Question

我一直在尝试很多方法来实现这一点，我认为正确的方法是设置这样的标头（我在nodejs / express app中这样做了）：

"Access-Control-Allow-Origin"  "*"
"Access-Control-Allow-Methods" "GET,PUT,POST,DELETE,OPTIONS"
"Access-Control-Allow-Headers" "X-Requested-With,Content-Type,Cache-Control"

我写过这样的功能：

(defn allow-cross-origin
  "middleware function to allow cross origin"
  [handler]
  (fn [request]
    (let [response (handler request)]
      (do
        (assoc-in response [:headers "Access-Control-Allow-Origin"]  "*")
        (assoc-in response [:headers "Access-Control-Allow-Methods"] "GET,PUT,POST,DELETE,OPTIONS")
        (assoc-in response [:headers "Access-Control-Allow-Headers"] "X-Requested-With,Content-Type,Cache-Control")))))

(def handler (-> app wrap-params allow-cross-origin))

我用curl -v测试了它，发现只有最后一个值真的存在于响应中。我只需要在头文件中写入多个键值对。怎么做？或许还有另一种解决问题的方法。

Answer 1

请注意，assoc-in仍然不会修改原始结构：response将始终具有与(handler request)相同的值。

(let [response {}]
   (assoc-in response [:headers "Access-Control-Allow-Origin"]  "*")
   (assoc-in response [:headers "Access-Control-Allow-Methods"] "GET,PUT,POST,DELETE,OPTIONS")
   (assoc-in response [:headers "Access-Control-Allow-Headers"] "X-Requested-With,Content-Type,Cache-Control"))
==> {:headers {"Access-Control-Allow-Headers" "X-Requested-With,Content-Type,Cache-Control"}}

这是你所看到的效果。要更改此设置，您必须确保再次使用assoc-in调用的结果。线程宏对此非常有用：

(let [response {}]
 (-> response
     (assoc-in [:headers "Access-Control-Allow-Origin"]  "*")
     (assoc-in [:headers "Access-Control-Allow-Methods"] "GET,PUT,POST,DELETE,OPTIONS")
     (assoc-in [:headers "Access-Control-Allow-Headers"] "X-Requested-With,Content-Type,Cache-Control")))
 => {:headers {"Access-Control-Allow-Headers" "X-Requested-With,Content-Type,Cache-Control", "Access-Control-Allow-Methods" "GET,PUT,POST,DELETE,OPTIONS", "Access-Control-Allow-Origin" "*"}}

如何在compojure中启用跨源请求？

1 个答案: