HORIZON PROJECT

# encodeurl

[![NPM Version][npm-image]][npm-url]

[![NPM Downloads][downloads-image]][downloads-url]

[![Node.js Version][node-version-image]][node-version-url]

[![Build Status][travis-image]][travis-url]

[![Test Coverage][coveralls-image]][coveralls-url]

Encode a URL to a percent-encoded form, excluding already-encoded sequences

## 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 encodeurl

```

## API

```js

var encodeUrl = require('encodeurl')

```

### encodeUrl(url)

Encode a URL to a percent-encoded form, excluding already-encoded sequences.

This function will take an already-encoded URL and encode all the non-URL

code points (as UTF-8 byte sequences). This function will not encode the

"%" character unless it is not part of a valid sequence (`%20` will be

left as-is, but `%foo` will be encoded as `%25foo`).

This encode is meant to be "safe" and does not throw errors. It will try as

hard as it can to properly encode the given URL, including replacing any raw,

unpaired surrogate pairs with the Unicode replacement character prior to

encoding.

This function is _similar_ to the intrinsic function `encodeURI`, except it

will not encode the `%` character if that is part of a valid sequence, will

not encode `[` and `]` (for IPv6 hostnames) and will replace raw, unpaired

surrogate pairs with the Unicode replacement character (instead of throwing).

## Examples

### Encode a URL containing user-controled data

```js

var encodeUrl = require('encodeurl')

var escapeHtml = require('escape-html')

http.createServer(function onRequest (req, res) {

  // get encoded form of inbound url

  var url = encodeUrl(req.url)

  // create html message

  var body = '<p>Location ' + escapeHtml(url) + ' not found</p>'

  // send a 404

  res.statusCode = 404

  res.setHeader('Content-Type', 'text/html; charset=UTF-8')

  res.setHeader('Content-Length', String(Buffer.byteLength(body, 'utf-8')))

  res.end(body, 'utf-8')

})

```

### Encode a URL for use in a header field

```js

var encodeUrl = require('encodeurl')

var escapeHtml = require('escape-html')

var url = require('url')

http.createServer(function onRequest (req, res) {

  // parse inbound url

  var href = url.parse(req)

  // set new host for redirect

  href.host = 'localhost'

  href.protocol = 'https:'

  href.slashes = true

  // create location header

  var location = encodeUrl(url.format(href))

  // create html message

  var body = '<p>Redirecting to new site: ' + escapeHtml(location) + '</p>'

  // send a 301

  res.statusCode = 301

  res.setHeader('Content-Type', 'text/html; charset=UTF-8')

  res.setHeader('Content-Length', String(Buffer.byteLength(body, 'utf-8')))

  res.setHeader('Location', location)

  res.end(body, 'utf-8')

})

```

## Testing

```sh

$ npm test

$ npm run lint

```

## References

- [RFC 3986: Uniform Resource Identifier (URI): Generic Syntax][rfc-3986]

- [WHATWG URL Living Standard][whatwg-url]

[rfc-3986]: https://tools.ietf.org/html/rfc3986

[whatwg-url]: https://url.spec.whatwg.org/

## License

[MIT](LICENSE)

[npm-image]: https://img.shields.io/npm/v/encodeurl.svg

[npm-url]: https://npmjs.org/package/encodeurl

[node-version-image]: https://img.shields.io/node/v/encodeurl.svg

[node-version-url]: https://nodejs.org/en/download

[travis-image]: https://img.shields.io/travis/pillarjs/encodeurl.svg

[travis-url]: https://travis-ci.org/pillarjs/encodeurl

[coveralls-image]: https://img.shields.io/coveralls/pillarjs/encodeurl.svg

[coveralls-url]: https://coveralls.io/r/pillarjs/encodeurl?branch=master

[downloads-image]: https://img.shields.io/npm/dm/encodeurl.svg

[downloads-url]: https://npmjs.org/package/encodeurl