Class-based endpoints produce an error on schema generation

[mbarrientos]

When using class-based endpoints, if no methods are explicitly passed to add_route, this will raise an error when generating the schema. (using starlette==0.11.4, starlette-api==0.6.2)

from starlette.requests import Request
from starlette.responses import Response
from starlette_api.applications import Starlette
from starlette_api.endpoints import HTTPEndpoint

app = Starlette(
    title="Test",
    version="1.0",
    description="Test",
    schema="/schema/",
    docs="/docs/",
    redoc="/redoc/",
)

class FooEndpoint(HTTPEndpoint):
    async def get(self, request: Request):
        return Response()

    async def post(self, request: Request):
        return Response()

app.add_route("/", FooEndpoint, name="foo")

Traceback:

INFO: ('127.0.0.1', 53618) - "GET /schema/ HTTP/1.1" 500
ERROR: Exception in ASGI application
Traceback (most recent call last):
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/uvicorn/protocols/http/httptools_impl.py", line 372, in run_asgi
    result = await asgi(self.receive, self.send)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/uvicorn/middleware/debug.py", line 83, in __call__
    raise exc from None
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/uvicorn/middleware/debug.py", line 80, in __call__
    await asgi(receive, self.send)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette/middleware/errors.py", line 125, in asgi
    raise exc from None
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette/middleware/errors.py", line 103, in asgi
    await asgi(receive, _send)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette/exceptions.py", line 74, in app
    raise exc from None
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette/exceptions.py", line 63, in app
    await instance(receive, sender)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette_api/routing.py", line 174, in awaitable
    response = await run_in_threadpool(injected_func)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette/concurrency.py", line 24, in run_in_threadpool
    return await loop.run_in_executor(None, func, *args)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/concurrent/futures/thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette_api/schemas.py", line 223, in schema
    return OpenAPIResponse(self.schema)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette_api/schemas.py", line 219, in schema
    return self.schema_generator.get_schema(self.routes)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette_api/schemas.py", line 175, in get_schema
    self.spec.add_path(path=path, operations={e.method: self.get_endpoint_schema(e) for e in endpoints})
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette_api/schemas.py", line 175, in <dictcomp>
    self.spec.add_path(path=path, operations={e.method: self.get_endpoint_schema(e) for e in endpoints})
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette_api/schemas.py", line 156, in get_endpoint_schema
    self.get_endpoint_parameters_schema(endpoint, schema)
  File "/Users/test/.virtualenvs/play/lib/python3.7/site-packages/starlette_api/schemas.py", line 114, in get_endpoint_parameters_schema
    for field in itertools.chain(endpoint.query_fields.values(), endpoint.path_fields.values())
AttributeError: 'NoneType' object has no attribute 'values'

[perdy]

Should be fixed with changes committed on 0429f27.

Thanks !