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Does the following code demonstrate proper use of Strategy design pattern for a simple networking layer in swift 3?

Some code smells I'm unsure about:

  • violates Single responsibiility principle. Each strategy class such as Find, has a method for a different type of implementation. This is because I could want to find an image, or a user, or a chatroom. which are stored at different nodes in Firebase. all these different find methods are clumped together in Find class.

  • At the call sight of a request, if I need to make multiple async request, I nest the next request call inside the closure of the call back. Is this Ok?

  • The request object allows access to every type of insert, and find method. so in my signup VC I could i have the option to download a chatroom. Is even having access to that kind of implementation bad?

I have posted the code below, and left out all the actual implementation for brevity.

Any tips or guidance is much appreciated! 

// USE CASE: Would go in viewDidLoad of ViewController
func testMyRequest () {

    let myRequest = Request(insert: Insert(), find: Find())

    myRequest.find?.user(with: "id", handler: { (user) in

        myRequest.find?.nearbyUsers(user: user, handler: { (users) in

            // update collectionView datasource
        })
    })
}

// Is this protocol necessary?
protocol RequestProtocol {
    // - Family of algorithms, related actions.
    var insert: Insert? { get set }
    var find: Find? { get set }
}


// ---------------------------

class Request: RequestProtocol {

    var insert: Insert?
    var find: Find?

    init(insert: Insert?, find: Find?) {
        self.insert = insert
        self.find = find
    }
}


// Use a singleton maybe for the classes below? Why wouldn't I?  

class Insert {

    init() { }

    func user(_ user: User) {
        // insert user to firebase implementation
    }

    func message(_ message: Message) -> Void  {
        // insert message to firebase impelmentation
    }

    func image(data: Data, user: User)  {
        // insert image to firebase impelmentation
    }
}


class Find {

    init() { }

    func user(with id: String, handler: @escaping (_ user: User) -> Void ) {
        // find user implementation
    }

    func allChatrooms(handler: @escaping ([Chatroom]) -> Void) {
        // find all chatrooms implementation
    }

    func nearbyUsers(user: User, handler: @escaping ([User]) -> Void ) {
        // find nearby Users relative to current User location implementation
    }

    // Private helper method
    private func findChatPartners (currentUser: User, chatrooms: [Chatroom] ) -> Set<String> {
    }

}

0 Answers0