Edit: En español: “Una mejor manera de controlar los atributos en SPIP”.
Lots of SPIP tags and filters generate HTML mark-up as output (the #LOGO_*
tags and |image_* filters are the most prominent) and we often need or want
to modify this mark-up in our templates. There are several built-in filters to
help with this
(inserer_attribut
to insert an attribute and
extraire_attribut
to extract the value of an attribute) but they are pretty long and tedious to
type. Given that I uses these filters quite often when implementing such
things as image galleries, and I still have to think quite hard to type the
French words correctly the can be a bit annoying. Thankfully, a small wrapper
(see below) can smooth these small annoyances away.
When it comes to accessing and modifying the values of attributes nothing, in
my opinion, comes any where near to jQuery’s attributes
API. The single jQuery attr
method allows you to get and set the
value for any attribute on any node: it takes one or two parameters, the name
of the attribute and, optionally, the value. If only the name is specified,
then attr simply extracts and returns the value of the attribute. If both a
name and a value are specified, then attr modifies the object setting
specified attribute to the specified value. This “polymorphic” style of
interface – where a single method has two complementary behaviours which are
distinguished by the number and/or types of the arguments – is everywhere in
jQuery and is part of what makes it so concise and so productive. Seeing as
it’s the best structure for such interfaces that I know (and also, one I use
daily), I decided that my wrapper should mirror it. Thus the attr filter was
born.
Like the jQuery attr method, the SPIP attr filter takes one or two
parameters (and an implicit “object”, but we’ll ignore if for now). If only
one, it passes the input on to extraire_attribut to get and return the
value. If called with two parameters, it calls inserer_attribut instead to
modify the tag. Like the idea, the code is reasonably straightforward; the
only even slightly unusual but is the use of
func_get_args
to get an array of the arguments passed into the function call. With such an
array, we can use count to
check how many arguments the function was given and decide whether we should
get or set the attribute. This is safer than specifying and checking a default
value (FALSE or NULL, for example) because some user may genuinely want to
use that value (perhaps NULL will mean delete the attribute in a future
version?) and silently ignoring user input is never good.
<?php
include_spip("inc/filtres");
/**
* The `attr` function allows the user to get and set the attributes of an
* HTML tag. It is intended to be used as a SPIP filter and depends on
* existing SPIP functionality.
*
* @param $tag
* The HTML code.
* @param $name
* The name of the attribute.
* @param $val...
* The new value for the attribute $nom. Optional.
* @return
* If $val was given, the code for tag with $name=$val
* Otherwise, the value for the $name attribute in $tag.
*/
function attr($tag, $name){
$args = func_get_args();
if (count($args) > 2) {
// SET
return inserer_attribut($tag, $name, $args[2]);
} else {
// GET
return extraire_attribut($tag, $name);
}
}Simply copy the code into the mes_fonctions.php file for your site (see
“Adding your own filters” in SPIP’s
Filters) and use attr in your SPIP
templates:
<a href="[(#FICHIER|attr{src})]" class="lightbox" title="#TITRE">
[(#FICHIER|image_reduire{100,100}|attr{alt,#TITRE})]
</a>There are a few changes that could be made to this function: passing $args
directly to inserer_attribut and extraire_attribut rather than the
individual variables, adding a $value=FALSE parameter for the sake of
documentation and then ignoring it (I’m not sure if this will work and don’t
care enough to try it), deleting attributes when passed e.g. NULL as a
value, etc. For the time being, however, it does the job.
A final note: you’ll probably need to be running PHP 5 for this to work – the
func_get_args documentation (linked above) mentions version 5.3.0 – and the
code above was modified after I last tested it, but should work anyway.