Can you use find queries on GridFS using javascript API?

Question

As I understand it, when you enter something into GridFS it gets entered into 2 different collections under the hood. One for the raw chunks of data and one for the meta data files.

Also from what I understand from MongoDB's documentation is that you can only retrieve a document from GridFS with an id or name.

var gs = new mongodb.GridStore(db, "test.png", "w", {
"content_type": "image/png",
"metadata":{
    "author": "Daniel"
},
"chunk_size": 1024*4

});

So what if I want to get a subset of documents from GridFS? For example what if I want all GridStores with:

metadata: {author: "Daniel"}

Why can't I use standard mongo queries { field: somevalue } and retrieve documents that way?

Does anybody know how this can be done? I'm using the javascript API on node.js.

What kind of subset are you talking about? Please give us an example. — Philipp, Dec 04 '13 at 17:33

score 6 · Accepted Answer · answered Dec 04 '13 at 20:49

You can query the db.files collection just like any other collection:

db.collection('fs.files')
  .find({ 'metadata.author' : 'Daniel' })
  .toArray(function(err, files) {
    if (err) throw err;
    files.forEach(function(file) {
      var gs = new mongodb.GridStore(db, file._id, 'r');
      ...
    });
  });

Although instead of plain forEach you may want to use async.each or any of the other async.* methods.

Can you use find queries on GridFS using javascript API?

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