Message format in JSON instead of XML

Martin Atkins mart at
Wed Nov 7 19:53:09 UTC 2007

Slavey Karadzhov wrote:
> Hi all,
>  I am interested in modifying Djabberd to send messages in JSON format 
> instead of XML. Is this possible and can you point me where to look in 
> the code?

In theory there's no reason why you can't do this, though it probably 
won't be easy because several parts of DJabberd works directly on 
objects representing XML elements.

If you can define a complete mapping of all possible XML-based XMPP 
stanzas to JSON and a matching reverse mapping, then you could implement 
this by subclassing DJabberd::Connection and overriding the write_stanza 
method to transform the data into JSON before writing to the stream.

You'd also need to override and wrap event_read to read in JSON instead 
of XML and then turn it into a convincing enough DOM tree that the rest 
of DJabberd would be able to process it.

I think by the time you'd done all this you'd probably have just traded 
the overhead of sending XML over the wire for the processing overhead of 
constantly marshalling between JSON and XML, and if your JSON structure 
was indeed able to represent any possible XML DOM it probably wouldn't 
be much smaller than the equivalent XML after all.

If you have a specific application in mind there's probably an easier 
way of doing it using a plugin, but I can't speculate on that without 
more information.

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