typeerror: app.use() requires middleware function

问题描述 投票：0回答：8

我正在使用快速模板引擎学习 node.js，我正在学习 udemy 课程“通过构建 10 个项目来学习 node.js”，同时在教授运行 

npm start localhost:3000
开始时听讲座，而我的弹出错误指示 app.use 需要中间件功能 我试过匹配代码和它一样。请帮我解决我被困在这里几个小时的错误，尝试了很多编辑，但它对我不起作用。

当我尝试运行“npm start”时弹出以下错误

TypeError: app.use() 需要中间件函数

这里是app.js代码：

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var expressValidator = require('express-validator');
var cookieParser = require('cookie-parser');
var session = require('express-session');
var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;
var bodyParser = require('body-parser');
var multer = require('multer');
var flash = require('connect-flash');
var mongo = require('mongodb');
var mongoose = require('mongoose');
var db = mongoose.connection;

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

var app = express();

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

//Handle File Uploads
app.use(multer({
  dest: './uploads'
}));

// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: false
}));

//Handle Express Sessions
app.use(session({
  secret: 'secret',
  saveUninitialied: true,
  resave: true
}));

//Passport
app.use(passport.initialize());
app.use(passport.session());

//Validator
app.use(expressValidator({
  errorFormatter: function(param, msg, value) {
    var namespace = param.split('.'),
      root = namespace.shift(),
      formParam = root;

    while (namespace.length) {
      formParam += '[' + namespace.shift() + ']';
    }
    return {
      param: formParam,
      msg: msg,
      value: value
    };
  }
}));

app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use(flash());

app.use(function(req, res, next) {
  res.locals.messages = require('express-messages')(req, res);
  next();
});

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
    });
  });
}

// 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;

这里是package.json文件

{
  "name": "nodeauth",
  "version": "1.0.0",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  },
  "dependencies": {
    "body-parser": "~1.12.4",
    "cookie-parser": "~1.3.5",
    "debug": "~2.2.0",
    "express": "~4.12.4",
    "jade": "~1.9.2",
    "morgan": "~1.5.3",
    "serve-favicon": "~2.2.1",
    "mongodb": "*",
    "mongoose": "*",
    "connect-flash": "*",
    "express-validator": "*",
    "express-session": "*",
    "express-messages": "*",
    "passport": "*",
    "passport-local": "*",
    "passport-http": "*",
    "multer": "*"
  }
}

这是更新的 app.js（删除 multar 后）

var express          = require('express'),
    path             = require('path'),
    favicon          = require('serve-favicon'),
    logger           = require('morgan'),
    cookieParser     = require('cookie-parser'),
    expressValidator = require('express-validator'),
    session          = require('express-session'),
    passport         = require('passport'),
    LocalStrategy    = require('passport-local').Strategy,
    bodyParser       = require('body-parser'),
    flash            = require('connect-flash'),
    mongo            = require('mongodb'),
    mongoose         = require('mongoose'),

    db = mongoose.connection,

    routes = require('./routes/index'),
    users  = require('./routes/users'),

    app = express();

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

// handle file uploads

//multer delted


// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));

// handle express sessions
app.use(session({
  secret: 'keyboard cat',
  resave: true,
  saveUninitialized: true
}));

// passport
app.use(passport.initialize());
app.use(passport.session());

// validator
app.use(expressValidator({
  errorFormatter: function(param, msg, value) {
    var namespace = param.split('.'),
        root      = namespace.shift(),
        formParam = root;

    while(namespace.length) {
      formParam += '[' + namespace.shift() + ']';
    }

    return {
      param: formParam,
      msg  : msg,
      value: value
    };
  }
}));

app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

// flash
app.use(flash());

// express messages
app.use(function(req, res, next) {
  res.locals.messages = require('express-messages')(req, res);
  next();
});

app.get('*', function(req, res, next) {
  res.locals.user = req.user || null;
  next();
});

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
    });
  });
}

// 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: {}
  });
});


//Express server
var http = require('http');
var server = http.createServer(app);

app.get('/', function(req, res) {
    res.send("Hello World!");
});

server.listen(3000, 'localhost');
server.on('listening', function() {
    console.log('Express server started on port %s at %s', server.address().port, server.address().address);
});

module.exports = app;

谢谢

javascript node.js express mean
8个回答
62
投票

原来是这样的。删掉这一行，

app.use(multer({ dest: './uploads' }));

并将其用作，

var multer = require('multer');
var upload = multer({ dest: './uploads' });

我也在学习同样的课程

27
投票

变化：

//Handle File Uploads
app.use(multer({
  dest: './uploads'
}));

对于类似的东西：

app.use(multer({dest:'./uploads/'}).single('singleInputFileName'));

或

app.use(multer({dest:'./uploads/'}).array('multiInputFileName'));

注意要有类似的东西：

<form action="/postPhotos" enctype="multipart/form-data">
    <input type="file" name="singleInputFileName">
    <input type="submit" value="Upload photo">
</form>

对于第一种情况，或者：

<form action="/postPhotos" enctype="multipart/form-data">
    <input type="file" name="multiInputFileName" multiple>
    <input type="submit" value="Upload photo">
</form>

对于第二个，在你的 html 中。

11
投票

这对我有用：

app.use(multer({
  dest: path.join(__dirname, 'public/upload/temp')
}).any());
9
投票

我也在做那门课程并遇到了同样的问题。我按照他们 github 上的 Multer 使用说明解决了这个错误：https://github.com/expressjs/multer

这是他们自述文件中的代码：

    var multer  = require('multer')
    var upload = multer({ dest: 'uploads/' })

& 这是我在做那个教程时用来克服错误的代码：

    var multer = require('multer');
    var upload = multer({ dest: './uploads' });

希望对您有所帮助:)

3
投票

你可以简单地使用：

app.set(multer({dest: "./uploads"}));

对我也有用。

1
投票

只改变这一行

app.use(multer({dest:'./uploads'}));

到

var upload =multer({dest:'./uploads'});
1
投票

替换

app.use(multer({dest:'./uploads'}));

到

var upload = multer({dest:'./uploads'});

为我工作。

0
投票

var upload = multer({dest:'./uploads'});

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