Vapor 4 PostgreSQL CRUD without http requests

Question

I am writing backend using Swift 5 and Vapor 4, database is PostgreSQL 12. I have a question: how to interact with database (CRUD) locally, without POST or GET requests? All tutorials show how to CRUD only based on Request through HTTPS again. I already asked this question: Vapor 3 PostgreSQL CRUD without requests http BUT IT'S NOT A DUPLICATE QUESTION, Vapor 4 works completely different! Please, look at my current, working class for Vapor 3 (based on this answer: Is is possible to use Vapor 3 Postgres Fluent in a standalone script?):

import Vapor
import FluentPostgreSQL

final class WorkWithPostgres {
    
    private let databaseConfig = PostgreSQLDatabaseConfig(hostname: "localhost", port: 5432, username: "RutrackerTech", database: "vaporpostgres", password: "ru628trac4er")
    
    let postgres: PostgreSQLDatabase
    
    static let shared = WorkWithPostgres()
    
    private init() {
        postgres = PostgreSQLDatabase(config: databaseConfig)
    }
    
    /// Will it create undeleted memory leaks?
    func shutdownGracefully(worker: MultiThreadedEventLoopGroup, completion: (() -> Void)?) {
        worker.shutdownGracefully { error in
            completion?()
        }
    }
    
    /// Will it create udeleted memory leaks?
    func connect(completion: ((MultiThreadedEventLoopGroup, PostgreSQLConnection) -> Void)?) {
        let worker = MultiThreadedEventLoopGroup(numberOfThreads: 1)
        let eventLoopFuturePostgreSQLConnection = postgres.newConnection(on: worker)
        let _ = eventLoopFuturePostgreSQLConnection.map { postgreSQLConnection in
            completion?(worker, postgreSQLConnection)
        }
    }
    
    func readAll<T: PostgreSQLModel>(postgreSQLModel: T.Type, completion: (([T]) -> Void)?) {
        connect { worker, connection in
            let _ = postgreSQLModel.query(on: connection).all().map { databaseData in
                self.shutdownGracefully(worker: worker) {
                    completion?(databaseData)
                }
            }
        }
    }
    
    func create<T: PostgreSQLModel>(postgreSQLModel: T) {
        connect { worker, connection in
            let _ = postgreSQLModel.save(on: connection).whenComplete {
                self.shutdownGracefully(worker: worker, completion: nil)
            }
        }
    }
    
}

The biggest problem: I cannot find replacement to PostgreSQLDatabase in FluentPostgresDriver or in Fluent. Or, maybe, should be another approach to solve this task?

Thank you for reading, I will be thankful for any help or advice!

Answer 1

So, correct idea not to work with database like I did with Vapor 3. Now, in Vapor 4, you should use Database instance. Where to get it? I can suggest 2 options for you. First is boot(_ app: Application) in boot.swift or in configure(_ app: Application) in configure.swift. So app will have options to work with database like this: <Model>.query(on: app.db). Second option is req in any request. req should be of type Request, like this: <Model>.query(on: req.db). By Model, you can take any class inherited of class Model, for example: final class User: Model, Content { You should organise your code to be called from boot.swift or configure.swift or from any request, for example, in routes.swift