add mw to resolve ip address

README.md

@@ -84,15 +84,23 @@ Middleware values are plain `func(http.Handler) http.Handler`, so any stdlib-com
 
 The `pkg/middleware` package ships:
 
-- **`Logger`** — emits a structured `http.request` record (method, path, status, duration) via [splinter](https://git.juancwu.dev/juancwu/splinter)'s default logger.
+- **`Logger`** — emits a structured `http.request` record (method, path, status, duration, client) via [splinter](https://git.juancwu.dev/juancwu/splinter)'s default logger. The `client` field is `r.RemoteAddr`, so pairing with `RealIP` makes it the resolved client IP.
 - **`LoggerWith(*splinter.Logger)`** — same, but routes records through the supplied splinter logger instead of the default.
 - **`Recoverer`** — catches panics inside handlers, wraps the value with [errx](https://git.juancwu.dev/juancwu/errx) under op `middleware.Recoverer`, logs it with the stack, and writes a 500 response.
+- **`RealIP`** — replaces `r.RemoteAddr` with the originating client IP from `CF-Connecting-IP`, `True-Client-IP`, `X-Real-IP`, or `X-Forwarded-For` (in that order). Always trusts these headers — only register it when the service sits behind a trusted proxy.
+- **`RealIPWith(trusted ...netip.Prefix)`** — same, but only honors the headers when the immediate peer's IP falls within one of the trusted prefixes. Requests from outside the allowlist pass through untouched.
 
 ```go
 custom := splinter.New(splinter.WithStream(...))
 mux.Use(middleware.Recoverer, middleware.LoggerWith(custom))
 ```
 
+When using `RealIP` together with `Logger`, register `RealIP` first so the logged `client` field is the resolved client IP rather than the proxy's peer address:
+
+```go
+mux.Use(middleware.RealIP, middleware.Logger)
+```
+
 ## Path parameters
 
 lightmux is a thin wrapper, so path parameters work the stdlib way: