Ocarina

A library to receive metadata and Open Graph information from URLs.

Introduction

Hi, we're Awkward. We were looking for a way to visualize information behind links to present these in our iOS reddit client called Beam. We initially used a server to receive metadata, but the server became quite crowded with calls. We built Ocarina as a solution to that problem. Fallbacks for basic HTML tags and Twitter card information make this metadata fetcher unique. We welcome you to use Ocarina for your own projects.

Features

Fetching of basic metadata for individual links using the OGP protocol or basic HTML tags (twitter card information also available)
Memory cache of metadata for each link
Prefetching a set of links to make views more responsive
Link information can include: type, title, description, image, image size, favicon, and Apple touch icon

Installation

Drag Ocarina.xcodeproj into your project
Go to your project
Select General
Under "Frameworks, Libraries, and Embedded Content" press + and select Ocarina.framework
Select Build Settings
Search for Other Linker Flags and add -lxml2 (Make sure you click "All" at the top instead of "Basic" to see Other Linker Flags)

Usage

Fetching information for a single link

let url = URL(string: "https://awkward.co")!
url.oca.fetchInformation(completionHandler: { (information, error) in
  if let information = information {
    print(String(describing: information.title))
  } else if let error = error {
    print(String(describing: error))
  }

})

Prefetching multiple links

OcarinaPrefetcher allows prefetching links into the cache, this allows for the UI to look more responsive.

let urls = [
  URL(string: "https://awkward.co")!,
  URL(string: "https://facebook.com")!,
  URL(string: "https://nytimes.com")!,
  URL(string: "https://latimes.com")!
]
let prefetcher = OcarinaPrefetcher(urls: urls, completionHandler: { (errors) in§
  print("Done pre-fetching links")
})

For other uses, see the example project

Contributing

Contributing is easy. If you want to report an error of any kind, please create an issue. If you want to propose a change, a pull request is the right way to go.

License

Ocarina is available under the MIT license. See the LICENSE file for more info.

awkward/Ocarina