Implements Request class in Python SDK.

src/pyodide/internal/workers.py

@@ -1,6 +1,8 @@
 # This module defines a Workers API for Python. It is similar to the API provided by
 # JS Workers, but with changes and additions to be more idiomatic to the Python
 # programming language.
+import http.client
+import json
 from collections.abc import Generator, Iterable, MutableMapping
 from contextlib import ExitStack, contextmanager
 from enum import StrEnum
@@ -18,7 +20,7 @@
     "js.ReadableStream | js.URLSearchParams"
 )
 Body = "str | FormData | JSBody"
-Headers = dict[str, str] | list[tuple[str, str]]
+Headers = "dict[str, str] | list[tuple[str, str]] | js.Headers"
 
 
 # https://developers.cloudflare.com/workers/runtime-apis/request/#the-cf-property-requestinitcfproperties
@@ -42,7 +44,7 @@ class RequestInitCfProperties(TypedDict, total=False):
 # This matches the Request options:
 # https://developers.cloudflare.com/workers/runtime-apis/request/#options
 class FetchKwargs(TypedDict, total=False):
-    headers: Headers | None
+    headers: "Headers | None"
     body: "Body | None"
     method: HTTPMethod = HTTPMethod.GET
     redirect: str | None
@@ -53,16 +55,14 @@ class FetchKwargs(TypedDict, total=False):
 #       duplicates are lost, we should fix that so it returns a http.client.HTTPMessage
 class FetchResponse(pyodide.http.FetchResponse):
     # TODO: Consider upstreaming the `body` attribute
+    # TODO: Behind a compat flag make this return a native stream (StreamReader?), or perhaps
+    #       behind a different name, maybe `stream`?
     @property
-    def body(self) -> Body:
+    def body(self) -> "js.ReadableStream":
         """
-        Returns the body from the JavaScript Response instance.
+        Returns the body as a JavaScript ReadableStream from the JavaScript Response instance.
         """
-        b = self.js_response.body
-        if b.constructor.name == "FormData":
-            return FormData(b)
-        else:
-            return b
+        return self.js_response.body
 
     @property
     def js_object(self) -> "js.Response":
@@ -74,14 +74,13 @@ def js_object(self) -> "js.Response":
     Some methods are implemented by `FetchResponse`, these include `buffer`
     (replacing JavaScript's `arrayBuffer`), `bytes`, `json`, and `text`.
 
-    Some methods are intentionally not implemented, these include `blob`.
-
     There are also some additional methods implemented by `FetchResponse`.
     See https://pyodide.org/en/stable/usage/api/python-api/http.html#pyodide.http.FetchResponse
     for details.
     """
 
     async def formData(self) -> "FormData":
+        self._raise_if_failed()
         try:
             return FormData(await self.js_response.formData())
         except JsException as exc:
@@ -96,6 +95,10 @@ def replace_body(self, body: Body) -> "FetchResponse":
         js_resp = js.Response.new(b, self.js_response)
         return FetchResponse(js_resp.url, js_resp)
 
+    async def blob(self) -> "Blob":
+        self._raise_if_failed()
+        return _js_value_to_py(await self.js_object.blob())
+
 
 async def fetch(
     resource: str,
@@ -125,6 +128,18 @@ def _manage_pyproxies():
         destroy_proxies(proxies)
 
 
+def _to_js_headers(headers: Headers):
+    if isinstance(headers, list):
+        # We should have a list[tuple[str, str]]
+        return js.Headers.new(headers)
+    elif isinstance(headers, dict):
+        return js.Headers.new(headers.items())
+    elif hasattr(headers, "constructor") and headers.constructor.name == "Headers":
+        return headers
+    else:
+        raise TypeError("Received unexpected type for headers argument")
+
+
 class Response(FetchResponse):
     def __init__(
         self,
@@ -160,13 +175,7 @@ def _create_options(
         if status_text:
             options["statusText"] = status_text
         if headers:
-            if isinstance(headers, list):
-                # We should have a list[tuple[str, str]]
-                options["headers"] = js.Headers.new(headers)
-            elif isinstance(headers, dict):
-                options["headers"] = js.Headers.new(headers.items())
-            else:
-                raise TypeError("Received unexpected type for headers argument")
+            options["headers"] = _to_js_headers(headers)
 
         return options
 
@@ -457,3 +466,137 @@ def name(self) -> str:
     @property
     def last_modified(self) -> int:
         return self._js_blob.last_modified
+
+
+class Request:
+    def __init__(self, input: "Request | str", **other_options: Unpack[FetchKwargs]):
+        if "method" in other_options and isinstance(
+            other_options["method"], HTTPMethod
+        ):
+            other_options["method"] = other_options["method"].value
+
+        if "headers" in other_options:
+            other_options["headers"] = _to_js_headers(other_options["headers"])
+        self._js_request = js.Request.new(
+            input._js_request if isinstance(input, Request) else input, **other_options
+        )
+
+    @property
+    def js_object(self) -> "js.Request":
+        return self._js_request
+
+    # TODO: expose `body` as a native Python stream in the future, follow how we define `Response`
+    @property
+    def body(self) -> "js.ReadableStream":
+        return self.js_object.body
+
+    @property
+    def body_used(self) -> bool:
+        return self.js_object.bodyUsed
+
+    @property
+    def cache(self) -> str:
+        return self.js_object.cache
+
+    @property
+    def credentials(self) -> str:
+        return self.js_object.credentials
+
+    @property
+    def destination(self) -> str:
+        return self.js_object.destination
+
+    @property
+    def headers(self) -> http.client.HTTPMessage:
+        result = http.client.HTTPMessage()
+
+        for entry in self.js_object.headers:
+            result[entry[0]] = entry[1]
+
+        return result
+
+    @property
+    def integrity(self) -> str:
+        return self.js_object.integrity
+
+    @property
+    def is_history_navigation(self) -> bool:
+        return self.js_object.isHistoryNavigation
+
+    @property
+    def keepalive(self) -> bool:
+        return self.js_object.keepalive
+
+    @property
+    def method(self) -> HTTPMethod:
+        return HTTPMethod[self.js_object.method]
+
+    @property
+    def mode(self) -> str:
+        return self.js_object.mode
+
+    @property
+    def redirect(self) -> str:
+        return self.js_object.redirect
+
+    @property
+    def referrer(self) -> str:
+        return self.js_object.referrer
+
+    @property
+    def referrer_policy(self) -> str:
+        return self.js_object.referrerPolicy
+
+    @property
+    def url(self) -> str:
+        return self.js_object.url
+
+    def _raise_if_failed(self) -> None:
+        # TODO: https://github.com/pyodide/pyodide/blob/a53c17fd8/src/py/pyodide/http.py#L252
+        if self.body_used:
+            # TODO: Use BodyUsedError in newer Pyodide versions.
+            raise OSError("Body already used")
+
+    """
+    Instance methods defined below.
+
+    The naming of these methods should match Request's methods when possible.
+
+    TODO: AbortController support.
+    """
+
+    async def buffer(self) -> "js.ArrayBuffer":
+        # The naming of this method matches that of Response.
+        self._raise_if_failed()
+        return await self.js_object.arrayBuffer()
+
+    async def formData(self) -> "FormData":
+        self._raise_if_failed()
+        try:
+            return FormData(await self.js_object.formData())
+        except JsException as exc:
+            raise _to_python_exception(exc) from exc
+
+    async def blob(self) -> Blob:
+        self._raise_if_failed()
+        return _js_value_to_py(await self.js_object.blob())
+
+    async def bytes(self) -> bytes:
+        self._raise_if_failed()
+        return (await self.buffer()).to_bytes()
+
+    def clone(self) -> "Request":
+        if self.body_used:
+            # TODO: Use BodyUsedError in newer Pyodide versions.
+            raise OSError("Body already used")
+        return Request(
+            self.js_object.clone(),
+        )
+
+    async def json(self, **kwargs: Any) -> Any:
+        self._raise_if_failed()
+        return json.loads(await self.text(), **kwargs)
+
+    async def text(self) -> str:
+        self._raise_if_failed()
+        return await self.js_object.text()

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

@@ -2,7 +2,7 @@
 from http import HTTPMethod, HTTPStatus
 
 import js
-from workers import Blob, File, FormData, Response, fetch
+from workers import Blob, File, FormData, Request, Response, fetch
 
 import pyodide.http
 from pyodide.ffi import to_js
@@ -324,6 +324,33 @@ async def can_use_cf_fetch_opts(env):
     assert text == "success"
 
 
+async def request_unit_tests(env):
+    req = Request("https://test.com", method=HTTPMethod.POST)
+    assert req.method == HTTPMethod.POST
+
+    # Verify that we can pass JS headers to Request
+    js_headers = js.Headers.new()
+    js_headers.set("foo", "bar")
+    req_with_headers = Request("http://example.com", headers=js_headers)
+    assert req_with_headers.headers["foo"] == "bar"
+
+    # Verify that we can pass a dictionary as headers to Request
+    req_with_headers = Request("http://example.com", headers={"aaaa": "test"})
+    assert req_with_headers.headers["aaaa"] == "test"
+
+    # Verify that BodyUserError is thrown correctly.
+    req_used_twice = Request(
+        "http://example.com", body='{"field": 42}', method=HTTPMethod.POST
+    )
+    data = await req_used_twice.json()
+    assert data["field"] == 42
+    try:
+        req_used_twice.clone()
+        raise ValueError("Expected to throw")  # noqa: TRY301
+    except Exception as exc:
+        assert exc.__class__.__name__ == "OSError"  # TODO: BodyUsedError when available
+
+
 async def test(ctrl, env):
     await can_return_custom_fetch_response(env)
     await can_modify_response(env)
@@ -340,3 +367,4 @@ async def test(ctrl, env):
     await can_request_form_data_blob(env)
     await replace_body_unit_tests(env)
     await can_use_cf_fetch_opts(env)
+    await request_unit_tests(env)