推迟响应Node.js中的请求

Question

当我的Node.js Express服务器（正在侦听端口3000）收到请求时，它会路由到一个必须向另一个网站发出POST并在响应初始请求之前获得响应的函数。

这可能吗？

这是我正在使用的代码：

app.get('/silence/:host', routes.silence);

http.createServer(app).listen(app.get('port'), function(){
  console.log('Express server listening on port ' + app.get('port'));
});

---

exports.silence = function(request, response){
   var hostname = utils.validateHost(request);
   if (stash.createSilencer(hostname)) {
      response.writeHead(200, {"Content-Type": "application/json"});
      response.write('{ "success" : true, "message" : "Successfully silenced host'" }');
      response.end();
   }
}

---

exports.createSilencer = function(hostname) {
   var options = {
      url: 'http://x.x.com:4567/create/silencer/' + hostname ,
      method: 'POST',
      body: '{ "timestamp": ' + utils.timestamp() + '} '
   };
   request(options, silencer_callback);
   ##### DONT WANT TO RETURN UNTIL THE silencer_callback IS INVOKED
   return true;
}

---

function silencer_callback(error, response, body) {
    if (!error && response.statusCode == 200) {
        var info = JSON.parse(body);
        console.log("Response Recieved");
    }
}

Answer 1

诀窍是，在收到POST请求的响应之前，您不会调用response.write()和response.end()。您只需退出方法而不发送回复。一旦有了POST请求的结果，就可以完成初始响应。

exports.silence = function(req, res){    
    var hostname = utils.validateHost(req);
    stash.createSilencer(hostname, function(error, response, body) {
      if (!error && response.statusCode == 200) {
        var info = JSON.parse(body);
        console.log("Response Received");
      }
      // we get POST-response, lets response to initial request here
      res.writeHead(200, {"Content-Type": "application/json"});
      res.write('{ "success" : !error, "message" : "Successfully silenced host'" }');
      res.end();
    });
    // return from the function, but do not send response back yet
}

exports.createSilencer = function(hostname, callback) {
    var options = {
        url: 'http://x.x.com:4567/create/silencer/' + hostname ,
        method: 'POST',
        body: '{ "timestamp": ' + utils.timestamp() + '} '
    };
    request(options, callback);
    // return from the function, but do not send response back yet
}