How to stream MongoDB Query Results with nodejs?

node-mongodb-driver (the underlying layer that every mongoDB client uses in nodejs) except the cursor API that others mentioned has a nice stream API (#458). Unfortunately i did not find it documented elsewhere.

Update: there are docs also here.

It can be used like this:

var stream = collection.find().stream()stream.on('error', function (err) {  console.error(err)})stream.on('data', function (doc) {  console.log(doc)})

It actually implements the ReadableStream interface, so it has all the goodies (pause/resume etc)

Streaming in Mongoose became available in version 2.4.0 which appeared three months after you've posted this question:

Model.where('created').gte(twoWeeksAgo).stream().pipe(writeStream);

More elaborated examples can be found on their documentation page.

mongoose is not really "driver", it's actually an ORM wrapper around the MongoDB driver (node-mongodb-native).

To do what you're doing, take a look at the driver's .find and .each method. Here's some code from the examples:

// Find all records. find() returns a cursorcollection.find(function(err, cursor) {  sys.puts("Printing docs from Cursor Each")  cursor.each(function(err, doc) {    if(doc != null) sys.puts("Doc from Each " + sys.inspect(doc));  })                    });

To stream the results, you're basically replacing that sys.puts with your "stream" function. Not sure how you plan to stream the results. I think you can do response.write() + response.flush(), but you may also want to checkout socket.io.