In my company we have developped some applications. We have to create an API for one application (say application A), so that the others can use it (an its data).
The question is : we already have developped PHP classes for the model of Application A, if we want to create an API, should we :
– re-use these classes (too much functionnalities for an API, too heavy…)
– create one PHP class, with some basic functions, that takes in input and returns only raw values (like strings, array… NOT complex classes)
– create another set of PHP classes, simpler, and designed only to be used by an external application (so only to get data easily)
Usually, an API is the 2nd solution (to be used as well with PHP than as a web service for example), but i find it too bad that we made a complex and usefull class modelisation, then we tear it apart just to have functions, strings and array.
The 3rd one seems to me to be the compromise, but a collegue of mine insist that this is not an API. Too bad…
What do you think ?
Solution number 3 might be the best one from an architectural point of view. Basically you are using a Facade Design Pattern to simplify your API. Since I am dealing with it at the moment: In Patterns Of Enterprise Application Architecture this approach is described as the service layer which makes totally sense since you don’t want to expose any user (meaning whoever will deal with your API) to more complexity than is actually needed or desired.
This includes using the easiest possible interface and transfer objects (raw values if they make sense). As soon as your Facade is being called through remoting services (like a webservice) you will eventually have to break repsonses and requests down to raw values (data containers) anyway.