LinkedIn / Twitter / Facebook as OAuth and OpenId use
Firstly I understand OpenId is for authentication and OAuth is for authorisation and unlike other questions on the site I am not asking which should be used for which but whether anyone can advise a solution for my issue.
I want to allow users to login to my site via their LinkedIn/Twitter/Facebook account once logged in say via LinkedIn they could also then authorise their Twitter and Facebook account as a optional login method. This would allow the user to authenticate via any of the three but end up with their user account on my site as the end result.
I also want to use the authorisation they have provided to get basic user details (profile pic/name etc) and post status updates.
I don't want to ask a user to login with their account via openId then have to authorise the same account again via oauth to allow my site to publish to their service feed and have to do this for each of the 3 services.
Any ideas or issues to this issue?
Answer
If you are using ASP.NET MVC, DotNetOpenAuth is an excellent solution for supporting OpenID/OAuth sites. StackOverflow is using it, and they are quite picky for the code they use in the site.
The integration if OpenID with DotNetOpenAuth is quite straightforward. I have not tried OAuth, but I don't expect it to be of any less quality.
Unfortunately, Facebook does not support OpenID/OAuth, so you need to use a different solution for it. The one I use is Clarity Consulting's Facebook Developer Toolkit. It works, although I do have certain complaints about the quality of the code; unfortunately I haven't found anything better yet. (Note: If anyone knows a better alternative, by all means let me know)
The basic integration of Facebook Connect with the Facebook Developer Toolkit is also relatively straightforward. However, their object model is somewhat messed up, due to their attempt to stay as close to the Facebook APIs, so the HTTP API patterns are bleeding through a lot. Still, it does the work.
Update: Now that Facebook announced that they'll be supporting OAuth 2.0, DotNetOpenAuth might turn out to be the best solution.