File download is not working with nodejs gridfs - node.js

Question

i'm uploading images to gridfs-stream using node and express..uploading is working fine but am unable to download
app.post('/upload', function (req, res) {
var tempfile = req.files.displayImage.path;
var origname = req.files.displayImage.name;
var _id = guid();
var writestream = gfs.createWriteStream({
filename: _id
});
// open a stream to the temporary file created by Express...
fs.createReadStream(tempfile)
.on('end', function () {
res.send(_id);
})
.on('error', function () {
res.send('ERR');
})
// and pipe it to gfs
.pipe(writestream);
});
app.get('/download', function (req, res) {
// TODO: set proper mime type + filename, handle errors, etc...
gfs
// create a read stream from gfs...
.createReadStream({
filename: req.param('filename')
})
// and pipe it to Express' response
.pipe(res);
});
the above code is unable to download the image by this cmd download?filename=acf58ae4-c853-f9f3-5c66-c395b663298a

Answer 1

You might need to check your values in params. But hopefully this near minimal sample provides some help:
Update
And it has helped, because it highlights that you are looking up the _id as a filename. Instead you should be doing this:
.createReadStream({
_id: req.param('filename')
})
if not
.createReadStream({
_id: mongoose.Types.ObjectId(req.param('filename'))
})
Since the _id field is different to the filename
app.js
var express = require('express');
var routes = require('./routes');
var http = require('http');
var path = require('path');
var app = express();
var mongoose = require('mongoose');
var Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo;
var conn = mongoose.createConnection('mongodb://localhost/mytest');
conn.once('open', function() {
console.log('opened connection');
gfs = Grid(conn.db);
// all environments
app.set('port', process.env.PORT || 3000);
app.use(express.logger('dev'));
app.use(app.router);
// development only
if ('development' == app.get('env')) {
app.use(express.errorHandler());
}
app.get('/', routes.index);
http.createServer(app).listen(app.get('port'), function(){
console.log('Express server listening on port ' + app.get('port'));
});
});
routes/index.js
exports.index = function(req, res){
res.set('Content-Type', 'image/jpeg');
gfs.createReadStream({
filename: 'receptor.jpg'
}).pipe(res);
};