node.js + express 3 + socket.io =发送后无法设置标头

Question

我是学习node.js的新手,似乎遇到了一个无法修复的错误.

它是一个非常简单的初学者代码所以不需要太多解释,更多的是它在localhost上工作正常,但在生产服务器上中断.

App.js

var express = require('express')
  , routes = require('./routes')
  , http = require('http')
  , path = require('path');

var app = express();

app.configure(function(){
  app.set('port', process.env.PORT || 8000);
  app.set('views', __dirname + '/views');
  app.set('view engine', 'jade');
  app.use(express.favicon());
  app.use(express.logger('dev'));
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(app.router);
  app.use(express.static(path.join(__dirname, 'public')));
});

app.configure('development', function(){
  app.use(express.errorHandler());
});

app.get('/', routes.index);

var server = app.listen(8000);
var io = require('socket.io').listen(server);

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

这是可怕的错误!

http.js:644
    throw new Error('Can\'t set headers after they are sent.');
          ^
Error: Can't set headers after they are sent.
    at ServerResponse.OutgoingMessage.setHeader (http.js:644:11)
    at ServerResponse.res.setHeader (/home1/artalatc/public_html/cloud1/node_modules/express/node_modules/connect/lib/patch.js:59:22)
    at next (/home1/artalatc/public_html/cloud1/node_modules/express/node_modules/connect/lib/proto.js:153:13)
    at Function.app.handle (/home1/artalatc/public_html/cloud1/node_modules/express/node_modules/connect/lib/proto.js:198:3)
    at Server.app (/home1/artalatc/public_html/cloud1/node_modules/express/node_modules/connect/lib/connect.js:66:31)
    at Manager.handleRequest (/home1/artalatc/public_html/cloud1/node_modules/socket.io/lib/manager.js:564:28)
    at Server.<anonymous> (/home1/artalatc/public_html/cloud1/node_modules/socket.io/lib/manager.js:118:10)
    at Server.EventEmitter.emit (events.js:115:20)
    at HTTPParser.parser.onIncoming (http.js:1793:12)
    at HTTPParser.parserOnHeadersComplete [as onHeadersComplete] (http.js:111:23)

问题似乎是var io = require('socket.io').listen(server);因为评论这样就消除了错误.

Answer 1

您使用的是什么版本的Node？

当我使用0.9.x时,我遇到了同样的问题.我把Node降级到0.8.4,问题似乎已经消失了.

我最好的猜测是Node已经改变了Socket.io不同意的东西.

Answer 2

您使用的是哪个版本的express？查看https://github.com/visionmedia/express/wiki/Migration-from-2.x-to-3.x或尝试以下操作：

var server = app.listen(8000);
var io = require('socket.io').listen(server);