ENH Add raise_for_status to FetchResponse (#4053)

docs/project/changelog.md

@@ -48,9 +48,6 @@ myst:
   present also on `Task`s as well as `Future`s.
   {pr}`3748`
 
-- {{ Enhancement }} Added `headers` property to `pyodide.http.FetchResponse`.
-  {pr}`2078`
-
 - {{ Enhancement }} Added methods to a `PyProxy` of a `list` to make these work
   as drop-in replacements for JavaScript Arrays.
   {pr}`3853`
@@ -70,9 +67,13 @@ myst:
   `pyodide-lock.json`
   {pr}`3824`
 
-- {{ Breaking }} Changed the FetchResponse body getter methods to no longer
-  throw an OSError exception for 400 and above response status codes
-  {pr}`3986`
+- {{ Enhancement }} Added `headers` property to `pyodide.http.FetchResponse`.
+  {pr}`2078`
+
+- {{ Breaking }} Changed the `FetchResponse` body getter methods to no longer
+  throw an `OSError` exception for 400 and above response status codes. Added
+  `FetchResponse.raise_for_status` to raise an `OSError` for error status codes.
+  {pr}`3986` {pr}`4053`
 
 ### Packages
 

src/py/pyodide/http.py

@@ -141,6 +141,22 @@ def _raise_if_failed(self) -> None:
         if self.js_response.bodyUsed:
             raise OSError("Response body is already used")
 
+    def raise_for_status(self) -> None:
+        """Raise an :py:exc:`OSError` if the status of the response is an error (4xx or 5xx)"""
+        http_error_msg = ""
+        if 400 <= self.status < 500:
+            http_error_msg = (
+                f"{self.status} Client Error: {self.status_text} for url: {self.url}"
+            )
+
+        if 500 <= self.status < 600:
+            http_error_msg = (
+                f"{self.status} Server Error: {self.status_text} for url: {self.url}"
+            )
+
+        if http_error_msg:
+            raise OSError(http_error_msg)
+
     def clone(self) -> "FetchResponse":
         """Return an identical copy of the :py:class:`FetchResponse`.
 

src/tests/test_pyodide_http.py

@@ -54,6 +54,50 @@ async def test_pyfetch_return_400_status_body(selenium, url_notfound):
     assert body == "404 Not Found"
 
 
+@pytest.fixture
+def raise_for_status_fixture(httpserver):
+    httpserver.expect_request("/200").respond_with_data(
+        b"Some data here!",
+        content_type="text/text",
+        headers={"Access-Control-Allow-Origin": "*"},
+        status=200,
+    )
+    httpserver.expect_request("/404").respond_with_data(
+        b"Not Found",
+        content_type="text/text",
+        headers={"Access-Control-Allow-Origin": "*"},
+        status=404,
+    )
+    httpserver.expect_request("/504").respond_with_data(
+        b"Gateway timeout",
+        content_type="text/text",
+        headers={"Access-Control-Allow-Origin": "*"},
+        status=504,
+    )
+    return {p: httpserver.url_for(p) for p in ["/200", "/404", "/504"]}
+
+
+@run_in_pyodide
+async def test_pyfetch_raise_for_status(selenium, raise_for_status_fixture):
+    import pytest
+
+    from pyodide.http import pyfetch
+
+    resp = await pyfetch(raise_for_status_fixture["/200"])
+    resp.raise_for_status()
+    assert await resp.string() == "Some data here!"
+
+    resp = await pyfetch(raise_for_status_fixture["/404"])
+    with pytest.raises(OSError, match="404 Client Error: NOT FOUND for url: .*/404"):
+        resp.raise_for_status()
+
+    resp = await pyfetch(raise_for_status_fixture["/504"])
+    with pytest.raises(
+        OSError, match="504 Server Error: GATEWAY TIMEOUT for url: .*/504"
+    ):
+        resp.raise_for_status()
+
+
 @run_in_pyodide
 async def test_pyfetch_unpack_archive(selenium):
     import pathlib