我用模块表达强大
当我加载页面2次时，在控制台上
GET /users 304 6.948 ms - -
GET /users 304 213.344 ms - -
Error: Can't set headers after they are sent.
at validateHeader (_http_outgoing.js:489:11)
at ServerResponse.setHeader (_http_outgoing.js:496:3)
at ServerResponse.header (/home/neolinux/Encoding-Service/encode-service/node_modules/express/lib/response.js:730:10)
at ServerResponse.contentType (/home/neolinux/Encoding-Service/encode-service/node_modules/express/lib/response.js:558:15)
at ServerResponse.send (/home/neolinux/Encoding-Service/encode-service/node_modules/express/lib/response.js:145:14)
at done (/home/neolinux/Encoding-Service/encode-service/node_modules/express/lib/response.js:967:10)
at Object.exports.renderFile (/home/neolinux/Encoding-Service/encode-service/node_modules/pug/lib/index.js:422:12)
at View.exports.__express [as engine] (/home/neolinux/Encoding-Service/encode-service/node_modules/pug/lib/index.js:465:11)
at View.render (/home/neolinux/Encoding-Service/encode-service/node_modules/express/lib/view.js:127:8)
at tryRender (/home/neolinux/Encoding-Service/encode-service/node_modules/express/lib/application.js:640:10)
这是我的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 index = require('./routes/index');
var users = require('./routes/users');
const util=require("util");
var app = express();
const formidable = require('express-formidable');
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use(formidable({
uploadDir: path.join(__dirname, '/Upload'),
}));
app.use('/', index);
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 handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
module.exports = app;
现在，如果我删除了难以克服的错误，那么您必须没有错误。任何想法 ？
快递v 4.5
节点v8
不要阅读下一个文本，这只是为了消除stackoverflow错误！我不知道如何为该问题添加更多信息。
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最佳答案
有一个解决方案，中间件版本中有可表达的问题，
每个事件处理程序都有两个，这意味着每个事件被处理两次，从而导致两个next（）调用，因此出现有关标头设置太晚的异常。
解决方案在app.js中：
const formidable = require('formidable');
app.use(function (req, res, next) {
var form = new formidable.IncomingForm({
encoding: 'utf-8',
uploadDir: path.join(__dirname, '/Upload'),
multiples: true,
keepExtensions: true
})
form.once('error', console.log)
form.parse(req, function (err, fields, files) {
Object.assign(req, {fields, files});
next();
})
})
app.use('/', index);