see-link

See-Link

See-a-Link! Get the preview metadata like title, description, image, video, etc from a link or a link extracted from the given text.

See-Link looks through the open-graph, twitter cards markup and other meta tags to get the preview information from the link. It visits a link in a headless browser and scrapes the required information. It can also return the dominant color of the page in case the theme-color is needed but no meta info is found.

To know more about how See-Link works checkout this wiki.

Check out this article to know about meta tags, SEO and their need for generating link previews.

Table of Contents

• Features
• Getting Started
• Usage
• API
• Options
• Test
• License

Features

• Get the dominant color of the page if required.
• Can return images present in html body incase meta tags are not available.
• Can be customized to return the info as per the requirement.
• Uses stealth measures and user-agent can be customized to bypass restrictions setup by sites to prevent bot scraping.

NOTE

• A different domain cannot be requested from your web app (browsers block cross-origin-requests). If you do not know how same-origin-policy works, here is a great article, therefore this library works on node (back-end environments) and certain mobile run-times (like react-native).

• This library fetches the website and parses its html using puppeteer, as if the user would visit the page. This means that some websites might redirect you to a sign-up page. You can try to change the user-agent property (by default it uses Facebook's user agent) and the response you get then might be different, but there is nothing wrong with this library.

Getting Started

npm install see-link

Usage

Its quite simple:

const seeLink = require('see-link');

(async () => {
    const preview = await seeLink('https://www.bharatsharma.me');

    // You can directly pass a url as above or pass a chunk of text
    // and seeLink will extract the first link from it. Like this:

    const preview_text = await seeLink('This text will be parsed by seeLink https://www.bharatsharma.me');

    console.log(preview);
})();

The above code will result in the following output:

{
  title: 'Bharat Sharma',
  description: 'Personal website of Bharat Sharma',
  image: 'https://bharatsharma.me/assets/images/logo.png',
  domainName: 'bharatsharma.me'
}

API

function seeLink(url: string, options?: seeLink.Options): Promise<SeeLinkRes>

seeLink takes a url and options object (optional). The url string can be any link or a text containing a link. It rejects with an error if there was no URL in the text provided.

seeLink returns a promise that resolves to the preview metadata of the following type:

SeeLinkRes {
  title: string;
  description: string;
  image: string;
  domainName: string;
  video?: string;
  themeColor?: string;
  favIcon?: string;
  type?: string;
}

Options

Additionally you can pass an options object to the function to change the default behaviour:

Option Name	Function	Type
detailedPreview	Get all the possible metadata supported by the see-link (eg: video, theme-color, type, favIcon)	boolean
getVideo	Get the video metadata along with the default result	boolean
getThemeColor	Get the theme-color metadata along with the default result	boolean
getDominantThemeColor	When getThemeColor is set to true and no theme-color meta info is found then get the dominant color of the page. By default it's true	boolean
args	Arguments to pass to the puppeteer.launch function	string[]
userAgent	User-Agent to use when visiting the website	string
timeout	Timeout in milliseconds for the request	number
executablePath	Path to the chrome/chromium executable	string
headless	Whether to run the browser in headless mode	boolean

Test

The library is tested using Mocha and Chai. You can run the tests by running the following command in the project root:

./test.sh

If bash: ./test.sh: Permission denied error is thrown, you can make the test executable by running the following command:

chmod +x test.sh

Alternatively, you can run the tests by running the following commands in the project root:

npm run-script test-server

then in another terminal run the following command:

npm test

NOTE: The test server runs on port 3000 by default. You can change the port number in test_setup/config.js file.

License

See-Link is released under the MIT License.