 | <span id="name">?</span> | |
126 | <span id="email">?</span> | |
127 | <span id="gender">?</span> | |
128 | ||
129 | Now, let's say our data structure is this: | |
130 | ||
131 | $ref = { email => 'jim@beam.com', gender => 'lots' } ; | |
132 | ||
133 | And let's start with the most strict way to get what you want: | |
134 | ||
135 | $tree->content_handler(email => $ref->{email} , gender => $ref->{gender}) ; | |
136 | ||
137 | In this case, you manually state the mapping between id tags and | |
138 | hashref keys and then C<content_handler> retrieves the hashref data | |
139 | and pops it in the specified place. | |
140 | ||
141 | Now let's look at the two (actually 2 and a half) other hash-mapping | |
142 | methods. | |
143 | ||
144 | $tree->hashmap(id => $ref); | |
145 | ||
146 | Now, what this function does is super-destructive. It finds every | |
147 | element in the tree with an attribute named id (since 'id' is a | |
148 | parameter, it could find every element with some other attribute also) | |
149 | and replaces the content of those elements with the hashref value. | |
150 | ||
151 | So, in the case above, the | |
152 | ||
153 | <span id="name">?</span> | |
154 | ||
155 | would come out as | |
156 | ||
157 | <span id="name"></span> | |
158 | ||
159 | (it would be blank) - because there is nothing in the hash with that | |
160 | value, so it substituted | |
161 | ||
162 | $ref->{name} | |
163 | ||
164 | which was blank and emptied the contents. | |
165 | ||
166 | Now, let's assume we want to protect name from being auto-assigned. | |
167 | Here is what you do: | |
168 | ||
169 | $tree->hashmap(id => $ref, ['name']); | |
170 | ||
171 | That last array ref is an exclusion list. | |
172 | ||
173 | But wouldnt it be nice if you could do a hashmap, but only assigned | |
174 | things which are defined in the hashref? C<< defmap() >> to the | |
175 | rescue: | |
176 | ||
177 | $tree->defmap(id => $ref); | |
178 | ||
179 | does just that, so | |
180 | ||
181 | <span id="name">?</span> | |
182 | ||
183 | would be left alone. | |
184 | ||
185 | =head4 $elem->hashmap($attr_name, \%hashref, \@excluded, $debug) | |
186 | ||
187 | This method is designed to take a hashref and populate a series of | |
188 | elements. For example: | |
189 | ||
190 | <table> | |
191 | <tr sclass="tr" class="alt" align="left" valign="top"> | |
192 | <td smap="people_id">1</td> | |
193 | <td smap="phone">(877) 255-3239</td> | |
194 | <td smap="password">*********</td> | |
195 | </tr> | |
196 | </table> | |
197 | ||
198 | In the table above, there are several attributes named C<< smap >>. If | |
199 | we have a hashref whose keys are the same: | |
200 | ||
201 | my %data = (people_id => 888, phone => '444-4444', password => 'dont-you-dare-render'); | |
202 | ||
203 | Then a single API call allows us to populate the HTML while excluding | |
204 | those ones we dont: | |
205 | ||
206 | $tree->hashmap(smap => \%data, ['password']); | |
207 | ||
208 | Note: the other way to prevent rendering some of the hash mapping is | |
209 | to not give that element the attr you plan to use for hash mapping. | |
210 | ||
211 | Also note: the function C<< hashmap >> has a simple easy-to-type API. | |
212 | Interally, it calls C<< hash_map >> (which has a more verbose keyword | |
213 | calling API). Thus, the above call to C<hashmap()> results in this | |
214 | call: | |
215 | ||
216 | $tree->hash_map(hash => \%data, to_attr => 'sid', excluding => ['password']); | |
217 | ||
218 | =head4 $elem->defmap($attr_name, \%hashref, $debug) | |
219 | ||
220 | C<defmap> was described above. | |
221 | ||
222 | =head3 $elem->replace_content(@new_elem) | |
223 | ||
224 | Replaces all of C<$elem>'s content with C<@new_elem>. | |
225 | ||
226 | =head3 $elem->wrap_content($wrapper_element) | |
227 | ||
228 | Wraps the existing content in the provided element. If the provided | |
229 | element happens to be a non-element, a push_content is performed | |
230 | instead. | |
231 | ||
232 | =head3 $elem->set_child_content(@look_down, $content) | |
233 | ||
234 | This method looks down $tree using the criteria specified in | |
235 | @look_down using the the HTML::Element look_down() method. | |
236 | ||
237 | After finding the node, it detaches the node's content and pushes | |
238 | $content as the node's content. | |
239 | ||
240 | =head3 $tree->content_handler(%id_content) | |
241 | ||
242 | This is a convenience method. Because the look_down criteria will | |
243 | often simply be: | |
244 | ||
245 | id => 'fixme' | |
246 | ||
247 | to find things like: | |
248 | ||
249 | <a id=fixme href=http://www.somesite.org>replace_content</a> | |
250 | ||
251 | You can call this method to shorten your typing a bit. You can simply | |
252 | type | |
253 | ||
254 | $elem->content_handler( fixme => 'new text' ) | |
255 | ||
256 | Instead of typing: | |
257 | ||
258 | $elem->set_child_content(sid => 'fixme', 'new text') | |
259 | ||
260 | ALSO NOTE: you can pass a hash whose keys are C<id>s and whose values | |
261 | are the content you want there and it will perform the replacement on | |
262 | each hash member: | |
263 | ||
264 | my %id_content = (name => "Terrence Brannon", | |
265 | email => 'tbrannon@in.com', | |
266 | balance => 666, | |
267 | content => $main_content); | |
268 | $tree->content_handler(%id_content); | |
269 | ||
270 | =head3 $tree->highlander($subtree_span_id, $conditionals, @conditionals_args) | |
271 | ||
272 | This allows for "if-then-else" style processing. Highlander was a | |
273 | movie in which only one would survive. Well, in terms of a tree when | |
274 | looking at a structure that you want to process in C<if-then-else> | |
275 | style, only one child will survive. For example, given this HTML | |
276 | template: | |
277 | ||
278 | <span klass="highlander" id="age_dialog"> | |
279 | <span id="under10"> | |
280 | Hello, does your mother know you're | |
281 | using her AOL account? | |
282 | </span> | |
283 | <span id="under18"> | |
284 | Sorry, you're not old enough to enter | |
285 | (and too dumb to lie about your age) | |
286 | </span> | |
287 | <span id="welcome"> | |
288 | Welcome | |
289 | </span> | |
290 | </span> | |
291 | ||
292 | We only want one child of the C<span> tag with id C<age_dialog> to | |
293 | remain based on the age of the person visiting the page. | |
294 | ||
295 | So, let's setup a call that will prune the subtree as a function of | |
296 | age: | |
297 | ||
298 | sub process_page { | |
299 | my $age = shift; | |
300 | my $tree = HTML::TreeBuilder->new_from_file('t/html/highlander.html'); | |
301 | ||
302 | $tree->highlander | |
303 | (age_dialog => | |
304 | [ | |
305 | under10 => sub { $_[0] < 10}, | |
306 | under18 => sub { $_[0] < 18}, | |
307 | welcome => sub { 1 } | |
308 | ], | |
309 | $age | |
310 | ); | |
311 | ||
312 | And there we have it. If the age is less than 10, then the node with | |
313 | id C<under10> remains. For age less than 18, the node with id | |
314 | C<under18> remains. Otherwise our "else" condition fires and the child | |
315 | with id C<welcome> remains. | |
316 | ||
317 | =head3 $tree->passover(@id_of_element) | |
318 | ||
319 | In some cases, you know exactly which element(s) should survive. In | |
320 | this case, you can simply call C<passover> to remove it's (their) | |
321 | siblings. For the HTML above, you could delete C<under10> and | |
322 | C<welcome> by simply calling: | |
323 | ||
324 | $tree->passover('under18'); | |
325 | ||
326 | Because passover takes an array, you can specify several children to | |
327 | preserve. | |
328 | ||
329 | =head3 $tree->highlander2($tree, $conditionals, @conditionals_args) | |
330 | ||
331 | Right around the same time that C<table2()> came into being, | |
332 | Seamstress began to tackle tougher and tougher processing problems. It | |
333 | became clear that a more powerful highlander was needed... one that | |
334 | not only snipped the tree of the nodes that should not survive, but | |
335 | one that allows for post-processing of the survivor node. And one that | |
336 | was more flexible with how to find the nodes to snip. | |
337 | ||
338 | Thus (drum roll) C<highlander2()>. | |
339 | ||
340 | So let's look at our HTML which requires post-selection processing: | |
341 | ||
342 | <span klass="highlander" id="age_dialog"> | |
343 | <span id="under10"> | |
344 | Hello, little <span id=age>AGE</span>-year old, | |
345 | does your mother know you're using her AOL account? | |
346 | </span> | |
347 | <span id="under18"> | |
348 | Sorry, you're only <span id=age>AGE</span> | |
349 | (and too dumb to lie about your age) | |
350 | </span> | |
351 | <span id="welcome"> | |
352 | Welcome, isn't it good to be <span id=age>AGE</span> years old? | |
353 | </span> | |
354 | </span> | |
355 | ||
356 | In this case, a branch survives, but it has dummy data in it. We must | |
357 | take the surviving segment of HTML and rewrite the age C<span> with | |
358 | the age. Here is how we use C<highlander2()> to do so: | |
359 | ||
360 | sub replace_age { | |
361 | my $branch = shift; | |
362 | my $age = shift; | |
363 | $branch->look_down(id => 'age')->replace_content($age); | |
364 | } | |
365 | ||
366 | my $if_then = $tree->look_down(id => 'age_dialog'); | |
367 | ||
368 | $if_then->highlander2( | |
369 | cond => [ | |
370 | under10 => [ | |
371 | sub { $_[0] < 10} , | |
372 | \&replace_age | |
373 | ], | |
374 | under18 => [ | |
375 | sub { $_[0] < 18} , | |
376 | \&replace_age | |
377 | ], | |
378 | welcome => [ | |
379 | sub { 1 }, | |
380 | \&replace_age | |
381 | ] | |
382 | ], | |
383 | cond_arg => [ $age ] | |
384 | ); | |
385 | ||
386 | We pass it the tree (C<$if_then>), an arrayref of conditions (C<cond>) | |
387 | and an arrayref of arguments which are passed to the C<cond>s and to | |
388 | the replacement subs. | |
389 | ||
390 | The C<under10>, C<under18> and C<welcome> are id attributes in the | |
391 | tree of the siblings of which only one will survive. However, should | |
392 | you need to do more complex look-downs to find the survivor, then | |
393 | supply an array ref instead of a simple scalar: | |
394 | ||
395 | $if_then->highlander2( | |
396 | cond => [ | |
397 | [class => 'r12'] => [ | |
398 | sub { $_[0] < 10} , | |
399 | \&replace_age | |
400 | ], | |
401 | [class => 'z22'] => [ | |
402 | sub { $_[0] < 18} , | |
403 | \&replace_age | |
404 | ], | |
405 | [class => 'w88'] => [ | |
406 | sub { 1 }, | |
407 | \&replace_age | |
408 | ] | |
409 | ], | |
410 | cond_arg => [ $age ] | |
411 | ); | |
412 | ||
413 | =head3 $tree->overwrite_attr($mutation_attr => $mutating_closures) | |
414 | ||
415 | This method is designed for taking a tree and reworking a set of nodes | |
416 | in a stereotyped fashion. For instance let's say you have 3 remote | |
417 | image archives, but you don't want to put long URLs in your img src | |
418 | tags for reasons of abstraction, re-use and brevity. So instead you do | |
419 | this: | |
420 | ||
421 | <img src="/img/smiley-face.jpg" fixup="src lnc"> | |
422 | <img src="/img/hot-babe.jpg" fixup="src playboy"> | |
423 | <img src="/img/footer.jpg" fixup="src foobar"> | |
424 | ||
425 | and then when the tree of HTML is being processed, you make this call: | |
426 | ||
427 | my %closures = ( | |
428 | lnc => sub { my ($tree, $mute_node, $attr_value)= @_; "http://lnc.usc.edu$attr_value" }, | |
429 | playboy => sub { my ($tree, $mute_node, $attr_value)= @_; "http://playboy.com$attr_value" } | |
430 | foobar => sub { my ($tree, $mute_node, $attr_value)= @_; "http://foobar.info$attr_value" } | |
431 | ) | |
432 | ||
433 | $tree->overwrite_attr(fixup => \%closures) ; | |
434 | ||
435 | and the tags come out modified like so: | |
436 | ||
437 | <img src="http://lnc.usc.edu/img/smiley-face.jpg" fixup="src lnc"> | |
438 | <img src="http://playboy.com/img/hot-babe.jpg" fixup="src playboy"> | |
439 | <img src="http://foobar.info/img/footer.jpg" fixup="src foobar"> | |
440 | ||
441 | =head3 $tree->mute_elem($mutation_attr => $mutating_closures, [ $post_hook ] ) | |
442 | ||
443 | This is a generalization of C<overwrite_attr>. C<overwrite_attr> | |
444 | assumes the return value of the closure is supposed overwrite an | |
445 | attribute value and does it for you. C<mute_elem> is a more general | |
446 | function which does nothing but hand the closure the element and let | |
447 | it mutate it as it jolly well pleases :) | |
448 | ||
449 | In fact, here is the implementation of C<overwrite_attr> to give you a | |
450 | taste of how C<mute_attr> is used: | |
451 | ||
452 | sub overwrite_action { | |
453 | my ($mute_node, %X) = @_; | |
454 | ||
455 | $mute_node->attr($X{local_attr}{name} => $X{local_attr}{value}{new}); | |
456 | } | |
457 | ||
458 | ||
459 | sub HTML::Element::overwrite_attr { | |
460 | my $tree = shift; | |
461 | ||
462 | $tree->mute_elem(@_, \&overwrite_action); | |
463 | } | |
464 | ||
465 | =head2 Tree-Building Methods | |
466 | ||
467 | =head3 Unrolling an array via a single sample element (<ul> container) | |
468 | ||
469 | This is best described by example. Given this HTML: | |
470 | ||
471 | <strong>Here are the things I need from the store:</strong> | |
472 | <ul> | |
473 | <li class="store_items">Sample item</li> | |
474 | </ul> | |
475 | ||
476 | We can unroll it like so: | |
477 | ||
478 | my $li = $tree->look_down(class => 'store_items'); | |
479 | ||
480 | my @items = qw(bread butter vodka); | |
481 | ||
482 | $tree->iter($li => @items); | |
483 | ||
484 | To produce this: | |
485 | ||
486 | <html> | |
487 | <head></head> | |
488 | <body>Here are the things I need from the store: | |
489 | <ul> | |
490 | <li class="store_items">bread</li> | |
491 | <li class="store_items">butter</li> | |
492 | <li class="store_items">vodka</li> | |
493 | </ul> | |
494 | </body> | |
495 | </html> | |
496 | ||
497 | Now, you might be wondering why the API call is: | |
498 | ||
499 | $tree->iter($li => @items) | |
500 | ||
501 | instead of: | |
502 | ||
503 | $li->iter(@items) | |
504 | ||
505 | and there is no good answer. The latter would be more concise and it | |
506 | is what I should have done. | |
507 | ||
508 | =head3 Unrolling an array via n sample elements (<dl> container) | |
509 | ||
510 | C<iter()> was fine for awhile, but some things (e.g. definition lists) | |
511 | need a more general function to make them easy to do. Hence | |
512 | C<iter2()>. This function will be explained by example of unrolling a | |
513 | simple definition list. | |
514 | ||
515 | So here's our mock-up HTML from the designer: | |
516 | ||
517 | <dl class="dual_iter" id="service_plan"> | |
518 | <dt>Artist</dt> | |
519 | <dd>A person who draws blood.</dd> | |
520 | ||
521 | <dt>Musician</dt> | |
522 | <dd>A clone of Iggy Pop.</dd> | |
523 | ||
524 | <dt>Poet</dt> | |
525 | <dd>A relative of Edgar Allan Poe.</dd> | |
526 | ||
527 | <dt class="adstyle">sample header</dt> | |
528 | <dd class="adstyle2">sample data</dd> | |
529 | </dl> | |
530 | ||
531 | ||
532 | And we want to unroll our data set: | |
533 | ||
534 | my @items = ( | |
535 | ['the pros' => 'never have to worry about service again'], | |
536 | ['the cons' => 'upfront extra charge on purchase'], | |
537 | ['our choice' => 'go with the extended service plan'] | |
538 | ); | |
539 | ||
540 | ||
541 | Now, let's make this problem a bit harder to show off the power of | |
542 | C<iter2()>. Let's assume that we want only the last <dt> and it's | |
543 | accompanying <dd> (the one with "sample data") to be used as the | |
544 | sample data for unrolling with our data set. Let's further assume that | |
545 | we want them to remain in the final output. | |
546 | ||
547 | So now, the API to C<iter2()> will be discussed and we will explain | |
548 | how our goal of getting our data into HTML fits into the API. | |
549 | ||
550 | =over 4 | |
551 | ||
552 | =item * wrapper_ld | |
553 | ||
554 | This is how to look down and find the container of all the elements we | |
555 | will be unrolling. The <dl> tag is the container for the dt and dd | |
556 | tags we will be unrolling. | |
557 | ||
558 | If you pass an anonymous subroutine, then it is presumed that | |
559 | execution of this subroutine will return the HTML::Element | |
560 | representing the container tag. If you pass an array ref, then this | |
561 | will be dereferenced and passed to C<HTML::Element::look_down()>. | |
562 | ||
563 | default value: C<< ['_tag' => 'dl'] >> | |
564 | ||
565 | Based on the mock HTML above, this default is fine for finding our | |
566 | container tag. So let's move on. | |
567 | ||
568 | =item * wrapper_data | |
569 | ||
570 | This is an array reference of data that we will be putting into the | |
571 | container. You must supply this. C<@items> above is our | |
572 | C<wrapper_data>. | |
573 | ||
574 | =item * wrapper_proc | |
575 | ||
576 | After we find the container via C<wrapper_ld>, we may want to | |
577 | pre-process some aspect of this tree. In our case the first two sets | |
578 | of dt and dd need to be removed, leaving the last dt and dd. So, we | |
579 | supply a C<wrapper_proc> which will do this. | |
580 | ||
581 | default: undef | |
582 | ||
583 | =item * item_ld | |
584 | ||
585 | This anonymous subroutine returns an array ref of C<HTML::Element>s | |
586 | that will be cloned and populated with item data (item data is a "row" | |
587 | of C<wrapper_data>). | |
588 | ||
589 | default: returns an arrayref consisting of the dt and dd element | |
590 | inside the container. | |
591 | ||
592 | =item * item_data | |
593 | ||
594 | This is a subroutine that takes C<wrapper_data> and retrieves one | |
595 | "row" to be "pasted" into the array ref of C<HTML::Element>s found via | |
596 | C<item_ld>. I hope that makes sense. | |
597 | ||
598 | default: shifts C<wrapper_data>. | |
599 | ||
600 | =item * item_proc | |
601 | ||
602 | This is a subroutine that takes the C<item_data> and the | |
603 | C<HTML::Element>s found via C<item_ld> and produces an arrayref of | |
604 | C<HTML::Element>s which will eventually be spliced into the container. | |
605 | ||
606 | Note that this subroutine MUST return the new items. This is done So | |
607 | that more items than were passed in can be returned. This is useful | |
608 | when, for example, you must return 2 dts for an input data item. And | |
609 | when would you do this? When a single term has multiple spellings for | |
610 | instance. | |
611 | ||
612 | default: expects C<item_data> to be an arrayref of two elements and | |
613 | C<item_elems> to be an arrayref of two C<HTML::Element>s. It replaces | |
614 | the content of the C<HTML::Element>s with the C<item_data>. | |
615 | ||
616 | =item * splice | |
617 | ||
618 | After building up an array of C<@item_elems>, the subroutine passed as | |
619 | C<splice> will be given the parent container HTML::Element and the | |
620 | C<@item_elems>. How the C<@item_elems> end up in the container is up | |
621 | to this routine: it could put half of them in. It could unshift them | |
622 | or whatever. | |
623 | ||
624 | default: C<< $container->splice_content(0, 2, @item_elems) >> In other | |
625 | words, kill the 2 sample elements with the newly generated @item_elems | |
626 | ||
627 | =back | |
628 | ||
629 | So now that we have documented the API, let's see the call we need: | |
630 | ||
631 | $tree->iter2( | |
632 | # default wrapper_ld ok. | |
633 | wrapper_data => \@items, | |
634 | wrapper_proc => sub { | |
635 | my ($container) = @_; | |
636 | ||
637 | # only keep the last 2 dts and dds | |
638 | my @content_list = $container->content_list; | |
639 | $container->splice_content(0, @content_list - 2); | |
640 | }, | |
641 | ||
642 | # default item_ld is fine. | |
643 | # default item_data is fine. | |
644 | # default item_proc is fine. | |
645 | splice => sub { | |
646 | my ($container, @item_elems) = @_; | |
647 | $container->unshift_content(@item_elems); | |
648 | }, | |
649 | debug => 1, | |
650 | ); | |
651 | ||
652 | =head3 Select Unrolling | |
653 | ||
654 | The C<unroll_select> method has this API: | |
655 | ||
656 | $tree->unroll_select( | |
657 | select_label => $id_label, | |
658 | option_value => $closure, # how to get option value from data row | |
659 | option_content => $closure, # how to get option content from data row | |
660 | option_selected => $closure, # boolean to decide if SELECTED | |
661 | data => $data # the data to be put into the SELECT | |
662 | data_iter => $closure # the thing that will get a row of data | |
663 | debug => $boolean, | |
664 | append => $boolean, # remove the sample <OPTION> data or append? | |
665 | ); | |
666 | ||
667 | Here's an example: | |
668 | ||
669 | $tree->unroll_select( | |
670 | select_label => 'clan_list', | |
671 | option_value => sub { my $row = shift; $row->clan_id }, | |
672 | option_content => sub { my $row = shift; $row->clan_name }, | |
673 | option_selected => sub { my $row = shift; $row->selected }, | |
674 | data => \@query_results, | |
675 | data_iter => sub { my $data = shift; $data->next }, | |
676 | append => 0, | |
677 | debug => 0 | |
678 | ); | |
679 | ||
680 | =head2 Tree-Building Methods: Table Generation | |
681 | ||
682 | Matthew Sisk has a much more intuitive (imperative) way to generate | |
683 | tables via his module L<HTML::ElementTable|HTML::ElementTable>. | |
684 | ||
685 | However, for those with callback fever, the following method is | |
686 | available. First, we look at a nuts and bolts way to build a table | |
687 | using only standard L<HTML::Tree> API calls. Then the C<table> method | |
688 | available here is discussed. | |
689 | ||
690 | =head3 Sample Model | |
691 | ||
692 | package Simple::Class; | |
693 | ||
694 | use Set::Array; | |
695 | ||
696 | my @name = qw(bob bill brian babette bobo bix); | |
697 | my @age = qw(99 12 44 52 12 43); | |
698 | my @weight = qw(99 52 80 124 120 230); | |
699 | ||
700 | ||
701 | sub new { | |
702 | my $this = shift; | |
703 | bless {}, ref($this) || $this; | |
704 | } | |
705 | ||
706 | sub load_data { | |
707 | my @data; | |
708 | ||
709 | for (0 .. 5) { | |
710 | push @data, { | |
711 | age => $age[rand $#age] + int rand 20, | |
712 | name => shift @name, | |
713 | weight => $weight[rand $#weight] + int rand 40 | |
714 | } | |
715 | } | |
716 | ||
717 | Set::Array->new(@data); | |
718 | } | |
719 | ||
720 | 1; | |
721 | ||
722 | =head4 Sample Usage: | |
723 | ||
724 | my $data = Simple::Class->load_data; | |
725 | ++$_->{age} for @$data | |
726 | ||
727 | =head3 Inline Code to Unroll a Table | |
728 | ||
729 | =head4 HTML | |
730 | ||
731 | <html> | |
732 | <table id="load_data"> | |
733 | <tr> <th>name</th><th>age</th><th>weight</th> </tr> | |
734 | <tr id="iterate"> | |
735 | <td id="name"> NATURE BOY RIC FLAIR </td> | |
736 | <td id="age"> 35 </td> | |
737 | <td id="weight"> 220 </td> | |
738 | </tr> | |
739 | </table> | |
740 | </html> | |
741 | ||
742 | ||
743 | =head4 The manual way (*NOT* recommended) | |
744 | ||
745 | require 'simple-class.pl'; | |
746 | use HTML::Seamstress; | |
747 | ||
748 | # load the view | |
749 | my $seamstress = HTML::Seamstress->new_from_file('simple.html'); | |
750 | ||
751 | # load the model | |
752 | my $o = Simple::Class->new; | |
753 | my $data = $o->load_data; | |
754 | ||
755 | # find the <table> and <tr> | |
756 | my $table_node = $seamstress->look_down('id', 'load_data'); | |
757 | my $iter_node = $table_node->look_down('id', 'iterate'); | |
758 | my $table_parent = $table_node->parent; | |
759 | ||
760 | ||
761 | # drop the sample <table> and <tr> from the HTML | |
762 | # only add them in if there is data in the model | |
763 | # this is achieved via the $add_table flag | |
764 | ||
765 | $table_node->detach; | |
766 | $iter_node->detach; | |
767 | my $add_table; | |
768 | ||
769 | # Get a row of model data | |
770 | while (my $row = shift @$data) { | |
771 | ||
772 | # We got row data. Set the flag indicating ok to hook the table into the HTML | |
773 | ++$add_table; | |
774 | ||
775 | # clone the sample <tr> | |
776 | my $new_iter_node = $iter_node->clone; | |
777 | ||
778 | # find the tags labeled name age and weight and | |
779 | # set their content to the row data | |
780 | $new_iter_node->content_handler($_ => $row->{$_}) | |
781 | for qw(name age weight); | |
782 | ||
783 | $table_node->push_content($new_iter_node); | |
784 | ||
785 | } | |
786 | ||
787 | # reattach the table to the HTML tree if we loaded data into some table rows | |
788 | ||
789 | $table_parent->push_content($table_node) if $add_table; | |
790 | ||
791 | print $seamstress->as_HTML; | |
792 | ||
793 | =head3 $tree->table() : API call to Unroll a Table | |
794 | ||
795 | require 'simple-class.pl'; | |
796 | use HTML::Seamstress; | |
797 | ||
798 | # load the view | |
799 | my $seamstress = HTML::Seamstress->new_from_file('simple.html'); | |
800 | # load the model | |
801 | my $o = Simple::Class->new; | |
802 | ||
803 | $seamstress->table | |
804 | ( | |
805 | # tell seamstress where to find the table, via the method call | |
806 | # ->look_down('id', $gi_table). Seamstress detaches the table from the | |
807 | # HTML tree automatically if no table rows can be built | |
808 | ||
809 | gi_table => 'load_data', | |
810 | ||
811 | # tell seamstress where to find the tr. This is a bit useless as | |
812 | # the <tr> usually can be found as the first child of the parent | |
813 | ||
814 | gi_tr => 'iterate', | |
815 | ||
816 | # the model data to be pushed into the table | |
817 | ||
818 | table_data => $o->load_data, | |
819 | ||
820 | # the way to take the model data and obtain one row | |
821 | # if the table data were a hashref, we would do: | |
822 | # my $key = (keys %$data)[0]; my $val = $data->{$key}; delete $data->{$key} | |
823 | ||
824 | tr_data => sub { | |
825 | my ($self, $data) = @_; | |
826 | shift @{$data} ; | |
827 | }, | |
828 | ||
829 | # the way to take a row of data and fill the <td> tags | |
830 | ||
831 | td_data => sub { | |
832 | my ($tr_node, $tr_data) = @_; | |
833 | $tr_node->content_handler($_ => $tr_data->{$_}) | |
834 | for qw(name age weight) | |
835 | } | |
836 | ); | |
837 | ||
838 | print $seamstress->as_HTML; | |
839 | ||
840 | =head4 Looping over Multiple Sample Rows | |
841 | ||
842 | * HTML | |
843 | ||
844 | <html> | |
845 | <table id="load_data" CELLPADDING=8 BORDER=2> | |
846 | <tr> <th>name</th><th>age</th><th>weight</th> </tr> | |
847 | <tr id="iterate1" BGCOLOR="white" > | |
848 | <td id="name"> NATURE BOY RIC FLAIR </td> | |
849 | <td id="age"> 35 </td> | |
850 | <td id="weight"> 220 </td> | |
851 | </tr> | |
852 | <tr id="iterate2" BGCOLOR="#CCCC99"> | |
853 | <td id="name"> NATURE BOY RIC FLAIR </td> | |
854 | <td id="age"> 35 </td> | |
855 | <td id="weight"> 220 </td> | |
856 | </tr> | |
857 | </table> | |
858 | </html> | |
859 | ||
860 | * Only one change to last API call. | |
861 | ||
862 | This: | |
863 | ||
864 | gi_tr => 'iterate', | |
865 | ||
866 | becomes this: | |
867 | ||
868 | gi_tr => ['iterate1', 'iterate2'] | |
869 | ||
870 | =head3 $tree->table2() : New API Call to Unroll a Table | |
871 | ||
872 | After 2 or 3 years with C<table()>, I began to develop production | |
873 | websites with it and decided it needed a cleaner interface, | |
874 | particularly in the area of handling the fact that C<id> tags will be | |
875 | the same after cloning a table row. | |
876 | ||
877 | First, I will give a dry listing of the function's argument | |
878 | parameters. This will not be educational most likely. A better way to | |
879 | understand how to use the function is to read through the incremental | |
880 | unrolling of the function's interface given in conversational style | |
881 | after the dry listing. But take your pick. It's the same information | |
882 | given in two different ways. | |
883 | ||
884 | =head4 Dry/technical parameter documentation | |
885 | ||
886 | C<< $tree->table2(%param) >> takes the following arguments: | |
887 | ||
888 | =over | |
889 | ||
890 | =item * C<< table_ld => $look_down >> : optional | |
891 | ||
892 | How to find the C<table> element in C<$tree>. If C<$look_down> is an | |
893 | arrayref, then use C<look_down>. If it is a CODE ref, then call it, | |
894 | passing it C<$tree>. | |
895 | ||
896 | Defaults to C<< ['_tag' => 'table'] >> if not passed in. | |
897 | ||
898 | =item * C<< table_data => $tabular_data >> : required | |
899 | ||
900 | The data to fill the table with. I<Must> be passed in. | |
901 | ||
902 | =item * C<< table_proc => $code_ref >> : not implemented | |
903 | ||
904 | A subroutine to do something to the table once it is found. Not | |
905 | currently implemented. Not obviously necessary. Just created because | |
906 | there is a C<tr_proc> and C<td_proc>. | |
907 | ||
908 | =item * C<< tr_ld => $look_down >> : optional | |
909 | ||
910 | Same as C<table_ld> but for finding the table row elements. Please | |
911 | note that the C<tr_ld> is done on the table node that was found | |
912 | I<instead> of the whole HTML tree. This makes sense. The C<tr>s that | |
913 | you want exist below the table that was just found. | |
914 | ||
915 | Defaults to C<< ['_tag' => 'tr'] >> if not passed in. | |
916 | ||
917 | =item * C<< tr_data => $code_ref >> : optional | |
918 | ||
919 | How to take the C<table_data> and return a row. Defaults to: | |
920 | ||
921 | sub { my ($self, $data) = @_; | |
922 | shift(@{$data}) ; | |
923 | } | |
924 | ||
925 | =item * C<< tr_proc => $code_ref >> : optional | |
926 | ||
927 | Something to do to the table row we are about to add to the table we | |
928 | are making. Defaults to a routine which makes the C<id> attribute | |
929 | unique: | |
930 | ||
931 | sub { | |
932 | my ($self, $tr, $tr_data, $tr_base_id, $row_count) = @_; | |
933 | $tr->attr(id => sprintf "%s_%d", $tr_base_id, $row_count); | |
934 | } | |
935 | ||
936 | =item * C<< td_proc => $code_ref >> : required | |
937 | ||
938 | This coderef will take the row of data and operate on the C<td> cells | |
939 | that are children of the C<tr>. See C<t/table2.t> for several usage | |
940 | examples. | |
941 | ||
942 | Here's a sample one: | |
943 | ||
944 | sub { | |
945 | my ($tr, $data) = @_; | |
946 | my @td = $tr->look_down('_tag' => 'td'); | |
947 | for my $i (0..$#td) { | |
948 | $td[$i]->splice_content(0, 1, $data->[$i]); | |
949 | } | |
950 | } | |
951 | ||
952 | =cut | |
953 | ||
954 | =head4 Conversational parameter documentation | |
955 | ||
956 | The first thing you need is a table. So we need a look down for that. | |
957 | If you don't give one, it defaults to | |
958 | ||
959 | ['_tag' => 'table'] | |
960 | ||
961 | What good is a table to display in without data to display?! So you | |
962 | must supply a scalar representing your tabular data source. This | |
963 | scalar might be an array reference, a C<next>able iterator, a DBI | |
964 | statement handle. Whatever it is, it can be iterated through to build | |
965 | up rows of table data. These two required fields (the way to find the | |
966 | table and the data to display in the table) are C<table_ld> and | |
967 | C<table_data> respectively. A little more on C<table_ld>. If this | |
968 | happens to be a CODE ref, then execution of the code ref is presumed | |
969 | to return the C<HTML::Element> representing the table in the HTML | |
970 | tree. | |
971 | ||
972 | Next, we get the row or rows which serve as sample C<tr> elements by | |
973 | doing a C<look_down> from the C<table_elem>. While normally one sample | |
974 | row is enough to unroll a table, consider when you have alternating | |
975 | table rows. This API call would need one of each row so that it can | |
976 | cycle through the sample rows as it loops through the data. | |
977 | Alternatively, you could always just use one row and make the | |
978 | necessary changes to the single C<tr> row by mutating the element in | |
979 | C<tr_proc>, discussed below. The default C<tr_ld> is C<< ['_tag' => | |
980 | 'tr'] >> but you can overwrite it. Note well, if you overwrite it with | |
981 | a subroutine, then it is expected that the subroutine will return the | |
982 | C<HTML::Element>(s) which are C<tr> element(s). The reason a | |
983 | subroutine might be preferred is in the case that the HTML designers | |
984 | gave you 8 sample C<tr> rows but only one prototype row is needed. So | |
985 | you can write a subroutine, to splice out the 7 rows you don't need | |
986 | and leave the one sample row remaining so that this API call can clone | |
987 | it and supply it to the C<tr_proc> and C<td_proc> calls. | |
988 | ||
989 | Now, as we move through the table rows with table data, we need to do | |
990 | two different things on each table row: | |
991 | ||
992 | =over 4 | |
993 | ||
994 | =item * get one row of data from the C<table_data> via C<tr_data> | |
995 | ||
996 | The default procedure assumes the C<table_data> is an array reference | |
997 | and shifts a row off of it: | |
998 | ||
999 | sub { | |
1000 | my ($self, $data) = @_; | |
1001 | shift @{$data}; | |
1002 | } | |
1003 | ||
1004 | Your function MUST return undef when there is no more rows to lay out. | |
1005 | ||
1006 | =item * take the C<tr> element and mutate it via C<tr_proc> | |
1007 | ||
1008 | The default procedure simply makes the id of the table row unique: | |
1009 | ||
1010 | sub { | |
1011 | my ($self, $tr, $tr_data, $row_count, $root_id) = @_; | |
1012 | $tr->attr(id => sprintf "%s_%d", $root_id, $row_count); | |
1013 | } | |
1014 | ||
1015 | =back | |
1016 | ||
1017 | Now that we have our row of data, we call C<td_proc> so that it can | |
1018 | take the data and the C<td> cells in this C<tr> and process them. This | |
1019 | function I<must> be supplied. | |
1020 | ||
1021 | =head3 Whither a Table with No Rows | |
1022 | ||
1023 | Often when a table has no rows, we want to display a message | |
1024 | indicating this to the view. Use conditional processing to decide what | |
1025 | to display: | |
1026 | ||
1027 | <span id=no_data> | |
1028 | <table><tr><td>No Data is Good Data</td></tr></table> | |
1029 | </span> | |
1030 | <span id=load_data> | |
1031 | <html> | |
1032 | <table id="load_data"> | |
1033 | <tr> <th>name</th><th>age</th><th>weight</th> </tr> | |
1034 | <tr id="iterate"> | |
1035 | <td id="name"> NATURE BOY RIC FLAIR </td> | |
1036 | <td id="age"> 35 </td> | |
1037 | <td id="weight"> 220 </td> | |
1038 | </tr> | |
1039 | </table> | |
1040 | </html> | |
1041 | </span> | |
1042 | ||
1043 | =head2 Tree-Killing Methods | |
1044 | ||
1045 | =head3 $tree->prune | |
1046 | ||
1047 | This removes any nodes from the tree which consist of nothing or | |
1048 | nothing but whitespace. See also delete_ignorable_whitespace in | |
1049 | L<HTML::Element>. | |
1050 | ||
1051 | =head2 Loltree Functions | |
1052 | ||
1053 | A loltree is an arrayref consisting of arrayrefs which is used by C<< | |
1054 | new_from__lol >> in L<HTML::Element> to produce HTML trees. The CPAN | |
1055 | distro L<XML::Element::Tolol> creates such XML trees by parsing XML | |
1056 | files, analagous to L<XML::Toolkit>. The purpose of the functions in | |
1057 | this section is to allow you manipulate a loltree programmatically. | |
1058 | ||
1059 | These could not be methods because if you bless a loltree, then | |
1060 | HTML::Tree will barf. | |
1061 | ||
1062 | =head3 HTML::Element::newchild($lol, $parent_label, @newchild) | |
1063 | ||
1064 | Given this initial loltree: | |
1065 | ||
1066 | my $initial_lol = [ note => [ shopping => [ item => 'sample' ] ] ]; | |
1067 | ||
1068 | This code: | |
1069 | ||
1070 | sub shopping_items { | |
1071 | my @shopping_items = map { [ item => _ ] } qw(bread butter beans); | |
1072 | @shopping_items; | |
1073 | } | |
1074 | ||
1075 | my $new_lol = HTML::Element::newnode($initial_lol, item => shopping_items()); | |
1076 | ||
1077 | will replace the single sample with a list of shopping items: | |
1078 | ||
1079 | [ | |
1080 | 'note', | |
1081 | [ | |
1082 | 'shopping', | |
1083 | [ | |
1084 | 'item', | |
1085 | 'bread' | |
1086 | ], | |
1087 | [ | |
1088 | 'item', | |
1089 | 'butter' | |
1090 | ], | |
1091 | [ | |
1092 | 'item', | |
1093 | 'beans' | |
1094 | ] | |
1095 | ||
1096 | ] | |
1097 | ]; | |
1098 | ||
1099 | Thanks to kcott and the other Perlmonks in this thread: | |
1100 | http://www.perlmonks.org/?node_id=912416 | |
1101 | ||
1102 | ||
1103 | =head1 SEE ALSO | |
1104 | ||
1105 | =head2 L<HTML::Tree> | |
1106 | ||
1107 | A perl package for creating and manipulating HTML trees. | |
1108 | ||
1109 | =head2 L<HTML::ElementTable> | |
1110 | ||
1111 | An L<HTML::Tree> - based module which allows for manipulation of HTML | |
1112 | trees using cartesian coordinations. | |
1113 | ||
1114 | =head2 L<HTML::Seamstress> | |
1115 | ||
1116 | An L<HTML::Tree> - based module inspired by XMLC | |
1117 | (L<http://xmlc.enhydra.org>), allowing for dynamic HTML generation via | |
1118 | tree rewriting. | |
1119 | ||
1120 | =head2 Push-style templating systems | |
1121 | ||
1122 | A comprehensive cross-language | |
1123 | L<list of push-style templating systems|http://perlmonks.org/?node_id=674225>. | |
1124 | ||
1125 | =head1 TODO | |
1126 | ||
1127 | =over | |
1128 | ||
1129 | =item * highlander2 | |
1130 | ||
1131 | currently the API expects the subtrees to survive or be pruned to be | |
1132 | identified by id: | |
1133 | ||
1134 | $if_then->highlander2([ | |
1135 | under10 => sub { $_[0] < 10} , | |
1136 | under18 => sub { $_[0] < 18} , | |
1137 | welcome => [ | |
1138 | sub { 1 }, | |
1139 | sub { | |
1140 | my $branch = shift; | |
1141 | $branch->look_down(id => 'age')->replace_content($age); | |
1142 | } | |
1143 | ] | |
1144 | ], $age); | |
1145 | ||
1146 | but, it should be more flexible. the C<under10>, and C<under18> are | |
1147 | expected to be ids in the tree... but it is not hard to have a check | |
1148 | to see if this field is an array reference and if it, then to do a | |
1149 | look down instead: | |
1150 | ||
1151 | $if_then->highlander2([ | |
1152 | [class => 'under10'] => sub { $_[0] < 10} , | |
1153 | [class => 'under18'] => sub { $_[0] < 18} , | |
1154 | [class => 'welcome'] => [ | |
1155 | sub { 1 }, | |
1156 | sub { | |
1157 | my $branch = shift; | |
1158 | $branch->look_down(id => 'age')->replace_content($age); | |
1159 | } | |
1160 | ] | |
1161 | ], $age); | |
1162 | ||
1163 | =head1 AUTHOR and ACKS | |
1164 | ||
1165 | Original author Terrence Brannon, E<lt>tbone@cpan.orgE<gt>. | |
1166 | ||
1167 | Adopted by Marius Gavrilescu C<< <marius@ieval.ro> >>. | |
1168 | ||
1169 | I appreciate the feedback from M. David Moussa Leo Keita regarding | |
1170 | some issues with the test suite, namely (1) CRLF leading to test | |
1171 | breakage in F<t/crunch.t> and (2) using the wrong module in | |
1172 | F<t/prune.t> thus not having the right functionality available. | |
1173 | ||
1174 | Many thanks to BARBIE for his RT bug report. | |
1175 | ||
1176 | Many thanks to perlmonk kcott for his work on array rewriting: | |
1177 | L<http://www.perlmonks.org/?node_id=912416>. It was crucial in the | |
1178 | development of newchild. | |
1179 | ||
1180 | =head1 COPYRIGHT AND LICENSE | |
1181 | ||
1182 | Coypright (C) 2014 by Marius Gavrilescu | |
1183 | ||
1184 | Copyright (C) 2004-2012 by Terrence Brannon | |
1185 | ||
1186 | This library is free software; you can redistribute it and/or modify | |
1187 | it under the same terms as Perl itself, either Perl version 5.8.4 or, | |
1188 | at your option, any later version of Perl 5 you may have available. | |
1189 | ||
1190 | ||
1191 | =cut |