872 lines
28 KiB
Markdown
872 lines
28 KiB
Markdown
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<div align="center">
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<img src="docs/media/Banner.svg" alt="Node Fetch"/>
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<br>
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<p>A light-weight module that brings <a href="https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API">Fetch API</a> to Node.js.</p>
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<a href="https://github.com/node-fetch/node-fetch/actions"><img src="https://github.com/node-fetch/node-fetch/workflows/CI/badge.svg?branch=master" alt="Build status"></a>
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<a href="https://coveralls.io/github/node-fetch/node-fetch"><img src="https://img.shields.io/coveralls/github/node-fetch/node-fetch" alt="Coverage status"></a>
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<a href="https://packagephobia.now.sh/result?p=node-fetch"><img src="https://badgen.net/packagephobia/install/node-fetch" alt="Current version"></a>
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<a href="https://www.npmjs.com/package/node-fetch"><img src="https://img.shields.io/npm/v/node-fetch" alt="Install size"></a>
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<a href="https://github.com/sindresorhus/awesome-nodejs"><img src="https://awesome.re/mentioned-badge.svg" alt="Mentioned in Awesome Node.js"></a>
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<a href="https://discord.gg/Zxbndcm"><img src="https://img.shields.io/discord/619915844268326952?color=%237289DA&label=Discord" alt="Discord"></a>
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<br>
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<br>
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<b>Consider supporting us on our Open Collective:</b>
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<br>
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<br>
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<a href="https://opencollective.com/node-fetch"><img src="https://opencollective.com/node-fetch/donate/button.png?color=blue" alt="Open Collective"></a>
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</div>
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---
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**You might be looking for the [v2 docs](https://github.com/node-fetch/node-fetch/tree/2.x#readme)**
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<!-- TOC -->
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- [Motivation](#motivation)
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- [Features](#features)
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- [Difference from client-side fetch](#difference-from-client-side-fetch)
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- [Installation](#installation)
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- [Loading and configuring the module](#loading-and-configuring-the-module)
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- [Upgrading](#upgrading)
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- [Common Usage](#common-usage)
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- [Plain text or HTML](#plain-text-or-html)
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- [JSON](#json)
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- [Simple Post](#simple-post)
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- [Post with JSON](#post-with-json)
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- [Post with form parameters](#post-with-form-parameters)
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- [Handling exceptions](#handling-exceptions)
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- [Handling client and server errors](#handling-client-and-server-errors)
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- [Handling cookies](#handling-cookies)
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- [Advanced Usage](#advanced-usage)
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- [Streams](#streams)
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- [Accessing Headers and other Metadata](#accessing-headers-and-other-metadata)
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- [Extract Set-Cookie Header](#extract-set-cookie-header)
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- [Post data using a file](#post-data-using-a-file)
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- [Request cancellation with AbortSignal](#request-cancellation-with-abortsignal)
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- [API](#api)
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- [fetch(url[, options])](#fetchurl-options)
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- [Options](#options)
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- [Default Headers](#default-headers)
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- [Custom Agent](#custom-agent)
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- [Custom highWaterMark](#custom-highwatermark)
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- [Insecure HTTP Parser](#insecure-http-parser)
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- [Class: Request](#class-request)
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- [new Request(input[, options])](#new-requestinput-options)
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- [Class: Response](#class-response)
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- [new Response([body[, options]])](#new-responsebody-options)
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- [response.ok](#responseok)
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- [response.redirected](#responseredirected)
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- [response.type](#responsetype)
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- [Class: Headers](#class-headers)
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- [new Headers([init])](#new-headersinit)
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- [Interface: Body](#interface-body)
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- [body.body](#bodybody)
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- [body.bodyUsed](#bodybodyused)
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- [body.arrayBuffer()](#bodyarraybuffer)
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- [body.blob()](#bodyblob)
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- [body.formData()](#formdata)
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- [body.json()](#bodyjson)
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- [body.text()](#bodytext)
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- [Class: FetchError](#class-fetcherror)
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- [Class: AbortError](#class-aborterror)
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- [TypeScript](#typescript)
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- [Acknowledgement](#acknowledgement)
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- [Team](#team)
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- [Former](#former)
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- [License](#license)
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<!-- /TOC -->
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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 Jason Miller's [isomorphic-unfetch](https://www.npmjs.com/package/isomorphic-unfetch) or Leonardo Quixada's [cross-fetch](https://github.com/lquixada/cross-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][whatwg-fetch] and [stream spec](https://streams.spec.whatwg.org/) implementation details, document known differences.
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- Use native promise and async functions.
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- Use native Node streams for body, on both request and response.
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- Decode content encoding (gzip/deflate/brotli) properly, and convert string output (such as `res.text()` and `res.json()`) to UTF-8 automatically.
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- Useful extensions such as redirect limit, response size limit, [explicit errors][error-handling.md] for troubleshooting.
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## Difference from client-side fetch
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- See known differences:
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- [As of v3.x](docs/v3-LIMITS.md)
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- [As of v2.x](docs/v2-LIMITS.md)
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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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## Installation
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Current stable release (`3.x`) requires at least Node.js 12.20.0.
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```sh
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npm install node-fetch
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```
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## Loading and configuring the module
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### ES Modules (ESM)
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```js
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import fetch from 'node-fetch';
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```
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### CommonJS
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`node-fetch` from v3 is an ESM-only module - you are not able to import it with `require()`.
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If you cannot switch to ESM, please use v2 which remains compatible with CommonJS. Critical bug fixes will continue to be published for v2.
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```sh
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npm install node-fetch@2
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```
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Alternatively, you can use the async `import()` function from CommonJS to load `node-fetch` asynchronously:
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```js
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// mod.cjs
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const fetch = (...args) => import('node-fetch').then(({default: fetch}) => fetch(...args));
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```
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### Providing global access
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To use `fetch()` without importing it, you can patch the `global` object in node:
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```js
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// fetch-polyfill.js
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import fetch, {
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Blob,
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blobFrom,
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blobFromSync,
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File,
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fileFrom,
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fileFromSync,
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FormData,
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Headers,
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Request,
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Response,
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} from 'node-fetch'
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if (!globalThis.fetch) {
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globalThis.fetch = fetch
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globalThis.Headers = Headers
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globalThis.Request = Request
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globalThis.Response = Response
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}
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// index.js
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import './fetch-polyfill'
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// ...
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```
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## Upgrading
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Using an old version of node-fetch? Check out the following files:
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- [2.x to 3.x upgrade guide](docs/v3-UPGRADE-GUIDE.md)
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- [1.x to 2.x upgrade guide](docs/v2-UPGRADE-GUIDE.md)
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- [Changelog](https://github.com/node-fetch/node-fetch/releases)
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## Common Usage
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NOTE: The documentation below is up-to-date with `3.x` releases, if you are using an older version, please check how to [upgrade](#upgrading).
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### Plain text or HTML
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```js
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import fetch from 'node-fetch';
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const response = await fetch('https://github.com/');
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const body = await response.text();
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console.log(body);
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```
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### JSON
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```js
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import fetch from 'node-fetch';
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const response = await fetch('https://api.github.com/users/github');
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const data = await response.json();
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console.log(data);
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```
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### Simple Post
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```js
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import fetch from 'node-fetch';
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const response = await fetch('https://httpbin.org/post', {method: 'POST', body: 'a=1'});
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const data = await response.json();
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console.log(data);
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```
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### Post with JSON
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```js
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import fetch from 'node-fetch';
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const body = {a: 1};
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const response = await fetch('https://httpbin.org/post', {
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method: 'post',
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body: JSON.stringify(body),
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headers: {'Content-Type': 'application/json'}
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});
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const data = await response.json();
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console.log(data);
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```
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### Post with form parameters
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`URLSearchParams` is available on the global object in Node.js as of v10.0.0. See [official documentation](https://nodejs.org/api/url.html#url_class_urlsearchparams) for more usage methods.
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NOTE: The `Content-Type` header is only set automatically to `x-www-form-urlencoded` when an instance of `URLSearchParams` is given as such:
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```js
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import fetch from 'node-fetch';
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const params = new URLSearchParams();
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params.append('a', 1);
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const response = await fetch('https://httpbin.org/post', {method: 'POST', body: params});
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const data = await response.json();
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console.log(data);
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```
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### Handling exceptions
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NOTE: 3xx-5xx responses are _NOT_ exceptions, and should be handled in `then()`, see the next section.
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Wrapping the fetch function into a `try/catch` block will catch _all_ exceptions, such as errors originating from node core libraries, like network errors, and operational errors which are instances of FetchError. See the [error handling document][error-handling.md] for more details.
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```js
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import fetch from 'node-fetch';
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try {
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await fetch('https://domain.invalid/');
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} catch (error) {
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console.log(error);
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}
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```
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### Handling client and server errors
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It is common to create a helper function to check that the response contains no client (4xx) or server (5xx) error responses:
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```js
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import fetch from 'node-fetch';
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class HTTPResponseError extends Error {
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constructor(response, ...args) {
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super(`HTTP Error Response: ${response.status} ${response.statusText}`, ...args);
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this.response = response;
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}
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}
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const checkStatus = response => {
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if (response.ok) {
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// response.status >= 200 && response.status < 300
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return response;
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} else {
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throw new HTTPResponseError(response);
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}
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}
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const response = await fetch('https://httpbin.org/status/400');
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try {
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checkStatus(response);
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} catch (error) {
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console.error(error);
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const errorBody = await error.response.text();
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console.error(`Error body: ${errorBody}`);
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}
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```
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### Handling cookies
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Cookies are not stored by default. However, cookies can be extracted and passed by manipulating request and response headers. See [Extract Set-Cookie Header](#extract-set-cookie-header) for details.
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## Advanced Usage
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### Streams
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The "Node.js way" is to use streams when possible. You can pipe `res.body` to another stream. This example uses [stream.pipeline](https://nodejs.org/api/stream.html#stream_stream_pipeline_streams_callback) to attach stream error handlers and wait for the download to complete.
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```js
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import {createWriteStream} from 'node:fs';
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import {pipeline} from 'node:stream';
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import {promisify} from 'node:util'
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import fetch from 'node-fetch';
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const streamPipeline = promisify(pipeline);
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const response = await fetch('https://github.githubassets.com/images/modules/logos_page/Octocat.png');
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if (!response.ok) throw new Error(`unexpected response ${response.statusText}`);
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await streamPipeline(response.body, createWriteStream('./octocat.png'));
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```
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In Node.js 14 you can also use async iterators to read `body`; however, be careful to catch
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errors -- the longer a response runs, the more likely it is to encounter an error.
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```js
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import fetch from 'node-fetch';
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const response = await fetch('https://httpbin.org/stream/3');
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try {
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for await (const chunk of response.body) {
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console.dir(JSON.parse(chunk.toString()));
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}
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} catch (err) {
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console.error(err.stack);
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}
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```
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In Node.js 12 you can also use async iterators to read `body`; however, async iterators with streams
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did not mature until Node.js 14, so you need to do some extra work to ensure you handle errors
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directly from the stream and wait on it response to fully close.
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```js
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import fetch from 'node-fetch';
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const read = async body => {
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let error;
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body.on('error', err => {
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error = err;
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});
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for await (const chunk of body) {
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console.dir(JSON.parse(chunk.toString()));
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}
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return new Promise((resolve, reject) => {
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body.on('close', () => {
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error ? reject(error) : resolve();
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});
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});
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};
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try {
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const response = await fetch('https://httpbin.org/stream/3');
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await read(response.body);
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} catch (err) {
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console.error(err.stack);
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}
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```
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### Accessing Headers and other Metadata
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```js
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import fetch from 'node-fetch';
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const response = await fetch('https://github.com/');
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console.log(response.ok);
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console.log(response.status);
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console.log(response.statusText);
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console.log(response.headers.raw());
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console.log(response.headers.get('content-type'));
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```
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### Extract Set-Cookie Header
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Unlike browsers, you can access raw `Set-Cookie` headers manually using `Headers.raw()`. This is a `node-fetch` only API.
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```js
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import fetch from 'node-fetch';
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const response = await fetch('https://example.com');
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// Returns an array of values, instead of a string of comma-separated values
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console.log(response.headers.raw()['set-cookie']);
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```
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### Post data using a file
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```js
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import fetch {
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Blob,
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blobFrom,
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blobFromSync,
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File,
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fileFrom,
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fileFromSync,
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} from 'node-fetch'
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const mimetype = 'text/plain'
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const blob = fileFromSync('./input.txt', mimetype)
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const url = 'https://httpbin.org/post'
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const response = await fetch(url, { method: 'POST', body: blob })
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const data = await response.json()
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console.log(data)
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```
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node-fetch comes with a spec-compliant [FormData] implementations for posting
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multipart/form-data payloads
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```js
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import fetch, { FormData, File, fileFrom } from 'node-fetch'
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const httpbin = 'https://httpbin.org/post'
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const formData = new FormData()
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const binary = new Uint8Array([ 97, 98, 99 ])
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const abc = new File([binary], 'abc.txt'), { type: 'text/plain' })
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formData.set('greeting', 'Hello, world!')
|
||
|
formData.set('file-upload', abc, 'new name.txt')
|
||
|
|
||
|
const response = await fetch(httpbin, { method: 'POST', body: formData })
|
||
|
const data = await response.json()
|
||
|
|
||
|
console.log(data)
|
||
|
```
|
||
|
|
||
|
If you for some reason need to post a stream coming from any arbitrary place,
|
||
|
then you can append a [Blob] or a [File] look-a-like item.
|
||
|
|
||
|
The minium requirement is that it has:
|
||
|
1. A `Symbol.toStringTag` getter or property that is either `Blob` or `File`
|
||
|
2. A known size.
|
||
|
3. And either a `stream()` method or a `arrayBuffer()` method that returns a ArrayBuffer.
|
||
|
|
||
|
The `stream()` must return any async iterable object as long as it yields Uint8Array (or Buffer)
|
||
|
so Node.Readable streams and whatwg streams works just fine.
|
||
|
|
||
|
```js
|
||
|
formData.append('upload', {
|
||
|
[Symbol.toStringTag]: 'Blob',
|
||
|
size: 3,
|
||
|
*stream() {
|
||
|
yield new Uint8Array([97, 98, 99])
|
||
|
},
|
||
|
arrayBuffer() {
|
||
|
return new Uint8Array([97, 98, 99]).buffer
|
||
|
}
|
||
|
}, 'abc.txt')
|
||
|
```
|
||
|
|
||
|
### Request cancellation with AbortSignal
|
||
|
|
||
|
You may cancel requests with `AbortController`. A suggested implementation is [`abort-controller`](https://www.npmjs.com/package/abort-controller).
|
||
|
|
||
|
An example of timing out a request after 150ms could be achieved as the following:
|
||
|
|
||
|
```js
|
||
|
import fetch, { AbortError } from 'node-fetch';
|
||
|
|
||
|
// AbortController was added in node v14.17.0 globally
|
||
|
const AbortController = globalThis.AbortController || await import('abort-controller')
|
||
|
|
||
|
const controller = new AbortController();
|
||
|
const timeout = setTimeout(() => {
|
||
|
controller.abort();
|
||
|
}, 150);
|
||
|
|
||
|
try {
|
||
|
const response = await fetch('https://example.com', {signal: controller.signal});
|
||
|
const data = await response.json();
|
||
|
} catch (error) {
|
||
|
if (error instanceof AbortError) {
|
||
|
console.log('request was aborted');
|
||
|
}
|
||
|
} finally {
|
||
|
clearTimeout(timeout);
|
||
|
}
|
||
|
```
|
||
|
|
||
|
See [test cases](https://github.com/node-fetch/node-fetch/blob/master/test/) for more examples.
|
||
|
|
||
|
## API
|
||
|
|
||
|
### fetch(url[, options])
|
||
|
|
||
|
- `url` A string representing the URL for fetching
|
||
|
- `options` [Options](#fetch-options) for the HTTP(S) request
|
||
|
- Returns: <code>Promise<[Response](#class-response)></code>
|
||
|
|
||
|
Perform an HTTP(S) fetch.
|
||
|
|
||
|
`url` should be an absolute URL, such as `https://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`.
|
||
|
|
||
|
<a id="fetch-options"></a>
|
||
|
|
||
|
### Options
|
||
|
|
||
|
The default values are shown after each option key.
|
||
|
|
||
|
```js
|
||
|
{
|
||
|
// 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, or a Node.js Readable stream
|
||
|
redirect: 'follow', // Set to `manual` to extract redirect headers, `error` to reject redirect
|
||
|
signal: null, // Pass an instance of AbortSignal to optionally abort requests
|
||
|
|
||
|
// The following properties are node-fetch extensions
|
||
|
follow: 20, // maximum redirect count. 0 to not follow redirect
|
||
|
compress: true, // support gzip/deflate content encoding. false to disable
|
||
|
size: 0, // maximum response body size in bytes. 0 to disable
|
||
|
agent: null, // http(s).Agent instance or function that returns an instance (see below)
|
||
|
highWaterMark: 16384, // the maximum number of bytes to store in the internal buffer before ceasing to read from the underlying resource.
|
||
|
insecureHTTPParser: false // Use an insecure HTTP parser that accepts invalid HTTP headers when `true`.
|
||
|
}
|
||
|
```
|
||
|
|
||
|
#### Default Headers
|
||
|
|
||
|
If no values are set, the following request headers will be sent automatically:
|
||
|
|
||
|
| Header | Value |
|
||
|
| ------------------- | ------------------------------------------------------ |
|
||
|
| `Accept-Encoding` | `gzip,deflate,br` _(when `options.compress === true`)_ |
|
||
|
| `Accept` | `*/*` |
|
||
|
| `Connection` | `close` _(when no `options.agent` is present)_ |
|
||
|
| `Content-Length` | _(automatically calculated, if possible)_ |
|
||
|
| `Host` | _(host and port information from the target URI)_ |
|
||
|
| `Transfer-Encoding` | `chunked` _(when `req.body` is a stream)_ |
|
||
|
| `User-Agent` | `node-fetch` |
|
||
|
|
||
|
|
||
|
Note: when `body` is a `Stream`, `Content-Length` is not set automatically.
|
||
|
|
||
|
#### Custom Agent
|
||
|
|
||
|
The `agent` option allows you to specify networking related options which are out of the scope of Fetch, including and not limited to the following:
|
||
|
|
||
|
- Support self-signed certificate
|
||
|
- Use only IPv4 or IPv6
|
||
|
- Custom DNS Lookup
|
||
|
|
||
|
See [`http.Agent`](https://nodejs.org/api/http.html#http_new_agent_options) for more information.
|
||
|
|
||
|
In addition, the `agent` option accepts a function that returns `http`(s)`.Agent` instance given current [URL](https://nodejs.org/api/url.html), this is useful during a redirection chain across HTTP and HTTPS protocol.
|
||
|
|
||
|
```js
|
||
|
import http from 'node:http';
|
||
|
import https from 'node:https';
|
||
|
|
||
|
const httpAgent = new http.Agent({
|
||
|
keepAlive: true
|
||
|
});
|
||
|
const httpsAgent = new https.Agent({
|
||
|
keepAlive: true
|
||
|
});
|
||
|
|
||
|
const options = {
|
||
|
agent: function(_parsedURL) {
|
||
|
if (_parsedURL.protocol == 'http:') {
|
||
|
return httpAgent;
|
||
|
} else {
|
||
|
return httpsAgent;
|
||
|
}
|
||
|
}
|
||
|
};
|
||
|
```
|
||
|
|
||
|
<a id="custom-highWaterMark"></a>
|
||
|
|
||
|
#### Custom highWaterMark
|
||
|
|
||
|
Stream on Node.js have a smaller internal buffer size (16kB, aka `highWaterMark`) from client-side browsers (>1MB, not consistent across browsers). Because of that, when you are writing an isomorphic app and using `res.clone()`, it will hang with large response in Node.
|
||
|
|
||
|
The recommended way to fix this problem is to resolve cloned response in parallel:
|
||
|
|
||
|
```js
|
||
|
import fetch from 'node-fetch';
|
||
|
|
||
|
const response = await fetch('https://example.com');
|
||
|
const r1 = await response.clone();
|
||
|
|
||
|
const results = await Promise.all([response.json(), r1.text()]);
|
||
|
|
||
|
console.log(results[0]);
|
||
|
console.log(results[1]);
|
||
|
```
|
||
|
|
||
|
If for some reason you don't like the solution above, since `3.x` you are able to modify the `highWaterMark` option:
|
||
|
|
||
|
```js
|
||
|
import fetch from 'node-fetch';
|
||
|
|
||
|
const response = await fetch('https://example.com', {
|
||
|
// About 1MB
|
||
|
highWaterMark: 1024 * 1024
|
||
|
});
|
||
|
|
||
|
const result = await res.clone().arrayBuffer();
|
||
|
console.dir(result);
|
||
|
```
|
||
|
|
||
|
#### Insecure HTTP Parser
|
||
|
|
||
|
Passed through to the `insecureHTTPParser` option on http(s).request. See [`http.request`](https://nodejs.org/api/http.html#http_http_request_url_options_callback) for more information.
|
||
|
|
||
|
#### Manual Redirect
|
||
|
|
||
|
The `redirect: 'manual'` option for node-fetch is different from the browser & specification, which
|
||
|
results in an [opaque-redirect filtered response](https://fetch.spec.whatwg.org/#concept-filtered-response-opaque-redirect).
|
||
|
node-fetch gives you the typical [basic filtered response](https://fetch.spec.whatwg.org/#concept-filtered-response-basic) instead.
|
||
|
|
||
|
```js
|
||
|
const fetch = require('node-fetch');
|
||
|
|
||
|
const response = await fetch('https://httpbin.org/status/301', { redirect: 'manual' });
|
||
|
|
||
|
if (response.status === 301 || response.status === 302) {
|
||
|
const locationURL = new URL(response.headers.get('location'), response.url);
|
||
|
const response2 = await fetch(locationURL, { redirect: 'manual' });
|
||
|
console.dir(response2);
|
||
|
}
|
||
|
```
|
||
|
|
||
|
<a id="class-request"></a>
|
||
|
|
||
|
### Class: Request
|
||
|
|
||
|
An HTTP(S) request containing information about URL, method, headers, and the body. This class implements the [Body](#iface-body) interface.
|
||
|
|
||
|
Due to the nature of Node.js, the following properties are not implemented at this moment:
|
||
|
|
||
|
- `type`
|
||
|
- `destination`
|
||
|
- `mode`
|
||
|
- `credentials`
|
||
|
- `cache`
|
||
|
- `integrity`
|
||
|
- `keepalive`
|
||
|
|
||
|
The following node-fetch extension properties are provided:
|
||
|
|
||
|
- `follow`
|
||
|
- `compress`
|
||
|
- `counter`
|
||
|
- `agent`
|
||
|
- `highWaterMark`
|
||
|
|
||
|
See [options](#fetch-options) for exact meaning of these extensions.
|
||
|
|
||
|
#### new Request(input[, options])
|
||
|
|
||
|
<small>_(spec-compliant)_</small>
|
||
|
|
||
|
- `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](https://developer.mozilla.org/en-US/docs/Web/API/Request/Request).
|
||
|
|
||
|
In most cases, directly `fetch(url, options)` is simpler than creating a `Request` object.
|
||
|
|
||
|
<a id="class-response"></a>
|
||
|
|
||
|
### Class: Response
|
||
|
|
||
|
An HTTP(S) response. This class implements the [Body](#iface-body) interface.
|
||
|
|
||
|
The following properties are not implemented in node-fetch at this moment:
|
||
|
|
||
|
- `trailer`
|
||
|
|
||
|
#### new Response([body[, options]])
|
||
|
|
||
|
<small>_(spec-compliant)_</small>
|
||
|
|
||
|
- `body` A `String` or [`Readable` stream][node-readable]
|
||
|
- `options` A [`ResponseInit`][response-init] options dictionary
|
||
|
|
||
|
Constructs a new `Response` object. The constructor is identical to that in the [browser](https://developer.mozilla.org/en-US/docs/Web/API/Response/Response).
|
||
|
|
||
|
Because Node.js does not implement service workers (for which this class was designed), one rarely has to construct a `Response` directly.
|
||
|
|
||
|
#### response.ok
|
||
|
|
||
|
<small>_(spec-compliant)_</small>
|
||
|
|
||
|
Convenience property representing if the request ended normally. Will evaluate to true if the response status was greater than or equal to 200 but smaller than 300.
|
||
|
|
||
|
#### response.redirected
|
||
|
|
||
|
<small>_(spec-compliant)_</small>
|
||
|
|
||
|
Convenience property representing if the request has been redirected at least once. Will evaluate to true if the internal redirect counter is greater than 0.
|
||
|
|
||
|
#### response.type
|
||
|
|
||
|
<small>_(deviation from spec)_</small>
|
||
|
|
||
|
Convenience property representing the response's type. node-fetch only supports `'default'` and `'error'` and does not make use of [filtered responses](https://fetch.spec.whatwg.org/#concept-filtered-response).
|
||
|
|
||
|
<a id="class-headers"></a>
|
||
|
|
||
|
### Class: Headers
|
||
|
|
||
|
This class allows manipulating and iterating over a set of HTTP headers. All methods specified in the [Fetch Standard][whatwg-fetch] are implemented.
|
||
|
|
||
|
#### new Headers([init])
|
||
|
|
||
|
<small>_(spec-compliant)_</small>
|
||
|
|
||
|
- `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.
|
||
|
|
||
|
```js
|
||
|
// Example adapted from https://fetch.spec.whatwg.org/#example-headers-class
|
||
|
import {Headers} from 'node-fetch';
|
||
|
|
||
|
const meta = {
|
||
|
'Content-Type': 'text/xml'
|
||
|
};
|
||
|
const headers = new Headers(meta);
|
||
|
|
||
|
// The above is equivalent to
|
||
|
const meta = [['Content-Type', 'text/xml']];
|
||
|
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');
|
||
|
const headers = new Headers(meta);
|
||
|
const copyOfHeaders = new Headers(headers);
|
||
|
```
|
||
|
|
||
|
<a id="iface-body"></a>
|
||
|
|
||
|
### Interface: Body
|
||
|
|
||
|
`Body` is an abstract interface with methods that are applicable to both `Request` and `Response` classes.
|
||
|
|
||
|
#### body.body
|
||
|
|
||
|
<small>_(deviation from spec)_</small>
|
||
|
|
||
|
- Node.js [`Readable` stream][node-readable]
|
||
|
|
||
|
Data are encapsulated in the `Body` object. Note that while the [Fetch Standard][whatwg-fetch] requires the property to always be a WHATWG `ReadableStream`, in node-fetch it is a Node.js [`Readable` stream][node-readable].
|
||
|
|
||
|
#### body.bodyUsed
|
||
|
|
||
|
<small>_(spec-compliant)_</small>
|
||
|
|
||
|
- `Boolean`
|
||
|
|
||
|
A boolean property for if this body has been consumed. Per the specs, a consumed body cannot be used again.
|
||
|
|
||
|
#### body.arrayBuffer()
|
||
|
|
||
|
#### body.formData()
|
||
|
|
||
|
#### body.blob()
|
||
|
|
||
|
#### body.json()
|
||
|
|
||
|
#### body.text()
|
||
|
|
||
|
`fetch` comes with methods to parse `multipart/form-data` payloads as well as
|
||
|
`x-www-form-urlencoded` bodies using `.formData()` this comes from the idea that
|
||
|
Service Worker can intercept such messages before it's sent to the server to
|
||
|
alter them. This is useful for anybody building a server so you can use it to
|
||
|
parse & consume payloads.
|
||
|
|
||
|
<details>
|
||
|
<summary>Code example</summary>
|
||
|
|
||
|
```js
|
||
|
import http from 'node:http'
|
||
|
import { Response } from 'node-fetch'
|
||
|
|
||
|
http.createServer(async function (req, res) {
|
||
|
const formData = await new Response(req, {
|
||
|
headers: req.headers // Pass along the boundary value
|
||
|
}).formData()
|
||
|
const allFields = [...formData]
|
||
|
|
||
|
const file = formData.get('uploaded-files')
|
||
|
const arrayBuffer = await file.arrayBuffer()
|
||
|
const text = await file.text()
|
||
|
const whatwgReadableStream = file.stream()
|
||
|
|
||
|
// other was to consume the request could be to do:
|
||
|
const json = await new Response(req).json()
|
||
|
const text = await new Response(req).text()
|
||
|
const arrayBuffer = await new Response(req).arrayBuffer()
|
||
|
const blob = await new Response(req, {
|
||
|
headers: req.headers // So that `type` inherits `Content-Type`
|
||
|
}.blob()
|
||
|
})
|
||
|
```
|
||
|
|
||
|
</details>
|
||
|
|
||
|
<a id="class-fetcherror"></a>
|
||
|
|
||
|
### Class: FetchError
|
||
|
|
||
|
<small>_(node-fetch extension)_</small>
|
||
|
|
||
|
An operational error in the fetching process. See [ERROR-HANDLING.md][] for more info.
|
||
|
|
||
|
<a id="class-aborterror"></a>
|
||
|
|
||
|
### Class: AbortError
|
||
|
|
||
|
<small>_(node-fetch extension)_</small>
|
||
|
|
||
|
An Error thrown when the request is aborted in response to an `AbortSignal`'s `abort` event. It has a `name` property of `AbortError`. See [ERROR-HANDLING.MD][] for more info.
|
||
|
|
||
|
## TypeScript
|
||
|
|
||
|
**Since `3.x` types are bundled with `node-fetch`, so you don't need to install any additional packages.**
|
||
|
|
||
|
For older versions please use the type definitions from [DefinitelyTyped](https://github.com/DefinitelyTyped/DefinitelyTyped):
|
||
|
|
||
|
```sh
|
||
|
npm install --save-dev @types/node-fetch@2.x
|
||
|
```
|
||
|
|
||
|
## Acknowledgement
|
||
|
|
||
|
Thanks to [github/fetch](https://github.com/github/fetch) for providing a solid implementation reference.
|
||
|
|
||
|
## Team
|
||
|
|
||
|
| [![David Frank](https://github.com/bitinn.png?size=100)](https://github.com/bitinn) | [![Jimmy Wärting](https://github.com/jimmywarting.png?size=100)](https://github.com/jimmywarting) | [![Antoni Kepinski](https://github.com/xxczaki.png?size=100)](https://github.com/xxczaki) | [![Richie Bendall](https://github.com/Richienb.png?size=100)](https://github.com/Richienb) | [![Gregor Martynus](https://github.com/gr2m.png?size=100)](https://github.com/gr2m) |
|
||
|
| ----------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------- |
|
||
|
| [David Frank](https://bitinn.net/) | [Jimmy Wärting](https://jimmy.warting.se/) | [Antoni Kepinski](https://kepinski.ch) | [Richie Bendall](https://www.richie-bendall.ml/) | [Gregor Martynus](https://twitter.com/gr2m) |
|
||
|
|
||
|
###### Former
|
||
|
|
||
|
- [Timothy Gu](https://github.com/timothygu)
|
||
|
- [Jared Kantrowitz](https://github.com/jkantr)
|
||
|
|
||
|
## License
|
||
|
|
||
|
[MIT](LICENSE.md)
|
||
|
|
||
|
[whatwg-fetch]: https://fetch.spec.whatwg.org/
|
||
|
[response-init]: https://fetch.spec.whatwg.org/#responseinit
|
||
|
[node-readable]: https://nodejs.org/api/stream.html#stream_readable_streams
|
||
|
[mdn-headers]: https://developer.mozilla.org/en-US/docs/Web/API/Headers
|
||
|
[error-handling.md]: https://github.com/node-fetch/node-fetch/blob/master/docs/ERROR-HANDLING.md
|
||
|
[FormData]: https://developer.mozilla.org/en-US/docs/Web/API/FormData
|
||
|
[Blob]: https://developer.mozilla.org/en-US/docs/Web/API/Blob
|
||
|
[File]: https://developer.mozilla.org/en-US/docs/Web/API/File
|