javascript-node.js http.request事件流-我的END事件去了哪里？

我正在制定一个狡猾的计划,其中涉及将node.js用作另一个服务之前的代理服务器.

简而言之：

>将传入请求分派到静态文件(如果存在)
>否则,将请求分派到另一个服务

我已经掌握了基础知识,但是现在尝试使Sencha Connect完全正常工作,以便可以访问所提供的所有kick-ass中间件.

所有动作都发生在下面的dispatchProxy中

connect(
  connect.logger(), 
  connect.static(__dirname + '/public'),
  (request, response) ->  
    dispatchProxy(request, response)
).listen(8000)

dispatchProxy = (request, response) ->  

  options = {host: host, port: port, method: request.method, headers: request.headers, path: request.url}

  proxyRequest = http.request(options, (proxyResponse) ->
    proxyResponse.on('data', (chunk) ->
     response.write(chunk, 'binary')
    )

    proxyResponse.on('end', (chunk) ->        
     response.end()
    )

    response.writeHead proxyResponse.statusCode, proxyResponse.headers    
  )

  request.on('data', (chunk) ->
    proxyRequest.write(chunk, 'binary')
  )

  # this is never triggered for GETs
  request.on('end', ->
    proxyRequest.end()
  )

  # so I have to have this here
  proxyRequest.end()

您会在上面的最后一行中注意到proxyRequest.end().

我发现,在处理GET请求时,永远不会触发请求的END事件,因此需要调用proxyRequest.end(). POST请求会按预期触发DATA和END事件.

有几个问题：

>对此proxyRequest.end()的调用安全吗？也就是说,即使在事件循环之外调用了proxyResponse,仍然会完成吗？
> GET不触发END事件是否正常,还是在连接堆栈中的某个位置捕获了END？

解决方法:

问题是结束事件较少,而数据事件较多.如果客户端发出GET请求,则会有标头且没有数据.这与POST不同,在POST中,请求者正在发送数据,因此on(“ data”)处理程序将被命中.因此(请原谅我的JS示例,我对coffeescript不太熟悉)：

var http = require('http');

// You won't see the output of request.on("data")
http.createServer(function (request, response) {
  request.on("end", function(){
    console.log("here");
  });
  request.on("data", function(data) {
    console.log("I am here");
    console.log(data.toString("utf8"));
  });
  response.writeHead(200, {'Content-Type': 'text/plain'});
  response.end('Hello World\n');
}).listen(8124);

console.log('Server running at http://127.0.0.1:8124/');

如果我对该服务器进行curl调用,则数据事件将永远不会被命中,因为GET请求只不过是标题.因此,您的逻辑变为：

// okay setup the request...
// However, the callback doesn't get hit until you
// start writing some data or ending the proxyRequest!
proxyRequest = http.request(options, (proxyResponse) ->
  // So this doesn't get hit yet...
  proxyResponse.on('data', (chunk) ->
   response.write(chunk, 'binary')
  )

  // and this doesn't get hit yet
  proxyResponse.on('end', (chunk) ->
   // which is why your response.on("end") event isn't getting hit yet        
   response.end()
  )

  response.writeHead proxyResponse.statusCode, proxyResponse.headers    
)

// This doesn't get hit!
request.on('data', (chunk) ->
  proxyRequest.write(chunk, 'binary')
)

// So this isn't going to happen until your proxyRequest
// callback handler gets hit, which hasn't happened because
// unlike POST there's no data in your GET request
request.on('end', ->
  proxyRequest.end()
)

// now the proxy request call is finally made, which
// triggers the callback function in your http request setup
proxyRequest.end()

所以是的,由于我刚才提到的逻辑分支,您将不得不为GET请求手动调用proxyRequest.end().

标签：node-js,connect,proxy,coffeescript,javascript
来源： https://codeday.me/bug/20191102/1992295.html