RESTful interface to PHP forum software

Question

I'm looking to integrate a light-weight forum feature into an existing GWT website. The front-end is written in GWT/SmartGWT and the backend is written in PHP. The communication is through a RESTful API using JSON.

I have looked into the forums of some popular software (SMF, phpBB, etc.) but was unable to find any references to a RESTful web API to make integration into an existing non-PHP site easier. The closest I came is to vBulletin's Mobile API - https://www.vbulletin.com/forum/content.php/334-mobile-api. Unfortunately, vBulletin isn't free.

Some recent threads I have seen on some of the forums basically say that the user should write their own web services wrapper around the internal API. However, that seem like a bad solution that can lead to all kinds of additional bugs.

So, my question is this - does anyone know of an existing, free forum software (PHP, Perl, Ruby OK, but NOT Java) that provides a RESTful web services interface?

An ancillary question to this is: has anyone used Restler (http://luracast.com/products/restler/) to turn a forum software's published API into a RESTful interface? I'm sure this method would be fraught with potential problems, but one can always hope.

PS: I saw the following older questions on stackoverflow, but they don't seem to be that helpful and are now kind of old:

• Open-Source Forum with API
• PHP forum software that integrates easily with existing website? -- the OP's website is built in PHP, which makes integration a lot easier
• forum software with a simple RESTful API support -- Elgg, while a great social networking framework, doesn't include a forum plugin!
• A forum solution with an Q&A option and API -- same issue as OP, Drupal is really heavy-weight and all I want is the forum functionality.

Answer 1

Looks like Vanilla Forums fits your bill, they support JSON/XML based API