BridgeNet

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Installation

Bridge is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'BridgeNet'

Description

BridgeNet is a lightweight library for implementing the messages delivery system within the app. It can be a replacement for NotificationCenter or Observer Observable pattern in the application.

We can explain the BridgeNet as an undirected graph. Each node of the graph has Type and ID. ID is a unique UUID string and Type is an enum usually or any other Hashable type you prefer for storing it.

The main idea of the BridgeNet is to make messages delivery system flexible and not coupled with a specific implementation. To keep it, the BridgeNet doesn't have the adjacency list or adjacency matrix for node connections storing for the graph. You don't need any global object or Singleton to send the message from one node to another. The only thing you need to know is the destination Type. If you have more than one node in the system with the same Type but you want to send the message to the specific node you also have to specify the ID of the destination node.

For example you have an object structure in the app that can be presented as a graph from the picture:

Node types

The Type of all objects can be described as an enum:

enum NodeType: BridgeNodeTypable {
    case root
    case blue
    case green
    case red
}

Node holder implementation

Each object that wants to send and receive messages throw the BridgeNet should confirm several protocols:

• BridgeNodeConnectable to have the ability connect nodes to each other
• BridgeCallable to implement the recieving functionality

For example, that's how the simple UIView that presents the red node from the picture could look like:

class RedView: UIView {

    var bridgeNode: BridgeNode<NodeType>?

    func initBridge() {
        bridgeNode = BridgeNode<NodeType>(withAddress: BridgeNodeAddress<NodeType>(withAutogeneratedIdAndType: .red))
        bridgeNode?.add(delegate: self)
    }
}

extension RedView: BridgeNodeConnectable {}

extension RedView: BridgeCallable {

    func recieve<NodeType>(message: BridgeMessage<NodeType>) {
        guard let color = message.value as? UIColor else { return }
        backgroundColor = color
    }

}

This view is just getting messages from other nodes, and changes there own background color according to the color been getting from the message.

The functionality of the node connection is already implemented in the BridgeNodeConnectable protocol extension.

IMPORTANT: when you create the BridgeNode element, you also can specify the working Queue and the completion Queue for it. By default BridgeNet is using there own concurrent DispatchQueue as a working one and the Main Queue for completion. The thread-safety of the message delivery process is guaranteed by the internal architecture but only in case of using the same threads for each BridgeNode element

Nodes connection

To add the new BridgeNode to the graph, you have to connect it to the existing one. For example, let's take a look at how to connect the redView to the current object:

bridgeNode!.add(node: redView.connect(node: bridgeNode!))

Message sending

To send any information by the BridgeNet you need to create the BridgeMessage object. For the message you have to specify:

• the source node of the message
• the destination node
• the data you want to send
• the optional callback that can be called by the destination object after receiving the message

If you want to send the message to all the nodes of a specific type, you can create it like this:

let message = BridgeMessage<NodeType>(fromSourse: bridgeNode!.address,
                                      toDestination: BridgeNodeAddress<NodeType>(withOnlyType: .red),
                                      withValue: UIColor.white)

to create the message to the specific node in this type you also have to specify the ID

To send the message call send from the BridgeNode object:

bridgeNode!.send(message: message)

Author

Alexey Pichukov , pichukov@gmail.com

License

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