response-time

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Response time for Node.js servers.

This module creates a middleware that records the response time for
requests in HTTP servers. The "response time" is defined here as the
elapsed time from when a request enters this middleware to when the
headers are written out to the client.

Installation

This is a Node.js module available through the
npm registry. Installation is done using the
npm install command:

``sh
$ npm install response-time
`

API

`js
var responseTime = require('response-time')
`

$3

Create a middleware that adds a X-Response-Time header to responses. If
you don't want to use this module to automatically set a header, please
see the section about responseTime(fn).

#### Options

The responseTime function accepts an optional options object that may
contain any of the following keys:

##### digits

The fixed number of digits to include in the output, which is always in
milliseconds, defaults to 3 (ex: 2.300ms).

##### header

The name of the header to set, defaults to X-Response-Time.

##### suffix

Boolean to indicate if units of measurement suffix should be added to
the output, defaults to true (ex: 2.300ms vs 2.300).

$3

Create a new middleware that records the response time of a request and
makes this available to your own function fn. The fn argument will be
invoked as fn(req, res, time), where time is a number in milliseconds.

Examples

$3

`js
var express = require('express')
var responseTime = require('response-time')

var app = express()

app.use(responseTime())

app.get('/', function (req, res) {
res.send('hello, world!')
})
`

$3

`js
var finalhandler = require('finalhandler')
var http = require('http')
var responseTime = require('response-time')

// create "middleware"
var _responseTime = responseTime()

http.createServer(function (req, res) {
var done = finalhandler(req, res)
_responseTime(req, res, function (err) {
if (err) return done(err)

// respond to request
res.setHeader('content-type', 'text/plain')
res.end('hello, world!')
})
})
`

$3

`js
var express = require('express')
var responseTime = require('response-time')
var StatsD = require('node-statsd')

var app = express()
var stats = new StatsD()

stats.socket.on('error', function (error) {
console.error(error.stack)
})

app.use(responseTime(function (req, res, time) {
var stat = (req.method + req.url).toLowerCase()
.replace(/[:.]/g, '')
.replace(/\//g, '_')
stats.timing(stat, time)
}))

app.get('/', function (req, res) {
res.send('hello, world!')
})
``

License

MIT

[npm-version-image]: https://badgen.net/npm/v/response-time
[npm-url]: https://npmjs.org/package/response-time
[npm-downloads-image]: https://badgen.net/npm/dm/response-time
[node-image]: https://badgen.net/npm/node/response-time
[node-url]: https://nodejs.org/en/download
[ci-image]: https://badgen.net/github/checks/express/response-time/master?label=ci
[ci-url]: https://github.com/express/response-time/actions/workflows/ci.yml
[coveralls-image]: https://badgen.net/coveralls/c/github/express/response-time/master
[coveralls-url]: https://coveralls.io/r/express/response-time?branch=master