Use Xcode for server-side development

1:36 - Simple, server package manifest

// swift-tools-version: 5.7

import PackageDescription

let package = Package(
    name: "MyServer",
    platforms: [.macOS("12.0")],
    products: [
        .executable(
            name: "MyServer",
            targets: ["MyServer"]),
    ],
    dependencies: [
        .package(url: "https://github.com/vapor/vapor.git", .upToNextMajor(from: "4.0.0")),
    ],
    targets: [
        .executableTarget(
            name: "MyServer",
            dependencies: [
                .product(name: "Vapor", package: "vapor")
            ]),
        .testTarget(
            name: "MyServerTests",
            dependencies: ["MyServer"]),
    ]
)

2:00 - Simple, server code

import Vapor

@main
public struct MyServer {
    public static func main() async throws {
        let webapp = Application()
        webapp.get("greet", use: Self.greet)
        webapp.post("echo", use: Self.echo)
        try webapp.run()
    }

    static func greet(request: Request) async throws -> String {
        return "Hello from Swift Server"
    }

    static func echo(request: Request) async throws -> String {
        if let body = request.body.string {
            return body
        }
        return ""
    }
}

3:42 - Using curl to test the local server

curl http://127.0.0.1:8080/greet; echo
curl http://127.0.0.1:8080/echo --data "Hello from WWDC 2022"; echo

4:10 - Simple, iOS app server abstraction

import Foundation

struct MyServerClient {
    let baseURL = URL(string: "http://127.0.0.1:8080")!

    func greet() async throws -> String {
        let url = baseURL.appendingPathComponent("greet")
        let (data, _) = try await URLSession.shared.data(for: URLRequest(url: url))
        guard let responseBody = String(data: data, encoding: .utf8) else {
            throw Errors.invalidResponseEncoding
        }
        return responseBody
    }

    enum Errors: Error {
        case invalidResponseEncoding
    }
}

5:00 - Simple, iOS app server call SwiftUI integration

import SwiftUI

struct ContentView: View {
    @State var serverGreeting = ""
    var body: some View {
        Text(serverGreeting)
            .padding()
            .task {
                do {
                    let myServerClient = MyServerClient()
                    self.serverGreeting = try await myServerClient.greet()
                } catch {
                    self.serverGreeting = String(describing: error)
                }
            }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

9:51 - Food truck, basic server

import Foundation
import Vapor

@main
struct FoodTruckServerBootstrap {
    public static func main() async throws {
        // initialize the server
        let foodTruckServer = FoodTruckServer()
        // initialize the web framework and configure the http routes
        let webapp = Application()
        webapp.get("donuts", use: foodTruckServer.listDonuts)
        try webapp.run()
    }
}

struct FoodTruckServer {
    private let storage = Storage()

    func listDonuts(request: Request) async -> Response.Donuts {
        let donuts = self.storage.listDonuts()
        return Response.Donuts(donuts: donuts)
    }

    enum Response {
        struct Donuts: Content {
            var donuts: [Model.Donut]
        }
    }
}

struct Storage {
    var donuts = [Model.Donut]()

    func listDonuts() -> [Model.Donut] {
        return self.donuts
    }
}

enum Model {
    struct Donut: Codable {
        var id: Int
        var name: String
        var date: Date
        var dough: Dough
        var glaze: Glaze?
        var topping: Topping?
    }

    struct Dough: Codable {
        var name: String
        var description: String
        var flavors: FlavorProfile
    }

    struct Glaze: Codable {
        var name: String
        var description: String
        var flavors: FlavorProfile
    }

    struct Topping: Codable {
        var name: String
        var description: String
        var flavors: FlavorProfile
    }

    public struct FlavorProfile: Codable {
        var salty: Int?
        var sweet: Int?
        var bitter: Int?
        var sour: Int?
        var savory: Int?
        var spicy: Int?
    }
}

12:18 - Food truck, server donuts menu

[
  {
      "id": 0,
      "name": "Deep Space",
      "date": "2022-04-20T00:00:00Z",
      "dough": {
          "name": "Space Strawberry",
          "description": "The Space Strawberry plant grows its fruit as ready-to-pick donut dough.",
          "flavors": {
              "sweet": 3,
              "savory": 2
          }
      },
      "glaze": {
          "name": "Delta Quadrant Slice",
          "description": "Locally sourced, wormhole-to-table slice of the delta quadrant of the galaxy. Now with less hydrogen!",
          "flavors": {
              "salty": 1,
              "sour": 3,
              "spicy": 1
          }
      },
      "topping": {
          "name": "Rainbow Sprinkles",
          "description": "Cultivated from the many naturally occurring rainbows on various ocean planets.",
          "flavors": {
              "salty": 2,
              "sweet": 2,
              "sour": 1
          }
      }
  },
  {
      "id": 1,
      "name": "Chocolate II",
      "date": "2022-04-20T00:00:00Z",
      "dough": {
          "name": "Chocolate II",
          "description": "When Harold Chocolate II discovered this substance in 3028, it finally unlocked the ability of interstellar travel.",
          "flavors": {
              "salty": 1,
              "sweet": 3,
              "bitter": 1,
              "sour": -1,
              "savory": 1
          }
      },
      "glaze": {
          "name": "Chocolate II",
          "description": "A thin layer of melted Chocolate II, flash frozen to fit the standard Space Donut shape. Also useful for cleaning starship engines.",
          "flavors": {
              "salty": 1,
              "sweet": 2,
              "bitter": 1,
              "sour": -1,
              "savory": 2
          }
      },
      "topping": {
          "name": "Chocolate II",
          "description": "Particles of Chocolate II moulded into a sprinkle fashion. Do not feed to space whales.",
          "flavors": {
              "salty": 1,
              "sweet": 2,
              "bitter": 1,
              "sour": -1,
              "savory": 2
          }
      }
  },
  {
      "id": 2,
      "name": "Coffee Caramel",
      "date": "2022-04-20T00:00:00Z",
      "dough": {
          "name": "Hardened Coffee",
          "description": "Unlike other donut sellers, our coffee dough is simply a lot of coffee compressed into an ultra dense torus.",
          "flavors": {
              "sweet": -2,
              "bitter": 4,
              "sour": 2,
              "spicy": 1
          }
      },
      "glaze": {
          "name": "Caramel",
          "description": "Some good old fashioned Earth caramel.",
          "flavors": {
              "salty": 2,
              "sweet": 3,
              "sour": -1,
              "savory": 1
          }
      },
      "topping": {
          "name": "Nebula Bits",
          "description": "Scooped up by starships traveling through a sugar nebula.",
          "flavors": {
              "sweet": 4,
              "spicy": 1
          }
      }
  }
]

12:23 - Food truck, server package manifest

// swift-tools-version: 5.7

import PackageDescription

let package = Package(
    name: "FoodTruckServer",
    platforms: [.macOS("12.0")],
    products: [
        .executable(
            name: "FoodTruckServer",
            targets: ["FoodTruckServer"]),
    ],
    dependencies: [
        .package(url: "https://github.com/vapor/vapor.git", .upToNextMajor(from: "4.0.0")),
    ],
    targets: [
        .executableTarget(
            name: "FoodTruckServer",
            dependencies: [
                .product(name: "Vapor", package: "vapor")
            ],
            resources: [
                .copy("menu.json")
            ]
        ),
        .testTarget(
            name: "FoodTruckServerTests",
            dependencies: ["FoodTruckServer"]),
    ]
)

12:30 - Food truck, server with integrated storage

import Foundation
import Vapor

@main
struct FoodTruckServerBootstrap {
    public static func main() async throws {
        // initialize the server
        let foodTruckServer = FoodTruckServer()
        try await foodTruckServer.bootstrap()
        // initialize the web framework and configure the http routes
        let webapp = Application()
        webapp.get("donuts", use: foodTruckServer.listDonuts)
        try webapp.run()
    }
}

struct FoodTruckServer {
    private let storage = Storage()

    func bootstrap() async throws {
        try await self.storage.load()
    }

    func listDonuts(request: Request) async -> Response.Donuts {
        let donuts = await self.storage.listDonuts()
        return Response.Donuts(donuts: donuts)
    }

    enum Response {
        struct Donuts: Content {
            var donuts: [Model.Donut]
        }
    }
}

actor Storage {
    let jsonDecoder: JSONDecoder
    var donuts = [Model.Donut]()

    init() {
        self.jsonDecoder = JSONDecoder()
        self.jsonDecoder.dateDecodingStrategy = .iso8601
    }

    func load() throws {
        guard let path = Bundle.module.path(forResource: "menu", ofType: "json") else {
            throw Errors.menuFileNotFound
        }
        guard let data = FileManager.default.contents(atPath: path) else {
            throw Errors.failedLoadingMenu
        }

        self.donuts = try self.jsonDecoder.decode([Model.Donut].self, from: data)
    }

    func listDonuts() -> [Model.Donut] {
        return self.donuts
    }

    enum Errors: Error {
        case menuFileNotFound
        case failedLoadingMenu
    }
}

enum Model {
    struct Donut: Codable {
        var id: Int
        var name: String
        var date: Date
        var dough: Dough
        var glaze: Glaze?
        var topping: Topping?
    }

    struct Dough: Codable {
        var name: String
        var description: String
        var flavors: FlavorProfile
    }

    struct Glaze: Codable {
        var name: String
        var description: String
        var flavors: FlavorProfile
    }

    struct Topping: Codable {
        var name: String
        var description: String
        var flavors: FlavorProfile
    }

    public struct FlavorProfile: Codable {
        var salty: Int?
        var sweet: Int?
        var bitter: Int?
        var sour: Int?
        var savory: Int?
        var spicy: Int?
    }
}

14:42 - Using curl and jq to test the local server

curl http://127.0.0.1:8080/donuts | jq .
curl http://127.0.0.1:8080/donuts | jq '.donuts[] .name'