iOSエンジニアがバックエンド入門する #Swift – Qiita

struct AddressInfoListController: RouteCollection {
...
    @Sendable
    func getAddressInfoList(req: Request) async throws -> Response {
        let addressInfoList: [AddressInfo] = try await AddressInfo.query(on: req.db)
            .filter(\.$postalCode == "1000001")
            .all()
        return try await addressInfoList.encodeResponse(for: req)
    }
}

// 本コードは正常に動作しない．あくまでも説明のためのもの
import Fluent
import Vapor

struct OpenAPIController: APIProtocol {
    var request: Request! // こんなふうにRequestにアクセスしたい！

    func searchAddresses(_ input: Operations.searchAddresses.Input) async throws -> Operations.searchAddresses.Output {
        let addressInfoList: [AddressInfo] = try await AddressInfo.query(on: request.db) // ここでDatabaseにアクセスするから
            .filter(\.$postalCode == request.query.get(at: "postal_code")) // ここで検索すべき郵便番号にもアクセスしたい
            .all()
        return .ok(
            .init(
                body: .json(
                    addressInfoList.map(Components.Schemas.AddressInfo.init)
                )
            )
        )
    }
}

// DatabaseのエンティティオブジェクトであるAddressInfoから，APIエンドポイントの型であるComponents.Schemas.AddressInfoを生成する
extension Components.Schemas.AddressInfo {
    init(from entity: AddressInfo) {
    ... // 後述
    }
}

@@ -20,6 +20,9 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-openapi-generator", from: "1.3.0"),
         .package(url: "https://github.com/apple/swift-openapi-runtime", from: "1.5.0"),
         .package(url: "https://github.com/swift-server/swift-openapi-vapor", from: "1.0.1"),
+        // DI
+        .package(url: "https://github.com/pointfreeco/swift-dependencies", from: "1.3.9"),
     ],
     targets: [
         .executableTarget(
@@ -33,6 +36,8 @@ let package = Package(
                 // OpenAPI
                 .product(name: "OpenAPIRuntime", package: "swift-openapi-runtime"),
                 .product(name: "OpenAPIVapor", package: "swift-openapi-vapor"),
+                // DI
+                .product(name: "Dependencies", package: "swift-dependencies"),
             ],
             swiftSettings: swiftSettings,
             plugins: [

import Dependencies
import Vapor

extension DependencyValues {

  var request: Request {
    get { self[RequestKey.self] }
    set { self[RequestKey.self] = newValue }
  }

  private enum RequestKey: DependencyKey {
    static var liveValue: Request {
      fatalError("Value of type \(Value.self) is not registered in this context")
    }
  }
}

+import Fluent
 import Vapor
+import Dependencies
 
 struct OpenAPIController: APIProtocol {
+    @Dependency(\.request) var request // これで差し込まれたrequestを使用できる
+
     func searchAddresses(_ input: Operations.searchAddresses.Input) async throws -> Operations.searchAddresses.Output {
-        // 一旦stubを返す
-        .ok(
+        let addressInfoList: [AddressInfo] = try await AddressInfo.query(on: request.db)
+            .filter(\.$postalCode == request.query.get(at: "postal_code"))
+            .all()
+        return .ok(
             .init(
                 body: .json(
-                    [
-                        .init(
-                            id: "1",
-                            postalCode: "1000001",
-                            prefectureKana: "トウキョウト",
-                            prefectureKanji: "東京都",
-                            cityKana: "チヨダク",
-                            cityKanji: "千代田区",
-                            streetKana: "チヨダ",
-                            streetKanji: "千代田"
-                        )
-                    ]
+                    addressInfoList.map(Components.Schemas.AddressInfo.init)
                 )
             )
         )
     }
 }
+
+extension Components.Schemas.AddressInfo {
+    init(from entity: AddressInfo) {
+        id = entity.id?.uuidString
+        postalCode = entity.postalCode
+        prefectureKana = entity.prefectureKana
+        prefectureKanji = entity.prefectureKanji
+        cityKana = entity.cityKana
+        cityKanji = entity.cityKanji
+        streetKana = entity.streetKana
+        streetKanji = entity.streetKanji
+    }
+}

import Dependencies
import Vapor

struct OpenAPIRequestInjectionMiddleware: AsyncMiddleware {
  func respond(
    to request: Request,
    chainingTo responder: any AsyncResponder
  ) async throws -> Response {
    try await withDependencies {
      $0.request = request // 新しいrequestが来るたびに，Dependenciesの環境値のrequestを上書きする
    } operation: {
      try await responder.respond(to: request) // 上書きしたrequestで続きの処理をする
    }
  }
}

enum Entrypoint {
         // let executorTakeoverSuccess = NIOSingletons.unsafeTryInstallSingletonPosixEventLoopGroupAsConcurrencyGlobalExecutor()
         // app.logger.debug("Tried to install SwiftNIO's EventLoopGroup as Swift's global concurrency executor", metadata: ["success": .stringConvertible(executorTakeoverSuccess)])
         
-        let transport = VaporTransport(routesBuilder: app)
+        let requestInjectionMiddleware = OpenAPIRequestInjectionMiddleware()
+        let transport = VaporTransport(routesBuilder: app.grouped(requestInjectionMiddleware))
         let handler = OpenAPIController()
         try handler.registerHandlers(on: transport, serverURL: Servers.Server1.url())
         do {

[
  {
    "cityKana" : "チヨダク",
    "cityKanji" : "千代田区",
    "id" : "FB5FE262-7A0D-461E-9268-E04B2BFD18CA",
    "postalCode" : "1000001",
    "prefectureKana" : "トウキョウト",
    "prefectureKanji" : "東京都",
    "streetKana" : "チヨダ",
    "streetKanji" : "千代田"
  }
]

[
  {
    "cityKana" : "チヨダク",
    "cityKanji" : "千代田区",
    "id" : "5C0A6E12-D474-4FD9-B86E-9081E31777D5",
    "postalCode" : "1000002",
    "prefectureKana" : "トウキョウト",
    "prefectureKanji" : "東京都",
    "streetKana" : "コウキョガイエン",
    "streetKanji" : "皇居外苑"
  }
]