Express file upload with multer and gridfs (corrupted file ?) - express

Question

I'm trying to upload a file (an image), the upload is fine, the file is stored in Mongo and have the same content type and same size as the original file, then when I try to download it, the file is corrupted but keeps the same content type (if I upload a pdf, it is recognized as a pdf, if it is a png, it is also recognized, but I can't open them).
I don't understand what is wrong with this, it is pretty simple and standard.
For the upload from the client, I use angular ng-upload, for the download, it is a simple GET request to the route defined in the code.
EDIT :
The file is well uploaded on the server, so the problem is when I try to read it from GridFS.
The file that is downloaded is bigger than the one uploaded ! So the file isn't as the original and is corrupted, why ?
Here is my code.
//BACKEND
//ROUTES
var multer = require('multer');
var upload = multer({ dest: './tmp/'});
router.post('/:id/logo',upload.single('file'), uploadFile);
router.get('/:id/logo', getFile);
//Controller
var Grid = require('gridfs-stream');
var mongoose = require('mongoose');
var fs = require('fs');
uploadLogo = function(req, res) {
var gfs = Grid(mongoose.connection.db, mongoose.mongo);
var writeStream = gfs.createWriteStream();
fs.createReadStream(req.file.path).pipe(writeStream);
writeStream.on('close', function(file) {
res.status(200).send({fileId: file._id});
});
writeStream.on('error', function(e) {
res.status(500).send("Could not upload file");
});
}
getFile = function(req, res) {
var gfs = Grid(mongoose.connection.db, mongoose.mongo);
// Check if the file exist
gfs.findOne({ _id: req.params.id}, function(err, file) {
if(err) {
res.status(404).end();
} else if(!file){
res.status(404).end();
} else {
var readstream = gfs.createReadStream({
_id: file._id
});
res.set('Content-Type', file.contentType);
readstream.on('error', function (err) {
res.send(500, err);
});
readstream.on('open', function () {
readstream.pipe(res);
});
}
});
}
//FRONT END
$scope.newFileUpload = function(file) {
$scope.upload(file);
}
$scope.upload = function(file) {
if (file && !angular.isUndefined(file.name)) {
Upload.upload({
url: 'api/' + $scope.myId + '/logo',
fields: {
'type': 'logo'
},
file: file
}).success(function(data, status, headers, config) {
$scope.imageId = data.fileId;
}).error(function(data, status, headers, config) {
console.log('file upload error status: ' + status);
});
}
};
//THE HTML
<div class="drop-box"
ngf-drop
ngf-select
ng-model="imageLogo"
ngf-drag-over-class="dragover"
ngf-allow-dir="true"
accept="image/*"
ngf-pattern="'image/*'"
ngf-change="newFileUpload(imageLogo)"
ngf-multiple="false"
ngf-resize="{width: 200, height: 50}">
Drop logo image here or click to upload</div>
<input type="file" nv-file-select uploader="uploader"/>