CODEWITHSUNDEEP
node.jsmongodbexpress
cauchi
cauchi

Reputation: 1543

Downloading file in node using GridFS in production

I have an express app, which works when I run it locally. The issue is when downloading a file which as saved in mongoDB using GridFS. When running it locally (I just do ./bin/www and go to localhost:3000), I can download the file. But when I run it remotely, I download an html file.

This is the route which handles the response:

router.get('/getfile',function(req,res) {
    if (req.isAuthenticated())
    {
            var gfs = Grid(mongoose.connection, mongoose.mongo);
            var id = req.query.id;
            gfs.exist({_id: id}, function (err, found) {
                if (err) return handleError(err);
                if (!found)
                    res.send('Error on the database looking for the file.')
            });

            var readStream = gfs.createReadStream({
                _id: id
            }).pipe(res);
    }
    else
        res.redirect('/login');
});

and that is called by this line in a jade file:

td #[a(href="getfile?id=#{log.videoId}" download="video") #[span(name='video').glyphicon.glyphicon-download]]

On the server, I'm doing:

/logApp$ export NODE_ENV=production
/logApp$ ./bin/www

the mongoDB deamon is running. In fact, I can query the database. And I'm not writing any file! I want to read it.

EDIT: I found the error message:

MongoError: file with id #### not opened for writing

Upvotes: 4

Views: 1486

Answers (1)

danneu
danneu

Reputation: 9464

You need to move the code that pipes the file to the response into the gfs.exist callback so that it runs after the exist check.

gfs.exist({ _id: id }, function(err, found) {
    if (err) {
      handleError(err); 
      return;
    }

    if (!found) {
      res.send('Error on the database looking for the file.')
      return;
    }

    // We only get here if the file actually exists, so pipe it to the response
    gfs.createReadStream({ _id: id }).pipe(res);
});

Apparently you get that generic "not opened for writing" error if the file doesn't exist.

Upvotes: 1

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