Node.js & Amazon S3: How to iterate through all files in a bucket?

Using the official aws-sdk:

var allKeys = [];
function listAllKeys(marker, cb)
{
  s3.listObjects({Bucket: s3bucket, Marker: marker}, function(err, data){
    allKeys.push(data.Contents);

    if(data.IsTruncated)
      listAllKeys(data.Contents.slice(-1)[0].Key, cb);
    else
      cb();
  });
}

see s3.listObjects

In fact aws2js supports listing of objects in a bucket on a low level via s3.get() method call. To do it one has to pass prefix parameter which is documented on Amazon S3 REST API page:

var s3 = require('aws2js').load('s3', awsAccessKeyId, awsSecretAccessKey);    
s3.setBucket(bucketName);

var folder = encodeURI('some/path/to/S3/folder');
var url = '?prefix=' + folder;

s3.get(url, 'xml', function (error, data) {
    console.log(error);
    console.log(data);
});

The data variable in the above snippet contains a list of all objects in the bucketName bucket.

Published knox-copy when I couldn't find a good existing solution. Wraps all the pagination details of the Rest API into a familiar node stream:

var knoxCopy = require('knox-copy');

var client = knoxCopy.createClient({
  key: '<api-key-here>',
  secret: '<secret-here>',
  bucket: 'mrbucket'
});

client.streamKeys({
  // omit the prefix to list the whole bucket
  prefix: 'buckets/of/fun' 
}).on('data', function(key) {
  console.log(key);
});

If you're listing fewer than 1000 files a single page will work:

client.listPageOfKeys({
  prefix: 'smaller/bucket/o/fun'
}, function(err, page) {
  console.log(page.Contents); // <- Here's your list of files
});

Although @Meekohi's answer does technically work, I've had enough heartache with the S3 portion of the AWS SDK for NodeJS. After all the previous struggling with modules such as aws-sdk, s3, knox, I decided to install s3cmd via the OS package manager and shell-out to it using child_process

Something like:

    var s3cmd = new cmd_exec('s3cmd', ['ls', filepath, 's3://'+inputBucket],
            function (me, data) {me.stdout += data.toString();},
            function (me) {me.exit = 1;}
    );
    response.send(s3cmd.stdout);

(Using the cmd_exec implementation from this question)

This approach just works really well - including for other problematic things like file upload.