Get Full Contents of Amazon s3 Bucket

getFullContentsOfAmazonS3Bucket.js

'use strict';

var applicationConfigs = require('expressively').configs,
    AWS = require('aws-sdk'),
    BB = require('bluebird'),
    path = require('path'),
    logger = require('../lib/logger'),
    s3Instance;

AWS.config.update({
    accessKeyId: applicationConfigs.grasshopper.assets.engines.amazon.accessKeyId,
    secretAccessKey: applicationConfigs.grasshopper.assets.engines.amazon.secretAccessKey,
    region: applicationConfigs.grasshopper.assets.engines.amazon.region
});

s3Instance = new AWS.S3();

module.exports = function getFullContentsOfAmazonBucket(bucketId) {
    return _getBatchRecursive(bucketId, [])
        .then(function(collectedObjects) {
            return collectedObjects
                .filter(function(amazonImageObject) {
                    return !!path.extname(amazonImageObject.Key);
                })
                .map(function(amazonImageObject) {
                    return applicationConfigs.assetsPrefix + amazonImageObject.Key;
                });
        })
        .catch(function(err) {
            logger.error(`COULD NOT RETRIEVE AMAZON BUCKET: ${bucketId}`);
            logger.error(err);
        });
};

function _getBatchRecursive(bucketId, collectedObjects, marker) {
    var s3Options = {
        Bucket: applicationConfigs.grasshopper.assets.engines.amazon.bucket,
        Prefix: bucketId
    };

    if(marker) {
        s3Options.Marker = marker;
    }

    return new BB(function(resolve, reject) {
        s3Instance.listObjects(s3Options,
            function(err, data) {
                if(err) {
                    reject(err);
                } else {
                    collectedObjects = collectedObjects.concat(data.Contents);

                    if (data.IsTruncated) {
                        return _getBatchRecursive(bucketId, collectedObjects, data.Contents[data.Contents.length -1].Key)
                            .then(resolve);
                    } else {
                        resolve(collectedObjects);
                    }
                }
            });
    });
}