Revel-pre-hackathon-Vapor-workshop

This repo contains Swift Vapor preparation guidelines and content for an upcoming Revel hackathon

Prerequisites

• Xcode 9 or later
• Swift 4.1 (We'll use Vapor 3. Vapor 4 is the latest version, it requires Swift 5.1)
• Postman
• Docker installed

Installing Vapor Toolbox

• Vapor toolbox is a tool for creating, building, running Vapor projects.
• Generating Xcode projects
• Deploying projects with Vapor Cloud

Checking status of prerequisites

eval "$(curl -sL check.vapor.sh)"

Installing on macOS

brew install vapor/tap/vapor

Installing on Linux

eval "$(curl -sL https://apt.vapor.sh)"

Building first app

Create, Build and Start an app

vapor new VaporWorkshop

vapor build

vapor run

The template project is built and running on http://localhost:8080/hello

Creating XCode project file, implementing custom routes

Stop the currently running app with Control-C

Generate an XCode project file

vapor xcode -y

Simple request examples

router.get("hello", String.parameter) { req -> String in
    let name = try req.parameters.next(String.self)
    return "Hello, \(name)!"
}

//Accepting data
router.post(RevelThread.self, at: "thread") { req, data -> String in
    return "Thread with title: \(data.title) posted."
}

//Returning json
router.post(RevelThread.self, at: "thread") { req, data -> RevelThread in
    return data
}

Configuring Database

Choose from:

• SQLite
• MySQL
• PostgreSQL

Run the chosen DB in Docker

docker run --name postres -e POSTGRES_DB=vapor \-e POSTGRES_USER=vapor -e POSTGRES_PASSWORD=password \-p 5432:5432 -d postgres

Check status

docker ps

Configure the app

• Package.swift
• vapor xcode -y
• Configure.swift
• RevelThread.swift

Async requests - Futures and Promises

In Vapor a promise to deliver the result at some point of time is called Future. There are two main functions for dealing with unwrapping the result:

flatMap(to:) // use when promise closure returns a Future

map(to:) // use when promise closure returns a type other than Future

CRUD database operations examples

    router.post("api", "threads") { req -> Future<RevelThread> in
        return try req.content.decode(RevelThread.self)
            .flatMap(to: RevelThread.self) { thread in

            return thread.save(on: req)
        }
    }

    // get all threads
    router.get("api", "threads") { req -> Future<[RevelThread]> in
        return RevelThread.query(on: req).all()
    }

    // get single with parameter
    router.get("api", "threads", RevelThread.parameter) { req -> Future<RevelThread> in
        return try req.parameters.next(RevelThread.self)
    }

    // update
    router.put("api", "threads", RevelThread.parameter) { req -> Future<RevelThread> in
        return try flatMap(to: RevelThread.self,
                           req.parameters.next(RevelThread.self),
                           req.content.decode(RevelThread.self)) { acronym, updatedAcronym in
                            acronym.title = updatedAcronym.title
                            return acronym.save(on: req)
        }
    }

    // delete
    router.delete("api", "threads", RevelThread.parameter) { req -> Future<HTTPStatus> in
        return try req.parameters
            .next(RevelThread.self)
            .delete(on: req)
            .transform(to: HTTPStatus.noContent)
    }