seedlabio / ocarina

A library to get metadata and Open Graph information from URLs

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

1. Drag Ocarina.xcodeproj into your project
2. Go to your project
3. Select Build Phases
4. Under Embed frameworks, press + and select Ocarina.framework
5. Select Build Settings
6. Search for Other Linker Flags and add -lxml2

Usage

Fetching information for a single link

let url = URL(string: "https://awkward.co")!
link.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.

Links

• Awkward
• Beam