MongoDB GridFS driver in NodeJS overwrites files with the same name

Question

I have the following code (removed error checking to keep it concise) which uses the node-mongodb-native.

var mongo = require('mongodb').MongoClient;
var grid = require('mongodb').GridStore;
var url = 'mongodb://localhost:27017/mydatabase';

mongo.connect(url, function(err, db) {
    var gs = new grid(db, 'myfile.txt', 'w', {
        "metadata": {
            // metadata here
        }   
    }); 
    gs.open(function(err, store) {
        gs.writeFile('~/myfile.txt', function(err, doc) {
            fs.unlink(req.files.save.path, function (err) {
                // error checking etc
            }); 
        }   
    }); 
});

If I run that once it works fine and stores the file in GridFS.

Now, if I delete that file on my system and create a new one with the same name, but different contents, and run it though that code again it uploads it. However, it seems to overwrite the file that is already stored in GridFS. _id stays the same, but md5 has been updated to the new value. So even though the file is different, because the name is the same it overwrites the current file in GridFS.

Is there a way to upload two files with the same name? If _id is unique, why does the driver overwrite the file based on file name alone?

I found a similar issue on GitHub, but I am using the latest version of the driver from npm and it does what I explained above.

score 3 · Accepted Answer · answered Jan 13 '13 at 17:06

3

Like a real filesystem, the filename becomes the logical key in GridFS for reading and writing. You cannot have two files with the same name.

You'll need to come up with a secondary index of some sort or a new generated file name.

For example, add a timestamp to the file name.

Or, create another collection that maps generated file names to the GridFS structure to whatever it is that you need.

answered Jan 13 '13 at 17:06

WiredPrairie

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I see what you mean. Upon looking at the documentation more throughly, it looks like the filename is actually optional. I will just put it in the metadata to query against and forget the filename field itself. [Files Collection](http://docs.mongodb.org/manual/applications/gridfs/#the-files-collection) – BytesGuy Jan 14 '13 at 00:02

score 0 · Answer 2 · answered Feb 22 '14 at 12:39

To avoid having to create additional unique identifiers for your files you should omit the 'write mode' option. This will allow gridfs to create a new file even if it contains the exact same data.

'w' overwrites data, which is why you are overwriting the existing file.

http://mongodb.github.io/node-mongodb-native/api-generated/gridstore.html

MongoDB GridFS driver in NodeJS overwrites files with the same name

2 Answers2