Merge pull request #2 from feldroy/fix-middleware-return-await

Pass inner app results through the middleware

Author: pydanny

src/staticware/middleware.py

@@ -19,15 +19,15 @@
 import hashlib
 import mimetypes
 import re
-from pathlib import Path
 from collections.abc import Awaitable, Callable
+from pathlib import Path
 from typing import Any
 
 # ASGI protocol types — inlined so we depend on nothing.
 type Scope = dict[str, Any]
 type Receive = Callable[[], Awaitable[dict[str, Any]]]
 type Send = Callable[[dict[str, Any]], Awaitable[None]]
-type ASGIApp = Callable[[Scope, Receive, Send], Awaitable[None]]
+type ASGIApp = Callable[[Scope, Receive, Send], Awaitable[Any]]
 
 
 class HashedStatic:
@@ -102,7 +102,7 @@ def _hash_files(self) -> None:
 
             self.file_map[relative] = hashed
             self._reverse[hashed] = relative
-            self._etags[relative] = f'"{hash_val}"'.encode('latin-1')
+            self._etags[relative] = f'"{hash_val}"'.encode("latin-1")
 
     def url(self, path: str) -> str:
         """Return the cache-busted URL for a static file path.
@@ -165,9 +165,7 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
                     if hdr_name == b"if-none-match" and hdr_value == etag:
                         await _send_text(send, 304, b"")
                         return
-                await _send_file(
-                    send, file_path, extra_headers=[(b"etag", etag)]
-                )
+                await _send_file(send, file_path, extra_headers=[(b"etag", etag)])
             else:
                 await _send_file(send, file_path)
             return
@@ -201,10 +199,9 @@ def _replace(self, match: re.Match[str]) -> str:
             return f"{self.static.prefix}/{self.static.file_map[path]}"
         return match.group(0)
 
-    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
+    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> Any:
         if scope["type"] != "http":
-            await self.app(scope, receive, send)
-            return
+            return await self.app(scope, receive, send)
 
         response_start: dict[str, Any] | None = None
         body_parts: list[bytes] = []
@@ -225,9 +222,7 @@ async def send_wrapper(message: dict[str, Any]) -> None:
 
             if message["type"] == "http.response.body":
                 if response_start is None:
-                    raise RuntimeError(
-                        "http.response.body received before http.response.start"
-                    )
+                    raise RuntimeError("http.response.body received before http.response.start")
                 if not is_html:
                     await send(message)
                     return
@@ -246,21 +241,17 @@ async def send_wrapper(message: dict[str, Any]) -> None:
                         pass
 
                     if response_start is None:
-                        raise RuntimeError(
-                            "http.response.body received before http.response.start"
-                        )
+                        raise RuntimeError("http.response.body received before http.response.start")
                     new_headers = [
-                        (k, str(len(full_body)).encode("latin-1"))
-                        if k == b"content-length"
-                        else (k, v)
+                        (k, str(len(full_body)).encode("latin-1")) if k == b"content-length" else (k, v)
                         for k, v in response_start.get("headers", [])
                     ]
                     response_start["headers"] = new_headers
                     await send(response_start)
                     await send({"type": "http.response.body", "body": full_body})
                 return
 
-        await self.app(scope, receive, send_wrapper)
+        return await self.app(scope, receive, send_wrapper)
 
 
 # ── Raw ASGI helpers ────────────────────────────────────────────────────
@@ -283,28 +274,36 @@ async def _send_file(
     if extra_headers:
         headers.extend(extra_headers)
 
-    await send({
-        "type": "http.response.start",
-        "status": 200,
-        "headers": headers,
-    })
-    await send({
-        "type": "http.response.body",
-        "body": content,
-    })
+    await send(
+        {
+            "type": "http.response.start",
+            "status": 200,
+            "headers": headers,
+        }
+    )
+    await send(
+        {
+            "type": "http.response.body",
+            "body": content,
+        }
+    )
 
 
 async def _send_text(send: Send, status: int, body: bytes) -> None:
     """Send a plain-text ASGI response."""
-    await send({
-        "type": "http.response.start",
-        "status": status,
-        "headers": [
-            (b"content-type", b"text/plain"),
-            (b"content-length", str(len(body)).encode("latin-1")),
-        ],
-    })
-    await send({
-        "type": "http.response.body",
-        "body": body,
-    })
+    await send(
+        {
+            "type": "http.response.start",
+            "status": status,
+            "headers": [
+                (b"content-type", b"text/plain"),
+                (b"content-length", str(len(body)).encode("latin-1")),
+            ],
+        }
+    )
+    await send(
+        {
+            "type": "http.response.body",
+            "body": body,
+        }
+    )

tests/test_staticware.py

@@ -22,7 +22,6 @@
 
 from staticware import HashedStatic, StaticRewriteMiddleware
 
-
 # ── Helpers ──────────────────────────────────────────────────────────────
 
 
@@ -61,7 +60,6 @@ def expected_hash(content: bytes, length: int = 8) -> str:
 # ── HashedStatic: hashing and url() ──────────────────────────────────────
 
 
-
 def test_file_map_contains_all_files(static: HashedStatic, static_dir: Path) -> None:
     assert "styles.css" in static.file_map
     assert "images/logo.png" in static.file_map
@@ -216,14 +214,16 @@ def make_html_app(html: str):
     body = html.encode("utf-8")
 
     async def app(scope: dict, receive: Any, send: Any) -> None:
-        await send({
-            "type": "http.response.start",
-            "status": 200,
-            "headers": [
-                (b"content-type", b"text/html; charset=utf-8"),
-                (b"content-length", str(len(body)).encode("latin-1")),
-            ],
-        })
+        await send(
+            {
+                "type": "http.response.start",
+                "status": 200,
+                "headers": [
+                    (b"content-type", b"text/html; charset=utf-8"),
+                    (b"content-length", str(len(body)).encode("latin-1")),
+                ],
+            }
+        )
         await send({"type": "http.response.body", "body": body})
 
     return app
@@ -233,14 +233,16 @@ def make_json_app(data: bytes):
     """Create a dummy ASGI app that returns JSON."""
 
     async def app(scope: dict, receive: Any, send: Any) -> None:
-        await send({
-            "type": "http.response.start",
-            "status": 200,
-            "headers": [
-                (b"content-type", b"application/json"),
-                (b"content-length", str(len(data)).encode("latin-1")),
-            ],
-        })
+        await send(
+            {
+                "type": "http.response.start",
+                "status": 200,
+                "headers": [
+                    (b"content-type", b"application/json"),
+                    (b"content-length", str(len(data)).encode("latin-1")),
+                ],
+            }
+        )
         await send({"type": "http.response.body", "body": data})
 
     return app
@@ -318,10 +320,12 @@ async def test_rewrite_raises_runtime_error_on_body_before_start(
 
     async def broken_app(scope: dict, receive: Any, send: Any) -> None:
         # Skip http.response.start entirely — straight to body.
-        await send({
-            "type": "http.response.body",
-            "body": b"<html>oops</html>",
-        })
+        await send(
+            {
+                "type": "http.response.body",
+                "body": b"<html>oops</html>",
+            }
+        )
 
     app = StaticRewriteMiddleware(broken_app, static=static)
     with pytest.raises(RuntimeError):
@@ -335,14 +339,16 @@ async def test_rewrite_streaming_html_response(static: HashedStatic) -> None:
 
     async def streaming_app(scope: dict, receive: Any, send: Any) -> None:
         total = len(chunk1) + len(chunk2)
-        await send({
-            "type": "http.response.start",
-            "status": 200,
-            "headers": [
-                (b"content-type", b"text/html; charset=utf-8"),
-                (b"content-length", str(total).encode("latin-1")),
-            ],
-        })
+        await send(
+            {
+                "type": "http.response.start",
+                "status": 200,
+                "headers": [
+                    (b"content-type", b"text/html; charset=utf-8"),
+                    (b"content-length", str(total).encode("latin-1")),
+                ],
+            }
+        )
         await send({"type": "http.response.body", "body": chunk1, "more_body": True})
         await send({"type": "http.response.body", "body": chunk2, "more_body": False})
 
@@ -373,14 +379,16 @@ async def test_rewrite_non_utf8_html_passes_through(static: HashedStatic) -> Non
     raw_body = b"<html>\x80\x81\x82 not valid utf-8</html>"
 
     async def bad_encoding_app(scope: dict, receive: Any, send: Any) -> None:
-        await send({
-            "type": "http.response.start",
-            "status": 200,
-            "headers": [
-                (b"content-type", b"text/html; charset=utf-8"),
-                (b"content-length", str(len(raw_body)).encode("latin-1")),
-            ],
-        })
+        await send(
+            {
+                "type": "http.response.start",
+                "status": 200,
+                "headers": [
+                    (b"content-type", b"text/html; charset=utf-8"),
+                    (b"content-length", str(len(raw_body)).encode("latin-1")),
+                ],
+            }
+        )
         await send({"type": "http.response.body", "body": raw_body})
 
     app = StaticRewriteMiddleware(bad_encoding_app, static=static)
@@ -397,9 +405,7 @@ def make_mount_scope(path: str, *, root_path: str = "") -> dict[str, Any]:
     return {"type": "http", "path": path, "root_path": root_path, "method": "GET"}
 
 
-async def test_serve_with_root_path_scope(
-    static: HashedStatic, static_dir: Path
-) -> None:
+async def test_serve_with_root_path_scope(static: HashedStatic, static_dir: Path) -> None:
     """Starlette-style mount: root_path set, path still includes the prefix.
 
     Starlette sets scope["root_path"] = "/static" and leaves
@@ -414,9 +420,7 @@ async def test_serve_with_root_path_scope(
     assert resp.text == "body { color: red; }"
 
 
-async def test_serve_with_stripped_path(
-    static: HashedStatic, static_dir: Path
-) -> None:
+async def test_serve_with_stripped_path(static: HashedStatic, static_dir: Path) -> None:
     """Litestar-style mount: framework strips the prefix from scope["path"].
 
     The sub-app sees scope["root_path"] = "/static" and
@@ -466,18 +470,14 @@ async def test_serve_with_mismatched_mount_and_prefix(static_dir: Path) -> None:
 # ── HashedStatic: ETag and conditional requests ──────────────────────
 
 
-def make_scope_with_headers(
-    path: str, headers: list[tuple[bytes, bytes]] | None = None
-) -> dict[str, Any]:
+def make_scope_with_headers(path: str, headers: list[tuple[bytes, bytes]] | None = None) -> dict[str, Any]:
     scope: dict[str, Any] = {"type": "http", "path": path, "method": "GET"}
     if headers:
         scope["headers"] = headers
     return scope
 
 
-async def test_etag_on_unhashed_response(
-    static: HashedStatic, static_dir: Path
-) -> None:
+async def test_etag_on_unhashed_response(static: HashedStatic, static_dir: Path) -> None:
     """Original filename response includes an ETag header with the content hash."""
     resp = ResponseCollector()
     await static(make_scope("/static/styles.css"), receive, resp)
@@ -489,9 +489,7 @@ async def test_etag_on_unhashed_response(
     assert resp.headers[b"etag"] == f'"{h}"'.encode("latin-1")
 
 
-async def test_conditional_request_returns_304(
-    static: HashedStatic, static_dir: Path
-) -> None:
+async def test_conditional_request_returns_304(static: HashedStatic, static_dir: Path) -> None:
     """If-None-Match with matching ETag returns 304 and empty body."""
     css_content = (static_dir / "styles.css").read_bytes()
     h = expected_hash(css_content)
@@ -528,3 +526,58 @@ async def test_hashed_url_no_etag(static: HashedStatic) -> None:
     await static(make_scope(f"/static/{hashed_name}"), receive, resp)
     assert resp.status == 200
     assert b"etag" not in resp.headers, "Hashed URL should not include an etag header"
+
+
+# ── StaticRewriteMiddleware: return value propagation ──────────────
+
+
+async def test_rewrite_middleware_returns_inner_app_result(
+    static: HashedStatic,
+) -> None:
+    """Middleware should propagate the inner app's return value on the HTTP path.
+
+    ASGI apps normally return None, but the spec does not forbid return values.
+    Frameworks like Starlette rely on ``return await self.app(...)`` so that
+    return values propagate through the middleware chain.  A bare ``await``
+    without ``return`` silently discards the result.
+    """
+    sentinel = "app_result"
+
+    async def inner_app(scope: dict, receive: Any, send: Any) -> str:
+        body = b"<html>hello</html>"
+        await send(
+            {
+                "type": "http.response.start",
+                "status": 200,
+                "headers": [
+                    (b"content-type", b"text/html; charset=utf-8"),
+                    (b"content-length", str(len(body)).encode("latin-1")),
+                ],
+            }
+        )
+        await send({"type": "http.response.body", "body": body})
+        return sentinel
+
+    app = StaticRewriteMiddleware(inner_app, static=static)
+    resp = ResponseCollector()
+    result = await app(make_scope("/"), receive, resp)
+    assert result == sentinel
+
+
+async def test_rewrite_middleware_returns_inner_app_result_non_http(
+    static: HashedStatic,
+) -> None:
+    """Middleware should propagate the inner app's return value for non-HTTP scopes.
+
+    When the scope type is not "http", the middleware forwards directly to the
+    inner app.  It must ``return await self.app(...)`` so the return value is
+    not silently discarded.
+    """
+    sentinel = "ws_result"
+
+    async def inner_app(scope: dict, receive: Any, send: Any) -> str:
+        return sentinel
+
+    app = StaticRewriteMiddleware(inner_app, static=static)
+    result = await app({"type": "websocket", "path": "/"}, receive, ResponseCollector())
+    assert result == sentinel