TodoLambdaHandler-Handler.swift

struct TodoLamdaHandler: EventLoopLambdaHandler {
    
    //...
  
    // Main handler
    func handle(context: Lambda.Context, event: APIGateway.Request) -> EventLoopFuture<APIGateway.Response> {
        guard let handler = Handler.current else {
            return context.eventLoop.makeSucceededFuture(APIGateway.Response(with: APIError.requestError, statusCode: .badRequest))
        }
        
        switch handler {
        case .create:
            return handleCreate(context: context, event: event)
        case .read:
            return handleRead(context: context, event: event)
        case .update:
            return handleUpdate(context: context, event: event)
        case .delete:
            return handleDelete(context: context, event: event)
        case .list:
            return handleList(context: context, event: event)
        }
    }
    
    // Handling Create Todo
    func handleCreate(context: Lambda.Context, event: APIGateway.Request) -> EventLoopFuture<APIGateway.Response> {
        guard let newTodo: Todo = try? event.bodyObject() else {
            return context.eventLoop.makeSucceededFuture(APIGateway.Response(with: APIError.requestError, statusCode: .badRequest))
        }
        return todoService.createTodo(todo: newTodo)
            .map { todo in
                APIGateway.Response(with: todo, statusCode: .ok)
        }.flatMapError {
            self.catchError(context: context, error: $0)
        }
    }
    
    // Handling Read Todo
    func handleRead(context: Lambda.Context, event: APIGateway.Request) -> EventLoopFuture<APIGateway.Response> {
        guard let id = event.pathParameters?[Todo.DynamoDBField.id] else {
            return context.eventLoop.makeSucceededFuture(APIGateway.Response(with: APIError.requestError, statusCode: .notFound))
        }
        return todoService.getTodo(id: id)
            .map { todo in
                APIGateway.Response(with: todo, statusCode: .ok)
        }.flatMapError {
            self.catchError(context: context, error: $0)
        }
    }
    
    // Handling Update Todo
    func handleUpdate(context: Lambda.Context, event: APIGateway.Request) -> EventLoopFuture<APIGateway.Response> {
        guard let updatedTodo: Todo = try? event.bodyObject() else {
            return context.eventLoop.makeSucceededFuture(APIGateway.Response(with: APIError.requestError, statusCode: .badRequest))
        }
        return todoService.updateTodo(todo: updatedTodo)
            .map { todo in
                APIGateway.Response(with: todo, statusCode: .ok)
        }.flatMapError {
            self.catchError(context: context, error: $0)
        }
    }
    
    // Handling Delete Todo
    func handleDelete(context: Lambda.Context, event: APIGateway.Request) -> EventLoopFuture<APIGateway.Response> {
        guard let id = event.pathParameters?[Todo.DynamoDBField.id] else {
            return context.eventLoop.makeSucceededFuture(APIGateway.Response(with: APIError.requestError, statusCode: .badRequest))
        }
        return todoService.deleteTodo(id: id)
            .map {
                APIGateway.Response(with: EmptyResponse(), statusCode: .ok)
        }.flatMapError {
            self.catchError(context: context, error: $0)
        }
    }
    
    // Handling Todos List
    func handleList(context: Lambda.Context, event: APIGateway.Request) -> EventLoopFuture<APIGateway.Response> {
        return todoService.getAllTodos()
            .map { todos in
                APIGateway.Response(with: todos, statusCode: .ok)
        }.flatMapError {
            self.catchError(context: context, error: $0)
        }
    }
    
    // Catch Error
    func catchError(context: Lambda.Context, error: Error) -> EventLoopFuture<APIGateway.Response> {
        let response = APIGateway.Response(with: error, statusCode: .notFound)
        return context.eventLoop.makeSucceededFuture(response)
    }
}