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javascript - how to upload image file and display using express nodejs

I have used following code :

fileupload.html

<html>
<head>
<title>File Uploading Form</title>
</head>
<body>
<h3>File Upload:</h3>
Select a file to upload: <br />
<form action="http://127.0.0.1:8081/file_upload" method="POST" enctype="multipart/form-data">
<input type="file" name="file" size="50" />
<br />
<input type="submit" value="Upload File" />
</form>
</body>
</html>

fileupload.js:

var express = require('express');
var app = express();
var fs = require("fs");

var bodyParser = require('body-parser');
var multer  = require('multer');

//console.log(multer);

app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: false }));
app.use(multer({ dest: '/tmp/'}));

app.get('/fileupload.html', function (req, res) {
   res.sendFile( __dirname + "/" + "fileupload.html" );
})

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)
})

I have used these above code for file uploading But when excute using node fileupload.js in terminal i am getting type error TypeError('app.use() requires middleware functions');

Can any one help to resolved this problem.

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1 Reply

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by (71.8m points)

You're trying to use multer's old API. It changed awhile back, see the documentation for more information.

In your particular case of uploading a single file, you would remove the app.use(multer({ ... })) line and instead use .single() and req.file like:

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

// File input field name is simply 'file'
app.post('/file_upload', upload.single('file'), function(req, res) {
  var file = __dirname + '/' + req.file.filename;
  fs.rename(req.file.path, file, function(err) {
    if (err) {
      console.log(err);
      res.send(500);
    } else {
      res.json({
        message: 'File uploaded successfully',
        filename: req.file.filename
      });
    }
  });
});

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