feat: add package with service extension for custom image handling and permissions convenience methods (#2)

* feat: add package with service extension for custom image handling and permissions convenience methods

* add default notification options

Author: ameter

Package.swift

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+// swift-tools-version: 5.7
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "AmplifUtilsNotifications",
+    platforms: [.iOS(.v13), .macOS(.v10_15)],
+    products: [
+        .library(
+            name: "AmplifyUtilsNotifications",
+            targets: ["AmplifyUtilsNotifications"]),
+    ],
+    dependencies: [
+    ],
+    targets: [
+        .target(
+            name: "AmplifyUtilsNotifications",
+            dependencies: []),
+        .testTarget(
+            name: "AmplifyUtilsNotificationsTests",
+            dependencies: ["AmplifyUtilsNotifications"]),
+    ]
+)

Sources/AmplifyUtilsNotifications/AUNotificationPayload.swift

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+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+
+/// Defines the location of the image URL in a notification payload.
+///
+/// Conform to this protocol to define notification payload formats for use with AUNotificationService.
+/// It is not necessary to define the full message schema. Defining the subset of the message that
+/// contains the remote image URL is sufficient. See `PinpointNotificationPayload` for an example.
+public protocol AUNotificationPayload: Decodable {
+    var remoteImageURL: String? { get }
+}
+
+extension AUNotificationPayload {
+    init(decoding userInfo: [AnyHashable : Any]) throws {
+        let json = try JSONSerialization.data(withJSONObject: userInfo, options: .prettyPrinted)
+        self = try JSONDecoder().decode(Self.self, from: json)
+    }
+}

Sources/AmplifyUtilsNotifications/AUNotificationPermissions.swift

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+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+import UserNotifications
+
+#if canImport(AppKit)
+import AppKit
+typealias Application = NSApplication
+#elseif canImport(UIKit)
+import UIKit
+typealias Application = UIApplication
+#endif
+
+/// Provides convenience methods for requesting and checking notifications permissions.
+public class AUNotificationPermissions {
+    
+    /// Check if notifications are allowed
+    public static var allowed: Bool {
+        get async {
+            await withCheckedContinuation { continuation in
+                UNUserNotificationCenter.current().getNotificationSettings { settings in
+                    continuation.resume(returning: settings.authorizationStatus == .authorized ? true : false)
+                }
+            }
+        }
+    }
+    
+    /// Request notification permissions
+    /// - Parameter options: Requested notification options
+    @discardableResult
+    public static func request(_ options: UNAuthorizationOptions? = nil) async throws -> Bool {
+        let options = options ?? [.badge, .alert, .sound]
+        let notificationsAllowed = try await UNUserNotificationCenter.current().requestAuthorization(
+            options: options
+        )
+        
+        if notificationsAllowed {
+            // Register with Apple Push Notification service
+            await Application.shared.registerForRemoteNotifications()
+        }
+        
+        return notificationsAllowed
+    }
+}

Sources/AmplifyUtilsNotifications/AUNotificationService.swift

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+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import UserNotifications
+import os.log
+
+/// Attaches an image to a remote notification before it’s delivered to the user.
+///
+/// The image will be downloaded from a URL specified in the incoming notification. The
+/// format of the notification payload and name of the field containing the image URL is
+/// specified in payloadSchema, which conforms to AUNotificationPayload.
+open class AUNotificationService: UNNotificationServiceExtension {
+    
+    /// Defines the format of incomming notification payloads.
+    ///
+    /// You can override the default value in the initializer of a child class.
+    ///
+    /// Default: PinpointNotificationPayload
+    open var payloadSchema: AUNotificationPayload.Type = PinpointNotificationPayload.self
+    
+    var contentHandler: ((UNNotificationContent) -> Void)?
+    var bestAttemptContent: UNMutableNotificationContent?
+    
+    /// Called when in incomming notification is received. Allows modification of the notification request before delivery.
+    /// - Parameters:
+    ///   - request: The original notification request. Use this object to get the original content of the notification.
+    ///   - contentHandler: The block to execute with the modified content.
+    open override func didReceive(
+        _ request: UNNotificationRequest,
+        withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void
+    ) {
+        self.contentHandler = contentHandler
+        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)
+        
+        defer {
+            contentHandler(bestAttemptContent ?? request.content)
+        }
+        
+        if let bestAttemptContent = bestAttemptContent {
+            // Modify the notification content
+            guard let attachment = getImageAttachment(request) else { return }
+            
+            os_log(.debug, "created attachment")
+            bestAttemptContent.attachments = [attachment]
+        }
+    }
+    
+    /// Called when the system is terminating the extension.
+    open override func serviceExtensionTimeWillExpire() {
+        // Called just before the extension will be terminated by the system.
+        // Use this as an opportunity to deliver your "best attempt" at modified content,
+        // otherwise the original push payload will be used.
+        os_log(.debug, "time expired")
+        if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
+            contentHandler(bestAttemptContent)
+        }
+    }
+
+    private func getImageAttachment(_ request: UNNotificationRequest) -> UNNotificationAttachment? {
+        guard let payloadData = try? payloadSchema.init(decoding: request.content.userInfo),
+              let mediaURLString = payloadData.remoteImageURL,
+              let mediaType = mediaURLString.split(separator: ".").last,
+              let mediaURL = URL(string: mediaURLString),
+              let mediaData = try? Data(contentsOf: mediaURL) else {
+            return nil
+        }
+        os_log(.debug, "got image data")
+        
+        let fileManager = FileManager.default
+        let temporaryFolderName = ProcessInfo.processInfo.globallyUniqueString
+        let temporaryFolderURL = URL(fileURLWithPath: NSTemporaryDirectory())
+            .appendingPathComponent(temporaryFolderName, isDirectory: true)
+        
+        do {
+            try fileManager.createDirectory(at: temporaryFolderURL,
+                                            withIntermediateDirectories: true,
+                                            attributes: nil)
+            
+            // supported image types: jpg, gif, png
+            let imageFileIdentifier = "\(UUID().uuidString).\(String(mediaType))"
+            let fileURL = temporaryFolderURL.appendingPathComponent(imageFileIdentifier)
+            try mediaData.write(to: fileURL)
+            
+            return try UNNotificationAttachment(identifier: imageFileIdentifier, url: fileURL)
+        } catch {
+            return nil
+        }
+    }
+}

Sources/AmplifyUtilsNotifications/Payloads/PinpointNotificationPayload.swift

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+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+
+struct PinpointNotificationPayload: AUNotificationPayload {
+    var remoteImageURL: String? {
+        data.mediaURL
+    }
+
+    let data: PayloadData
+    
+    struct PayloadData: Decodable {
+        let mediaURL: String
+        
+        enum CodingKeys: String, CodingKey {
+            case mediaURL = "media-url"
+        }
+    }
+}

Tests/AmplifyUtilsNotificationsTests/AmplifyUtilsNotificationsTests.swift

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+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import XCTest
+@testable import AmplifyUtilsNotifications
+
+final class AmplifyUtilsNotificationsTests: XCTestCase {
+
+}