httpx environ["SERVER_PORT"] can't be "None" (Fix)

The Fix

Upgrade to version 0.17.0 or later.

Based on closed encode/httpx issue #1468 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Jump to Verify Open PR/Commit

@@ -74,6 +74,9 @@ def request(
         scheme, host, port, full_path = url
         path, _, query = full_path.partition(b"?")
+        if port is None:
+            port = {b"http": 80, b"https": 443}[scheme]
+

repro.py

=================================== FAILURES ===================================
____________ test_convert_asgi_to_wsgi[app1-a2wsgi-ASGIMiddleware] _____________

app = <a2wsgi.asgi.ASGIMiddleware object at 0x7fced147eb80>
name = 'a2wsgi-ASGIMiddleware'

    @pytest.mark.parametrize(
        "app, name",
        [(wsgi_echo, "pure-WSGI"), (ASGIMiddleware(asgi_echo), "a2wsgi-ASGIMiddleware")],
    )
    def test_convert_asgi_to_wsgi(app, name):
        with httpx.Client(app=app, base_url="http://testserver") as client:
            start_time = time.time_ns()
            for _ in range(100):
              client.post("/", data=b"hello world")

a2wsgi/benchmark.py:99:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
/usr/local/lib/python3.8/site-packages/httpx/_client.py:992: in post
    return self.request(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:733: in request
    return self.send(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:767: in send
    response = self._send_handling_auth(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:805: in _send_handling_auth
    response = self._send_handling_redirects(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:837: in _send_handling_redirects
    response = self._send_single_request(request, timeout)
/usr/local/lib/python3.8/site-packages/httpx/_client.py:861: in _send_single_request
    (status_code, headers, stream, ext) = transport.request(
/usr/local/lib/python3.8/site-packages/httpx/_transports/wsgi.py:113: in request
    result = _skip_leading_empty_chunks(result)
/usr/local/lib/python3.8/site-packages/httpx/_transports/wsgi.py:10: in _skip_leading_empty_chunks
    for chunk in body:
a2wsgi/a2wsgi/asgi.py:160: in __call__
    self.app(build_scope(environ), self.asgi_receive, self.asgi_send)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

environ = {'CONTENT_LENGTH': '11', 'HTTP_ACCEPT': '*/*', 'HTTP_ACCEPT_ENCODING': 'gzip, deflate', 'HTTP_CONNECTION': 'keep-alive', ...}

    def build_scope(environ: Environ) -> Scope:
        headers = [
            (
                each[5:].lower().replace("_", "-").encode("latin1"),
                environ[each].encode("latin1"),
            )
            for each in environ.keys()
            if each.startswith("HTTP_")
        ]
        if environ.get("CONTENT_TYPE"):
            headers.append((b"content-type", environ["CONTENT_TYPE"].encode("latin1")))
        if environ.get("CONTENT_LENGTH"):
            headers.append((b"content-length", environ["CONTENT_LENGTH"].encode("latin1")))

        if environ.get("REMOTE_ADDR") and environ.get("REMOTE_PORT"):
            client = (environ.get("REMOTE_ADDR"), int(environ.get("REMOTE_PORT")))
        else:
            client = None

        return {
            "type": "http",
            "asgi": {"version": "3.0", "spec_version": "3.0"},
            "http_version": environ.get("SERVER_PROTOCOL", "http/1.0").split("/")[1],
            "method": environ["REQUEST_METHOD"],
            "scheme": environ.get("wsgi.url_scheme", "http"),
            "path": environ["PATH_INFO"].encode("latin1").decode("utf8"),
            "query_string": environ["QUERY_STRING"].encode("ascii"),
            "root_path": environ.get("SCRIPT_NAME", "").encode("latin1").decode("utf8"),
            "client": client,
          "server": (environ["SERVER_NAME"], int(environ["SERVER_PORT"])),
            "headers": headers,
        }
E       ValueError: invalid literal for int() with base 10: 'None'

a2wsgi/a2wsgi/asgi.py:94: ValueErro
... (truncated) ...

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

fix.md

Option A — Upgrade to fixed release\nUpgrade to version 0.17.0 or later.\nWhen NOT to use: This fix is not applicable if the application does not use WSGITransport.\n\n

Why This Fix Works in Production

Trigger: environ["SERVER_PORT"] can't be "None"
Mechanism: The WSGITransport did not handle cases where SERVER_PORT is None
Why the fix works: Handle default ports in WSGITransport to ensure SERVER_PORT is correctly populated. (first fixed release: 0.17.0).

Production impact:

If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.

Why This Breaks in Prod

Shows up under Python 3.8 in real deployments (not just unit tests).
The WSGITransport did not handle cases where SERVER_PORT is None
Production symptom (often without a traceback): environ["SERVER_PORT"] can't be "None"

Proof / Evidence

GitHub issue: #1468
Fix PR: https://github.com/encode/httpx/pull/1469
First fixed release: 0.17.0
Reproduced locally: No (not executed)
Last verified: 2026-02-08
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.41

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“@abersheeran Good catch! Indeed, in WSGITransport the url is unpacked as scheme, host, port, full_path, and port is an Optional[int], obtained from here: https://github.com/encode/httpx/blob/86964054d60da7796c65e501ba021440b14cc36c/httpx/_models.py#L208-L214 S”

@florimondmanca · 2021-02-16 · source

Failure Signature (Search String)

environ["SERVER_PORT"] can't be "None"
=================================== FAILURES ===================================

Copy-friendly signature

signature.txt

Failure Signature
-----------------
environ["SERVER_PORT"] can't be "None"
=================================== FAILURES ===================================

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
environ["SERVER_PORT"] can't be "None"
=================================== FAILURES ===================================

Minimal Reproduction

repro.py

=================================== FAILURES ===================================
____________ test_convert_asgi_to_wsgi[app1-a2wsgi-ASGIMiddleware] _____________

app = <a2wsgi.asgi.ASGIMiddleware object at 0x7fced147eb80>
name = 'a2wsgi-ASGIMiddleware'

    @pytest.mark.parametrize(
        "app, name",
        [(wsgi_echo, "pure-WSGI"), (ASGIMiddleware(asgi_echo), "a2wsgi-ASGIMiddleware")],
    )
    def test_convert_asgi_to_wsgi(app, name):
        with httpx.Client(app=app, base_url="http://testserver") as client:
            start_time = time.time_ns()
            for _ in range(100):
              client.post("/", data=b"hello world")

a2wsgi/benchmark.py:99:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
/usr/local/lib/python3.8/site-packages/httpx/_client.py:992: in post
    return self.request(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:733: in request
    return self.send(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:767: in send
    response = self._send_handling_auth(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:805: in _send_handling_auth
    response = self._send_handling_redirects(
/usr/local/lib/python3.8/site-packages/httpx/_client.py:837: in _send_handling_redirects
    response = self._send_single_request(request, timeout)
/usr/local/lib/python3.8/site-packages/httpx/_client.py:861: in _send_single_request
    (status_code, headers, stream, ext) = transport.request(
/usr/local/lib/python3.8/site-packages/httpx/_transports/wsgi.py:113: in request
    result = _skip_leading_empty_chunks(result)
/usr/local/lib/python3.8/site-packages/httpx/_transports/wsgi.py:10: in _skip_leading_empty_chunks
    for chunk in body:
a2wsgi/a2wsgi/asgi.py:160: in __call__
    self.app(build_scope(environ), self.asgi_receive, self.asgi_send)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

environ = {'CONTENT_LENGTH': '11', 'HTTP_ACCEPT': '*/*', 'HTTP_ACCEPT_ENCODING': 'gzip, deflate', 'HTTP_CONNECTION': 'keep-alive', ...}

    def build_scope(environ: Environ) -> Scope:
        headers = [
            (
                each[5:].lower().replace("_", "-").encode("latin1"),
                environ[each].encode("latin1"),
            )
            for each in environ.keys()
            if each.startswith("HTTP_")
        ]
        if environ.get("CONTENT_TYPE"):
            headers.append((b"content-type", environ["CONTENT_TYPE"].encode("latin1")))
        if environ.get("CONTENT_LENGTH"):
            headers.append((b"content-length", environ["CONTENT_LENGTH"].encode("latin1")))

        if environ.get("REMOTE_ADDR") and environ.get("REMOTE_PORT"):
            client = (environ.get("REMOTE_ADDR"), int(environ.get("REMOTE_PORT")))
        else:
            client = None

        return {
            "type": "http",
            "asgi": {"version": "3.0", "spec_version": "3.0"},
            "http_version": environ.get("SERVER_PROTOCOL", "http/1.0").split("/")[1],
            "method": environ["REQUEST_METHOD"],
            "scheme": environ.get("wsgi.url_scheme", "http"),
            "path": environ["PATH_INFO"].encode("latin1").decode("utf8"),
            "query_string": environ["QUERY_STRING"].encode("ascii"),
            "root_path": environ.get("SCRIPT_NAME", "").encode("latin1").decode("utf8"),
            "client": client,
          "server": (environ["SERVER_NAME"], int(environ["SERVER_PORT"])),
            "headers": headers,
        }
E       ValueError: invalid literal for int() with base 10: 'None'

a2wsgi/a2wsgi/asgi.py:94: ValueErro
... (truncated) ...

Environment

Python: 3.8

What Broke

Requests to the server failed due to missing SERVER_PORT, causing timeouts.

Why It Broke

The WSGITransport did not handle cases where SERVER_PORT is None

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

Upgrade to version 0.17.0 or later.

When NOT to use: This fix is not applicable if the application does not use WSGITransport.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Fix reference: https://github.com/encode/httpx/pull/1469

First fixed release: 0.17.0

Last verified: 2026-02-08. Validate in your environment.

When NOT to Use This Fix

This fix is not applicable if the application does not use WSGITransport.

Verify Fix

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Add a CI check that diffs key outputs after upgrades (OpenAPI schema snapshots, JSON payload shapes, CLI output).
Upgrade behind a canary and run integration tests against the canary before 100% rollout.
Make timeouts explicit and test them (unit + integration) to avoid silent behavior changes.
Instrument retries (attempt count + reason) and alert on spikes to catch dependency slowdowns.

Version Compatibility Table

Version	Status
0.17.0	Fixed

Related Issues

No related fixes found.

Cluster: httpx:configuration-error All hubs All clusters

Related clusters: Data consistency Other Timeout

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.