FA-7581 / WebSocket and browser transport policies / Open access

Websocket upgrade requires both upgrade and connection tokens · case 01

Websocket upgrade requires both upgrade and connection tokens.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The faulty implementation uses `upgrade.lower() == "websocket"` for the websocket-upgrade-requires-both-upgrade-and-connection-tokens decision.

VERIFIED REPAIR

Apply the explicit websocket-upgrade-requires-both-upgrade-and-connection-tokens contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `"upgrade" in connection` and still violates a separate fixture.

Case contract

Bounded offline decision model: websocket upgrade requires both upgrade and connection tokens. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.

Why this case matters

This deterministic websocket and browser transport policies model isolates the websocket-upgrade-requires-both-upgrade-and-connection-tokens policy at a network component boundary.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(upgrade, connection):
    return upgrade.lower() == "websocket"
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('websocket', []), False)", "check('fixture 2', solve('other', ['upgrade']), False)", "check('fixture 3', solve('WebSocket', ['Upgrade']), True)", "check('fixture 4', solve('websocket', ['keep-alive', 'upgrade']), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`False`	`False`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`False`	Failed

SHA-256 / 93acf246b104fe3a043d551e69b69681285338a9202ca0aeddb942d609b3f69d

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(upgrade, connection):
    return "upgrade" in connection
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('websocket', []), False)", "check('fixture 2', solve('other', ['upgrade']), False)", "check('fixture 3', solve('WebSocket', ['Upgrade']), True)", "check('fixture 4', solve('websocket', ['keep-alive', 'upgrade']), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`True`	`False`	Failed
fixture 3	`False`	`True`	Failed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / e1597b661844860a6eb7c9d12b73eb325955c84aba044f2dec461770333cf1f7

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(upgrade, connection):
    return upgrade.lower() == "websocket" and "upgrade" in {x.lower() for x in connection}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('websocket', []), False)", "check('fixture 2', solve('other', ['upgrade']), False)", "check('fixture 3', solve('WebSocket', ['Upgrade']), True)", "check('fixture 4', solve('websocket', ['keep-alive', 'upgrade']), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`False`	`False`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / ae354d56a91850496c17791bf4e74f7d79210a0a81eb82650ffc8187077a3dd0

Verification & scope

Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:13.420399+00:00.

Case digest / 17fbcc932d451951c498633349e75db63bc3ae17cda17dd7ef00525ec5df477e