Web Link Preview

This library aims to help developers to create website link previews, given a web link. There are a few web conventions to use; a site's theme color or icon, or OpenGraph describing the link.

• Performant - HEAD requests to not download file binaries, regex for parsing.
• Cached - Inject own cache or uses default NSCache.
• Extensible - Additionally parse different metadata from HEAD tag.
• Preview Methods - Additional methods to parse metadata into relevant information.
  • URL parsing - Create URLs from absolute or relative hyperlink references.
  • Hex colors - UIColor from Hex string (6,7,8,9 length)
  • Text color - UIColor for black or white text above a site's theme color.

Requirements

• iOS 8.0+ / macOS 10.9+ / tvOS 9.0+ / watchOS 2.0+
• Xcode 10.3+
• Swift 4.2+

Installation

CocoaPods

CocoaPods is a dependency manager for Cocoa projects. For usage and installation instructions, visit their website. To integrate WebLinkPreview into your Xcode project using CocoaPods, specify it in your Podfile:

pod 'WebLinkPreview'

Carthage

Carthage is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks. To integrate WebLinkPreview into your Xcode project using Carthage, specify it in your Cartfile:

github "philip-bui/web-link-preview"

Swift Package Manager

The Swift Package Manager is a tool for automating the distribution of Swift code and is integrated into the swift compiler. It is in early development, but WebLinkPreview does support its use on supported platforms.

Once you have your Swift package set up, adding WebLinkPreview as a dependency is as easy as adding it to the dependencies value of your Package.swift.

dependencies: [
    .package(url: "https://github.com/philip-bui/web-link-preview.git", from: "1.0.0"))
]

Usage

import WebLinkPreview

// ViewController.swift - Load url.
_ = WebLinkMetadata(url: "https://www.youtube.com") { webLinkMetadata, error in
	guard let webLinkMetadata = webLinkMetadata else {
		return // Handle error.
	}
	webLinkMetadata.content // enum [.html, .image(URL), .video(URL), .other(URL)]
	webLinkMetadata.iconURL // URL for largest sized <link rel="icon" ...>
	webLinkMetadata.themeUIColor // UIColor for <meta name="theme-color" ...>
	webLinkMetadata["image"] // String for <meta property="og:image" ...>
	webLinkMetadata[.image] // OpenGraph enum for above
	// Any UI operations should be performed on main thread.
}

Improvements

• Support more String Encodings from Content-Type charset. Supports UTF-8 and Latin1.
• Use Cache-Control and Expires headers for NSCache expiration.
• HTTP Stub testing.
• Youtube Link Type. Youtube provides embedded video links and not video files, which other libraries solve.
• Duplicate OpenGraph tags. Common for sites to have multiple images, should arrays be used instead.

License

WebLinkPreview is available under the MIT license. See LICENSE for details.