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https://github.com/jshttp/on-headers
Execute a listener when a response is about to write headers.
https://github.com/jshttp/on-headers
event headers http javascript nodejs
Last synced: 4 days ago
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Execute a listener when a response is about to write headers.
- Host: GitHub
- URL: https://github.com/jshttp/on-headers
- Owner: jshttp
- License: mit
- Created: 2014-05-14T01:30:01.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2024-05-14T17:13:19.000Z (6 months ago)
- Last Synced: 2024-10-30T13:56:37.706Z (14 days ago)
- Topics: event, headers, http, javascript, nodejs
- Language: JavaScript
- Size: 65.4 KB
- Stars: 154
- Watchers: 17
- Forks: 20
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: HISTORY.md
- License: LICENSE
Awesome Lists containing this project
README
# on-headers
[![NPM Version][npm-version-image]][npm-url]
[![NPM Downloads][npm-downloads-image]][npm-url]
[![Node.js Version][node-image]][node-url]
[![Build Status][ci-image]][ci-url]
[![Coverage Status][coveralls-image]][coveralls-url]
Execute a listener when a response is about to write headers.
## Installation
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 on-headers
```
## API
```js
var onHeaders = require('on-headers')
```
### onHeaders(res, listener)
This will add the listener `listener` to fire when headers are emitted for `res`.
The listener is passed the `response` object as it's context (`this`). Headers are
considered to be emitted only once, right before they are sent to the client.
When this is called multiple times on the same `res`, the `listener`s are fired
in the reverse order they were added.
## Examples
```js
var http = require('http')
var onHeaders = require('on-headers')
http
.createServer(onRequest)
.listen(3000)
function addPoweredBy () {
// set if not set by end of request
if (!this.getHeader('X-Powered-By')) {
this.setHeader('X-Powered-By', 'Node.js')
}
}
function onRequest (req, res) {
onHeaders(res, addPoweredBy)
res.setHeader('Content-Type', 'text/plain')
res.end('hello!')
}
```
## Testing
```sh
$ npm test
```
## License
[MIT](LICENSE)
[ci-image]: https://badgen.net/github/checks/jshttp/on-headers/master?label=ci
[ci-url]: https://github.com/jshttp/on-headers/actions/workflows/ci.yml
[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/on-headers/master
[coveralls-url]: https://coveralls.io/r/jshttp/on-headers?branch=master
[node-image]: https://badgen.net/npm/node/on-headers
[node-url]: https://nodejs.org/en/download
[npm-downloads-image]: https://badgen.net/npm/dm/on-headers
[npm-url]: https://npmjs.org/package/on-headers
[npm-version-image]: https://badgen.net/npm/v/on-headers