Add mount_path for mounting app at sub-path (#334)

* Add mount_path for mounting app at sub-path

* Add test

jupyverse_api/jupyverse_api/app/__init__.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import logging
 from collections import defaultdict
 from typing import Dict, List
@@ -16,8 +18,13 @@ class App:
     _app: FastAPI
     _router_paths: Dict[str, List[str]]
 
-    def __init__(self, app: FastAPI):
-        self._app = app
+    def __init__(self, app: FastAPI, mount_path: str | None = None):
+        if mount_path is None:
+            self._app = app
+        else:
+            subapi = FastAPI()
+            app.mount(mount_path, subapi)
+            self._app = subapi
         app.add_exception_handler(RedirectException, _redirect_exception_handler)
         self._router_paths = defaultdict(list)
 

jupyverse_api/jupyverse_api/main/__init__.py

@@ -13,13 +13,21 @@
 
 
 class AppComponent(Component):
+    def __init__(
+        self,
+        *,
+        mount_path: str | None = None,
+    ) -> None:
+        super().__init__()
+        self.mount_path = mount_path
+
     async def start(
         self,
         ctx: Context,
     ) -> None:
         app = await ctx.request_resource(FastAPI)
 
-        _app = App(app)
+        _app = App(app, mount_path=self.mount_path)
         ctx.add_resource(_app)
 
 

tests/test_app.py

@@ -0,0 +1,46 @@
+import pytest
+from asphalt.core import Context
+from fastapi import APIRouter
+from httpx import AsyncClient
+from jupyverse_api import Router
+from jupyverse_api.app import App
+from jupyverse_api.main import JupyverseComponent
+
+from utils import configure
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "mount_path",
+    (
+        None,
+        "/foo",
+    ),
+)
+async def test_mount_path(mount_path, unused_tcp_port):
+    components = configure({"app": {"type": "app"}}, {"app": {"mount_path": mount_path}})
+
+    async with Context() as ctx, AsyncClient() as http:
+        await JupyverseComponent(
+            components=components,
+            port=unused_tcp_port,
+        ).start(ctx)
+
+        app = await ctx.request_resource(App)
+        router = APIRouter()
+
+        @router.get("/")
+        async def get():
+            pass
+
+        Router(app).include_router(router)
+
+        response = await http.get(f"http://127.0.0.1:{unused_tcp_port}")
+        expected = 200 if mount_path is None else 404
+        assert response.status_code == expected
+
+        response = await http.get(f"http://127.0.0.1:{unused_tcp_port}/bar")
+        assert response.status_code == 404
+
+        response = await http.get(f"http://127.0.0.1:{unused_tcp_port}/foo")
+        expected = 404 if mount_path is None else 200