如何将 app.js 中的变量导出到 Node js 中的另一个路由

Question

我在我的节点项目中使用 socket.io，想知道如何导出 io 变量

这是我到目前为止所做的，但我收到了这个错误：Object #<Object> has no method 'on'

在 app.js 中：

        var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var routes = require('./routes/index')(io);
var users = require('./routes/user');

var app = require('express')();
var server = require('http').Server(app);
var io = require('socket.io')(server);
server.listen(4000);

require('./routes/index')(io);

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

// app.use(favicon(__dirname + '/public/img/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: true
}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);
app.use('/users', users);

/// catch 404 and forward to error handler
app.use(function(req, res, next) {
    var err = new Error('Not Found');
    err.status = 404;
    next(err);
});

/// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
    app.use(function(err, req, res, next) {
        res.status(err.status || 500);
        res.render('error', {
            message: err.message,
            error: err,
            title: 'error'
        });
    });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
        message: err.message,
        error: {},
        title: 'error'
    });
});
/*
io.on('connection', function (socket) {
  socket.emit('news', { hello: 'world' });
  socket.on('my other event', function (data) {
    console.log(data);
  });
});
*/

module.exports = app;

在 index.js 中

var io = require('../app');

io.on('connection', function (socket) {
  socket.emit('news', { hello: 'world' });
  socket.on('my other event', function (data) {
    console.log(data);
  });
});

我想要导出变量的原因是我不必像在 app.js 中那样定义 io 是 index.js，这导致我基本上同时定义了服务器和应用程序变量！

我只想在 index.js 路由中完成所有 socket.io 的工作（除了必须在 index.js 中重新定义 app、server 和 io 变量）！

希望我已经充分解释了我自己

谢谢！

Answer 1

您的依赖项设置不正确。您在 io 初始化之前执行 index.js

var routes = require('./routes/index');
/* index.js starts being executed at this point
 * hence, io is undefined inside index.js
 */

相反，你为什么不试试

app.js

var app = require('express')();
var server = require('http').Server(app);
var io = require('socket.io')(server);
server.listen(4000);
module.exports = io;

var routes = require('./routes/index');
var users = require('./routes/user');

index.js

 var io = require('../app');

io.on('connection', function (socket) {
    socket.emit('news', { hello: 'world' });
    socket.on('my other event', function (data) {
    console.log(data);
    });
});

Answer 2

我认为您需要使用套接字。

io.sockets.on('connection', ... ); 

Answer 3

看起来像一个循环依赖（app.js 需要 index.js 而 index.js 需要 app.js）

试试这个。

将 app.js 更改为：

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var users = require('./routes/user');

var app = require('express')();
var server = require('http').Server(app);
var io = require('socket.io')(server);
server.listen(4000);

require('./routes/index')(io);

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

// app.use(favicon(__dirname + '/public/img/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: true
}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/users', users);

/// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

/// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err,
      title: 'error'
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {},
    title: 'error'
  });
});
/*
 io.on('connection', function (socket) {
 socket.emit('news', { hello: 'world' });
 socket.on('my other event', function (data) {
 console.log(data);
 });
 });
 */

module.exports = app;

将 index.js 更改为：

module.exports = function(io){
  io.on('connection', function (socket) {
    socket.emit('news', { hello: 'world' });
    socket.on('my other event', function (data) {
      console.log(data);
    });
  });
}  

Answer 4

在 app.js 中使用“global.io”而不是“var io”