Hands-On Swift 5 Microservices Development

Asynchronous events

If you have dealt with network connections in the past, you will be familiar with the concept. There are two ways of looking at requests: synchronously and asynchronously.

Synchronously means you send a request (for example, to a server) and your code will wait for a response before it continues. An example would look like this. This is the actual code from a Vapor 2 project:

let user = User()    // User is a model that is connected to a databaseuser.id = 2          // set some attributetry user.save()      // saves this model to the database print("saved")       // this line is called after we saved

The last line is only called after the user is saved; the whole program waits for the saving process to be finished. In contrast to the synchronous ...