Feature/google auth lib

CHANGELOG.md

@@ -8,6 +8,9 @@
 
 ## master
 
+### Added
+- Replaces custom solution for getting auth credentials with [google auth library](https://github.com/googleapis/google-auth-library-swift) ([#36](https://github.com/AckeeCZ/ACKLocalization/pull/36), kudos to @babacros)
+
 ## 1.5.0
 
 ## Added 

Package.swift

@@ -18,14 +18,17 @@ let package = Package(
             targets: ["ACKLocalization"]),
     ],
     dependencies: [
-        .package(url:"https://github.com/vapor/jwt-kit", .upToNextMajor(from: "4.3.0")),
+        .package(
+            url: "https://github.com/googleapis/google-auth-library-swift",
+            .upToNextMajor(from: "0.5.2")
+        ),
     ],
     targets: [
         // Targets are the basic building blocks of a package. A target can define a module or a test suite.
         // Targets can depend on other targets in this package, and on products in packages which this package depends on.
         .target(
             name: "ACKLocalizationCore",
-            dependencies: ["JWTKit"]),
+            dependencies: ["OAuth2"]),
         .target(
             name: "ACKLocalization",
             dependencies: ["ACKLocalizationCore"]),

Sources/ACKLocalizationCore/ACKLocalization.swift

@@ -60,7 +60,7 @@ public final class ACKLocalization {
     /// Fetches content of given sheet from spreadsheet using given `serviceAccount`
     ///
     /// If not `spreadsheetTabName` is provided, the first in the spreadsheet is used
-    public func fetchSheetValues(_ spreadsheetTabName: String?, spreadsheetId: String, serviceAccount: ServiceAccount) -> AnyPublisher<ValueRange, LocalizationError> {
+    public func fetchSheetValues(_ spreadsheetTabName: String?, spreadsheetId: String, serviceAccount: Data) -> AnyPublisher<ValueRange, LocalizationError> {
         let sheetsAPI = self.sheetsAPI
 
         return authAPI.fetchAccessToken(serviceAccount: serviceAccount)
@@ -326,9 +326,17 @@ public final class ACKLocalization {
         do {
             if let serviceAccountPath = config.serviceAccount {
                 let serviceAccount = try loadServiceAccount(from: serviceAccountPath)
-                return fetchSheetValues(config.spreadsheetTabName, spreadsheetId: config.spreadsheetID, serviceAccount: serviceAccount)
+                return fetchSheetValues(
+                    config.spreadsheetTabName,
+                    spreadsheetId: config.spreadsheetID,
+                    serviceAccount: serviceAccount
+                )
             } else if let apiKey = config.apiKey {
-                return fetchSheetValues(config.spreadsheetTabName, spreadsheetId: config.spreadsheetID, apiKey: apiKey)
+                return fetchSheetValues(
+                    config.spreadsheetTabName,
+                    spreadsheetId: config.spreadsheetID,
+                    apiKey: apiKey
+                )
             } else if let serviceAccountPath = ProcessInfo.processInfo.environment[Constants.serviceAccountPath] {
                 let serviceAccount = try loadServiceAccount(from: serviceAccountPath)
                 return fetchSheetValues(
@@ -338,16 +346,20 @@ public final class ACKLocalization {
                 )
             } else if let apiKey = ProcessInfo.processInfo.environment[Constants.apiKey] {
                 let apiKey = APIKey(value: apiKey)
-                return fetchSheetValues(config.spreadsheetTabName, spreadsheetId: config.spreadsheetID, apiKey: apiKey)
+                return fetchSheetValues(
+                    config.spreadsheetTabName,
+                    spreadsheetId: config.spreadsheetID,
+                    apiKey: apiKey
+                )
             } else {
                 let errorMessage = """
                 Unable to load API key or service account path. Please check if:
-                
+
                 - `apiKey` or `serviceAccount` attribute is provided in `localization.json` file
                 or
                 - `\(Constants.apiKey)` or `\(Constants.serviceAccountPath)` environment variable is set
                 """
-                
+
                 throw LocalizationError(message: errorMessage)
             }
         } catch {
@@ -385,16 +397,16 @@ public final class ACKLocalization {
     }
 
     /// Loads service account from given `config`
-    private func loadServiceAccount(from path: String) throws -> ServiceAccount {
+    private func loadServiceAccount(from path: String) throws -> Data {
         guard let serviceAccountData = FileManager.default.contents(atPath: path) else {
             throw LocalizationError(message: "Unable to load service account at " + path)
         }
-
-        do {
-            return try JSONDecoder().decode(ServiceAccount.self, from: serviceAccountData)
-        } catch {
-            throw LocalizationError(message: "Unable to read service account from `" + path + "` - " + error.localizedDescription)
+
+        guard !serviceAccountData.isEmpty else {
+            throw LocalizationError(message: "Invalid service account data")
         }
+
+        return serviceAccountData
     }
 
     /// Actually writes given `rows` to given `file`

Sources/ACKLocalizationCore/Services/AuthAPIService.swift

@@ -7,12 +7,12 @@
 
 import Combine
 import Foundation
-import JWTKit
+import OAuth2
 
 /// Protocol wrapping a service that fetches an access token from further communication
 public protocol AuthAPIServicing {
     /// Fetch access token for given `serviceAccount`
-    func fetchAccessToken(serviceAccount: ServiceAccount) -> AnyPublisher<AccessToken, RequestError>
+    func fetchAccessToken(serviceAccount: Data) -> AnyPublisher<AccessToken, RequestError>
 }
 
 /// Service that fetches an access token from further communication
@@ -28,41 +28,36 @@ public struct AuthAPIService: AuthAPIServicing {
     // MARK: - API calls
 
     /// Fetch access token for given `serviceAccount`
-    public func fetchAccessToken(serviceAccount: ServiceAccount) -> AnyPublisher<AccessToken, RequestError> {
-        let jwt = try? self.jwt(
-            for: serviceAccount,
-            claims: claims(serviceAccount: serviceAccount, validFor: 60)
-        )
-        let requestData = AccessTokenRequest(assertion: jwt ?? "")
-        var request = URLRequest(url: serviceAccount.tokenURL)
-        request.httpMethod = "POST"
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        request.httpBody = try? JSONEncoder().encode(requestData)
+    public func fetchAccessToken(serviceAccount: Data) -> AnyPublisher<AccessToken, RequestError> {
+        Deferred {
+            Future<AccessToken, RequestError> { promise in
+                guard let tokenProvider = ServiceAccountTokenProvider(
+                    credentialsData: serviceAccount,
+                    scopes: ["https://www.googleapis.com/auth/spreadsheets.readonly"]
+                ) else {
+                    promise(.failure(.init(message: "Creating provider failed")))
+                    return
+                }
 
-        return session.dataTaskPublisher(for: request)
-            .validate()
-            .decode(type: AccessToken.self, decoder: JSONDecoder())
-            .mapError(RequestError.init)
-            .eraseToAnyPublisher()
+                do {
+                    try tokenProvider.withToken { token, error in
+                        if let token = token, let accessToken = token.AccessToken {
+                            let token = AccessToken(
+                                accessToken: accessToken,
+                                expiration: TimeInterval(token.ExpiresIn ?? 0),
+                                type: token.TokenType ?? ""
+                            )
+                            promise(.success(token))
+                        } else if let error {
+                            promise(.failure(.init(underlyingError: error, message: "Retrieving access token failed")))
+                        } else {
+                            promise(.failure(.init(message: "Access token was not provided")))
+                        }
+                    }
+                } catch {
+                    promise(.failure(.init(underlyingError: error, message: "Retrieving access token failed")))
+                }
+            }
+        }.eraseToAnyPublisher()
     }
-
-    // MARK: - Private helpers
-
-    /// Create JWT token that will be sent to retrieve access token
-        private func jwt(for serviceAccount: ServiceAccount, claims: GoogleClaims) throws -> String {
-            let signers = JWTSigners()
-            try signers.use(.rs256(key: .private(pem: serviceAccount.privateKey)))
-            return try signers.sign(claims)
-        }
-
-        private func claims(serviceAccount sa: ServiceAccount, validFor interval: TimeInterval) -> GoogleClaims {
-            let now = Int(Date().timeIntervalSince1970)
-
-            return .init(
-                serviceAccount: sa,
-                scope: .readOnly,
-                exp: now + Int(interval),
-                iat: now
-            )
-        }
 }

Tests/ACKLocalizationCoreTests/Mocks/AuthAPIServiceMock.swift

@@ -7,9 +7,10 @@
 
 import ACKLocalizationCore
 import Combine
+import Foundation
 
 final class AuthAPIServiceMock: AuthAPIServicing {
-    func fetchAccessToken(serviceAccount: ServiceAccount) -> AnyPublisher<AccessToken, RequestError> {
+    func fetchAccessToken(serviceAccount: Data) -> AnyPublisher<AccessToken, RequestError> {
         Empty().eraseToAnyPublisher()
     }
 }