metadata-scraper

A Javascript library for scraping/parsing metadata from a web page.

👋 Introduction

metadata-scraper is a Javascript library which scrapes/parses metadata from web pages. You only need to supply it with a URL or an HTML string and it will use different rules to find the most relevant metadata like:

• Title
• Description
• Favicons/Images
• Language
• Keywords
• Author
• and more (full list below)

🚀 Get started

Install metadata-scraper via npm:

npm install metadata-scraper

📚 Usage

Import metadata-scraper and pass it a URL or options object:

const getMetaData = require('metadata-scraper')

const url = 'https://github.com/BetaHuhn/metadata-scraper'

getMetaData(url).then((data) => {
	console.log(data)
})

Or with async/await:

const getMetaData = require('metadata-scraper')

async function run() {
	const url = 'https://github.com/BetaHuhn/metadata-scraper'
	const data = await getMetaData(url)
	console.log(data)
}

run()

This will return:

{
	title: 'BetaHuhn/metadata-scraper',
	description: 'A Javascript library for scraping/parsing metadata from a web page.',
	language: 'en',
	url: 'https://github.com/BetaHuhn/metadata-scraper',
	provider: 'GitHub',
	twitter: '@github',
	image: 'https://avatars1.githubusercontent.com/u/51766171?s=400&v=4',
	icon: 'https://github.githubassets.com/favicons/favicon.svg'
}

You can see a list of all metadata which metadata-scraper tries to scrape below.

⚙️ Configuration

You can change the behaviour of metadata-scraper by passing an options object:

const getMetaData = require('metadata-scraper')

const options = {
	url: 'https://github.com/BetaHuhn/metadata-scraper', // URL of web page
	maxRedirects: 0, // Maximum number of redirects to follow (default: 5)
	ua: 'MyApp', // Specify User-Agent header
	lang: 'de-CH', // Specify Accept-Language header
	timeout: 1000, // Request timeout in milliseconds (default: 10000ms)
	forceImageHttps: false, // Force all image URLs to use https (default: true)
	customRules: {} // more info below
}

getMetaData(options).then((data) => {
	console.log(data)
})

You can specify the URL by either passing it as the first parameter, or by setting it in the options object.

📖 Examples

Here are some examples on how to use metadata-scraper:

Basic

Pass a URL as the first parameter and metadata-scraper automatically scrapes it and returns everything it finds:

const getMetaData = require('metadata-scraper')
const data = await getMetaData('https://github.com/BetaHuhn/metadata-scraper')

Example file located at examples/basic.js.

---

HTML String

If you already have an HTML string and don't want metadata-scraper to make an http request, specify it in the options object:

const getMetaData = require('metadata-scraper')

const html = `
	<meta name="og:title" content="Example">
	<meta name="og:description" content="This is an example.">
`

const options {
	html: html, 
	url: 'https://example.com' // Optional URL to make relative image paths absolute
}

const data = await getMetaData(options)

Example file located at examples/html.js.

---

Custom Rules

Look at the rules.ts file in the src directory to see all rules which will be used.

You can expand metadata-scraper easily by specifying custom rules:

const getMetaData = require('metadata-scraper')

const options = {
	url: 'https://github.com/BetaHuhn/metadata-scraper',
	customRules: {
		name: {
			rules: [
				[ 'meta[name="customName"][content]', (element) => element.getAttribute('content') ]
			],
			processor: (text) => text.toLowerCase()
		}
	}
}

const data = await getMetaData(options)

customRules needs to contain one or more objects, where the key (name above) will identify the value in the returned data.

You can then specify different rules for each item in the rules array.

The first item is the query which gets inserted into the browsers querySelector function, and the second item is a function which gets passed the HTML element:

[ 'querySelector', (element) => element.innerText ]

You can also specify a processor function which will process/transform the result of one of the matched rules:

{
	processor: (text) => text.toLowerCase()
}

If you find a useful rule, let me know and I will add it (or create a PR yourself).

Example file located at examples/custom.js.

📇 All metadata

Here's what metadata-scraper currently tries to scrape:

{
	title: 'Title of page or article',
	description: 'Description of page or article',
	language: 'Language of page or article',
	type: 'Page type',
	url: 'URL of page',
	provider: 'Page provider',
	keywords: ['array', 'of', 'keywords'],
	section: 'Section/Category of page',
	author: 'Article author',
	published: 1605221765, // Date the article was published
	modified: 1605221765, // Date the article was modified
	robots: ['array', 'for', 'robots'],
	copyright: 'Page copyright',
	email: 'Contact email',
	twitter: 'Twitter handle',
	facebook: 'Facebook account id',
	image: 'Image URL',
	icon: 'Favicon URL',
	video: 'Video URL',
	audio: 'Audio URL'
}

If you find a useful metatag, let me know and I will add it (or create a PR yourself).

💻 Development

Issues and PRs are very welcome!

Please check out the contributing guide before you start.

This project adheres to Semantic Versioning. To see differences with previous versions refer to the CHANGELOG.

❔ About

This library was developed by me (@betahuhn) in my free time. If you want to support me:

Credits

This library is based on Mozilla's page-metadata-parser. I converted it to TypeScript, implemented a few new features, and added more rules.

License

Copyright 2020 Maximilian Schiller

This project is licensed under the MIT License - see the LICENSE file for details.