无法在Nodejs中执行文件上传程序

Not able to execute a fileupload program in Nodejs

本文关键字：文件 程序 执行 Nodejs      更新时间：2023-09-26

我有一个简单的程序，我试图从在线教程http://www.tutorialspoint.com/nodejs/nodejs_express_framework.htm执行，但我得到一个异常如下:

我对nodejs比较陌生，任何形式的帮助或指导都将非常感激。

使用NodeJS版本:4.1.1。

TypeError: app.use() requires middleware functions
    at EventEmitter.use (c:'nital'my-data'my-sample-apps'nodejs'tutorialspoint-samples'node_modules'express'lib'application.js:209:11)
    at Object.<anonymous> (c:'nital'my-data'my-sample-apps'nodejs'tutorialspoint-samples'Sample37.js:11:5)
    at Module._compile (module.js:434:26)
    at Object.Module._extensions..js (module.js:452:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Function.Module.runMain (module.js:475:10)
    at startup (node.js:117:18)
    at node.js:951:3

FileUploadDemo.js 

var express = require('express');
var app = express();
var fs = require("fs");
var bodyParser = require('body-parser');
var multer = require('multer');
app.use(express.static('public'));
app.use(bodyParser.urlencoded({extended: false}));
app.use(multer({dest: 'C:/tmp/'}));
app.get('/upload.html', function (req, res) {
    res.sendFile(__dirname + "/" + "upload.html");
});
//uploading the file here
app.post('/file_upload', function (req, res) {
    console.log(req.files.file.name);
    console.log(req.files.file.path);
    console.log(req.files.file.type);
    var file = __dirname + "/" + req.files.file.name;
    fs.readFile(req.files.file.path, function (err, data) {
        fs.writeFile(file, data, function (err) {
            if (err) {
                console.log(err);
            } else {
                response = {
                    message: 'File uploaded successfully',
                    filename: req.files.file.name
                };
            }
            console.log(response);
            res.end(JSON.stringify(response));
        });
    });
});
var server = app.listen(8081, function () {
    var host = server.address().address;
    var port = server.address().port;
    console.log("Example app listening at http://%s:%s", host, port)
});

看起来multer的api发生了变化。由于本教程使用npm install multer --save，因此它会引入最新版本，而不是确保您拥有的版本是兼容的。关于如何使用它的详细信息可以在npm页面上找到。看来你现在需要添加特定的中间件到特定的路由:

// Remove this line: app.use(multer({dest: 'C:/tmp/'}));
// Put this in instead
var upload = multer({ dest: 'C:/tmp/' });
// Change this: app.post('/file_upload', function (req, res) {
// to
app.post('/file_upload', upload.single('file'), function (req, res) {

虽然您可能仍然可以使用app.use将其添加到所有路由，但您肯定需要将其更改为使用上载。单个(或其他他们选择的中间件)。

下面是我比较的与nodejs教程不同的代码。

server.js 

//20160720 tested!
//[dif]:= different from http://www.tutorialspoint.com/nodejs/nodejs_express_framework.htm
var express = require('express');
var app = express();
var fs = require("fs");
var bodyParser = require('body-parser');
var multer = require('multer');
app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: false }));
//[dif]app.use(multer({ dest: '/tmp/'}));
var upload = multer({ dest: '/tmp/'}); 

app.get('/index.htm', function (request, response) {response.sendFile( __dirname + "/" + "index.htm" );})
//[dif]app.post('/file_upload', function (request, response) {
app.post('/file_upload', upload.single('file'), function (request, response) {
/*[dif]
   console.log(request.files.file.name);
   console.log(request.files.file.path);
   console.log(request.files.file.type);
   var file = __dirname + "/" + request.files.file.name;
   fs.readFile( request.files.file.path, function (err, data) {
[dif]*/
   console.log(request.file.originalname);
   console.log(request.file.path);
   console.log(request.file.mimetype);

//[dif]   var file = __dirname + "/" + request.file.name;
   var file = __dirname + "/" + request.file.originalname;
   fs.readFile( request.file.path, function (err, data) {
        fs.writeFile(file, data, function (err) {
         if( err ){
              console.log( err );
         }else{
               uploadResponse = {
                   message:'File uploaded successfully',
//[dif]                   filename:request.files.file.name
                   filename:request.file.originalname
              };
          }
          console.log( uploadResponse );
          response.end( JSON.stringify( uploadResponse ) );
       });
   });
})
var server = app.listen(8081, function () {
  var host = server.address().address
  var port = server.address().port
  console.log("Example app listening at http://%s:%s", host, port)
})

如果你得到错误- " error: enent: no such file or directory，打开'C:'tmp'ce194372b624b45f2c881140fecad07f'错误(本地)"您应该在根路径中创建tmp文件夹来保存临时文件。在我的例子中是"c:'tmp"，而"ce194372b624b45f2c881140fecad07f"是临时文件。文件上传成功后，请删除。

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