Wondering what’s next for npm?Check out our public roadmap! »

    electron-fetch
    TypeScript icon, indicating that this package has built-in type declarations

    1.7.3 • Public • Published

    electron-fetch

    npm version build status coverage status

    A light-weight module that brings window.fetch to Electron's background process. Forked from node-fetch.

    Motivation

    Instead of implementing XMLHttpRequest over Electron's net module to run browser-specific Fetch polyfill, why not go from native net.request to fetch API directly? Hence electron-fetch, minimal code for a window.fetch compatible API on Electron's background runtime.

    Why not simply use node-fetch? Well, Electron's net module does a better job than Node.js' http module at handling web proxies.

    Features

    • Stay consistent with window.fetch API.
    • Runs on both Electron and Node.js, using either Electron's net module, or Node.js http module as backend.
    • Make conscious trade-off when following whatwg fetch spec and stream spec implementation details, document known difference.
    • Use native promise.
    • 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 (when running on Node.js), 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.fetch offers, feel free to open an issue.
    • Pull requests are welcomed too!

    Difference from node-fetch

    • Removed node-fetch specific options, such as compression.
    • Added electron-specific options to specify the Session & to enable using cookies from it.
    • Added electron-specific option useElectronNet, which can be set to false when running on Electron in order to behave as Node.js.
    • Removed possibility to use custom Promise implementation (it's 2018, Promise is available everywhere!).
    • Removed the possibility to forbid content compression (incompatible with Electron's net module, and of limited interest)
    • standard-ized the code.

    Install

    $ npm install electron-fetch --save

    Usage

    import fetch from 'electron-fetch'
    // or
    // const fetch = require('electron-fetch').default
    
    // 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 electron-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
    
    const 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])

    • url A string representing the URL for fetching
    • options Options for the HTTP(S) request
    • Returns: Promise<Response>

    Perform an HTTP(S) fetch.

    url should be an absolute url, such as http://example.com/. A path-relative URL (/file/under/root) or protocol-relative URL (//can-be-http-or-https.com/) will result in a rejected promise.

    Options

    The default values are shown after each option key.

    const defaultOptions = {
    	// These properties are part of the Fetch Standard
    	method: 'GET',
    	headers: {},        // request headers. format is the identical to that accepted by the Headers constructor (see below)
    	body: null,         // request body. can be null, a string, a Buffer, a Blob, or a Node.js Readable stream
    	redirect: 'follow', // (/!\ only works when running on Node.js) set to `manual` to extract redirect headers, `error` to reject redirect
        signal: null,       // the AbortSignal from an AbortController instance.
    
    	// The following properties are electron-fetch extensions
    	follow: 20,         // (/!\ only works when running on Node.js) 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)
    	size: 0,            // maximum response body size in bytes. 0 to disable
    	session: session.defaultSession, // (/!\ only works when running on Electron) Electron Session object.,
    	agent: null,        // (/!\ only works when useElectronNet is false) Node HTTP Agent.,
    	useElectronNet: true, // When running on Electron, defaults to true. On Node.js, defaults to false and cannot be set to true.
    	useSessionCookies: true, // (/!\ only works when running on Electron >= 7) Whether or not to automatically send cookies from session.,
    	user: undefined,    // When running on Electron behind an authenticated HTTP proxy, username to use to authenticate
    	password: undefined // When running on Electron behind an authenticated HTTP proxy, password to use to authenticate
    }
    Default Headers

    If no values are set, the following request headers will be sent automatically:

    Header Value
    Accept-Encoding gzip,deflate
    Accept */*
    Connection close
    Content-Length (automatically calculated, if possible)
    User-Agent electron-fetch/1.0 (+https://github.com/arantes555/electron-fetch)

    Class: Request

    An HTTP(S) request containing information about URL, method, headers, and the body. This class implements the Body interface.

    Due to the nature of Node.js, the following properties are not implemented at this moment:

    • type
    • destination
    • referrer
    • referrerPolicy
    • mode
    • credentials
    • cache
    • integrity
    • keepalive

    The following electron-fetch extension properties are provided:

    • follow (/!\ only works when running on Node.js)
    • counter (/!\ only works when running on Node.js)
    • session (/!\ only works when running on Electron)
    • agent (/!\ only works when running on Node.js)
    • useElectronNet (/!\ only works when running on Electron, throws when set to true on Node.js)
    • useSessionCookies (/!\ only works when running on Electron >= 7. For electron < 11, it saves received cookies regardless of this option, but only sends them if true. For electron >= 11, it saves them only if true.)

    See options for exact meaning of these extensions.

    new Request(input[, options])

    (spec-compliant)

    • input A string representing a URL, or another Request (which will be cloned)
    • options [Options][#fetch-options] for the HTTP(S) request

    Constructs a new Request object. The constructor is identical to that in the browser.

    In most cases, directly fetch(url, options) is simpler than creating a Request object.

    Class: Response

    An HTTP(S) response. This class implements the Body interface.

    The following properties are not implemented in electron-fetch at this moment:

    • Response.error()
    • Response.redirect()
    • type
    • redirected
    • trailer

    new Response([body[, options]])

    (spec-compliant)

    Constructs a new Response object. The constructor is identical to that in the browser.

    Because Node.js & Electron's background do not implement service workers (for which this class was designed), one rarely has to construct a Response directly.

    Class: Headers

    This class allows manipulating and iterating over a set of HTTP headers. All methods specified in the Fetch Standard are implemented.

    new Headers([init])

    (spec-compliant)

    • init Optional argument to pre-fill the Headers object

    Construct a new Headers object. init can be either null, a Headers object, an key-value map object, or any iterable object.

    // Example adapted from https://fetch.spec.whatwg.org/#example-headers-class
    
    const meta = {
      'Content-Type': 'text/xml',
      'Breaking-Bad': '<3'
    }
    const headers = new Headers(meta)
    
    // The above is equivalent to
    const meta = [
      [ 'Content-Type', 'text/xml' ],
      [ 'Breaking-Bad', '<3' ]
    ]
    const headers = new Headers(meta)
    
    // You can in fact use any iterable objects, like a Map or even another Headers
    const meta = new Map()
    meta.set('Content-Type', 'text/xml')
    meta.set('Breaking-Bad', '<3')
    const headers = new Headers(meta)
    const copyOfHeaders = new Headers(headers)

    Interface: Body

    Body is an abstract interface with methods that are applicable to both Request and Response classes.

    The following methods are not yet implemented in electron-fetch at this moment:

    • formData()

    body.body

    (deviation from spec)

    The data encapsulated in the Body object. Note that while the Fetch Standard requires the property to always be a WHATWG ReadableStream, in electron-fetch it is a Node.js Readable stream.

    body.bodyUsed

    (spec-compliant)

    • Boolean

    A boolean property for if this body has been consumed. Per spec, a consumed body cannot be used again.

    body.arrayBuffer()

    body.blob()

    body.json()

    body.text()

    (spec-compliant)

    • Returns: Promise

    Consume the body and return a promise that will resolve to one of these formats.

    body.buffer()

    (electron-fetch extension)

    • Returns: Promise<Buffer>

    Consume the body and return a promise that will resolve to a Buffer.

    body.textConverted()

    (electron-fetch extension)

    • Returns: Promise<String>

    Identical to body.text(), except instead of always converting to UTF-8, encoding sniffing will be performed and text converted to UTF-8, if possible.

    Class: FetchError

    (electron-fetch extension)

    An operational error in the fetching process. See ERROR-HANDLING.md for more info.

    License

    MIT

    Acknowledgement

    Thanks to github/fetch for providing a solid implementation reference. Thanks to node-fetch for providing a solid base to fork.

    Install

    npm i electron-fetch

    DownloadsWeekly Downloads

    29,897

    Version

    1.7.3

    License

    MIT

    Unpacked Size

    113 kB

    Total Files

    7

    Last publish

    Collaborators

    • avatar
    • avatar