Authentication with CodeIgniter API

I have been working on a PHP project recently and I have created an API that will be consumed by mobile clients. I am using CodeIgniter as it provides a nice restful interface out of the box. I am unexperienced in PHP development and especially securing PHP web services. I was hoping to solicit some information about how I should go about implementing user authentication with my API. The information is not super sensitive but I do need clients to authenticate with the service.

Since my clients are mobile devices I'm uncertain how to go about implementing a membership provider model using CI since I won't have the luxury of a session (or do I?). Will my users merely send their credentials each time a request is made using SSL? Can some开发者_运维百科one provide me with some direction or documentation that might help?

Thanks!

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Use Phil Sturgeon's Rest API. He's already built these things in.

http://philsturgeon.co.uk/blog/2009/06/REST-implementation-for-CodeIgniter