dynamodb.js

/*
 * This is a wrapper for AWS Dynamo DB Document Client.
 * License: MIT License
 *
 * required AWS SDK And jQuery.
 * However, it is a good idea to replace Deferred with Promise.
 *
 * How to use.
 *
 * 1, Insert HTML tag.
 * <script src="https://sdk.amazonaws.com/js/aws-sdk-2.95.0.min.js"></script>
 * <script src="dist/dynamodb.js"></script>
 *
 * 2, Set _accessKeyId and _secretAccessKey as necessary, or set AWS.config.credentials using AWS Cognito Identity.
 *
 * Example of use.
 * var dynamodb = AWSDyDBDC.getInstance();
 * dynamodb.get(__PARAMS__).then(__CODE__).fail(__CODE__).always(__CODE__);
 */
var AWSDyDBDC = (function(){

  var _region = 'ap-northeast-1';
  var _accessKeyId = '';
  var _secretAccessKey = '';

  var _docClient = null;

  var _getDocClient = function(){
    if (_docClient === null) {
      _docClient = new AWS.DynamoDB.DocumentClient();
      console.log('AWS.DynamoDB.DocumentClient Ready.');
    }
    return _docClient;
  };

  var _constructor = function(){
    if (typeof AWS !== 'object') {
      throw new Error('RequiredObjectDoesNotExist');
    }
    AWS.config.region = _region;
    if (_accessKeyId && _secretAccessKey) {
      AWS.config.update({
        accessKeyId: _accessKeyId,
        secretAccessKey: _secretAccessKey
      });
    }
  };

  _constructor.prototype.getInstance = function(){
    return this;
  };

  _constructor.prototype.promiseCallback = function(callback){
    var deferred = $.Deferred();
    if (typeof callback === 'function') {
      return callback(deferred);
    }
    return deferred.reject();
  };

  _constructor.prototype.put = function(params){
    var _params = params || {
      TableName: '',
      Item: {},
    };
    return this.promiseCallback(function(deferred){
      _getDocClient().put(_params, function(err, data){
        return ((err) ? deferred.reject(err) : deferred.resolve(data));
      });
      return deferred.promise();
    });
  };

  _constructor.prototype.get = function(params){
    var _params = params || {
      TableName: '',
      Key: {},
    };
    return this.promiseCallback(function(deferred){
      _getDocClient().get(_params, function(err, data){
        return ((err) ? deferred.reject(err) : deferred.resolve(data));
      });
      return deferred.promise();
    });
  };

  _constructor.prototype.update = function(params){
    var _params = params || {
      TableName: '',
      Key: {},
      ExpressionAttributeNames: {},
      ExpressionAttributeValues: {},
      UpdateExpression: '',
    };
    return this.promiseCallback(function(deferred){
      _getDocClient().update(_params, function(err, data){
        return ((err) ? deferred.reject(err) : deferred.resolve(data));
      });
      return deferred.promise();
    });
  };

  _constructor.prototype.delete = function(params){
    var _params = params || {
      TableName: '',
      Key: {},
    };
    return this.promiseCallback(function(deferred){
      _getDocClient().delete(_params, function(err, data){
        return ((err) ? deferred.reject(err) : deferred.resolve(data));
      });
      return deferred.promise();
    });
  };

  _constructor.prototype.scan = function(tableName, useSort, sortKey){
    var params = {
      TableName: tableName || '',
    };
    useSort = useSort || false;
    sortKey = sortKey || 'id';
    return this.promiseCallback(function(deferred){
      _getDocClient().scan(params, function(err, data){
        if (err) { return deferred.reject(err); }
        var items = (useSort) ? data.Items.sort(function(a, b){
          if (a[sortKey] < b[sortKey]) return -1;
          if (a[sortKey] > b[sortKey]) return 1;
          return 0;
        }) : data.Items ;
        return deferred.resolve(items);
      });
      return deferred.promise();
    });
  };

  return new _constructor();
})();