Allow passing FastAPI app options (#4282)

* App: don't force docs_url and redoc_url to None

* App.create_app: allow passing in app_kwargs

* start_server + launch: allow passing in app_kwargs

* Changelog

* Apply suggestions from code review

Co-authored-by: Abubakar Abid <abubakar@huggingface.co>

* Use .launch for tests

---------

Co-authored-by: Abubakar Abid <abubakar@huggingface.co>

CHANGELOG.md

@@ -16,6 +16,7 @@ No changes to highlight.
 - Refactor web component `initial_height` attribute by [@whitphx](https://github.com/whitphx) in [PR 4223](https://github.com/gradio-app/gradio/pull/4223)
 - Relocate `mount_css` fn to remove circular dependency [@whitphx](https://github.com/whitphx) in [PR 4222](https://github.com/gradio-app/gradio/pull/4222)
 - Upgrade Black to 23.3 by [@akx](https://github.com/akx) in [PR 4259](https://github.com/gradio-app/gradio/pull/4259)
+- `Interface.launch()` and `Blocks.launch()` now accept an `app_kwargs` argument to allow customizing the configuration of the underlying FastAPI app, by [@akx](https://github.com/akx) in [PR 4282](https://github.com/gradio-app/gradio/pull/4282)
 
 ## Breaking Changes:
 

gradio/blocks.py

@@ -1615,6 +1615,7 @@ Received outputs:
         blocked_paths: list[str] | None = None,
         root_path: str = "",
         _frontend: bool = True,
+        app_kwargs: dict[str, Any] | None = None,
     ) -> tuple[FastAPI, str, str]:
         """
         Launches a simple web server that serves the demo. Can also be used to create a
@@ -1648,6 +1649,7 @@ Received outputs:
             allowed_paths: List of complete filepaths or parent directories that gradio is allowed to serve (in addition to the directory containing the gradio python file). Must be absolute paths. Warning: if you provide directories, any files in these directories or their subdirectories are accessible to all users of your app.
             blocked_paths: List of complete filepaths or parent directories that gradio is not allowed to serve (i.e. users of your app are not allowed to access). Must be absolute paths. Warning: takes precedence over `allowed_paths` and all other directories exposed by Gradio by default.
             root_path: The root path (or "mount point") of the application, if it's not served from the root ("/") of the domain. Often used when the application is behind a reverse proxy that forwards requests to the application. For example, if the application is served at "https://example.com/myapp", the `root_path` should be set to "/myapp".
+            app_kwargs: Additional keyword arguments to pass to the underlying FastAPI app as a dictionary of parameter keys and argument values. For example, `{"docs_url": "/docs"}`
         Returns:
             app: FastAPI app object that is running the demo
             local_url: Locally accessible link to the demo
@@ -1747,6 +1749,7 @@ Received outputs:
                 ssl_keyfile,
                 ssl_certfile,
                 ssl_keyfile_password,
+                app_kwargs=app_kwargs,
             )
             self.server_name = server_name
             self.local_url = local_url

gradio/networking.py

@@ -89,6 +89,7 @@ def start_server(
     ssl_keyfile: str | None = None,
     ssl_certfile: str | None = None,
     ssl_keyfile_password: str | None = None,
+    app_kwargs: dict | None = None,
 ) -> tuple[str, int, str, App, Server]:
     """Launches a local server running the provided Interface
     Parameters:
@@ -99,6 +100,8 @@ def start_server(
         ssl_keyfile: If a path to a file is provided, will use this as the private key file to create a local server running on https.
         ssl_certfile: If a path to a file is provided, will use this as the signed certificate for https. Needs to be provided if ssl_keyfile is provided.
         ssl_keyfile_password: If a password is provided, will use this with the ssl certificate for https.
+        app_kwargs: Additional keyword arguments to pass to the gradio.routes.App constructor.
+
     Returns:
         port: the port number the server is running on
         path_to_local_server: the complete address that the local server can be accessed at
@@ -143,7 +146,7 @@ def start_server(
     else:
         host = server_name
 
-    app = App.create_app(blocks)
+    app = App.create_app(blocks, app_kwargs=app_kwargs)
 
     if blocks.save_to is not None:  # Used for selenium tests
         blocks.save_to["port"] = port

gradio/routes.py

@@ -115,7 +115,11 @@ class App(FastAPI):
         self.uploaded_file_dir = os.environ.get("GRADIO_TEMP_DIR") or str(
             Path(tempfile.gettempdir()) / "gradio"
         )
-        super().__init__(**kwargs, docs_url=None, redoc_url=None)
+        # Allow user to manually set `docs_url` and `redoc_url`
+        # when instantiating an App; when they're not set, disable docs and redoc.
+        kwargs.setdefault("docs_url", None)
+        kwargs.setdefault("redoc_url", None)
+        super().__init__(**kwargs)
 
     def configure_app(self, blocks: gradio.Blocks) -> None:
         auth = blocks.auth
@@ -141,8 +145,12 @@ class App(FastAPI):
         return self.blocks
 
     @staticmethod
-    def create_app(blocks: gradio.Blocks) -> App:
-        app = App(default_response_class=ORJSONResponse)
+    def create_app(
+        blocks: gradio.Blocks, app_kwargs: Dict[str, Any] | None = None
+    ) -> App:
+        app_kwargs = app_kwargs or {}
+        app_kwargs.setdefault("default_response_class", ORJSONResponse)
+        app = App(**app_kwargs)
         app.configure_app(blocks)
 
         app.add_middleware(

test/test_networking.py

@@ -81,3 +81,20 @@ class TestURLs:
     def test_url_ok(self):
         res = networking.url_ok("https://www.gradio.app")
         assert res
+
+
+def test_start_server_app_kwargs():
+    """
+    Test that start_server accepts app_kwargs and they're propagated to FastAPI.
+    """
+    io = Interface(lambda x: x, "number", "number")
+    app, _, _ = io.launch(
+        show_error=True,
+        prevent_thread_lock=True,
+        app_kwargs={
+            "docs_url": "/docs",
+        },
+    )
+    client = TestClient(app)
+    assert client.get("/docs").status_code == 200
+    io.close()