Seed from go-template-repo, renamed to simplexcalc

The template's files at a77fd30, without its history or LICENSE, after
script/rename simplexcalc.

Model: opus-5-5

internal/server/http.go

@@ -0,0 +1,55 @@
+package server
+
+import (
+	"log/slog"
+	"net/http"
+	"time"
+)
+
+// HTTP server hardening limits. These are the connection-level bounds;
+// the per-request deadline is middleware.Timeout, driven by
+// REQUEST_TIMEOUT.
+const (
+	// readHeaderTimeout is the slowloris bound: request headers must
+	// arrive within it, and it starts on connection accept.
+	readHeaderTimeout = 5 * time.Second
+
+	// readTimeout covers headers plus body. Bodies are capped by
+	// MAX_REQUEST_BODY, which transfers well inside this even on a
+	// slow mobile link.
+	readTimeout = 30 * time.Second
+
+	// writeTimeout must exceed the per-request timeout: it starts when
+	// the headers are read, so it spans handler execution, and a
+	// smaller value would cut the connection instead of letting the
+	// request context deadline end the request with a status. The
+	// margin is added to whatever REQUEST_TIMEOUT is configured to.
+	writeTimeoutMargin = 15 * time.Second
+
+	// idleTimeout bounds how long an idle keep-alive connection is
+	// held; browsers reconnect transparently.
+	idleTimeout = 120 * time.Second
+
+	maxHeaderBytes = 1 << 20
+)
+
+// newHTTPServer builds the http.Server.
+//
+// ErrorLog is set on purpose: net/http internals (TLS handshake
+// errors, request parse errors, panics net/http itself recovers) write
+// through it, and unset they would emit plain text on stderr via the
+// default log package — a few lines of unstructured output in the
+// middle of a JSON log stream, which is exactly the kind of thing a log
+// pipeline drops on the floor.
+func (s *Server) newHTTPServer(listenAddr string) *http.Server {
+	return &http.Server{
+		Addr:              listenAddr,
+		ReadHeaderTimeout: readHeaderTimeout,
+		ReadTimeout:       readTimeout,
+		WriteTimeout:      s.params.Config.RequestTimeout + writeTimeoutMargin,
+		IdleTimeout:       idleTimeout,
+		MaxHeaderBytes:    maxHeaderBytes,
+		Handler:           s,
+		ErrorLog:          slog.NewLogLogger(s.log.Handler(), slog.LevelError),
+	}
+}