added description interface to extend it

[danieledangeli]

I've added an interface at the Description object and changed as protected its attribute.
I do that because in this way it's allowed to extend the description object. For example if I want to add a different way to fetch the operation, I can pass as an option another method for "defaultCommandFactory" that will receive my custom Description object that implements the DescriptionInterface.

[czenker]

You missed an occurrence in GuzzleHttp\Command\Guzzle\Parameter's constructor. An instanceof check is done there.

Otherwise I really like the idea.

[danieledangeli]

Ok I did it. 💃

tl;dr
Just to explain better my first comment:
I made this PR just because I need to extend the description object.
I've seen that it's not a final class and then I just asked to myself: "why private method and not interfaces?"

A simple use case can be the ability to fetch a command (e.g "get.post") by name and a version (1.0, 2.0?). So instead keeping a simple array beteween commandName and Operation I'd like to have a commandName that match a set of operations (one for each version).
Just that! I did that with a workaround, so now should be more easy (Hope) 👍

[czenker]

Thanks daniele.

This patch would also help me. I'm trying to port Swizzle (it creates a Service Description from a Swagger Definition) to Guzzle4, but am missing the addModel and addOperation methods. It probably does not make sense to have them in guzzle-services, but it should be possible to modify the Definition class.

I'm not sure if we are living in a democracy here, but I would give this patch a 👍 😎

[danieledangeli]

Oh that's a good idea! Hope they can accept this path 😞