ogp_data_extract

A simple Dart library for extracting Open Graph protocol metadata from web pages. This library allows you to retrieve metadata items defined in "The Open Graph protocol."

Getting Started

Add the dependency to your package's pubspec.yaml file:

dependencies:
  ogp_data_extract: ^0.2.x

Then, install the package using the following commands:

With Dart:

$ dart pub get

With Flutter:

$ flutter pub get

Structure

This library supports the extraction of the following Open Graph protocol metadata fields, as specified in the Open Graph protocol documentation:

OgpData:
    - url
    - type
    - title
    - description
    - image
    - imageSecureUrl
    - imageType
    - imageWidth
    - imageHeight
    - imageAlt    
    - siteName
    - determiner
    - locale
    - localeAlternate    
    - latitude
    - longitude
    - streetAddress
    - locality
    - region
    - postalCode
    - countryName
    - email
    - phoneNumber
    - faxNumber
    - video
    - videoSecureUrl
    - videoHeight
    - videoWidth
    - videoType
    - audio
    - audioSecureUrl
    - audioTitle
    - audioArtist
    - audioAlbum
    - audioType
    - fbAdmins
    - fbAppId
    - twitterCard
    - twitterSite

Usage

Parse OgpData for a given URL

You can extract Open Graph metadata for a specific URL as shown in the following example:

void main() async {
    const String url = 'https://pub.dev/';
    final OgpData? ogpData = await OgpDataExtract.execute(url);
    print(ogpData?.url); // https://pub.dev/
    print(ogpData?.type); // website
    print(ogpData?.title); // The official repository for Dart and Flutter packages.
    print(ogpData?.description); // Pub is the package manager for the Dart programming language, containing reusable libraries & packages for Flutter, AngularDart, and general Dart programs.
    print(ogpData?.image); // https://pub.dev/static/img/pub-dev-icon-cover-image.png?hash=vg86r2r3mbs62hiv4ldop0ife5um2g5g
    print(ogpData?.siteName); // Dart packages
}

Specify the User-Agent when parsing

You can specify a custom User-Agent string for the request, which is useful for targeting specific devices or environments:

void main() async {
    const String url = 'https://pub.dev/';
    const String userAgent = 'Mozilla/5.0 (iPhone; CPU iPhone OS 12_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Mobile/15E148 Safari/604.1';
    final OgpData? ogpData = await OgpDataExtract.execute(url, userAgent: userAgent);
    print(ogpData);
}

Use the parser manually

If you already have the HTML content of a webpage, you can parse it manually using the following approach:

void main() async {
    const String url = 'https://pub.dev/';
    final http.Response response = await http.get(Uri.parse(url));
    final Document? document = OgpDataExtract.toDocument(response);
    final OgpData ogpData = OgpDataParser(document).parse();
    print(ogpData);
}

Fetch Favicon for a Web Page

In addition to Open Graph protocol extraction, this library also provides a utility to fetch the favicon URLs from a given webpage. This is useful for retrieving the associated website icons dynamically.

Example: Fetch Favicon

You can fetch all available favicon URLs for a given URL using the fetchFavicon method. Here's an example:

void main() async {
  const String url = 'https://pub.dev/';
  final List<String?> favicons = await OgpDataExtract.fetchFavicon(url);
  print(favicons); // Example output: ['/favicon.ico?hash=nk4nss8c7444fg0chird9erqef2vkhb8']
}

This method parses the tags in the webpage to find any icon-related metadata and returns a list of favicon URLs.

Credit

This library is inspired by metadata_fetch, but it is specifically designed for Open Graph protocol extraction.