Bun.serve http2: normalize req.url and give bodyless requests a null body, as HTTP/1.1 does - #40692
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WalkthroughThe PR adds Latin-1 string conversion and updates HTTP request handling. HTTP/2 detects completed request bodies through uWebSockets. HTTP/2 and HTTP/3 normalize request URLs. Tests cover URL and body behavior across HTTP/1.1 and HTTP/2. ChangesHTTP Latin-1 strings
HTTP request semantics
Suggested reviewers: Merge Risk: ⚪ Minimal · up to The PR normalizes HTTP/2 URLs and returns null bodies for bodyless requests, with the supplied tests passing. No actionable merge-blocking risk remains after normal review. 🚥 Pre-merge checks | ✅ 4✅ Passed checks (4 passed)
Full details: Description checkExplanation The description explains the problem, fix, verification steps, test results, and relevant background. It does not use the template headings exactly, but it provides the required information in equivalent sections. Comment |
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Updated 11:44 PM PT - Aug 27th, 2026
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Beyond the inline finding, I checked that declaredContentLength defaults to -1 in Http2Response (packages/bun-uws/src/Http2Context.h:233), so == 0 in uws_h2_res_request_body_ended means an explicit content-length: 0 header, not "unset" — a request with no content-length and a body still arms onData. Also confirmed remoteClosed is assigned from END_STREAM (Http2Context.h:1714) before the router dispatches, so it's readable at the arming point, and the href_from_string fallback-on-empty matches Request::ensure_url (src/runtime/webcore/Request.rs:934-937) exactly.
Extended reasoning...
The inline nit on the h1Request test helper stands on its own. I traced the two things a reviewer would most likely question in the native change: whether declaredContentLength == 0 conflates "no header" with "explicit 0" (it does not — the field initializes to -1 and is only set from a parsed header), and whether remoteClosed is populated by the time request_body_ended() is called from prepare_js_request_context_for (it is — set at stream construction from the END_STREAM flag before the router runs). The URL normalization addition mirrors the existing HTTP/1 ensure_url path line-for-line, including the empty-string fallback, so no new failure mode is introduced there.
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Inline comments:
In `@test/js/bun/http/serve-http2.test.ts`:
- Around line 205-208: Replace the manual method loop in the /body-null test
with describe.each() over the five HTTP methods, placing the request and
assertions in the parameterized test body so each method is reported
independently while preserving the existing expected headers and body.
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📒 Files selected for processing (6)
src/jsc/bindings/HTTPLatin1String.hsrc/runtime/server/server_body.rssrc/uws_sys/h2.rssrc/uws_sys/libuwsockets_h2.cpptest/js/bun/http/serve-http2-fixture.tstest/js/bun/http/serve-http2.test.ts
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No new issues found on this push, but a heads-up: commit 7379514 (ci: retrigger) re-added src/jsc/bindings/HTTPLatin1String.h, which 562abec had just deleted in response to the earlier dead-code comment — the header is still not #included anywhere in the tree.
What was reviewed: the MUX URL build now mirrors Request::ensure_url (borrowed BunString::from_bytes into href_from_string, one allocation on the hot path); the new request_body_ended() gate reads remoteClosed || declaredContentLength == 0 and only alters the h2 arm; the h1Request test helper now rejects on socket close so it can't hang on a length-less response.
Extended reasoning...
Overview
This PR makes Bun.serve's HTTP/2 request handling match HTTP/1.1 in two ways: req.url is run through the same WHATWG parser (bun_url::href_from_string) so dot-segments and percent-encoding normalize identically, and req.body is null (not an empty stream) when the HEADERS frame carried END_STREAM or content-length: 0. The change spans src/runtime/server/server_body.rs (arming rule + URL build), src/uws_sys/h2.rs and libuwsockets_h2.cpp (new uws_h2_res_request_body_ended FFI), the h2 fixture, and serve-http2.test.ts. It also adds src/jsc/bindings/HTTPLatin1String.h.
Security risks
The URL-normalization change routes h2 :path through the same parser h1 already uses, so it removes a per-transport divergence rather than introducing one; the raw uWS routing layer is unchanged. The body-arming change only narrows when a Locked body is installed — it does not relax any validation. No new untrusted parsing surface is added; declaredContentLength and remoteClosed are fields the C++ layer already sets before dispatch.
Level of scrutiny
Medium-high: this is per-request hot-path code in the server with new FFI surface, and the PR description notes it interacts with early-response / RST_STREAM behavior. Earlier review rounds already covered the allocation shape, comment length, and test-helper robustness, and commits landed for each. The one thing warranting a human look on this specific push is that the ci: retrigger commit (7379514) is not an empty commit — it silently re-adds the 49-line HTTPLatin1String.h header that 562abec removed. git show --stat confirms +49 on that commit and grep confirms nothing includes it. The author had resolved the thread after deleting it, so they likely did not intend the file to return.
Other factors
The behavioral changes have direct test coverage (h2 vs. an h1 oracle on the same port, END_STREAM and content-length: 0 cases across several methods), and the PR evidence block shows the new tests fail on main's release build. HTTP/3's request_body_ended() returns false, preserving existing behavior there. Not approving because the reverted dead-code file should be removed again before merge, and the server dispatch path generally merits a maintainer glance.
…body, as HTTP/1.1 does Over HTTP/2, req.url was the raw :path behind scheme://host, while the HTTP/1.1 path runs the request target through the WHATWG parser. The same resource produced different strings per transport: /a/../s, /./s and /%2e/s stayed as sent over h2 and became /s over h1. The MUX path now runs the same bun_url::href_from_string pass Request::ensure_url runs. A request that promised no body (END_STREAM on the HEADERS frame, or content-length: 0) got an empty ReadableStream as req.body over h2, where HTTP/1.1 gives null for a request with no Content-Length and no Transfer-Encoding. A new uws_h2_res_request_body_ended query gates the onData arming, so req.body is null in the same cases on both transports. HTTP/3 is unchanged: the QUIC FIN is not known when the headers are dispatched.
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Rebased onto current main as one commit (80de99f). The branch had picked up a copy of
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Thanks — the latest push addresses all three earlier notes (h1Request now rejects on close, the double clone_utf8 on the MUX URL path is gone, and the unused HTTPLatin1String.h was dropped). I re-reviewed and didn't find any bugs; a human look is still worthwhile since this changes req.url normalization on the h2 dispatch hot path, which any path-keyed guard depends on.
What was reviewed
href_from_stringfallback ladder inon_request_mux: empty → raw fallback, borrowed-pointer-equal →clone_latin1(WHATWG serialization is ASCII, so Latin-1 clone is byte-identical), otherwise owns the parser output.request_body_endedgating: h1 and h3 impls hard-returnfalse, so only h2 behavior changes;remoteClosedis set from END_STREAM before dispatch anddeclaredContentLengthdefaults to −1, so the== 0check doesn't fire on absent CL.- New tests use HTTP/1.1 on the same port as an oracle rather than hardcoding expected normalization, and cover both END_STREAM-on-HEADERS and CL:0-without-END_STREAM.
Extended reasoning...
Overview
The PR aligns two h2-vs-h1 behavioral gaps in Bun.serve: (1) req.url for HTTP/2/3 requests now goes through the same bun_url::href_from_string WHATWG normalization that Request::ensure_url applies for HTTP/1.1, so dot-segment collapsing and query percent-encoding match across transports; (2) a new RespLike::request_body_ended() (backed by uws_h2_res_request_body_ended reading remoteClosed || declaredContentLength == 0) lets the h2 path skip arming onData when the HEADERS frame already carried END_STREAM or declared content-length: 0, so req.body is null instead of an empty stream — matching h1. HTTP/3 returns false (QUIC FIN isn't known at dispatch), so its behavior is unchanged. Tests add a /body-null fixture route and use a raw HTTP/1.1 socket helper as an oracle for both properties across TLS and cleartext.
All three nits from earlier review rounds were addressed in the latest force-push: h1Request now wires socket.on('close', reject) with a diagnostic containing the partial response; the MUX URL build no longer allocates a throwaway clone_utf8 before reparsing (it passes a borrowed BunString::from_bytes and only clones on the fallback branches, with a ptr::eq fast path when the parser hands back the input unchanged); and the orphaned HTTPLatin1String.h header is no longer in the diff.
Security risks
URL normalization on the server request path is security-relevant: anything keyed on req.url (auth guards, caches, rate limiters) now sees the WHATWG-normalized form over h2 instead of the raw :path. This is a tightening toward the existing h1 behavior on the same port, not a new attack surface — the PR notes that uWS route matching itself is still on the raw path and unchanged. The clone_latin1 branch fires only when href_from_string returned the input pointer unchanged, meaning the URL was already in canonical WHATWG serialization (ASCII-only), so the Latin-1/UTF-8 distinction is moot there. The request_body_ended predicate reads two fields the C++ layer already sets before dispatch; the PR description states the C++ layer already rejects END_STREAM with content-length > 0, so the declaredContentLength == 0 check can't race a later non-empty DATA frame. I didn't find a bypass, but the exact interaction between href_from_string's borrowed-return contract and non-ASCII :authority values (IDN hosts) is the kind of thing a maintainer familiar with bun_url internals should confirm.
Level of scrutiny
Moderate-to-high. The production change is small (~30 lines net) and mirrors an existing h1 code path, but it sits on the per-request dispatch hot path for Bun.serve with http2: true and changes what user handlers observe in req.url and req.body. The oracle-style tests (comparing h2 against h1 on the same port rather than asserting hardcoded strings) are a good design and cover the stated matrix, and the PR reports both ASAN-debug and release runs green across the h2/h3/protocols suites.
Other factors
No outstanding human CHANGES_REQUESTED reviews. The one non-author-resolved thread (coderabbitai at serve-http2.test.ts:208) was resolved independently. Bug-hunt exit was dry_streak with zero findings this run. Given the security relevance of request-URL normalization and the new borrowed-vs-owned branching in the hot path, deferring for a maintainer sign-off rather than auto-approving.
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On the question of non-ASCII |
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CI on 80de99f (build 107401): 180 of 181 jobs pass. The one red lane is |
2 participants
Problem
http2: true,req.urlisscheme://hostplus the raw:path. The HTTP/1.1 path on the same port runs the request target through the WHATWG parser. So/a/../s,/./sand/%2e/sreach the handler as sent over h2 and as/sover h1. Anything keyed onreq.url(a guard, a logger, a cache) sees a different string per transport for the same resource. The cause is the eager URL build for MUX requests insrc/runtime/server/server_body.rs(prepare_js_request_context_for), which skipped thebun_url::href_from_stringpass thatRequest::ensure_urlapplies for h1.ReadableStreamasreq.body. HTTP/1.1 givesnullfor a request with no Content-Length and no Transfer-Encoding, includingcontent-length: 0. The arming rule wasreq_len > 0 || is_te || IS_MUX: every body-method request over h2 or h3 got a pending body.Fix
href_from_stringnormalization asensure_url, with the same fallback to the raw string when the parser rejects the input.uws_h2_res_request_body_ended(src/uws_sys/libuwsockets_h2.cpp): true when the stream is already half-closed by the peer or declaredcontent-length: 0.RespLike::request_body_endedexposes it, and the arming rule becomesreq_len > 0 || is_te || (IS_MUX && !request_body_ended). HTTP/3 answersfalse(the QUIC FIN is only seen by a later read), so its behavior is unchanged.content-length: 0with a later empty DATA frame only completes the stream. The C++ layer already rejects END_STREAM withcontent-length > 0.test/js/bun/http/serve-http2.test.ts, two new tests over TLS and cleartext (4 cases, all fail on main). Each compares h2 against an HTTP/1.1 request on the same port. Alsoserve-http2-protocol,serve-http2-lifecycle,serve-http3,serve-protocols(367 pass).Background
Request.urlfor HTTP/1 is computed lazily from the uWS request inRequest::ensure_url(src/runtime/webcore/Request.rs). HTTP/2 and HTTP/3 requests populateurlandheaderseagerly at dispatch because the uWS request handle does not outlive the callback.req.bodystarts asBodyValue::Null. When bytes may arrive, the server installs aLockedpending value and arms the transport's onData callback. The JSRequest.bodygetter reportsnullonly forNull.Http2Response::remoteClosedis set from the END_STREAM flag before the router runs, so the information is available at the point the body is armed.Notes
routes["/s"]still does not match/a/../son either transport. That is unchanged here and identical across transports.content-length: 0and no END_STREAM, the handler may answer before the empty DATA frame arrives. The stream then ends with RST_STREAM NO_ERROR after the response, the existing early-response path, and the late DATA frame is ignored./body-nullroute that returnsString(req.body === null).[review] gate passed · iteration 3 · 5 files touched
fails on main (without fix)
passes on PR (with fix)
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gate history · 5 passed · 0 rejected · iteration 3
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