Node.jsでfetchを使えるようにする

Node.jsでブラウザと同じようにfetchメソッドを使えるようにする「node-fetch」の紹介です。

🐮 インストール手順

プロジェクト直下で次のコマンドを実行します。

yarn add node-fetch

npm install --save node-fetch

🐝 利用方法

GET

まずは通常の書き方。

import fetch from 'node-fetch';

// HTMLの取得
fetch('https://github.com/')
	.then(res => res.text())
	.then(body => console.log(body));

// JSONの取得
fetch('https://api.github.com/users/github')
	.then(res => res.json())
	.then(json => console.log(json));

async/awaitを組み合わせた使い方。

import fetch from 'node-fetch';
const url = 'https://api.github.com/users/github';

(async () => {
  try {
    const response = await fetch(url);
    const json = await response.json();
    console.log(json.origin);
  } catch (error) {
    console.log(error);
  }
})();

POST

//　通常のPOST
const params = new URLSearchParams();
params.append('a', 1);
fetch('http://httpbin.org/post', { method: 'POST', body: params })
	.then(res => res.json())
	.then(json => console.log(json));

// JSONのPOST
const body = { a: 1 };
const options = {
	method: 'POST',
	body:    JSON.stringify(body),
	headers: { 'Content-Type': 'application/json' },
}
fetch('http://httpbin.org/post', option)
	.then(res => res.json())
	.then(json => console.log(json));

🎃 fetch APIの概要

fetchメソッドのAPIの概要です。詳細は「node-fetch」を参照ください。

fetch(url[, options])

// オプションとそのデフォルト値
{
	// 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', // set to `manual` to extract redirect headers, `error` to reject redirect

	// The following properties are node-fetch extensions
	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
	agent: null         // http(s).Agent instance, allows custom proxy, certificate etc.
}