Standard Library: `net/http` – Building a Simple Web Server

net/http Basics

This lesson explains the main concept clearly with beginner-friendly examples and background so you can learn why the code works.

Go’s standard library ships a fully‑featured HTTP server.

package main

import (
    "fmt"
    "log"
    "net/http"
)

func helloHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "Hello, Go HTTP!")
}

func main() {
    http.HandleFunc("/hello", helloHandler)
    log.Println("Server listening on :8080")
    log.Fatal(http.ListenAndServe(":8080", nil)
}

Routing with http.ServeMux

mux := http.NewServeMux()
mux.HandleFunc("/", home)
mux.HandleFunc("/api", apiHandler)
http.ListenAndServe(":8080", mux)

Middleware pattern (logging)

func logging(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        log.Printf("%s %s", r.Method, r.URL.Path)
        next.ServeHTTP(w, r)
    })
}

http.ListenAndServe(":8080", logging(mux))