[wp-hackers] Trackback and Pingback in WordPress

Dougal Campbell dougal at gunters.org
Wed Dec 8 16:41:31 UTC 2004

Matthew Mullenweg wrote:

> Mark Jaquith wrote:
>> If you specify a Trackback URI and also link to that post in your 
>> entry, a Trackback and a Pingback are both sent.  
> That's a bug.
>> Also, requiring manual input of trackback links is tiresome.  
> We could scan for rel="trackback" and trackback RDF when we do the 
> pingback scan.

Just as a further note, automatic trackback detection is somewhat 
trickier than pingback. Pingback was architected from the beginning to 
make automation easy.  The rel="trackback" stuff was added to TB later 
(is it even official?), and not all sites support it.With trackback, you 
typically have to read the entire document at the linked-to URI, try to 
parse it to find the trackback RDF, and then parse the appropriate info 
out of that.

Let alone the fact that parsing RDF (at least properly) is tricky in its 
own right. In many cases, you can just pull the needed info out with 
regular expressions. Or you could try to treat the RDF like regular XML 
and parse it that way. But if you run across a site where the author is 
*really* using RDF, and has added extra data, namespaces, etc. then you 
run into problems.

Even trying to automatically detect whether you're sending a trackback 
and a pingback to the same place isn't a clear-cut problem to tackle.


More information about the hackers mailing list