v3.0.0-beta.3

This beta adds Kubernetes-style health probes, configurable access logs, custom headers for early responses, connection and request header limits, alongside memory cache, compression and content negotiation fixes. It also includes security fixes. The related advisories will be published separately soon.

Security

• Request handling hardening. Hardened request handling in Basic auth, the memory cache, static file serving and markdown negotiation. Details will follow with the related advisories.

Added

• Configurable access log format. Added --access-log-format to log one line per request from %{token} placeholders such as %{remote_addr}, %{status}, %{bytes} and %{duration}, with environment variable and TOML support. An invalid format fails at startup. #785 by @frenzzy and @chrissnell
• Access log line on body completion. The access log line is now written once the response body finishes, so %{bytes} counts the bytes sent, including on-the-fly compression, and %{duration} covers the whole transfer. Aborted downloads log the bytes sent so far. (#795 by @joseluisq)
• Custom headers for early responses. Added an optional scope to [[advanced.headers]] rules. scope = "all" also applies headers to responses returned before the static file handler, such as redirects, 405, health probes, metrics, Basic auth challenges and the maintenance page. The default scope = "files" keeps the current behavior. (#784 by @frenzzy)
• Connection limit. Added --max-connections to limit the connections served at the same time across all listeners. New connections wait for a free slot instead of being rejected. The default 0 keeps connections unlimited. Connections closed by the idle or request header timeout are now logged at debug. (#799 by @joseluisq)
• Request header size limit. Added --max-header-size to limit the size of request headers in bytes, 16384 by default, with environment variable and TOML support. For HTTP/1 it includes the request line, for HTTP/2 it applies to the header list. Larger requests get 431 Request Header Fields Too Large, and a value of 0 fails at startup. (by @joseluisq)
• Readiness check for the root directory. /readyz now returns 503 while the --root directory is missing or not a directory, for example on an unmounted volume, while /livez stays 200. (#793 by @joseluisq)

Changed

• Breaking: Kubernetes-style health probes. --health now serves /livez (liveness) and /readyz (readiness) instead of /health. /readyz returns 503 once a shutdown signal arrives so load balancers can drain connections during --grace-period. (#751 by @TheBigUserOne)
• Breaking: Dual-stack default host. The default --host :: now accepts IPv4 connections too on Windows, FreeBSD and Linux with net.ipv6.bindv6only=1, matching Linux and macOS. SWS fails to start if another service already listens on 0.0.0.0 with the same port, and logs a warning where the OS refuses dual-stack sockets. (#804 by @joseluisq)
• Breaking: HSTS only over TLS. Strict-Transport-Security is now sent only when --tls is enabled, as RFC 6797 requires, and its value no longer includes preload. Behind a TLS-terminating proxy, add the header at the proxy or with an [[advanced.headers]] rule. (# by @joseluisq)
• Breaking: Proxy headers require trusted proxies. --log-x-real-ip, --log-forwarded-for and the %{x_real_ip} and %{forwarded_for} access log tokens now use the headers only for requests from --trusted-proxies, which trusts no proxy by default. SWS warns at startup when these headers are set to be logged without trusted proxies or on a Unix socket. (# by @joseluisq)
• Metrics label values. Request metrics now label the host with the matching [advanced.virtual-hosts] name, without the port, or other when none matches, and the method as GET, HEAD, OPTIONS or other. (# by @joseluisq)
• One log line per request. Without --access-log-format, each request now logs a single response line with its status after the response, replacing the incoming request line. Health probes stay at the debug level. (#786 by @frenzzy and @TheBigUserOne)
• Health probes excluded from metrics. /livez and /readyz requests no longer count toward the sws_http_* request metrics. (#792 by @joseluisq)
• Dependency updates. Updated dependencies and made chrono optional again (directory-listing), reducing the --no-default-features binary by about 33 KB. (#795, #806 by @joseluisq)
• Docker base image updates. Updated Alpine images to 3.24.4. (#801 by @joseluisq)
• AI-assisted contributor guidance. Improved the project skill files for AI-assisted tools. (#800 by @joseluisq)

Fixed

• Memory cache with directory requests. With [advanced.memory-cache], directory listings, other --index-files entries and <dir>.html siblings no longer return 404. Cached directory lookups now follow the --index-files order. (#802 by @joseluisq)
• Content-Length for pre-compressed variants. Pre-compressed files served from disk now include their Content-Length, also for byte ranges and HEAD requests, and count toward sws_http_response_bytes_total. (#803 by @joseluisq)
• Fallback page for missing assets. --page-fallback no longer replaces 404 responses for paths with a known non-HTML extension, such as /favicon.ico, unless the Accept header asks for HTML. Client-side routes and browser navigations still get the fallback page. (#787 by @jadhavgaurav)
• Vary header with markdown negotiation. With --accept-markdown, HTML and markdown responses now include Vary: Accept, and existing Vary: Accept-Encoding values no longer prevent adding it. (#789 by @davlgd)
• Vary header on directory listings. With --accept-markdown, directory listings in any format now include Vary: Accept, so shared caches keep JSON listings and markdown responses apart. (#798 by @joseluisq)
• Access log filtering and CONNECT targets. The access log is built only when its log level is enabled, and %{uri} logs the authority of CONNECT requests instead of /. (#794 by @joseluisq)
• Compression headers on empty responses. On-the-fly compression no longer sets Content-Encoding on 1xx, 204, 304 or empty responses, and pre-compressed files set it only on successful responses. HTTP/2 clients no longer reject 304 responses with compression enabled. (# by @joseluisq)
• Explicit security headers setting. --security-headers=false is now respected together with --tls, and a config file without security-headers no longer turns the headers back on. (# by @joseluisq)
• IPv4 trusted proxies on dual-stack listeners. IPv4 --trusted-proxies entries now match clients connecting through the default :: host, which appear as IPv4-mapped IPv6 addresses. (# by @joseluisq)

For more details see the v3.0.0-beta.3 milestone and the full changelog v3.0.0-beta.2...v3.0.0-beta.3.