feat: Keep attachment in cache

Author: Ambrdctr

Mail/MailApp.swift

@@ -18,6 +18,7 @@
 
 import InfomaniakDI
 import MailCore
+import Nuke
 import OSLog
 import SwiftUI
 import UIKit
@@ -35,6 +36,7 @@ struct MailApp: App {
         Logging.resetAppForUITestsIfNeeded()
         Logger.general.info("Application starting in foreground ? \(UIApplication.shared.applicationState != .background)")
         refreshAppBackgroundTask.register()
+        ImagePipeline.shared = ImagePipeline(configuration: .withDataCache)
     }
 
     var body: some Scene {

MailCore/Cache/Attachments/AttachmentCacheHelper.swift

@@ -0,0 +1,34 @@
+/*
+ Infomaniak Mail - iOS App
+ Copyright (C) 2025 Infomaniak Network SA
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import Foundation
+import Nuke
+
+struct AttachmentCacheHelper {
+    func getCache(resource: String?) -> Data? {
+        guard let resource, let resourceURL = URL(string: resource) else { return nil }
+        let request = ImageRequest(url: resourceURL)
+        return ImagePipeline.shared.cache.cachedData(for: request)
+    }
+
+    func storeCache(resource: String?, data: Data) {
+        guard let resource, let resourceURL = URL(string: resource) else { return }
+        let request = ImageRequest(url: resourceURL)
+        ImagePipeline.shared.cache.storeCachedData(data, for: request)
+    }
+}

MailCore/Cache/MailboxManager/MailboxManager+Message.swift

@@ -49,7 +49,14 @@ public extension MailboxManager {
             throw CancellationError()
         }
 
-        let data = try await apiFetcher.attachment(attachment: attachment, progressObserver: progressObserver)
+        let attachmentCacheHelper = AttachmentCacheHelper()
+        let data: Data
+        if let cachedData = attachmentCacheHelper.getCache(resource: attachment.resource) {
+            data = cachedData
+        } else {
+            data = try await apiFetcher.attachment(attachment: attachment, progressObserver: progressObserver)
+            attachmentCacheHelper.storeCache(resource: attachment.resource, data: data)
+        }
 
         let safeAttachment = ThreadSafeReference(to: attachment)
         try? writeTransaction { writableRealm in