Add Nested Routes Support and Documentation

[igorbenav]

Describe the bug or question
Handling something like this scenario:

router = APIRouter(prefix="/user/{user_id}")


@router.get("/posts/{post_id}")
def get_post(user_id: int, post_id: int):
    ...
    return {"user": user_id, "post:": post_id, "text": post_text}

curl localhost:8000/user/1/posts/2

{
  "user": 1,
  "post:": 2
  "text": "sample text"
}

[JakNowy]

I tried addressing this. After short research I thought that something like this would work out of the box:

class UserCRUD(fastcrud.FastCRUD):
    async def read(self, db: AsyncSession, root_param: int, read_param: int) -> Any:
        return {
            'root_param': root_param,
            'read_param': read_param,
        }

user_router = crud_router(
    crud=UserCRUD(User),
    model=User,
    session=deps.get_async_db,
    create_schema=UserIn,
    update_schema=UserUpdate,
    endpoint_names={'read': 'read/{read_param}'}
)

my_router = APIRouter()
my_router.include_router(user_router, prefix='root_router/{root_param}')

It turns out, that while the route gets properly built, the path params are not resolved dynamically as integers (they are parsed as raw path strings). Only default id gets recognized as a path param. I can see they are all gettin passed in

            self.router.add_api_route(
                f"{self.path}/{endpoint_name}/{_primary_keys_path_suffix}",
                ...
            )

but not sure what magic makes the _primary_keys_path_suffix resolve the params but not endpoint_name. Any thoughts on that? Is that approach ok or we want something else?

(note I have one more layer of /user/ nesting in my project but that's irrelevant here)

[JakNowy]

@igorbenav

[igorbenav]

I'll take a proper look at it later today

[igorbenav]

Sorry, had a really long day. I'll try to do it on friday