Implements Response.from_response and support for cf opts in Py fetch.

Author: dom96

src/pyodide/internal/workers.py

@@ -5,7 +5,7 @@
 from contextlib import ExitStack, contextmanager
 from enum import StrEnum
 from http import HTTPMethod, HTTPStatus
-from typing import TypedDict, Unpack
+from typing import Any, TypedDict, Unpack
 
 import js
 
@@ -21,10 +21,32 @@
 Headers = dict[str, str] | list[tuple[str, str]]
 
 
+# https://developers.cloudflare.com/workers/runtime-apis/request/#the-cf-property-requestinitcfproperties
+class RequestInitCfProperties(TypedDict, total=False):
+    apps: bool | None
+    cacheEverything: bool | None
+    cacheKey: str | None
+    cacheTags: list[str] | None
+    cacheTtl: int
+    cacheTtlByStatus: dict[str, int]
+    image: (
+        Any | None
+    )  # TODO: https://developers.cloudflare.com/images/transform-images/transform-via-workers/
+    mirage: bool | None
+    polish: str | None
+    resolveOverride: str | None
+    scrapeShield: bool | None
+    webp: bool | None
+
+
+# This matches the Request options:
+# https://developers.cloudflare.com/workers/runtime-apis/request/#options
 class FetchKwargs(TypedDict, total=False):
     headers: Headers | None
     body: "Body | None"
     method: HTTPMethod = HTTPMethod.GET
+    redirect: str | None
+    cf: RequestInitCfProperties | None
 
 
 # TODO: Pyodide's FetchResponse.headers returns a dict[str, str] which means
@@ -65,6 +87,15 @@ async def formData(self) -> "FormData":
         except JsException as exc:
             raise _to_python_exception(exc) from exc
 
+    def replace_body(self, body: Body) -> "FetchResponse":
+        """
+        Returns a new Response object with the same options (status, headers, etc) as
+        the original but with an updated body.
+        """
+        b = body.js_object if isinstance(body, FormData) else body
+        js_resp = js.Response.new(b, self.js_response)
+        return FetchResponse(js_resp.url, js_resp)
+
 
 async def fetch(
     resource: str,
@@ -99,7 +130,7 @@ def __init__(
         self,
         body: Body,
         status: HTTPStatus | int = HTTPStatus.OK,
-        statusText="",
+        status_text="",
         headers: Headers = None,
     ):
         """
@@ -108,7 +139,7 @@ def __init__(
         Based on the JS API of the same name:
         https://developer.mozilla.org/en-US/docs/Web/API/Response/Response.
         """
-        options = self._create_options(status, statusText, headers)
+        options = self._create_options(status, status_text, headers)
 
         # Initialise via the FetchResponse super-class which gives us access to
         # methods that we would ordinarily have to redeclare.
@@ -119,13 +150,15 @@ def __init__(
 
     @staticmethod
     def _create_options(
-        status: HTTPStatus | int = HTTPStatus.OK, statusText="", headers: Headers = None
+        status: HTTPStatus | int = HTTPStatus.OK,
+        status_text="",
+        headers: Headers = None,
     ):
         options = {
             "status": status.value if isinstance(status, HTTPStatus) else status,
         }
-        if len(statusText) > 0:
-            options["statusText"] = statusText
+        if status_text:
+            options["statusText"] = status_text
         if headers:
             if isinstance(headers, list):
                 # We should have a list[tuple[str, str]]
@@ -154,10 +187,10 @@ def redirect(url: str, status: HTTPStatus | int = HTTPStatus.FOUND):
     def json(
         data: str | dict[str, str],
         status: HTTPStatus | int = HTTPStatus.OK,
-        statusText="",
+        status_text="",
         headers: Headers = None,
     ):
-        options = Response._create_options(status, statusText, headers)
+        options = Response._create_options(status, status_text, headers)
         with _manage_pyproxies() as pyproxies:
             try:
                 return js.Response.json(

src/workerd/server/tests/python/BUILD.bazel

@@ -30,6 +30,8 @@ py_wd_test("subdirectory")
 
 py_wd_test(
     "sdk",
+    # TODO: will need to rebuild bundle to change the `status_text` field name
+    python_flags = ["development"],
     tags = [
         # TODO(someday): Fix asan failure for this, see https://github.com/cloudflare/workerd/pull/3140#discussion_r1858273318
         "no-asan",

src/workerd/server/tests/python/sdk/worker.py

@@ -1,11 +1,27 @@
+from contextlib import asynccontextmanager
 from http import HTTPMethod, HTTPStatus
 
 import js
 
+import pyodide.http
 from cloudflare.workers import Blob, File, FormData, Response, fetch
 from pyodide.ffi import to_js
 
 
+@asynccontextmanager
+async def _mock_fetch(check):
+    async def mocked_fetch(original_fetch, url, opts):
+        check(url, opts)
+        return await original_fetch(url, opts)
+
+    original_fetch = pyodide.http._jsfetch
+    pyodide.http._jsfetch = lambda url, opts: mocked_fetch(original_fetch, url, opts)
+    try:
+        yield
+    finally:
+        pyodide.http._jsfetch = original_fetch
+
+
 # Each path in this handler is its own test. The URLs that are being fetched
 # here are defined in server.py.
 async def on_fetch(request):
@@ -51,8 +67,18 @@ async def on_fetch(request):
     elif request.url.endswith("/undefined_opts"):
         # This tests two things:
         #   * `Response.redirect` static method
-        #   * that other options can be passed into `fetch`
-        resp = await fetch("https://example.com/redirect", redirect="manual")
+        #   * that other options can be passed into `fetch` (so that we can support
+        #       new options without updating this code)
+
+        # Mock pyodide.http._jsfetch to ensure `foobarbaz` gets passed in.
+        def fetch_check(url, opts):
+            assert opts.foobarbaz == 42
+
+        async with _mock_fetch(fetch_check):
+            resp = await fetch(
+                "https://example.com/redirect", redirect="manual", foobarbaz=42
+            )
+
         return resp
     elif request.url.endswith("/response_inherited"):
         expected = "test123"
@@ -89,6 +115,14 @@ async def on_fetch(request):
         assert data["blob.py"].content_type == "text/python"
         assert data["metadata"].name == "metadata.json"
 
+        return Response("success")
+    elif request.url.endswith("/cf_opts"):
+        resp = await fetch(
+            "http://example.com/redirect",
+            redirect="manual",
+            cf={"cacheTtl": 5, "cacheEverything": True, "cacheKey": "someCustomKey"},
+        )
+        assert resp.status == 301
         return Response("success")
     else:
         resp = await fetch("https://example.com/sub")
@@ -273,6 +307,23 @@ async def can_request_form_data_blob(env):
     assert text == "success"
 
 
+async def response_from_unit_tests(env):
+    response = Response("test", status=201, status_text="Created")
+    cloned = response.replace_body("other")
+    assert cloned.status == 201
+    assert cloned.status_text == "Created"
+    t = await cloned.text()
+    assert t == "other"
+
+
+async def can_use_cf_fetch_opts(env):
+    response = await env.SELF.fetch(
+        "http://example.com/cf_opts",
+    )
+    text = await response.text()
+    assert text == "success"
+
+
 async def test(ctrl, env):
     await can_return_custom_fetch_response(env)
     await can_modify_response(env)
@@ -287,3 +338,5 @@ async def test(ctrl, env):
     await form_data_unit_tests(env)
     await blob_unit_tests(env)
     await can_request_form_data_blob(env)
+    await response_from_unit_tests(env)
+    await can_use_cf_fetch_opts(env)