Serendipity Forums

Posted: **Thu Feb 02, 2006 3:47 am**

Hi all,

Is it possible to differentiate between internal and external links within posts or sidebar items so that I could theme them separately?

My expectation would be that a user simply includes the link in their post as per normal, but s9y then checks to see if the url is part of the blog or not and then appends a link_internal or link_external to the html style. I would then be able to add a different background image or change color. I most want this for posts if this is possible, but ultimately would love to see it within plugins as well.

Cheers
Carl

Posted: **Thu Feb 02, 2006 5:27 am**

Wow. Taller order than it seems.

An event plugin could go through the posts and modify the links with a style, kinda like a markup plugin does. It would probably check against the blog URL, and if it's not in the link, mark it with the appropriate class. Could get a bit complicated, since you'd have to account for any existing class, but not impossible.

Doing it for the plugins and sidebars is much more difficult. I don't think there's a hook that provides the Smarty-formatted output. On the other hand, maybe Smarty already thought of that...

Sure enough. Here's a plugin that should do what you want. It actually adds the class "external_link" to all links that don't include the blog URL. I haven't tested it, so use at your own risk.

Code: Select all

<?php
class serendipity_event_linkmarker extends serendipity_event {
    function introspect(&$propbag) {
        global $serendipity;

        $propbag->add('name',         'Link Marker');
        $propbag->add('version',      '0.1');
        $propbag->add('author',       'Jude Anthony');
        $propbag->add('stackable',     false);
        $propbag->add('event_hooks',   array(
                                            'genpage' => true
                                        )
        );
    }

    function event_hook($event, &$bag, &$eventData) {
        global $serendipity;

        $hooks = &$bag->get('event_hooks');

        if (isset($hooks[$event])) {
            switch($event) {
                case 'genpage':
                    if (!isset($serendipity['smarty'])) {
                        serendipity_smarty_init();
                    }
                    $serendipity['smarty']->register_outputfilter('marklinks');
                    break;
            }
        }

        return true;
    }

    function marklinks($tpl_output, &$smarty) {
      // Normalize class/href placement and some spacing
      $tpl_output = preg_replace('#<a([^>]*)href\s*=\s*"([^"])"([^>])class\s*=\s*"([^"]*)"([^>]*)>#',
          '<a $1 $3 $5 class="$4" href="$2">', $tpl_output);
      // Marking for links that already have a class
      $tpl_output = 
        preg_replace('#<a([^>]*)class\s*=\s*"([^"]*)"([^>]*)href\s*=\s*"((?<!' . $serendipity['baseURL'] . ')[^"]*)"([^>]*)>#', 
          '<a $1 $3 $5 class="$2 external_link" href="$4">', $tpl_output);
      // Marking for links without a class
      $tpl_output = 
        preg_replace('#<a([^>]*)href\s*=\s*"((?<!' . $serendipity['baseURL'] . ')[^"]*)"([^>]*)>#',
          '<a $1 $3 href="$2">', $tpl_output);

      return $tpl_output;   
    }
}
?>

Well, the more I look at that, the less I like it. It only accounts for href and class with double-quotes, and I'm not so sure about those (?<! constructs. But give it a try and see how it works for you.

Posted: **Thu Feb 02, 2006 4:22 pm**

Jude,

Thank you very much, I tried using your code and got this error message

Parse error: parse error, unexpected '{' in C:\obfuscated\path\by\carl\for\security\plugins\serendipity_plugin_entrylinks\serendipity_event_linkmarker.php on line 24

I just threw it into the entrylinks folder for now, I haven't amended the code as provided in any way.

Cheers
Carl

Posted: **Thu Feb 02, 2006 9:24 pm**

Weird. There is no { on line 24.

Of course, I did forget the ?> on the last line; you'll need to add it. I've edited it into the plugin above.

Maybe the problem is the directory name. It needs to be serendipity_event_linkmarker, not serendipity_plugin_entrylinks.

I'll give it a look on my server later today.

Posted: **Thu Feb 02, 2006 10:39 pm**

Fixed the error (missing paren, edited in above), but everything else blows up afterward. Looks like you can't use a function in a class for a callback. I'll have to see what I can do with that.

Posted: **Sat Feb 04, 2006 1:13 pm**

You can use the array($this, 'func_Callback') method of specifying the callback, which will wrap your current object for the func.

Regards,
Garvin

Posted: **Sat Feb 04, 2006 6:29 pm**

I really think a lot of users would appreciate a plugin like this, so if that makes the plugin work it would be very worthwhile.

Thanks,

Carl

Posted: **Sun Feb 05, 2006 5:19 pm**

Sorry I'm so slow this week, guys. Lots of family activities. I'm squeaking this out before I go to celebrate family birthdays.

I'm having trouble with the regular expressions, which is usually my strong point. These lookbehinds are killing me.

As I was reading the forum backlog, it occurred to me that the Content Rewriter plugin might do the job, at least for a bit. It does regular expression style replacements; if we put it below the other plugins, wouldn't it look at links when so configured?

Here's the most recent post, with links to better info: http://www.s9y.org/forums/viewtopic.php?t=4411

Meanwhile, I'll still be working on this. I find it interesting.

Posted: **Sun Feb 05, 2006 6:29 pm**

phew, glad to see you still like the idea, um, but as for the logic that you and Garvin are talking about, which dummy's guide do I need to buy to understand techtalk?

Doesn't lookbehind mean "watch out, look behind you!"

Posted: **Tue Feb 07, 2006 9:03 pm**

Sorry, Carl. Lookbehinds are weird patterns that you use in searches; the plugin I made above is nothing more than a pattern-replacement tool. It should search for a pattern like <a href="<not my blog url><anything else>">whatever</a>. But the logic to match the <not my blog url> bit has to look at stuff that's already been matched. So it's called a lookbehind.

Mine aren't working. I've never used them before, so I'm still trying to understand them. I'm considering other options, too. Just gotta get a couple of days free. (I spent most of last night figuring out how to wire up a particular piece of my electric car so it wouldn't electrocute my brother.)

As to the Content Rewriter, I was throwing it out as a bone, maybe something that could tide you over. I've never used it myself. I think I will be using it as the basis of the external link rewriter. Maybe I'll even just extend it.

Serendipity Forums

is this poss? links different for internal and external

is this poss? links different for internal and external