我是clojure的新手,正在编写一个库,将发布结果发送到服务器以获取响应。我通过将响应放在core.async通道上来消耗响应。这是理智还是有更好的方法?
以下是我正在做的事情的高级概述:
(defn my-post-request [channel options]
(client/post http://www.example.com options
(fn [{:keys [status headers body error]}] ;; asynchronous handle response
(go (>! channel body)))))
(defn request-caller [options]
(let [channel (chan)]
(my-post-request channel options)
(json/parse-string (<!! (go (<! channel))))))
以下是我使用的实际代码:https://github.com/gilmaso/btc-trading/blob/master/src/btc_trading/btc_china.clj#L63
它有效,但我很难确认这是否是正确的方法。
答案 0 :(得分:10)
core.async
功能强大,但在协调更复杂的异步性方面却非常有用。如果你总是想阻止回复,我建议使用promise
,因为它更简单:
(defn my-post-request [result options]
(client/post http://www.example.com options
(fn [{:keys [status headers body error]}] ;; asynchronous handle response
(deliver result body))))
(defn request-caller [options]
(let [result (promise)]
(my-post-request result options)
; blocks, waiting for the promise to be delivered
(json/parse-string @result)))
如果您确实想使用频道,可以稍微清理一下代码。重要的是,您不需要将所有内容都包装在go
块中; go
对于协调异步性来说是惊人的,但最终,一个频道是一个频道:
(defn my-post-request [channel options]
(client/post http://www.example.com options
(fn [{:keys [status headers body error]}] ;; asynchronous handle response
(put! channel body))))
(defn request-caller [options]
(let [channel (chan)]
(my-post-request channel options)
(json/parse-string (<!! channel))))