Modifying shortcode replacements via event handler?

[mpdude]

Is it possible to use either Events::FILTER_SHORTCODES or Events::REPLACE_SHORTCODES to modify/extend the replacement string provided by the handler?

I am looking for a way to insert additional HTML (say, a </div>...<div>) around shortcodes. When determining this additional HTML, I'd need to know at lease the shortcode name. And I would like to keep this out of the handler, because it is context/situation specific.

Any pointers?

[mpdude]

I may be headed in the wrong direction, but I think this would be straightforward if the ReplacedShortcode contained in the ReplaceShortcodesEvent were not read-only, so that I could just tweak the replacement strings...

[thunderer]

Yes, this is one of the use cases for Events::REPLACE_SHORTCODES. Here is a quick example I wrote for you, I hope I understood your problem correctly:

• create handlers with default handler that just returns the name and content,
• create REPLACE_SHORTCODES event handler with our replacement mechanism (copied directly from Processor),
• this mechanism wraps each shortcode replacement in a different HTML tag (see the rewrite method),
• creates processor with our event handler inside,
• asserts that the code works as expected at the bottom.

$handlers = new HandlerContainer();
$handlers->setDefault(function(ShortcodeInterface $s) { return $s->getName().$s->getContent(); });

$events = new EventContainer();
$events->addListener(Events::REPLACE_SHORTCODES, new class {
    public function __invoke(ReplaceShortcodesEvent $event)
    {
        $text = $event->getText();
        /** @var ReplacedShortcode $s */
        foreach(array_reverse($event->getReplacements()) as $s) {
            $offset = $s->getOffset();
            $length = mb_strlen($s->getText(), 'utf-8');
            $textLength = mb_strlen($text, 'utf-8');
            $prefix = mb_substr($text, 0, $offset, 'utf-8');
            $postfix = mb_substr($text, $offset + $length, $textLength, 'utf-8');

            $text = $prefix.$this->rewrite($s).$postfix;
        }

        $event->setResult($text);
    }

    private function rewrite(ReplacedShortcode $r)
    {
        return [
            'what' => function(ReplacedShortcode $r) { return '<p>'.$r->getReplacement().'</p>'; },
            'goes' => function(ReplacedShortcode $r) { return '<b>'.$r->getReplacement().'</b>'; },
            'around' => function(ReplacedShortcode $r) { return '<u>'.$r->getReplacement().'</u>'; },
        ][$r->getName()]($r);
    }
});

$processor = new Processor(new RegularParser(), $handlers);
$processor = $processor->withEventContainer($events);

$text = 'a [what] [goes /] [around /] [/what] z';
$expected = 'a <p>what <b>goes</b> <u>around</u> </p> z';
assert($expected === $processor->process($text));

[thunderer]

BTW The idea of an event before Events::REPLACE_SHORTCODES which allows you to tweak the replacement seems like a good idea. It may be a quite significant performance hit, but as an optional mechanism (no handler === no hit) should work quite well. The event handler would receive ReplacedShortcode and return the new replacement which would take place of the old one. The temporary name I came up with is Events::REWRITE_REPLACEMENT I need to investigate this further, thanks!

[mpdude]

Tomasz,

thanks a lot for your quick reply and the code example above. Indeed, I've seen something similar at #40 (comment) ;-).

I wonder if it really has to be as complicated as this, since there is already code to do this heavy lifting of merging the original content and the replacements together. I mean, if the ReplacedShortcode would allow to modify the replacement string, wouldn't we be done?

Yes, I do know about the advantages of immutable objects... 😀