当您指定{:async? true}
时,clj-http.client/get
将返回a future这是您得到的错误消息中的FutureWrapper
。
所以,如果你不需要异步,不要使用它。这是一个同步环处理程序的例子,它调用第三方url并返回返回的响应。
(defn handler [request]
(response {:result (client/get "http://example.com")}))
如果您确实需要异步,请使用异步版本的环处理程序。
(defn handler [request respond raise]
(client/get "http://example.com"
{:async? true}
(fn [response] (respond {:body "something"}))
(fn [exception] (raise {:body "error"}))))
不要忘记配置web服务器适配器以使用异步处理程序。例如,对于码头,设置:async?
标志true
像这样
(jetty/run-jetty app {:port 4000 :async? true :join? false})
如果要同时调用多个第三方URL和一次web客户端返回,使用promise帮助
(defn handler [request]
(let [result1 (promise)
result2 (promise)]
(client/get "http://example.com/"
{:async? true}
(fn [response] (deliver result1 {:success true :body "something"}))
(fn [exception] (deliver result1 {:success false :body "error"})))
(client/get "http://example.com/"
{:async? true}
(fn [response] (deliver result2 {:success true :body "something"}))
(fn [exception] (deliver result2 {:success false :body "error"})))
(cond
(and (:success @result1)
(:success @result2))
(response {:result1 (:body @result1)
:result2 (:body @result2)})
(not (:success @result1))
(throw (ex-info "fail1" (:body @result1)))
(not (:success @result2))
(throw (ex-info "fail2" (:body @result2))))))
来源
2017-12-03 04:08:08
tap
如果FutureWrapper是一个Java未来,然后尝试使用deref或@来解析它。 –