In the previous article we created very simple SyncService service that can send and receive data between iOS as watch app. Which is good for very simple scenarios, but when application complexity is growing it is really important to keep you code clean, and well organized. In this article we will try to isolate sync logic from the rest of the application.

In one of my project I had to synchronize data based on different events, in different part of application. But all that code had a lot in common. So, to clean up it a bit and make it more reusable I introduced generic SyncObject class that encapsulates all basic sync logic.

So, you have decided to create iOS application with its watch companion application. And, you need to exchange some data between two of them. For this scenario Apple provides simple WatchConnectivity framework, that specifically designed for this type of scenarios. This framework does most of the heavy lifting and your goal is simply to implement the business logic.

In this article consists of two parts:

• Part 1. Minimum you need to sync data.
• Part 2. One of the approaches to encapsulate complex sync data logic.

Lets get started. To isolate all logic in one place lets create a service. First of all we need to import WatchConnectivity framework. Also, we need to implement WCSessionDelegate delegate protocol that defines methods for receiving messages from WCSession.

Working with JSON format, probably one of the most common task in the software development, whether you organizing the data storage or send data over network or any other reason. Therefore it will be very common task in the mobile development. Likely, Swift provides build in functionality to work with JSON format.

To encode (serialize) or decode (deserialize) our object to JSON format we need to make sure that object implements Encodable protocol and/or Decodable protocol. Or simply it can implement Codable protocol that combines both Encodable and Decodable protocols.

Very often you need to get basic application information, for example to show user an application version or maybe some issue has occurred and you want to collect some details about user device. Some information are relatively easy to get some are not so.

So, lets get some basic information. Personally, I prefer keep that information isolated and in one place. Lets create AppInfo struct and add couple of imports.