cityofsurreynode-fetch
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, 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 for isomorphic usage (exports node-fetch for server-side, whatwg-fetch for client-side).
Features
- Stay consistent with
window.fetchAPI. - Make conscious trade-off when following whatwg fetch spec and stream spec 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()andres.json()) to UTF-8 automatically. - Useful extensions such as timeout, redirect limit, response size limit, explicit errors for troubleshooting.
Difference from client-side fetch
- See Known Differences for details.
- If you happen to use a missing feature that
window.fetchoffers, feel free to open an issue. - Pull requests are welcomed too!
Install
npm install node-fetch --save
Usage
import fetch from 'node-fetch';
// or
// const fetch = require('node-fetch');
// if you are using your own Promise library, set it through fetch.Promise. Eg.
// import Bluebird from 'bluebird';
// fetch.Promise = Bluebird;
// plain text or html
fetch('https://github.com/')
.then(res => res.text())
.then(body => console.log(body));
// json
fetch('https://api.github.com/users/github')
.then(res => res.json())
.then(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(err => console.error(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(res => {
const 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
import fileType from 'file-type';
fetch('https://assets-cdn.github.com/images/modules/logos_page/Octocat.png')
.then(res => res.buffer())
.then(buffer => fileType(buffer))
.then(type => { /* ... */ });
// meta
fetch('https://github.com/')
.then(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(res => res.json())
.then(json => console.log(json));
// post with stream from file
import { createReadStream } from 'fs';
const stream = createReadStream('input.txt');
fetch('http://httpbin.org/post', { method: 'POST', body: stream })
.then(res => res.json())
.then(json => console.log(json));
// post with JSON
var body = { a: 1 };
fetch('http://httpbin.org/post', {
method: 'POST',
body: JSON.stringify(body),
headers: { 'Content-Type': 'application/json' },
})
.then(res => res.json())
.then(json => console.log(json));
// post with form-data (detect multipart)
import FormData from 'form-data';
const form = new FormData();
form.append('a', 1);
fetch('http://httpbin.org/post', { method: 'POST', body: form })
.then(res => res.json())
.then(json => console.log(json));
// post with form-data (custom headers)
// note that getHeaders() is non-standard API
import FormData from 'form-data';
const form = new FormData();
form.append('a', 1);
fetch('http://httpbin.org/post', { method: 'POST', body: form, headers: form.getHeaders() })
.then(res => res.json())
.then(json => console.log(json));
// node 7+ with async function
(async function () {
const res = await fetch('https://api.github.com/users/github');
const json = await res.json();
console.log(json);
})();See test cases for more examples.
API
fetch(url, options)
Returns a Promise
Url
Should be an absolute url, eg http://example.com/
Options
Note that only method, headers, redirect and body are allowed in window.fetch. Other options are node.js extensions. The default values are shown after each option key.
{
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 for providing a solid implementation reference.