Response Time

Connect middleware to calculate response times.

Similar to response-time, except this implementation does not set a response header for the calculated time and does not override the default response.writeHead method.

The calculated response time is output to a callback provided on initialization. Accordingly, the module is better suited for logging response times and monitoring application performance.

Installation

$ npm install connect-middleware-response-time

Usage

To use the module,

var responseTime = require( 'connect-middleware-response-time' );

responseTime( clbk )

The middleware generator accepts a callback which should accept a numeric value as its only input.

var mw = responseTime( onTime );

function onTime( value ) {
	console.log( 'Response time: %s ms', value );
}

Notes

In the event that an HTTP response terminates prematurely, the returned response time is NaN.

Examples

var express = require( 'express' ),
	request = require( 'request' ),
	responseTime = require( 'connect-middleware-response-time' );

// Define a port:
var PORT = 7331;

// Create a new application:
var app = express();

// Use the response time middleware for all requests:
app.use( responseTime( logger ) );

// Bind a route:
app.get( '/', [ compute, send ] );

// Spin up a new server:
var server = app.listen( PORT, onListen );


function onListen() {
	request({
		'method': 'GET',
		'uri': 'http://127.0.0.1:' + PORT
	}, onResponse );
}

function onResponse( error, response, body ) {
	if ( error ) {
		throw new Error( error );
	}
	console.log( body );
}

function compute( request, response, next ) {
	var rand = Math.floor( Math.random()*2e6 ),
		idx = 0,
		x;
	for ( var i = 0; i < rand; i++ ) {
		x = Math.sqrt( ++idx );	
	}
	next();
}

function logger( value ) {
	console.log( 'Response time: %s ms', value );
}

function send( request, response, next ) {
	response
		.status( 200 )
		.send( '...computation finished...' );
}

To run an example from the top-level application directory,

$ node ./examples/index.js

Tests

Unit

Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:

$ make test

All new feature development should have corresponding unit tests to validate correct functionality.

Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

$ make test-cov

Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

$ make view-cov

License

MIT license.

Copyright

Copyright © 2014. Athan Reines.