webserver-example.go

// Small example how to do a web server in Go with stdlib.
// (c) 2017 by Sascha L. Teichmann
// The is Free Software covered by the terms of the MIT License.
// See https://opensource.org/licenses/MIT for details.

package main

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

type controller struct {
	name     string
	allNames []string
}

func (c *controller) handler(rw http.ResponseWriter, req *http.Request) {
	ctx := req.Context()
	name := ctx.Value("user").(string)
	fmt.Printf("user: %s\n", name)

	fmt.Fprintf(rw, "Hello %s %s\n", c.name, name)
}

func (c *controller) handler2(rw http.ResponseWriter, req *http.Request) {
	fmt.Fprintf(rw, "Helloooooo %s\n", c.name)
	for _, n := range c.allNames {
		fmt.Fprintf(rw, "Helloooooo %s\n", n)
	}
}

func middleware(fn http.Handler) http.Handler {
	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		fmt.Println("Before")
		ctx := req.Context()
		// Do something more fancy here.
		ctx = context.WithValue(ctx, "user", "from_middleware")
		req = req.WithContext(ctx)
		fn.ServeHTTP(rw, req)
	})
}

func main() {

	c := controller{name: "Peter", allNames: []string{"Jürgen", "Otto", "Claudia"}}

	mux := http.NewServeMux()

	mux.Handle("/index", middleware(http.HandlerFunc(c.handler)))
	mux.Handle("/hello", http.HandlerFunc(c.handler2))

	log.Fatalf("error: %v\n", http.ListenAndServe("localhost:8080", mux))
}