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node-fetch
==========
[![npm version][npm-image]][npm-url]
[![build status][travis-image]][travis-url]
[![coverage status][codecov-image]][codecov-url]
A light-weight module that brings `window.fetch` to Node.js
# Motivation
Instead of implementing `XMLHttpRequest` in Node.js to run browser-specific [Fetch polyfill](https://github.com/github/fetch), why not go from native `http` to `Fetch` API directly? Hence `node-fetch`, minimal code for a `window.fetch` compatible API on Node.js runtime.
See Matt Andrews' [isomorphic-fetch](https://github.com/matthew-andrews/isomorphic-fetch) for isomorphic usage (exports `node-fetch` for server-side, `whatwg-fetch` for client-side).
# Features
- Stay consistent with `window.fetch` API.
- Make conscious trade-off when following [whatwg fetch spec](https://fetch.spec.whatwg.org/) and [stream spec](https://streams.spec.whatwg.org/) implementation details, document known difference.
- Use native promise, but allow substituting it with [insert your favorite promise library].
- Use native stream for body, on both request and response.
- Decode content encoding (gzip/deflate) properly, and convert string output (such as `res.text()` and `res.json()`) to UTF-8 automatically.
- Useful extensions such as timeout, redirect limit, response size limit, [explicit errors](https://github.com/bitinn/node-fetch/blob/master/ERROR-HANDLING.md) for troubleshooting.
# Difference from client-side fetch
- See [Known Differences](https://github.com/bitinn/node-fetch/blob/master/LIMITS.md) for details.
- If you happen to use a missing feature that `window.fetch` offers, feel free to open an issue.
- Pull requests are welcomed too!
# Install
`npm install node-fetch --save`
# Usage
```javascript
var fetch = require('node-fetch');
// if you are on node v0.10, set a Promise library first, eg.
// fetch.Promise = require('bluebird');
// plain text or html
fetch('https://github.com/')
.then(function(res) {
return res.text();
}).then(function(body) {
console.log(body);
});
// json
fetch('https://api.github.com/users/github')
.then(function(res) {
return res.json();
}).then(function(json) {
console.log(json);
});
// catching network error
// 3xx-5xx responses are NOT network errors, and should be handled in then()
// you only need one catch() at the end of your promise chain
fetch('http://domain.invalid/')
.catch(function(err) {
console.log(err);
});
// stream
// the node.js way is to use stream when possible
fetch('https://assets-cdn.github.com/images/modules/logos_page/Octocat.png')
.then(function(res) {
var dest = fs.createWriteStream('./octocat.png');
res.body.pipe(dest);
});
// buffer
// if you prefer to cache binary data in full, use buffer()
// note that buffer() is a node-fetch only API
var fileType = require('file-type');
fetch('https://assets-cdn.github.com/images/modules/logos_page/Octocat.png')
.then(function(res) {
return res.buffer();
}).then(function(buffer) {
fileType(buffer);
});
// meta
fetch('https://github.com/')
.then(function(res) {
console.log(res.ok);
console.log(res.status);
console.log(res.statusText);
console.log(res.headers.raw());
console.log(res.headers.get('content-type'));
});
// post
fetch('http://httpbin.org/post', { method: 'POST', body: 'a=1' })
.then(function(res) {
return res.json();
}).then(function(json) {
console.log(json);
});
// post with stream from resumer
var resumer = require('resumer');
var stream = resumer().queue('a=1').end();
fetch('http://httpbin.org/post', { method: 'POST', body: stream })
.then(function(res) {
return res.json();
}).then(function(json) {
console.log(json);
});
// post with form-data (detect multipart)
var FormData = require('form-data');
var form = new FormData();
form.append('a', 1);
fetch('http://httpbin.org/post', { method: 'POST', body: form })
.then(function(res) {
return res.json();
}).then(function(json) {
console.log(json);
});
// post with form-data (custom headers)
// note that getHeaders() is non-standard API
var FormData = require('form-data');
var form = new FormData();
form.append('a', 1);
fetch('http://httpbin.org/post', { method: 'POST', body: form, headers: form.getHeaders() })
.then(function(res) {
return res.json();
}).then(function(json) {
console.log(json);
});
// node 0.12+, yield with co
var co = require('co');
co(function *() {
var res = yield fetch('https://api.github.com/users/github');
var json = yield res.json();
console.log(res);
});
```
See [test cases](https://github.com/bitinn/node-fetch/blob/master/test/test.js) for more examples.
# API
## fetch(url, options)
Returns a `Promise`
### Url
Should be an absolute url, eg `http://example.com/`
### Options
default values are shown, note that only `method`, `headers`, `redirect` and `body` are allowed in `window.fetch`, others are node.js extensions.
```
{
method: 'GET'
, headers: {} // request header. format {a:'1'} or {b:['1','2','3']}
, redirect: 'follow' // set to `manual` to extract redirect headers, `error` to reject redirect
, follow: 20 // maximum redirect count. 0 to not follow redirect
, timeout: 0 // req/res timeout in ms, it resets on redirect. 0 to disable (OS limit applies)
, compress: true // support gzip/deflate content encoding. false to disable
, size: 0 // maximum response body size in bytes. 0 to disable
, body: empty // request body. can be a string, buffer, readable stream
, agent: null // http.Agent instance, allows custom proxy, certificate etc.
}
```
# License
MIT
# Acknowledgement
Thanks to [github/fetch](https://github.com/github/fetch) for providing a solid implementation reference.
[npm-image]: https://img.shields.io/npm/v/node-fetch.svg?style=flat-square
[npm-url]: https://www.npmjs.com/package/node-fetch
[travis-image]: https://img.shields.io/travis/bitinn/node-fetch.svg?style=flat-square
[travis-url]: https://travis-ci.org/bitinn/node-fetch
[codecov-image]: https://img.shields.io/codecov/c/github/bitinn/node-fetch.svg?style=flat-square
[codecov-url]: https://codecov.io/gh/bitinn/node-fetch
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