golang(net/http)でBasic認証する

net/httpでBasic認証を使ったのでスニペットとしてメモ.

package main

import (
    "fmt"
    "net/http"
)

const (
    basicAuthUser     = "user"
    basicAuthPassword = "password"
)

func main() {
    http.HandleFunc("/need", needAuthHandler)
    http.HandleFunc("/unneed", unneedAuthHandler)

    http.ListenAndServe(":8080", nil)
}

// 認証が要るハンドラ
func needAuthHandler(w http.ResponseWriter, r *http.Request) {
    // Basic認証のヘッダ解析に失敗したらokにfalseが入るみたい
    user, pass, ok := r.BasicAuth()
    // 入力された内容のチェック
    if ok == false || user != basicAuthUser || pass != basicAuthPassword {
        w.Header().Set("WWW-Authenticate", `Basic realm="auth area"`)
        http.Error(w, "needs authenticate", http.StatusUnauthorized)
        return
    }
    fmt.Fprintln(w, "authed")
}

// 認証不要のハンドラ
func unneedAuthHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "Hello")
}

もう少し汎化して綺麗にするならこんな感じかしら.

package main

import (
    "fmt"
    "net/http"
)

const (
    // Basic認証のUserID
    basicAuthUser     = "user"
    // Basic認証のPassword
    basicAuthPassword = "password"
)

// 認証が必要なハンドラ用の型
type basicAuthHandler func(w http.ResponseWriter, r *http.Request, u string)

func main() {
    // ラッパーかます
    http.HandleFunc("/need", needBasicAuth(needAuthHandler))
    http.HandleFunc("/unneed", unneedBasicAuth(unneedAuthHandler))

    http.ListenAndServe(":8080", nil)
}

// 認証メソッド
// 必要ならDBとかにアクセス
func basicAuthenticate(user, pass string) bool {
    if user == basicAuthUser && pass == basicAuthPassword {
        return true
    }
    return false
}

// 認証が必要な場合のラッパ
func needBasicAuth(fn basicAuthHandler) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        user, pass, ok := r.BasicAuth()
        if ok == false || basicAuthenticate(user, pass) == false {
            w.Header().Set("WWW-Authenticate", `Basic realm="auth area"`)
            http.Error(w, "needs authenticate", http.StatusUnauthorized)
            return
        }
        fn(w, r, user)
    }
}

// 認証が不要な場合のラッパ
func unneedBasicAuth(fn basicAuthHandler) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        fn(w, r, "")
    }
}

// 認証が必要なハンドラ
func needAuthHandler(w http.ResponseWriter, r *http.Request, u string) {
    fmt.Fprintln(w, "authed")
}

// 認証が不要なハンドラ
func unneedAuthHandler(w http.ResponseWriter, r *http.Request, u string) {
    fmt.Fprintln(w, "Hello")
}