Example_httpServerConnContext.go

package main

import (
	"context"
	"fmt"
	"net"
	"net/http"
	"net/http/httptest"
)

func Example_httpServerConnContext() {
	srv := http.Server{
		Addr: "localhost:9090",
		ConnContext: func(ctx context.Context, c net.Conn) context.Context {
			return context.WithValue(ctx, "local-addr", c.LocalAddr())
		},
		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if addr, ok := r.Context().Value("local-addr").(net.Addr); ok {
				fmt.Println(addr)
			}
		}),
	}
	defer srv.Close()
	go func() {
		_ = srv.ListenAndServe()
	}()

	req := httptest.NewRequest(http.MethodGet, srv.Addr, nil)
	res := httptest.NewRecorder()
	srv.Handler.ServeHTTP(res, req)
	// Output:
	// localhost:9090
}