[TYPO3] Mark external links

[JoH]

>>> I'm trying to find a way to automatically mark external links with a
>>> little icon in front of the link and a standard link title text.
>>> I am searching for a solution whick works for all content elements,
>>> be it tt_content, tt_news or tt_products.
>>> Is this possible with typoscript?
>>
>> Thanks to all who helped me with this problem. I use Sebastian's idea
>> and it works great!
>>
>> As promised I've created a WIKI [1] that explains the different
>> methods to mark external links.
>>
>> Cheers,
>> Ro
>>
>> [1] http://wiki.typo3.org/index.php/External_links
>
> And now the inevitable question.... What if you don't want an actual
> image, but instead want the link to just have a class that handles
> the icon?

And other questions regarding the TypoScript version:

What if the link points to an alias?
Alias != intval(Alias)

What if it points to an anchor on the same page?
123#123 != intval(123#123)

What if the first part is a UID but it is followed by 3 other parts for
target, class and title?
123 _top linkclass linktitle != intval(123 _top linkclass linktitle)

The interesting thing with typolink is, that it already takes care of
internal and external links and renders them accordingly.
Each external link, be it with or without http://, www. or whatever, will be
recognized an prepended "http://" or "mailto:".
So you just have to check for the existence of http:// or mailto:  _after_
the link has been created by typolink and then create a wrap based on a
constant.
Internal links will never have http:// or mailto: in front of them, since
they point to index.php or a path on the same server if you are using
realURL or link to files.

If you want to do different checks, the easiest way is to put the link into
a register and call it for the checks, so that you just have to create the
link once.
You can split it by ":" before you put it into the register since the
interesting part for external links will be always in before this separator.

So this one will do the job:

lib.parseFunc.tags.link {
  typolink.parameter.append = LOAD_REGISTER
  typolink.parameter.append {
    isExternal {
      cObject = TEXT
      cObject {
        typolink.parameter.data = parameters:allParams
        typolink.returnLast = url
      }
      split {
        token = :
        cObjNum = 1||2
        1 = TEXT
        1.current = 1
      }
    }
  }
  outerWrap.cObject = CASE
  outerWrap.cObject {
    key.data = register:isExternal
    default = TEXT
    http = TEXT
    http.value = {$externalLinkWrap}
    mailto = TEXT
    mailto.value = {$mailtoLinkWrap}
  }
}

lib.parseFunc_RTE.tags.link {
  typolink.parameter.append <
lib.parseFunc.tags.link.typolink.parameter.append
  outerWrap < lib.parseFunc.tags.link.outerWrap
}

You can see it in action here:
http://www.4any1.de/index.php?id=2350&no_cache=1

In the debug table on top of the page you can see the original values that
are handed over to the typolink function.
I left the constants empty, so that you can see how they are used.
You can fill a real wrap like <div class="externallink">|</div> or just the
desired img-tag <img src="whatever" /> into the constant.

Advantages:
No userFunc necessary
Can be modified easily since there are no hardcoded tags
Can be extended easily by adding another split to the LOAD_REGISTER and more
variants to the CASE

Have fun with it

Joey

-- 
Wenn man keine Ahnung hat: Einfach mal Fresse halten!
(If you have no clues: simply shut your knob sometimes!)
Dieter Nuhr, German comedian
openBC: http://www.cybercraft.de
T3 cookbook: http://www.typo3experts.com