Melodic Caching for Swift
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Johnny macOS
Johnny tvOS
Johnny watchOS
Johnny.xcodeproj
Johnny
JohnnyTests
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LICENSE
README.md
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README.md

Logo

platform license

Johnny is a generic caching library written in Swift 3.

Features

Johnny can cache any model object that conforms to the Storable protocol.

Note, that since the protocol uses a static constructor function instead of an initializer, you can extend any class and make them conform to Storable, even if you don't have access to its source (for example, Apple's classes)

public protocol Storable {
    associatedtype Result
    static func fromData(data: Data) -> Result?
    func toData() -> Data
}
  • Out-of-the-box support:
    • String, Bool, Int, UInt, Int64, UInt64, Float, Double
    • URL, Data, Date
    • UIImage, UIColor
    • Arrays, Dictionaries and Sets of the above
  • Multiplatform, supporting iOS, macOS, tvOS & watchOS
  • First-level memory cache using NSCache
  • Second-level LRU disk cache
  • Disk access in background thread (always when saving, optionally when fetching)
  • Syncronous & Asynchronous API support
  • Automatic cache eviction on memory warnings & disk capacity reached
  • Unit tested
  • Concise, well-structured code to encourage contributions

Extra ❤️ for images:

  • func setImageWithURL extension on UIImageView, UIButton & NSImageView, optimized for cell reuse

Usage

Caching

Johnny.cache(user, key: "LocalUser")

// You can flag a value to be stored in the Library instead of the Caches folder if you don't want it to be automatically purged:
Johnny.cache(Date(), key: "FirstStart", library: true)

Pulling

// The type of the retrived value must be explicitly stated for the compiler.
let date: Date? = Johnny.pull("FirstStart")

// If you know you are retrieving a large object (> 1.5 MB) you can do it asynchronously
Johnny.pull("4KImage") { (image: UIImage?) in

}

Removing

Johnny.remove("LocalUser")

Examples

Collections

You can cache any collection of items conforming to the Storable protocol (most standard library data types already do)

let array: [String] = ["Folsom", "Prison", "Blues"]
let stringSet: Set<String> = ["I've", "been", "everywhere"]
// In case of dictionaries, the value must explicitly conform to Storable (so [String: AnyObject] does not work, while [String: Double] does)
let dictionary: [String: String] = ["first": "Solitary", "second": "man"]

Johnny.cache(array, key: "folsom")
Johnny.cache(stringSet, key: "everywhere")
Johnny.cache(dictionary, key: "solitary")

Custom types

Due to current Swift limitations, since the Storable protocol has an associatedType, conformance must be added through an extension. class User: Storable will not work.

struct User {
    
    enum Badassery: String { case Total }
    
    var name: String?
    var uid: Int
    var badassery: Badassery
}


extension User: Storable {
typealias Result = User

static func fromData(data: NSData) -> User.Result? {
    let dict = try! NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions()) as! [NSObject: AnyObject]

    let user = User()
    user.uid = dict["identification"] as! Int
    user.name = dict["name"] as? String
    user.badassery = Badassery(rawValue: dict["badassery"] as! String)!
    return user
}

func toData() -> NSData {
    let json = ["identification": uid, "name": name, "badassery": badassery.rawValue]
    return try! NSJSONSerialization.dataWithJSONObject(json, options: NSJSONWritingOptions())
    }
}

Using it with Johnny:

let lily = User(name: "Lily", uid: 84823682, badassery: .Total)
Johnny.cache(lily, key: "Lily")

let cachedLily: User = Johnny.pull("Lily")

Requirements

  • iOS 8.0+
  • macOS 10.10+
  • tvOS 9.0+
  • watchOS 2.0+
  • Swift 3.0+

Install

CocoaPods

pod 'Johnny'

Carthage

github "zolomatok/Johnny"

Manual

  • Clone the project
  • Select the scheme (platform) and build
  • Drag Johnny.framework to your project
  • In the project settings under your target's General tab, scroll down and add Johhny to the Embedded Binaries section if it's not already added.

Attribution

I'd like to thank the creators of Pantry and Haneke as those projects provided much of the inspiration and some code. Johnny was dreamed up to be the best of both worlds.

License

Johnny is released under the MIT license. See LICENSE for details.