feat: Keep attachment in cache (#1740)

Author: PhilippeWeidmann

MailCore/Cache/Attachments/AttachmentCacheHelper.swift

@@ -0,0 +1,36 @@
+/*
+ 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 {
+    let pipeline: ImagePipeline
+
+    func getCache(resource: String?) -> Data? {
+        guard let resource, let resourceURL = URL(string: resource) else { return nil }
+        let request = ImageRequest(url: resourceURL)
+        return pipeline.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)
+        pipeline.cache.storeCachedData(data, for: request)
+    }
+}

MailCore/Cache/MailboxManager/MailboxManager+Message.swift

@@ -49,18 +49,23 @@ public extension MailboxManager {
             throw CancellationError()
         }
 
-        let data = try await apiFetcher.attachment(attachment: attachment, progressObserver: progressObserver)
+        @InjectService var cacheHelper: AttachmentCacheHelper
+        if let cachedData = cacheHelper.getCache(resource: attachment.resource) {
+            return cachedData
+        } else {
+            let data = try await apiFetcher.attachment(attachment: attachment, progressObserver: progressObserver)
+            cacheHelper.storeCache(resource: attachment.resource, data: data)
 
-        let safeAttachment = ThreadSafeReference(to: attachment)
-        try? writeTransaction { writableRealm in
-            guard let liveAttachment = writableRealm.resolve(safeAttachment) else {
-                return
-            }
+            let safeAttachment = ThreadSafeReference(to: attachment)
+            try? writeTransaction { writableRealm in
+                guard let liveAttachment = writableRealm.resolve(safeAttachment) else {
+                    return
+                }
 
-            liveAttachment.saved = true
+                liveAttachment.saved = true
+            }
+            return data
         }
-
-        return data
     }
 
     func saveAttachmentLocally(attachment: Attachment, progressObserver: ((Double) -> Void)?) async {

MailCore/Utils/TargetAssembly.swift

@@ -24,6 +24,7 @@ import InfomaniakDI
 import InfomaniakLogin
 import InfomaniakNotifications
 import MyKSuite
+import Nuke
 import OSLog
 
 private let realmRootPath = "mailboxes"
@@ -126,6 +127,9 @@ open class TargetAssembly {
             },
             Factory(type: MyKSuiteStore.self) { _, _ in
                 MyKSuiteStore()
+            },
+            Factory(type: AttachmentCacheHelper.self) { _, _ in
+                AttachmentCacheHelper(pipeline: ImagePipeline(configuration: .withDataCache))
             }
         ]
     }