# connect-timeout

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Times out a request in the Connect/Express application framework.

## Install

This is a [Node.js](https://nodejs.org/en/) module available through the
[npm registry](https://www.npmjs.com/). Installation is done using the
[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):

```sh
$ npm install connect-timeout
```

## API

**NOTE** This module is not recommend as a "top-level" middleware (i.e.
`app.use(timeout('5s'))`) unless you take precautions to halt your own
middleware processing. See [as top-level middleware](#as-top-level-middleware)
for how to use as a top-level middleware.

While the library will emit a 'timeout' event when requests exceed the given
timeout, node will continue processing the slow request until it terminates.
Slow requests will continue to use CPU and memory, even if you are returning
a HTTP response in the timeout callback. For better control over CPU/memory,
you may need to find the events that are taking a long time (3rd party HTTP
requests, disk I/O, database calls) and find a way to cancel them, and/or
close the attached sockets.

### timeout(time, [options])

Returns middleware that times out in `time` milliseconds. `time` can also
be a string accepted by the [ms](https://www.npmjs.org/package/ms#readme)
module. On timeout, `req` will emit `"timeout"`.

#### Options

The `timeout` function takes an optional `options` object that may contain
any of the following keys:

##### respond

Controls if this module will "respond" in the form of forwarding an error.
If `true`, the timeout error is passed to `next()` so that you may customize
the response behavior. This error has a `.timeout` property as well as
`.status == 503`. This defaults to `true`.

### req.clearTimeout()

Clears the timeout on the request. The timeout is completely removed and
will not fire for this request in the future.

### req.timedout

`true` if timeout fired; `false` otherwise.

## Examples

### as top-level middleware

Because of the way middleware processing works, once this module
passes the request to the next middleware (which it has to do in order
for you to do work), it can no longer stop the flow, so you must take
care to check if the request has timedout before you continue to act
on the request.

```javascript
var bodyParser = require('body-parser')
var cookieParser = require('cookie-parser')
var express = require('express')
var timeout = require('connect-timeout')

// example of using this top-level; note the use of haltOnTimedout
// after every middleware; it will stop the request flow on a timeout
var app = express()
app.use(timeout('5s'))
app.use(bodyParser())
app.use(haltOnTimedout)
app.use(cookieParser())
app.use(haltOnTimedout)

// Add your routes here, etc.

function haltOnTimedout (req, res, next) {
  if (!req.timedout) next()
}

app.listen(3000)
```

### express 3.x

```javascript
var express = require('express')
var bodyParser = require('body-parser')
var timeout = require('connect-timeout')

var app = express()
app.post('/save', timeout('5s'), bodyParser.json(), haltOnTimedout, function (req, res, next) {
  savePost(req.body, function (err, id) {
    if (err) return next(err)
    if (req.timedout) return
    res.send('saved as id ' + id)
  })
})

function haltOnTimedout (req, res, next) {
  if (!req.timedout) next()
}

function savePost (post, cb) {
  setTimeout(function () {
    cb(null, ((Math.random() * 40000) >>> 0))
  }, (Math.random() * 7000) >>> 0)
}

app.listen(3000)
```

### connect

```javascript
var bodyParser = require('body-parser')
var connect = require('connect')
var timeout = require('connect-timeout')

var app = connect()
app.use('/save', timeout('5s'), bodyParser.json(), haltOnTimedout, function (req, res, next) {
  savePost(req.body, function (err, id) {
    if (err) return next(err)
    if (req.timedout) return
    res.send('saved as id ' + id)
  })
})

function haltOnTimedout (req, res, next) {
  if (!req.timedout) next()
}

function savePost (post, cb) {
  setTimeout(function () {
    cb(null, ((Math.random() * 40000) >>> 0))
  }, (Math.random() * 7000) >>> 0)
}

app.listen(3000)
```

## License

[MIT](LICENSE)

[npm-image]: https://img.shields.io/npm/v/connect-timeout.svg
[npm-url]: https://npmjs.org/package/connect-timeout
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[coveralls-url]: https://coveralls.io/r/expressjs/timeout?branch=master
[downloads-image]: https://img.shields.io/npm/dm/connect-timeout.svg
[downloads-url]: https://npmjs.org/package/connect-timeout
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