Create an API for people to work with my system?

[h4x0rmx]

I created a small custom-built content management system. We have some other applications/scripts that people want to integrate with this system.
I could just give them access to the database I use, but I really don't want to do it. I'd like to give them some kind of API or functions (I don't really know what's the best tool for this problem)... are there any tutorials out there or ideas that you'd recommend?
I'll appreciate your help!

[anakadote]

You could create a simple REST API that consists of a server-side script, or scripts, that return data that you approve and format. You could also assign a key to each party that wants access to the API, much like Twitter's REST API. So for instance, say someone wants to get an XML-formatted list of all entries, they could use curl to access the API using something like the following URI:

http://yoursite.com/API/?request=getEntries&key=aasf80sdfaddsajdf87890sadf

You could of course then add additional parameters to the query string, ie date restrictions, limit the number returned, etc.

/API/index.php would then of course see that "getEntries" is being requested, and after authenticating the provided key, your system can output the requested XML.

[h4x0rmx]

I'm not really sure I know what a REST API is. I'm not familiar with twitter's api either.
Is there any good page to learn how to make a REST API? 🙂

Thanks!