简单问题: http.get() 如何同步返回給客户端?
嗯嗯嗯,这应该是所有学习 node 的人必须过的一关:
- 使用 http 内置模块,进行url 获取时
- 因为 node 是异步的,从指定 url 下载数据,直到 end 事件发生时,才完成
- 但是,作为一个 post 或是 get 请求过程中,就无法简单的,自然思路的返回数据了,
e.g::
app.post '/chk', (req, res) ->
...
http.get options, (res) ->
data = ''
res.on 'data', (chunk) ->
data += chunk.toString()
res.on 'end', () ->
answer = JSON.parse(data)
console.log answer.success
res.send answer
- 这时,俺用 curl 什么的访问 127.0.0.1/chk ,給个网址
- 那么,返回时,怎么也无法简单的获得 answer
- 除了人工等待几秒,还有什么方案?
ps: 环境是:
- node > v0.6.8
- coffee v 1.2.0
- express v2.5.8
17 回复
javascript - Node.js. Http.get() function is not responding. - Stack Overflow http://stackoverflow.com/questions/8893167/node-js-http-get-function-is-not-responding
javascript - Node.js: Parse JSON object - Stack Overflow http://stackoverflow.com/questions/6486208/node-js-parse-json-object
等等,都是从 console 返回給后台,然而前台要怎么办?
app.post '/chk', (req, res) ->
...
http.get options, (gres) ->
data = ''
gres.on 'data', (chunk) ->
data += chunk.toString()
gres.on 'end', () ->
answer = JSON.parse(data)
console.log answer.success
res.end answer在 res.on 的 end 事件中,不论 res.write/send/end 都吼对象没有这个方法,
::
.../app.coffee:44
return res.end(answer.success);
^
TypeError: Object #<IncomingMessage> has no method 'end'
at IncomingMessage.<anonymous> (/Users/zoomq/Works/@NAE/no.de/urisaok/app.coffee:44:20)
at IncomingMessage.emit (events.js:88:20)
at HTTPParser.onMessageComplete (http.js:137:23)
at Socket.ondata (http.js:1147:24)
at TCP.onread (net.js:354:27)在 res.on 的 end 事件中,不论 res.write/send/end 都吼对象没有这个方法,
::
.../app.coffee:44
return res.end(answer.success);
^
TypeError: Object #<IncomingMessage> has no method 'end'
at IncomingMessage.<anonymous> (/Users/zoomq/Works/@NAE/no.de/urisaok/app.coffee:44:20)
at IncomingMessage.emit (events.js:88:20)
at HTTPParser.onMessageComplete (http.js:137:23)
at Socket.ondata (http.js:1147:24)
at TCP.onread (net.js:354:27)在 res.on 的 end 事件中,不论 res.write/send/end 都吼对象没有这个方法,
::
.../app.coffee:44
return res.end(answer.success);
^
TypeError: Object #<IncomingMessage> has no method 'end'
at IncomingMessage.<anonymous> (/Users/zoomq/Works/@NAE/no.de/urisaok/app.coffee:44:20)
at IncomingMessage.emit (events.js:88:20)
at HTTPParser.onMessageComplete (http.js:137:23)
at Socket.ondata (http.js:1147:24)
at TCP.onread (net.js:354:27)在 res.on 的 end 事件中,不论 res.write/send/end 都吼对象没有这个方法,
::
.../app.coffee:44
return res.end(answer.success);
^
TypeError: Object #<IncomingMessage> has no method 'end'
at IncomingMessage.<anonymous> (/Users/zoomq/Works/@NAE/no.de/urisaok/app.coffee:44:20)
at IncomingMessage.emit (events.js:88:20)
at HTTPParser.onMessageComplete (http.js:137:23)
at Socket.ondata (http.js:1147:24)
at TCP.onread (net.js:354:27)在 res.on 的 end 事件中,不论 res.write/send/end 都吼对象没有这个方法,
::
.../app.coffee:44
return res.end(answer.success);
^
TypeError: Object #<IncomingMessage> has no method 'end'
at IncomingMessage.<anonymous> (/Users/zoomq/Works/@NAE/no.de/urisaok/app.coffee:44:20)
at IncomingMessage.emit (events.js:88:20)
at HTTPParser.onMessageComplete (http.js:137:23)
at Socket.ondata (http.js:1147:24)
at TCP.onread (net.js:354:27)在 res.on 的 end 事件中,不论 res.write/send/end 都吼对象没有这个方法,
::
.../app.coffee:44
return res.end(answer.success);
^
TypeError: Object #<IncomingMessage> has no method 'end'
at IncomingMessage.<anonymous> (/Users/zoomq/Works/@NAE/no.de/urisaok/app.coffee:44:20)
at IncomingMessage.emit (events.js:88:20)
at HTTPParser.onMessageComplete (http.js:137:23)
at Socket.ondata (http.js:1147:24)
at TCP.onread (net.js:354:27)
//post function
function post(url, callback){
app.post(url,function(req,res){
...
res.on('end',function(){
...
callback(answer);
});
}
//good seperation
function sendAnswer(ans){
res.end(ans);
}
//do the job
post('/chk',sendAnswer);
npm install -g xd-synchttp
安装完成后，示例代码如下。
const sync = require('xd-synchttp');
let content = "";
try{
content = sync.http_get('http://www.csdn.net',0);//0为不超时，其他数值为超时秒数
}
catch(err){
console.log(err);
}
