Awesome Cache

Delightful on-disk cache (written in Swift). Backed by NSCache for maximum performance and support for expiry of single objects.

Usage

do {
    let cache = try Cache<NSString>(name: "awesomeCache")

    cache["name"] = "Alex"
    let name = cache["name"]
    cache["name"] = nil
} catch _ {
    print("Something went wrong :(")
}

Sync by design

AwesomeCache >= 3.0 is designed to have a sync API, making it easy to reason about the actual contents of the cache. This decision has been made based on feedback from the community, to keep the API of AwesomeCache small and easy to use.

The internals of the cache use a concurrent dispatch queue, that syncs reads and writes for thread safety. In case a particular caching operation blocks your main thread for too long, consider offloading the read and write operations to a different thread.

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {
    cache["name"] = "Alex"
}

Cache expiry

Objects can also be cached for a certain period of time.

cache.setObject("Alex", forKey: "name", expires: .Never) // same as cache["name"] = "Alex"
cache.setObject("Alex", forKey: "name", expires: .Seconds(2)) // name expires in 2 seconds
cache.setObject("Alex", forKey: "name", expires: .Date(Date(timeIntervalSince1970: 1428364800))) // name expires on 4th of July 2015

If an object is accessed after its expiry date, it is automatically removed from the cache and deleted from disk. However, you are responsible to delete expired objects regularly by calling removeExpiredObjects (e.g. on app launch).

Awesome API Caching

API responses are usually cached for a specific period of time. AwesomeCache provides an easy method to cache a block of asynchronous tasks.

cache.setObject(forKey: "name", cacheBlock: { success, failure in
  // Perform tasks, e.g. call an API
  let response = ...

  success(response, .Seconds(300)) // Cache response for 5 minutes
  // ... or failure(error)
}, completion: { object, isLoadedFromCache, error in
    if object {
        // object is now cached
    }
})

If the cache already contains an object, the completion block is called with the cached object immediately.

If no object is found or the cached object is already expired, the cacheBlock is called. You may perform any tasks (e.g. network calls) within this block. Upon completion of these tasks, make sure to call the success or failure block that is passed to the cacheBlock. The cacheBlock will not be re-evaluated until the object is expired or manually deleted.

The completion block is invoked as soon as the cacheBlock is finished and the object is cached.

Version Compatibility

Current Swift compatibility breakdown:

Installation

Manually

Just drag and drop the two .swift files in the AwesomeCache folder into your project.

Tests

Open the Xcode project and press ⌘-U to run the tests.

Alternatively, all tests can be run in the terminal using xctool.

xctool -scheme AwesomeCacheTests -sdk iphonesimulator test

Contributing

• Create something awesome, make the code better, add some functionality, whatever (this is the hardest part).
• Fork it
• Create new branch to make your changes
• Commit all your changes to your branch
• Submit a pull request

Contact

Feel free to get in touch.

• Website: http://schuch.me
• Twitter: @schuchalexander