advanced-creation.js

import process from 'node:process';
import crypto from 'node:crypto';
import got from '../../dist/source/index.js';

// Signing requests

/*
Got supports composing multiple instances together. This is very powerful.

You can create a client that limits download/upload size, then compose it with an instance that signs a request.

It's like plugins without any of the plugin mess.
You just create instances and then compose them together.

To mix them use `instanceA.extend(instanceB, instanceC, ...)`, that's all.

Let's begin.
*/

// Logging all `got(…)` calls
const logger = got.extend({
	handlers: [
		(options, next) => {
			console.log(`Sending ${options.method} to ${options.url}`);
			return next(options);
		},
	],
});

// Denying redirects to foreign hosts
const controlRedirects = got.extend({
	hooks: {
		beforeRedirect: [
			(options, response) => {
				const {origin} = response.request.options.url;
				if (options.url.origin !== origin) {
					throw new Error(`Redirection to ${options.url.origin} is not allowed from ${origin}`);
				}
			},
		],
	},
});

// Limiting download & upload size
// This can prevent crashing due to insufficient memory
const limitDownloadUpload = got.extend({
	handlers: [
		(options, next) => {
			const {downloadLimit, uploadLimit} = options.context;

			// Create an AbortController if limits are set and signal not already provided
			let controller;
			let {signal} = options;

			if ((downloadLimit || uploadLimit) && !signal) {
				controller = new AbortController();
				signal = controller.signal;
				options.signal = signal;
			}

			const promiseOrStream = next(options);

			if (typeof downloadLimit === 'number') {
				promiseOrStream.on('downloadProgress', progress => {
					if (progress.transferred > downloadLimit && progress.percent !== 1) {
						const error = new Error(`Exceeded the download limit of ${downloadLimit} bytes`);

						if (options.isStream) {
							promiseOrStream.destroy(error);
						} else {
							controller?.abort(error);
						}
					}
				});
			}

			if (typeof uploadLimit === 'number') {
				promiseOrStream.on('uploadProgress', progress => {
					if (progress.transferred > uploadLimit && progress.percent !== 1) {
						const error = new Error(`Exceeded the upload limit of ${uploadLimit} bytes`);

						if (options.isStream) {
							promiseOrStream.destroy(error);
						} else {
							controller?.abort(error);
						}
					}
				});
			}

			return promiseOrStream;
		},
	],
});

// No user agent
const noUserAgent = got.extend({
	headers: {
		'user-agent': undefined,
	},
});

// Custom endpoint
const httpbin = got.extend({
	prefixUrl: 'https://httpbin.org/',
});

const getMessageSignature = (data, secret) => crypto.createHmac('sha256', secret).update(data).digest('hex').toUpperCase();
const signRequest = got.extend({
	hooks: {
		beforeRequest: [
			options => {
				const secret = options.context.secret ?? process.env.SECRET;

				if (secret) {
					options.headers.sign = getMessageSignature(options.body ?? '', secret);
				}
			},
		],
	},
});

/*
* Putting it all together
*/
const merged = got.extend(
	noUserAgent,
	logger,
	limitDownloadUpload,
	httpbin,
	signRequest,
	controlRedirects,
);

// There's no 'user-agent' header :)
const {headers} = await merged.post('anything', {
	body: 'foobar',
	context: {
		secret: 'password',
	},
}).json();

console.log(headers);
// Sending POST to https://httpbin.org/anything
// {
//   Accept: 'application/json',
//   'Accept-Encoding': 'gzip, deflate, br',
//   'Content-Length': '6',
//   Host: 'httpbin.org',
//   Sign: 'EB0167A1EBF205510BAFF5DA1465537944225F0E0140E1880B746F361FF11DCA'
// }

const MEGABYTE = 1_048_576;
try {
	await merged('https://pop-iso.sfo2.cdn.digitaloceanspaces.com/21.04/amd64/intel/5/pop-os_21.04_amd64_intel_5.iso', {
		context: {
			downloadLimit: MEGABYTE,
		},
		prefixUrl: '',
	});
} catch (error) {
	// AbortError: This operation was aborted.
	console.log(error.message);
}