Rudimentary support for the Facebook Canvas

[bigokro]

I added changes to facebook.js to support Facebook Canvas apps:

http://developers.facebook.com/docs/appsonfacebook/tutorial/

This is related to issue #146 (#146)

This version requires two new configurations:

• canvasPath: the server path that Facebook will post to when a user goes to your app (what you configure as Canvas URL in Facebook, minus the hostname). Analogous to entryPath.
• canvasPage: the URL that users use to access your app on Facebook, configured as Canvas Page in Facebook.

There are several "to-do's" in here:

• Make "/auth/facebook/canvas" the default canvasPath
• Validate the signed_request that comes from Facebook for security reasons
• Support querystring data on the canvas page (I'm not sure yet what is needed here, so I haven't bothered)

[bnoguchi]

Thanks for your pull request. I think we ought to make this a separate module called facebookCanvas. You can inherit from the facebook module to do this via:

everyauth.facebook.submodule("facebookCanvas")
  .configurable({canvasPage: "..."})
  // Your other extensions follow with the
  // same chained method calls in your pull request

, placing this code under modules/facebookCanvas.js

[bnoguchi]

And don't forget to update the README for the pull request. Thanks!

[bigokro]

Ok, thanks for the feedback. I have my hands pretty full these days, so I can't predict how long it will take me to make it production-ready, but I'll keep you up to date.

As for the signature validation, are you using any specific library for SHA hashing? Is there one you'd accept adding as a dep to the project?

[bnoguchi]

Node has a built-in crypto module. See the following for docs and an example:

• http://nodejs.org/api/crypto.html
• http://stackoverflow.com/questions/7480158/how-do-i-use-node-js-crypto-to-create-a-hmac-sha1-hash

[bigokro]

Perfect! Thanks!

[bigokro]

I'm starting to get back to this. I was able to implement the crypto part, so thanks again for the tip.

About the everyauth submodule recommendation: looking at the other modules, I see that none of them are importing "everyauth". Instead, they are using everymodule. Is that what you meant?

[bigokro]

Give it a try. I've taken care of all the todo's, and moved it to a separate submodule.

[bnoguchi]

Thanks, finally merged this in.

[fabriziomoscon]

@bnoguchi I was wondering if there is any reason why the facebook canvas module hasn't been included in the express-3 branch. We tried to use it in a project and it seems to work correctly. Is there any design choice to remove it or is it something that can be added?

[efecan]

@fabriziomoscon I was wondering the same thing for about a month or so.