opentsdb-client/lib/request/get_response.js

HTTP client for querying OpenTSDB.

/**
*
*	OPENTSDB: GET/ response
*
*
*	DESCRIPTION:
*		- Response callback for GET request.
*
*
*	NOTES:
*		[1]
*
*
*	TODO:
*		[1]
*
*
*	LICENSE:
*		MIT
*
*	Copyright (c) 2014. Athan Reines.
*
*
*	AUTHOR:
*		Athan Reines. kgryte@gmail.com.
*
*/

'use strict';

/**
* FUNCTION: getResponse( clbk )
*	Returns a response handler.
*
* @param {Function} clbk - callback to invoke upon receiving a request response. Function should accept two arguments: [ error, data ].
* @returns {Function} response handler
*/
function getResponse( clbk ) {
	if ( typeof clbk !== 'function' ) {
		throw new TypeError( 'getResponse()::invalid input argument. Callback must be a function.' );
	}
	/**
	* FUNCTION: onResponse( error, response, body )
	*	Response handler.
	*
	* @private
	* @param {Object} error - error object
	* @param {Object} response - response object
	* @param {String} body - response body
	*/
	return function onResponse( error, response, body ) {
		var data;
		if ( error ) {
			clbk({
				'status': 502,
				'message': 'Request error. Unable to obtain data.'
			});
			return;
		}
		if ( !body ) {
			clbk({
				'status': 404,
				'message': 'No data returned. Empty body. Ensure all query parameters are correct.'
			});
			return;
		}
		try {
			data = JSON.parse( body );
		} catch ( err ) {
			clbk({
				'status': 502,
				'message': 'Unsupported data format. Response body cannot be parsed as JSON.'
			});
			return;
		}
		if ( Array.isArray( data ) && !data.length ) {
			clbk({
				'status': 404,
				'message': 'No data returned. Empty data array. Ensure all query parameters are correct.'
			});
			return;
		}
		clbk( null, data );
	}; // end FUNCTION onResponse()
} // end FUNCTION getResponse()


// EXPORTS //

module.exports = getResponse;