Provide a method to access client capabilities

It appears that the current LanguageServer API does not provide a way to programmatically access client capabilities. It’s important to properly detect when client doesn’t support a certain feature, so as to not generate a request that will fail. For example, the client may not support workspace/configuration, and so ls.get_configuration() request fails, which then crashes the client (and we don’t always have control over client code).

Would it be possible to add something like ls.client_capabilities() to request them? It would just directly return information cached from initialize request.

Thanks!

[danixeee]

@dinvlad rootUri can be accessed from the Workspace. Take a look here.

There is another way, which I recommend if you want to use the latest pygls from PyPI. Every user-registered language feature (registered with @server.feature(...)) is called after built-in language feature. For e.g., when initialization request is received, pygls automatically creates workspace and calculates server capabilities in built-in initialize method and if you register the same initialize method, it will be called and you can do anything you want:

@ json_server.feature(INITIALIZE)
def initialize(ls, params: InitializeParams):     # <- called after built-in initialize method
    ls.client_capabilities = params.capabilities

This should work until we close the issue #59. Hope this helps!

[dinvlad]

Awesome, understood. I thought the params here are the ones passed in the response, not the request. Closing this issue in anticipation for #59.

Thank you!