Unify how we allow to set headers and status code

[patrick91]

So at the moment we have a few integrations and they have a slightly different way to setting headers and status code.

The general idea is the same, we provide a response object in info.context. This object is based on the current integration, this is where the differences between integrations come into play.

I think we should provide a new object (unfortunately we can't replace the current one due to backwards compatibility) that allows to:

1. set/update response headers
2. set the status code

Having this could also help us prevent some mistakes, for example, should we allow to set the status code multiple times?

What do you think?

[jkimbo]

Maybe providing some methods on context? set_status_code, add_headers etc.

Also can we be sure that we can abstract away different server implementations? I know for example that ASGI running background tasks but Django doesn't.

[patrick91]

Maybe providing some methods on context? set_status_code, add_headers etc.

I was thinking of having a new property that had those methods

Also can we be sure that we can abstract away different server implementations? I know for example that ASGI running background tasks but Django doesn't.

I'd just go for headers and status code for now, we can keep access to the framework's request object if people need to do something more specific :)

[jkimbo]

Had a thought: if we construct our own info object then we could attach this object/method to the info object rather than through context? I think that makes more sense because context is defined mostly in user land.

[patrick91]

something like:

def a_resolver(info: Info) -> str:
    info.request.headers["example"]
    info.response.set_header("X-Framework", "Strawberry")
    return "ABC"

?

[patrick91]

We should do this for cookies as well (even if they are just headers :))

[jkimbo]

something like:

def a_resolver(info: Info) -> str:
    info.request.headers["example"]
    info.response.set_header("X-Framework", "Strawberry")
    return "ABC"

?

Yes I think that looks good.

[jthorniley]

something like:

def a_resolver(info: Info) -> str:
    info.request.headers["example"]
    info.response.set_header("X-Framework", "Strawberry")
    return "ABC"

?

I have two questions re this:

1. If the resolver is called from a websocket (generally a subscription, but it could be a single operation called over ws), this is fairly meaningless since you can't set cookies/headers at this point. So should it error? Silently ignore? (Or there might be other things you want to do with a websocket, like close it immediately with a websocket-specific status code)
2. How to test? At the moment, we test with something like:

   result: ExecutionResult = await execute(query, context_value=FakeContext)
   assert result.data == <blah>
   assert FakeContext.response.headers == <blah> # if needed
   

   So we can test any status code set on the django integration but this is obviously user defined. The GraphQL ExecutionResult doesn't define a place for it.

So I was just thinking maybe define two abstract base classes, like HttpContext and WebsocketContext and make them both (optionally) available:

def a_resolver(info: Info) -> str:
  http_context  = info.http_context  # HttpContext | None
  if http_context is None:
    # ... behaviour if called from websocket or non-http ...
  else:
    if http_context.response.status_code is not strawberry.DEFAULT:
      # ... behaviour if some other resolver has already set the status code ...
    else:
      http_context.response.status_code = 403
  return "value"

So then it would be up to integrations to implement and provide http_context and websocket_context on the info object (or if they don't support it, leave as None). Likewise in testing you can add them to the execute call (or not) and use e.g. a fake/mock object to check behaviours.