express-Formidable "发送后无法设置标题。"

Posted 2023-03-07

【中文标题】express-Formidable "发送后无法设置标题。"

【英文标题】：express-Formidable "Can't set headers after they are sent."

【发布时间】：2018-02-21 08:40:36

【问题描述】：

我使用的模块很强大

当我加载第 2 页时，我在控制台上有该页面

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;

你必须现在，如果我删除了强大的我没有错误。有什么想法吗？

表达 v 4.5 节点 v8

不要阅读下一段文字，这只是为了消除***错误！！！我不知道如何为这个问题添加更多信息。

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【参考方案1】：

有一个解决办法，express-formidable 中间件版本有问题，

每个事件处理程序有两个，这意味着每个事件被处理两次，导致两次 next() 调用，因此有关标头设置得太晚的异常。

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);

【讨论】：

在 express-formidable repo 中，该问题自 2 月以来已得到修复，但 NPM 包未更新。在那之前，直接使用formidable 或者安装修复它的特定提交："github:utatti/express-formidable#9986be6279"。