You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
82 lines
2.1 KiB
Markdown
82 lines
2.1 KiB
Markdown
6 years ago
|
# on-headers
|
||
|
|
|
||
|
|
[![NPM Version][npm-version-image]][npm-url]
|
||
|
|
[![NPM Downloads][npm-downloads-image]][npm-url]
|
||
|
|
[![Node.js Version][node-version-image]][node-version-url]
|
||
|
|
[![Build Status][travis-image]][travis-url]
|
||
|
|
[![Test Coverage][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
|
||
|
|
|
||
|
|
<!-- eslint-disable no-unused-vars -->
|
||
|
|
|
||
|
|
```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)
|
||
|
|
|
||
|
|
[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/on-headers/master
|
||
|
|
[coveralls-url]: https://coveralls.io/r/jshttp/on-headers?branch=master
|
||
|
|
[node-version-image]: https://badgen.net/npm/node/on-headers
|
||
|
|
[node-version-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
|
||
|
|
[travis-image]: https://badgen.net/travis/jshttp/on-headers/master
|
||
|
|
[travis-url]: https://travis-ci.org/jshttp/on-headers
|