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