How to let external applications communicate with your database and your site?

I understand the term used all over social networking sites is "API", I did some research on the web, and it seems to be a very big topic to cover.

As per my previous post, I have made a social networking site using asp.net 3.0 and C#. It's a small prototype.

A few tables such that the record of friends and their friends and their interest is kept. There are no privacy constraint at the moment

What I would like is to, "welcome developers please download the API for free and start making application开发者_运维技巧s for the social network". Consider application extracts interests of the friends of a friends who is using the application.

From what I understand, an API is a space to host an application either provided by me or the developer.

APIs are an interface to (all or some of) the functionalities of your application. In your particular scenario you can expose Web-apis by allowing remote http calls (for example by using web services).

http://en.wikipedia.org/wiki/Application_programming_interface#Web_APIs

It's a bit more complicated than just "Right-click add API..." but you have a few options:

WCF, WCF rest, and Data Services / oData

If you're in a desparate hurry to get an API out the quickest way will be to use oData/Data Services, you basically make your database queryable via the web. (You can restrict Read/Write access.)

It's as simple as creating an Entity Framework model for your database, and exposing that as a WCF Data Service and you're done.

http://msdn.microsoft.com/en-us/data/bb931106.aspx

http://www.odata.org/developers/odata-sdk