simple file server with simple basic auth

main.go

//
// main.go
package main

import (
	"fmt"
	"net/http"
	"os"

	"github.com/gorilla/securecookie"
	log "github.com/sirupsen/logrus"
)

var cookieHandler = securecookie.New(
	securecookie.GenerateRandomKey(64),
	securecookie.GenerateRandomKey(32))

func main() {

	http.HandleFunc("/", indexPageHandler)

	http.HandleFunc("/login", loginHandler)
	http.HandleFunc("/logout", logoutHandler)

	fs := http.FileServer(http.Dir("."))
	http.Handle("/logs/", someMiddleware(http.StripPrefix("/logs/", fs)))
	port := 9999
	log.Infof("Runing on %d", port)
	address := fmt.Sprintf(":%d", port)
	err := http.ListenAndServeTLS(address, "server.crt", "server.key", nil)
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}

func someMiddleware(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		userName := getUserName(r)
		log.Debugf("Username %s logged in", userName)
		// get host name
		hostName, err := os.Hostname()
		if err != nil {
			hostName = "Fridge"
		}
		if userName != "" {
			log.Info("Serving /logs")
			fmt.Fprintf(w, internalPage, hostName, userName)
			h.ServeHTTP(w, r)
		} else {
			log.Info("Redirect")
			log.Infof("%+v", r)
			http.Redirect(w, r, "/", 302)
		}
	})
}

const indexPage = `
	<h1>Login</h1>
	<form method="post" action="/login">
	<label for="name">User name</label>
	<input type="text" id="name" name="name">
	<label for="password">Password</label>
	<input type="password" id="password" name="password">
	<button type="submit">Login</button>
	</form>
	`

func indexPageHandler(response http.ResponseWriter, request *http.Request) {
	fmt.Fprintf(response, indexPage)
}

const internalPage = `
	<h1>%s log files</h1>
	<hr>
	<small>User: %s</small>
	<form method="post" action="/logout">
	<button type="submit">Logout</button>
	</form>
	`

func loginHandler(w http.ResponseWriter, r *http.Request) {
	name := r.FormValue("name")
	pass := r.FormValue("password")
	redirectTarget := "/logs"
	if name == "oxford" && pass == "H1_d9ghjL" {
		// dumb simple hardcoded credential check!
		// prob need to store in a db
		setSession(name, w)
	} else {
		http.Error(w, "authorization failed", http.StatusUnauthorized)
		return
	}
	http.Redirect(w, r, redirectTarget, 302)
}

func logoutHandler(response http.ResponseWriter, request *http.Request) {
	clearSession(response)
	http.Redirect(response, request, "/", 302)
}

func setSession(userName string, response http.ResponseWriter) {
	value := map[string]string{
		"name": userName,
	}
	if encoded, err := cookieHandler.Encode("session", value); err == nil {
		cookie := &http.Cookie{
			Name:  "session",
			Value: encoded,
			Path:  "/",
			// die after one hour!
			MaxAge: 3600,
		}
		http.SetCookie(response, cookie)
	}
}

func getUserName(request *http.Request) (userName string) {
	if cookie, err := request.Cookie("session"); err == nil {
		cookieValue := make(map[string]string)
		if err = cookieHandler.Decode("session", cookie.Value, &cookieValue); err == nil {
			userName = cookieValue["name"]
		}
	}
	return userName
}

func clearSession(response http.ResponseWriter) {
	cookie := &http.Cookie{
		Name:   "session",
		Value:  "",
		Path:   "/",
		MaxAge: -1,
	}
	http.SetCookie(response, cookie)
}