module to upload files to s3

index.js

const util = require('util');
const AWS = require('aws-sdk');
const path = require('path');

/**
 * getClient
 * @returns {object} s3 client instance
 */
const getClient = (function() {
  let s3Client;
  return function() {
    if (s3Client) {
      return s3Client;
    }
    s3Client = new AWS.S3({apiVersion: '2006-03-01'});
    return s3Client;
  };
})();

/**
 * listDirectory
 * @param {array} accumulator - array to accumulate listed files
 * @param {string} bucket - the s3 bucket
 * @param {string} prefix - the s3 prefix
 * @param {string} lastKey - the last key if the results were truncated
 * @returns {list} accumulator
 */
const listDirectory = (list, bucket, prefix, lastKey) => {
  if (!list) {
    list = [];
  }
  const s3Client = getClient();
  const params = {
    Bucket: bucket,
    Prefix: prefix,
  };

  if (lastKey) {
    params.NextMarker = lastKey;
  }

  return util.promisify(s3Client.listObjects.bind(s3Client))(
    params,
  ).then(data => {
    const keys = data.Contents.map(item => {
      return item.Key;
    });
    list.push(...keys);
    if (data.IsTruncated) {
      return listDirectory(list, bucket, prefix, keys[keys.length - 1]);
    }
    return list;
  });
};

module.exports = {
  /**
   * Check for existing key
   * @param {string} bucket
   * @param {string} prefix
   * @returns {promise}
   */
  exists: function(bucket, prefix) {
    const s3Client = getClient();
    const params = {
      Bucket: bucket,
      Key: prefix,
    };
    return util.promisify(s3Client.headObject.bind(s3Client))(params).then(
      _ => {
        return true;
      },
      _ => {
        return false;
      },
    );
  },

  /**
   * CleanFolder
   * Deletes all items in a folder
   * @param {string} bucket
   * @param {string} prefix
   * @returns {promise}
   */
  cleanFolder: function(bucket, prefix) {
    const s3Client = getClient();
    const deleteObjects = s3Client.deleteObjects.bind(s3Client);
    return listDirectory([], bucket, prefix).then(data => {
      if (!data.length) {
        return;
      }
      const params = {
        Bucket: bucket,
        Delete: {
          Objects: data.map(key => {
            return {Key: key};
          }),
        },
      };
      return util.promisify(deleteObjects)(params);
    });
  },

  /**
   * Copy a folder located at one prefix to another
   * @param {string} bucket
   * @param {string} sourcePrefix
   * @param {string} destPrefix
   * @returns {promise}
   */
  copyFolder: function(bucket, sourcePrefix, destPrefix) {
    const s3Client = getClient();
    const copyObject = s3Client.copyObject.bind(s3Client);
    const list = [];

    return listDirectory(list, bucket, sourcePrefix).then(data => {
      if (!data.length) {
        return;
      }
      return Promise.all(
        data.map(key => {
          const params = {
            Bucket: bucket,
            CopySource: path.join('/', bucket, key),
            Key: key.replace(sourcePrefix, destPrefix),
            ACL: 'public-read',
          };
          return util.promisify(copyObject)(params);
        }),
      );
    });
  },

  /**
   * uploadFile
   * @param {string} bucket
   * @param {string} key
   * @param {buffer} data
   * @param {string} contentType
   * @param {string} acl (default='private')
   * @returns {promise}
   */
  uploadFile: function(bucket, key, body, contentType, acl = 'private') {
    const s3Client = getClient();
    const params = {
      Bucket: bucket,
      ACL: acl,
      Key: key,
      Body: body,
      ContentType: contentType,
    };
    return util.promisify(s3Client.putObject.bind(s3Client))(params);
  },
};

package.json

{
  "name": "s3-upload",
  "version": "0.1.0"
}

S3Upload.js

// this file exists just to name the gist, and because gist ordering is asciibetical, it's name starts with a capital letter.