golang OAuth2服务端及客户端编写示例

服务端实现

1. 从OAuth2库导入相关的包：

import (
    "golang.org/x/oauth2"
    "golang.org/x/oauth2/google"
)

2. 定义OAuth2认证的配置：

var (
    googleOauthConfig *oauth2.Config
    oauthStateString = "random_string"
)

func init() {
    googleOauthConfig = &oauth2.Config{
        RedirectURL: "http://localhost:8080/oauth2callback",
        ClientID: "",
        ClientSecret: "",
        Scopes: []string{"https://www.googleapis.com/auth/userinfo.profile"},
        Endpoint: google.Endpoint,
    }
}

3. 编写HTTP处理程序：

func HandleHome(w http.ResponseWriter, r *http.Request) {
    var html = `
        
            
                Google Login
            
        
    `
    fmt.Fprintf(w, html, GetLoginURL(oauthStateString))
}

func GetLoginURL(state string) string {
    return googleOauthConfig.AuthCodeURL(state)
}

func HandleOAuth2Callback(w http.ResponseWriter, r *http.Request) {
    state := r.FormValue("state")
    if state != oauthStateString {
        fmt.Printf("invalid OAuth state, expected '%s', got '%s'\n", oauthStateString, state)
        http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
        return
    }

    code := r.FormValue("code")
    token, err := googleOauthConfig.Exchange(oauth2.NoContext, code)
    if err != nil {
        fmt.Printf("oauth2: %s", err.Error())
        http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
        return
    }

    client := googleOauthConfig.Client(oauth2.NoContext, token)
    resp, err := client.Get("https://www.googleapis.com/oauth2/v2/userinfo")
    if err != nil {
        fmt.Printf("Get: %s", err.Error())
        http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
        return
    }

    defer resp.Body.Close()

    contents, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        fmt.Printf("ReadAll: %s", err.Error())
        http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
        return
    }

    fmt.Fprintf(w, "Content: %s\n", contents)
}

4. 启动服务端监听：

http.HandleFunc("/", HandleHome)
http.HandleFunc("/oauth2callback", HandleOAuth2Callback)
http.ListenAndServe(":8080", nil)

客户端实现

1. 创建OAuth2配置：

var (
    googleOauthConfig *oauth2.Config
)

func init() {
    googleOauthConfig = &oauth2.Config{
        ClientID: "",
        ClientSecret: "",
        RedirectURL: "http://localhost:9000/oauth2callback",
        Scopes: []string{
            "https://www.googleapis.com/auth/userinfo.email",
            "https://www.googleapis.com/auth/userinfo.profile",
        },
        Endpoint: google.Endpoint,
    }
}

2. 发起OAuth2授权请求：

func HandleGoogleLogin(w http.ResponseWriter, r *http.Request) {
    url := googleOauthConfig.AuthCodeURL("state")
    http.Redirect(w, r, url, http.StatusTemporaryRedirect)
}

3. 处理OAuth2回调：

func HandleGoogleCallback(w http.ResponseWriter, r *http.Request) {
    code := r.FormValue("code")
    token, err := googleOauthConfig.Exchange(oauth2.NoContext, code)
    if err != nil {
        fmt.Fprintln(w, err)
        return
    }
    client := googleOauthConfig.Client(oauth2.NoContext, token)
    resp, err := client.Get("https://www.googleapis.com/oauth2/v2/userinfo")
    if err != nil {
        fmt.Fprintln(w, err)
        return
    }
    defer resp.Body.Close()
    contents, err := ioutil.ReadAll(resp.Body)
    fmt.Fprintf(w, "Content: %s\n", contents)
}

启动客户端：

http.HandleFunc("/login/google", HandleGoogleLogin)
http.HandleFunc("/oauth2callback", HandleGoogleCallback)
log.Fatal(http.ListenAndServe(":9000", nil))