golang下一些跨域问题的处理

• GET跨域处理

gmux.HandleFunc("/version", func(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Access-Control-Allow-Origin", "*")             //允许访问所有域
    w.Header().Add("Access-Control-Allow-Headers", "X-Requested-With, Content-Type,Origin, Authorization, Accept, Client-Security-Token, Accept-Encoding, X-Auth-Token, content-type") //header的类型
    w.Header().Set("content-type", "application/json")             //返回数据格式是json
    w.Header().Add("Access-Control-Allow-Methods","GET, POST, PUT, PATCH, POST, DELETE, OPTIONS");

    fmt.Fprint(w, "{\"version\":\"v1.2\"}")
}).Methods("GET")

• POST情况下的处理使用axios时需要注意OPTIONS请求的情况

gmux.HandleFunc("/xxx", func(w http.ResponseWriter, r *http.Request) {
            w.Header().Set("Access-Control-Allow-Origin", "*")             
            w.Header().Add("Access-Control-Allow-Headers", "X-Requested-With, Content-Type,Origin, Authorization, Accept, Client-Security-Token, Accept-Encoding, X-Auth-Token, content-type") 
            w.Header().Set("content-type", "application/json")             
            w.Header().Add("Access-Control-Allow-Methods","GET, POST, PUT, PATCH, POST, DELETE, OPTIONS");
            if r.Method == "OPTIONS" {
                return
            }
            if r.Header.Get("Content-Type") != "" {
                value, _ := header.ParseValueAndParams(r.Header, "Content-Type")
                if value != "application/json" {
                    msg := "Content-Type header is not application/json"
                    http.Error(w, msg, http.StatusUnsupportedMediaType)
                    return
                }
            }
            r.Body = http.MaxBytesReader(w, r.Body, 1048576)
            b, err := ioutil.ReadAll(r.Body)
            defer r.Body.Close()
            if err != nil {
                fmt.Println("b is null");
                http.Error(w, err.Error(), 500)
                return
            }
            //var data ExecBat
            //err = json.Unmarshal(b, &data)
            //if err != nil {
            //    fmt.Println("json.Unmarshal");
            //    http.Error(w, err.Error(), 500)
            //    return
            //}
            //code, err := base64.StdEncoding.DecodeString(data.Code)
            //if err != nil {
            //   fmt.Fprint(w,"error:", err)
            //}
            ...
        }).Methods("POST","OPTIONS")

• 静态文件的处理

dir, err := filepath.Abs(filepath.Dir(os.Args[0]))
if err != nil {
    fmt.Println(err)
}
gmux.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir(dir+"\\static"))))

gmux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
    http.ServeFile(w, r, dir+"\\index.html")
}).Methods("GET")