Creating a new entry with a unique ID

Following getTotal(), add the following handler for creating a new entry:

func newEntry(_ req: Request) throws -> Future<HTTPStatus> { // [1]
    let newID = UUID().uuidString // [2]
    return try req.content.decode(Entry.self).map(to: HTTPStatus.self) { entry in // [3]
        let newEntry = Entry(id: newID,
                             title: entry.title,
                             content: entry.content) // [4]
        guard let result = self.journal.create(newEntry) else { // [5]
            throw Abort(.badRequest) // [6]
        }
        print("Created: \(result)")
        return .ok // [7]
    }
}

The newEntry(_ req:) function handles the creation of a new entry in several steps:

1. Constructs a throwable function that returns a Future of HTTPStatus
2. Uses Swift's UUID() to create a unique ID for the new entry
3. Decodes the JSON object embedded in an HTTP request and serializes to an entry instance
4. Instantiates a new entry object using the new ID
5. Invokes the create() function of RouteController to add the new entry object to in-memory storage
6. Throws an Abort if the last step returns nil
7. Returns HTTPStatus.ok when reaching the end of the function

In [4], whatever ID that has been submitted is simply ignored, since the id field is always over-written with a new UUID. This guarantees that the id is unique, and this is very useful for you to debug the CRUD operations you've implemented.

The Abort in [6] is a default implementation of the AboutError protocol. Vapor always displays any error code specified in Abort to the end user, even in production mode where most error messages are suppressed.