[chaliy]

What changed

urllib.request and http.client in the CPython builtin can now make HTTP and HTTPS requests. Each request goes to the host through a new wasm import, bashkit.http_request. The host runs it through the same HttpClient pipeline as curl: allowlist, SSRF precheck, credential injection hooks, signing, the embedder's HttpTransport, and the response cap. TLS runs on the host, and the guest still has no sockets.

• Guest side: _bashkit.http() in C, plus an http.client adapter that replaces only the socket. http.client's own request and response code still runs, including keep-alive, HEAD and chunked uploads. HTTPSConnection is defined so urllib registers https.
• Host side (builtins/cpython/http.rs): validates the request record before dispatch (method set, URL and header caps, token names, no CR/LF/NUL) and drops host-owned headers such as Host and the framing headers.
• New CPythonLimits::max_http_requests (default 100 per call). Each request's timeout is capped by the call deadline.
• Context::http_client is now Option<&Arc<HttpClient>> so the per-call guest state can own a handle.
• New fuzz target, cpython_http_fuzz. The threat model gains TM-PY-CPY-012, L-CPY-002 is narrowed, and the docs have a new HTTP section.

This is step 1 of the plan in the scope doc. requests and httpx2 follow in a separate packages crate, behind an opt-in cpython-http feature.

Why

Python scripts could not reach the network at all, so urlopen failed. Routing requests at the HTTP level keeps every policy the embedder configured for curl (allowlist, credentials, audit), with no TLS or socket code in the guest.

Before

$ python3 -c 'import urllib.request; urllib.request.urlopen("https://93.184.216.34/json")'
urllib.error.URLError: <urlopen error unknown url type: https>

After

With .network(allowlist):

python3 -c 'import json, urllib.request
with urllib.request.urlopen("https://93.184.216.34/json") as r:
    print(r.status, json.load(r))'
200 {'ok': True}

• A denied host or private IP fails with URLError and "access denied", and the request never reaches the transport.
• Redirects to an off-allowlist host are denied at that hop.
• With no network configured, requests fail with "network access not configured".

12 new tests (cpython_http_tests) cover:

• GET/POST, 404, keep-alive, HEAD and chunked upload
• redirect re-checks
• private IPs
• Host retargeting
• CRLF injection
• placeholder credentials injected only on the host
• the request cap, request timeout and call deadline

All 12 pass on both the Pulley and native builds.

Risk

Medium. This opens a new egress path from the guest. Mitigations: everything goes through HttpClient, the host validates every request before dispatch, a request cap bounds floods, and errors are Display-only and capped at 512 bytes. The snapshot grows by about 3 KB gzipped and the stdlib zip by about 6 KB. Internal API change: Context::http_client is now an &Arc.

Checklist

• cargo test -p bashkit --features cpython,http_client --lib --test integration -- cpython (112 + 12 + unit tests)
• cargo test -p bashkit --features cpython-native,http_client --test integration -- cpython_http
• cargo clippy -p bashkit --features cpython,http_client --all-targets -- -D warnings, and the same with cpython only
• cargo check --workspace --all-targets --features http_client, and the fuzz target checked with cargo check
• cargo fmt --check, just check-okf, just check-doc-links
• Knowledge: cpython-wasm (HTTP bridge), threat model, limitations, log

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	bashkit	2e5ad2a	Commit Preview URL Branch Preview URL	Oct 07 2026, 03:28 PM