Http 与golang后端的CORS请求不'；t工作

我的实现遇到了一些问题。 我有一个用Golang编写的后端，UI（Angular2）在同一台服务器上

我尝试在后端设置CORS处理，但仍然不起作用，我不知道为什么

这是我的密码：

package main

import (
    "log"
    "net/http"

    "github.com/gorilla/mux"
    "github.com/rs/cors"
)

var router *mux.Router

func main() {
    router = mux.NewRouter()

    HandleFuncEx("/authentication", handleAuthentication)
    HandleFuncEx("/callA", handleCallA)
    HandleFuncEx("/callB", handleCallB)
    HandleFuncEx("/callC", handleCallC)

    handler := cors.New(cors.Options{
        AllowedOrigins: []string{"*"},
        AllowedMethods: []string{"GET", "POST", "PATCH"},
        AllowedHeaders: []string{"a_custom_header", "content_type"},
    }).Handler(router)
    http.ListenAndServe(":8000", handler)

}

func HandleFuncEx(pattern string, handler func(http.ResponseWriter, *http.Request)) {
    log.Println("handled function", pattern)
    router.HandleFunc(pattern, handler)
}

身份验证模式工作正常（是UI调用的第一个模式） 所有其他调用均未通过飞行前请求。 为什么会这样

谢谢大家的帮助

编辑：

这是一个非工作响应头的示例：

HTTP/1.1 200 OK
Vary: Origin
Vary: Access-Control-Request-Method
Vary: Access-Control-Request-Headers
Date: Fri, 07 Apr 2017 08:33:12 GMT
Content-Length: 0
Content-Type: text/plain; charset=utf-8

以下是请求的标题：

OPTIONS /users HTTP/1.1
Host: /* Removed by my company policy */
Connection: keep-alive
Access-Control-Request-Method: GET
Origin: /* Removed by my company policy */
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) 
AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36
Access-Control-Request-Headers: access_token
Accept: */*
Referer: /* Removed by my company policy */
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-GB,en;q=0.8,en-US;q=0.6,it;q=0.4,la;q=0.2

---

我使用Negroni作为中间件，代码如下：

func main() {

    c := cors.New(cors.Options{
        AllowedOrigins: []string{"*"},
        AllowedMethods: []string{"POST", "GET", "OPTIONS", "PUT", "DELETE"},
        AllowedHeaders: []string{"Accept", "content-type", "Content-Length", "Accept-Encoding", "X-CSRF-Token", "Authorization"},
    })

    router := mux.NewRouter()
    router = routers.SetAuthRoute(router)

    apiRoutes := routers.InitRoutes()

    router.PathPrefix("/api").Handler(negroni.New(
        negroni.HandlerFunc(controllers.ValidateTokenMiddleware),
        negroni.Wrap(apiRoutes),
    ))

    server := negroni.Classic()
    server.Use(c)
    server.UseHandler(router)
    server.Run("0.0.0.0:" + os.Getenv("PORT"))
}

如前所述，您需要将

选项

方法添加到

AllowedMethods

数组中

也请考虑添加<代码>接受< /代码>、<代码>接受语言< /代码>和<代码>内容类型< /代码> > <代码>允许的标题< /代码>作为良好的实践。< /P> 如果您不想使用

github.com/rs/cors

包，您可以自己编写一个简单的cors装饰器中间件，如下所示：

CORS装饰师

import (
    "net/http"

    "github.com/gorilla/mux"
)

// CORSRouterDecorator applies CORS headers to a mux.Router
type CORSRouterDecorator struct {
    R *mux.Router
}

// ServeHTTP wraps the HTTP server enabling CORS headers.
// For more info about CORS, visit https://www.w3.org/TR/cors/
func (c *CORSRouterDecorator) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
    if origin := req.Header.Get("Origin"); origin != "" {
        rw.Header().Set("Access-Control-Allow-Origin", origin)
        rw.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
        rw.Header().Set("Access-Control-Allow-Headers", "Accept, Accept-Language, Content-Type, YourOwnHeader")
    }
    // Stop here if its Preflighted OPTIONS request
    if req.Method == "OPTIONS" {
        return
    }

    c.R.ServeHTTP(rw, req)
}

r := mux.NewRouter()
r.Handle("/authentication", handleAuthentication)

http.Handle("/", &CORSRouterDecorator{r})

HTTP服务器

import (
    "net/http"

    "github.com/gorilla/mux"
)

// CORSRouterDecorator applies CORS headers to a mux.Router
type CORSRouterDecorator struct {
    R *mux.Router
}

// ServeHTTP wraps the HTTP server enabling CORS headers.
// For more info about CORS, visit https://www.w3.org/TR/cors/
func (c *CORSRouterDecorator) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
    if origin := req.Header.Get("Origin"); origin != "" {
        rw.Header().Set("Access-Control-Allow-Origin", origin)
        rw.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
        rw.Header().Set("Access-Control-Allow-Headers", "Accept, Accept-Language, Content-Type, YourOwnHeader")
    }
    // Stop here if its Preflighted OPTIONS request
    if req.Method == "OPTIONS" {
        return
    }

    c.R.ServeHTTP(rw, req)
}

r := mux.NewRouter()
r.Handle("/authentication", handleAuthentication)

http.Handle("/", &CORSRouterDecorator{r})

---

et voilá。

与其他两个回答类似，但我的案例我的项目托管在cloud9上，所以我有一些调整要做

这是我添加的代码：

    cor := cors.New(cors.Options{
        AllowedOrigins:   []string{"https://*.c9users.io", "http://myapp.c9users.io:8080", "https://*.c9.io"},
        AllowedMethods:   []string{"POST", "GET", "OPTIONS", "PUT"},
        AllowedHeaders:   []string{"Accept", "Accept-Language", "Content-Type"},
        AllowCredentials: true,
        Debug:            true,
    });

我不得不添加额外的http源代码，因为Safari使用http而不是https发出初始选项请求

---

已排序。

您是否可以共享chrome devtools的选项请求屏幕截图，该选项请求失败、请求已发送、响应已接收？CORS在执行实际请求之前，使用选项动词检查是否允许跨源。您必须允许选项，并用成功代码（2xx）响应它。