Web: CONTENT_LENGTH — incoming $_SERVER and outgoing CGI Content-Length

[PurHur]

Problem

CGI responses and phpc serve should expose accurate Content-Length when the body size is known. Today DevServer may rely on connection close for small responses; some clients and proxies behave better with explicit length. $_SERVER['CONTENT_LENGTH'] for incoming requests is separate but often paired in frameworks.

Outgoing: scripts cannot set Content-Length via header() reliably in all modes (#51). Incoming: POST bodies may not set CONTENT_LENGTH env when chunked (#287).

Goal

1. Incoming: populate $_SERVER['CONTENT_LENGTH'] from HTTP Content-Length header (or computed body size after read) in DevServer and AOT refresh.
2. Outgoing (v1): when serve driver buffers the full response body, emit Content-Length: N in CGI header block unless Transfer-Encoding: chunked is required later.

Scope

• lib/Web/DevServer.php — set CONTENT_LENGTH env + $_SERVER when body read
• lib/AOT/runtime/superglobals_refresh.c — copy CONTENT_LENGTH from env
• Optional: serve driver computes output length before sending headers
• PHPT + ServeTest for POST with Content-Length: 12
• Document interaction with Web: DevServer POST bodies without Content-Length (chunked transfer-encoding) #287 chunked requests (no CONTENT_LENGTH)

Acceptance criteria

docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  ./script/ci-local.sh --filter content_length

Fixture echoes $_SERVER['CONTENT_LENGTH'] matching posted body size.

Verification (local / Docker only)

No GitHub Actions required.

Dependencies

• Testing: ServeTest POST form submission via phpc serve #248 / Testing: ServeAotTest POST form submission via phpc serve --aot #285 POST serve tests
• Web: DevServer POST bodies without Content-Length (chunked transfer-encoding) #287 chunked POST (CONTENT_LENGTH absent)
• Web: CGI/1.1 request driver (stdin/stdout, env, Status line) #50 CGI driver

Links

• lib/Web/Superglobals.php, lib/Web/DevServer.php
• 🗺️ ROADMAP: Compile a small PHP web application (living document) #78 ROADMAP Phase 1 (web runtime)