Javascript 类型错误：app.use() 需要中间件功能
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typeerror: app.use() requires middleware function
提问by mean learner
I am learning node.js with express template engine, I am following udemy course "learn node.js by building 10 projects", while following a lecture when professor run npm start localhost:3000starts while mine pops up error indicating app.use requires middleware functionI have tried matching code and its same. Please help me to resolve the error i have been stuck here for hours tried a lot of edits but its not working for me.
我正在学习带有快速模板引擎的 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开始时听课，而我的弹出错误指示app.use 需要中间件功能我已经尝试过匹配代码和它的相同。请帮我解决这个错误，我在这里卡了几个小时尝试了很多编辑，但对我不起作用。
When I am trying to run 'npm start' following error pops up
当我尝试运行“npm start”时会弹出以下错误
TypeError: app.use() requires middleware functions
类型错误：app.use() 需要中间件函数
Here is app.js code:
这是 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;
Here is package.json file
这是 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": "*"
}
}
Here is updated app.js (after removing multar)
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;
Thank You
谢谢你
回答by Hasitha Prageeth
It worked in this way.delete this line,
它以这种方式工作。删除这一行，
app.use(multer({ dest: './uploads' }));
and use it as,
并将其用作，
var multer = require('multer');
var upload = multer({ dest: './uploads' });
I'm too following the same course
我也遵循同样的课程
回答by Rubén Marrero
Change:
改变：
//Handle File Uploads
app.use(multer({
dest: './uploads'
}));
For something like:
对于类似的事情：
app.use(multer({dest:'./uploads/'}).single('singleInputFileName'));
or
或者
app.use(multer({dest:'./uploads/'}).array('multiInputFileName'));
And be aware to have something like:
并注意有类似的东西：
<form action="/postPhotos" enctype="multipart/form-data">
<input type="file" name="singleInputFileName">
<input type="submit" value="Upload photo">
</form>
for the first case, or:
对于第一种情况，或：
<form action="/postPhotos" enctype="multipart/form-data">
<input type="file" name="multiInputFileName" multiple>
<input type="submit" value="Upload photo">
</form>
For the second one, in your html.
对于第二个，在您的 html 中。
回答by AbdulMomen ?????????
This worked with me:
这对我有用：
app.use(multer({
dest: path.join(__dirname, 'public/upload/temp')
}).any());
回答by MikeLee
I was also doing that course & ran into the same problem. I resolved the error by following the Multer usage instructions from their github: https://github.com/expressjs/multer
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
Here is the code from their README:
这是他们自述文件中的代码：
var multer = require('multer')
var upload = multer({ dest: 'uploads/' })
& here is the code I used to overcome the error while doing that tutorial:
& 这是我在做该教程时用来克服错误的代码：
var multer = require('multer');
var upload = multer({ dest: './uploads' });
Hope it helps :)
希望能帮助到你 ：）
回答by Ashraf
you can simply use :
你可以简单地使用：
app.set(multer({dest: "./uploads"}));
it works for me too.
它也适用于我。
回答by marwari
Replacing app.use(multer({dest:'./uploads'}));
更换 app.use(multer({dest:'./uploads'}));
to
到
var upload = multer({dest:'./uploads'});
worked for me.
为我工作。
回答by Edwin Ikechukwu Okonkwo
change only this line
只改变这一行
app.use(multer({dest:'./uploads'}));
to
到
var upload =multer({dest:'./uploads'});
