无法在node.js中启动应用程序，出现以下错误

Question

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$ npm start

nodeauth@1.0.0 start C:\\Users*****\\Desktop\\nodeauth node ./bin/www

C:\\Users***\\Desktop\\nodeauth\\node_modules\\express\\lib\\application.js:206 throw new TypeError('app.use() requires middleware functions'); ^

TypeError: app.use() requires middleware functions at EventEmitter.use >>...>

//app.js

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',
  saveUninitialized: 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;

Answer 1

You need to use app.use(multer({dest:'./uploads/'})) in the form of one of these:

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

ie:

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

And be sure to have something like:

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

In your html.