Javascript 继续在my node.js服务器上获取以下警告

我的控制台不断发出以下警告。这可能来自app.js或任何其他路由文件：

由于我的缓存处理，错误似乎即将出现。一旦用户注销，我就处理缓存

Error: Can't set headers after they are sent.
    at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:344:11)
    at ServerResponse.header (/home/ved/Dropbox/JAVA/eBay/test/node_modules/express/lib/response.js:718:10)
    at ServerResponse.send (/home/ved/Dropbox/JAVA/eBay/test/node_modules/express/lib/response.js:163:12)
    at done (/home/ved/Dropbox/JAVA/eBay/test/node_modules/express/lib/response.js:957:10)
    at View.exports.renderFile [as engine] (/home/ved/Dropbox/JAVA/eBay/test/node_modules/ejs/lib/ejs.js:363:10)
    at View.render (/home/ved/Dropbox/JAVA/eBay/test/node_modules/express/lib/view.js:126:8)
    at tryRender (/home/ved/Dropbox/JAVA/eBay/test/node_modules/express/lib/application.js:639:10)
    at EventEmitter.render (/home/ved/Dropbox/JAVA/eBay/test/node_modules/express/lib/application.js:591:3)
    at ServerResponse.render (/home/ved/Dropbox/JAVA/eBay/test/node_modules/express/lib/response.js:961:7)
    at /home/ved/Dropbox/JAVA/eBay/test/app.js:159:7
GET /fonts/glyphicons-halflings-regular.woff 404 1.673 ms - 968
GET /fonts/glyphicons-halflings-regular.ttf 404 1.738 ms - 968
POST /viewProductPage - - ms - -

app.js

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');


//DEFINING EXTERNAL DEPENDENCY TO ENABLE SESSIONS IN THE APPLICATION
var session = require('client-sessions');


//DEFINING THE BASE ROUTE
var routes = require('./routes/index');

//DEFINING THE ROUTE TO GET THE SYSTEM USERS
var users  = require('./routes/users');


//DEFINING THE ROUTE TO ACCESS sell.js
//sell.js HANDLES ALL THE ITEMS POSTED
//INTERACTS WITH THE DATABASE FOR THE SAME
var sell = require('./routes/sell');


//ROUTES TO getUserData.js
//DEFINED AS A BASE ROUTE TO ACCESS SESSION FOR ANY USE
var getUserData = require('./routes/getUserData');





var productsRetriever = require('./routes/productsRetriever');


//DEFINING THE DEPENDENCY TO ACCESS LOGIN CONTROLS FOR THE SYSTEM
//USER LOGIN AND MOST IMPORTANTLY ASSIGNING A SESSION TO THAT USER IS HANDLED BY login.js
//getUserData.js RETRIEVES THE SESSION OF A USER INITIATED IN login.js
var login    = require('./routes/login');





var productDetail    = require('./routes/productDetail');



//DEFINING THE DEPENDENCY TO ACCESS register.js
//register.js HANDLES ALL THE USER REGISTRATION PATHS AS WELL AS FUNCTIONS
var register = require('./routes/register');



//INITIATING AN INSTANCE OF express js IN OUR APPLICATION
//ASSIGNING IT TO A VARIABLE APP
var app      = express();



// all environments
//configure the sessions with our application
app.use(session({
    cookieName    : 'session',
    secret        : 'cmpe273_ebay_app_fall_2016',
    duration      : 30 * 60 * 1000, //setting the time for active session
    activeDuration: 5 * 60 * 1000 // setting time for the session to be active when the window is open // 5 minutes set currently
})); 





// view engine setup
//SETS BASE PATH FOR ALL THE FILES IN THE VIEW
app.set('views', path.join(__dirname, 'views'));
//ASSIGNING THE ejs ENGINE TO ALL THE FILES WITHIN VIEWS DIRECTORY
app.set('view engine', 'ejs');

// uncomment after placing your favicon in /public
app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));


//GETS THE PATH WHEN A USER FIRST VISITS OUR APPLICATION
app.get('/', routes);


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

app.get('/login', login.login);
app.post('/checklogin', login.checklogin);
app.get('/getAllUsers', login.getAllUsers);


app.get('/sell', sell.sell);
app.post('/addSellItem', sell.addSellItem);


//app.post('/checklogin', login.checklogin);
app.get('/homepage',login.redirectToHomepage);





app.post('/logout',login.logout);



app.post('/getUserInfo', getUserData.getUserData);

app.get('/viewProduct',productDetail.getProductPage);

app.post('/productsRetriever', productsRetriever.getProducts);


app.post('/viewProductPage', productDetail.getProductPageDetails);

app.get('/register', register.register);
app.post('/registerdone', register.registerdone);
app.get('/getAllRegisteredUsers', register.getAllRegisteredUsers);





// 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
    });
  });
}


// 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                               : {}
  });
});


module.exports                          = app;

---

这也发生在我身上

问题是（对我来说）我在路由中做了一些操作，并向用户发送了响应，但在错误发生后，它由错误处理中间件（app.js的底部）处理，并发送了错误响应

但是，由于请求已在您的API路由的早期响应，因此日志中会出现此错误消息。试着找出错误所在

---

尝试将console.log（）放入错误处理程序以查看跟踪。

此问题与此问题有何区别？您在哪个调用中收到此错误？您可以发布代码吗？@abdulbarik我无法理解。您是否在特定时间请求任何路由，因为此错误表明您正在发送多个响应项，根据日志判断，这些响应项将发生在

productDetail.getProductPageDetails

中。