cache notification icons and delete after 24 hours

app/src/main/java/io/heckel/ntfy/msg/DownloadIconWorker.kt

@@ -14,7 +14,7 @@ import io.heckel.ntfy.R
 import io.heckel.ntfy.app.Application
 import io.heckel.ntfy.db.*
 import io.heckel.ntfy.util.Log
-import io.heckel.ntfy.util.ensureSafeNewFile
+import io.heckel.ntfy.util.stringToHash
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import okhttp3.Response
@@ -44,7 +44,17 @@ class DownloadIconWorker(private val context: Context, params: WorkerParameters)
         subscription = repository.getSubscription(notification.subscriptionId) ?: return Result.failure()
         icon = notification.icon ?: return Result.failure()
         try {
-            downloadIcon()
+            val iconFile = createIconFile(icon)
+            if (!iconFile.exists()) {
+                downloadIcon(iconFile)
+            } else {
+                Log.d(TAG, "Loading icon from cache: ${icon.url}")
+                val iconUri = createIconUri(iconFile)
+                this.uri = iconUri // Required for cleanup in onStopped()
+                save(icon.copy(
+                    contentUri = iconUri.toString()
+                ))
+            }
         } catch (e: Exception) {
             failed(e)
         }
@@ -56,7 +66,7 @@ class DownloadIconWorker(private val context: Context, params: WorkerParameters)
         maybeDeleteFile()
     }
 
-    private fun downloadIcon() {
+    private fun downloadIcon(iconFile: File) {
         Log.d(TAG, "Downloading icon from ${icon.url}")
 
         try {
@@ -74,7 +84,7 @@ class DownloadIconWorker(private val context: Context, params: WorkerParameters)
                     return
                 }
                 val resolver = applicationContext.contentResolver
-                val uri = createUri(notification)
+                val uri = createIconUri(iconFile)
                 this.uri = uri // Required for cleanup in onStopped()
 
                 Log.d(TAG, "Starting download to content URI: $uri")
@@ -137,13 +147,17 @@ class DownloadIconWorker(private val context: Context, params: WorkerParameters)
         return size > maxAutoDownloadSize
     }
 
-    private fun createUri(notification: Notification): Uri {
+    private fun createIconFile(icon: Icon): File {
         val iconDir = File(context.cacheDir, ICON_CACHE_DIR)
         if (!iconDir.exists() && !iconDir.mkdirs()) {
             throw Exception("Cannot create cache directory for icons: $iconDir")
         }
-        val file = ensureSafeNewFile(iconDir, notification.id)
-        return FileProvider.getUriForFile(context, FILE_PROVIDER_AUTHORITY, file)
+        val hash = stringToHash(icon.url)
+        return File(iconDir, hash)
+    }
+
+    private fun createIconUri(iconFile: File): Uri {
+        return FileProvider.getUriForFile(context, FILE_PROVIDER_AUTHORITY, iconFile)
     }
 
     companion object {
@@ -152,7 +166,7 @@ class DownloadIconWorker(private val context: Context, params: WorkerParameters)
         const val MAX_ICON_DOWNLOAD_SIZE = 300000
 
         private const val TAG = "NtfyIconDownload"
-        private const val ICON_CACHE_DIR = "icons"
+        const val ICON_CACHE_DIR = "icons"
         private const val BUFFER_SIZE = 8 * 1024
     }
 }

app/src/main/java/io/heckel/ntfy/util/Util.kt

@@ -38,6 +38,7 @@ import okhttp3.RequestBody
 import okio.BufferedSink
 import okio.source
 import java.io.*
+import java.security.MessageDigest
 import java.security.SecureRandom
 import java.text.DateFormat
 import java.text.StringCharacterIterator
@@ -469,3 +470,10 @@ fun copyToClipboard(context: Context, notification: Notification) {
         .makeText(context, context.getString(R.string.detail_copied_to_clipboard_message), Toast.LENGTH_LONG)
         .show()
 }
+
+fun stringToHash(s: String): String {
+    val bytes = s.toByteArray();
+    val md = MessageDigest.getInstance("SHA-256")
+    val digest = md.digest(bytes)
+    return digest.fold("") { str, it -> str + "%02x".format(it) }
+}

app/src/main/java/io/heckel/ntfy/work/DeleteWorker.kt

@@ -7,11 +7,14 @@ import androidx.work.WorkerParameters
 import io.heckel.ntfy.BuildConfig
 import io.heckel.ntfy.db.ATTACHMENT_PROGRESS_DELETED
 import io.heckel.ntfy.db.Repository
+import io.heckel.ntfy.msg.DownloadIconWorker
 import io.heckel.ntfy.ui.DetailAdapter
 import io.heckel.ntfy.util.Log
 import io.heckel.ntfy.util.topicShortUrl
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import java.io.File
+import java.util.*
 
 /**
  * Deletes notifications marked for deletion and attachments for deleted notifications.
@@ -30,6 +33,7 @@ class DeleteWorker(ctx: Context, params: WorkerParameters) : CoroutineWorker(ctx
             deleteExpiredIcons() // Before notifications, so we will also catch manually deleted notifications
             deleteExpiredAttachments() // Before notifications, so we will also catch manually deleted notifications
             deleteExpiredNotifications()
+            cleanIconCache()
             return@withContext Result.success()
         }
     }
@@ -85,6 +89,23 @@ class DeleteWorker(ctx: Context, params: WorkerParameters) : CoroutineWorker(ctx
         }
     }
 
+    private fun cleanIconCache() {
+        Log.d(DeleteWorker.TAG, "Cleaning icons older than 24 hours from cache")
+        val iconDir = File(applicationContext.cacheDir, DownloadIconWorker.ICON_CACHE_DIR)
+        if (iconDir.exists()) {
+            for (f: File in iconDir.listFiles()) {
+                var lastModified = f.lastModified()
+                var today = Date()
+
+                var diffInHours = ((today.time - lastModified) / (1000 * 60 * 60))
+                if (diffInHours > 24) {
+                    Log.d(DeleteWorker.TAG, "Deleting cached icon: ${f.name}")
+                    f.delete()
+                }
+            }
+        }
+    }
+
     private suspend fun deleteExpiredNotifications() {
         Log.d(TAG, "Deleting expired notifications")
         val repository = Repository.getInstance(applicationContext)