[APT-9577] Add DRM for downloads for offline usage : release and remo…

…ve the downloaded license and license key ID when the corresponding download is removed
scribd · Feb 6, 2024 · fdd17ab · fdd17ab
1 parent efa2916
commit fdd17ab
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Showing 5 changed files with 44 additions and 1 deletion.
diff --git a/Armadillo/src/main/java/com/scribd/armadillo/download/DownloadEngine.kt b/Armadillo/src/main/java/com/scribd/armadillo/download/DownloadEngine.kt
@@ -76,7 +76,10 @@ internal class ExoplayerDownloadEngine @Inject constructor(
         })
     }
 
-    override fun removeDownload(audiobook: AudioPlayable) = downloadManager.removeDownload(audiobook.request.url)
+    override fun removeDownload(audiobook: AudioPlayable) {
+        downloadManager.removeDownload(audiobook.request.url)
+        offlineDrmManager.removeDownloadedDrm(audiobook)
+    }
 
     override fun removeAllDownloads() = downloadManager.removeAllDownloads()
 

diff --git a/Armadillo/src/main/java/com/scribd/armadillo/download/drm/DashDrmLicenseDownloader.kt b/Armadillo/src/main/java/com/scribd/armadillo/download/drm/DashDrmLicenseDownloader.kt
@@ -2,6 +2,7 @@ package com.scribd.armadillo.download.drm
 
 import android.content.Context
 import android.net.Uri
+import com.google.android.exoplayer2.drm.DrmSession
 import com.google.android.exoplayer2.drm.DrmSessionEventListener
 import com.google.android.exoplayer2.drm.OfflineLicenseHelper
 import com.google.android.exoplayer2.source.dash.DashUtil
@@ -68,4 +69,26 @@ internal class DashDrmLicenseDownloader @Inject constructor(private val context:
             }
         }
     }
+
+    override fun removeDrmLicense(audiobook: AudioPlayable) {
+        globalScope.launch(Dispatchers.IO) {
+            audiobook.request.drmInfo?.let { drmInfo ->
+                secureStorage.getDrmKeyId(context, audiobook.request.url, drmInfo.drmType.name)?.let { drmLicenseKeyId ->
+                    // Remove the key ID from storage immediately so we won't use it anymore
+                    secureStorage.removeDrmKeyId(context, audiobook.request.url, drmInfo.drmType.name)
+
+                    // Release the license with the server
+                    val offlineHelper = when (drmInfo.drmType) {
+                        DrmType.WIDEVINE -> OfflineLicenseHelper.newWidevineInstance(drmInfo.licenseServer, drmDataSourceFactory, drmEventDispatcher)
+                    }
+                    try {
+                        offlineHelper.releaseLicense(drmLicenseKeyId)
+                    } catch (e: DrmSession.DrmSessionException) {
+                        Log.e(DrmLicenseDownloader.TAG, "Failure to release DRM license")
+                        throw DrmDownloadException(e)
+                    }
+                }
+            }
+        }
+    }
 }
diff --git a/Armadillo/src/main/java/com/scribd/armadillo/download/drm/DrmLicenseDownloader.kt b/Armadillo/src/main/java/com/scribd/armadillo/download/drm/DrmLicenseDownloader.kt
@@ -13,4 +13,5 @@ internal interface DrmLicenseDownloader {
     }
 
     fun downloadDrmLicense(audiobook: AudioPlayable)
+    fun removeDrmLicense(audiobook: AudioPlayable)
 }
diff --git a/Armadillo/src/main/java/com/scribd/armadillo/download/drm/OfflineDrmManager.kt b/Armadillo/src/main/java/com/scribd/armadillo/download/drm/OfflineDrmManager.kt
@@ -18,4 +18,11 @@ internal class OfflineDrmManager @Inject constructor(
             else -> throw DrmContentTypeUnsupportedException(type)
         }.downloadDrmLicense(audiobook)
     }
+
+    fun removeDownloadedDrm(audiobook: AudioPlayable) {
+        when (@C.ContentType val type = Util.inferContentType(audiobook.request.url.toUri(), null)) {
+            C.TYPE_DASH -> dashDrmLicenseDownloader
+            else -> throw DrmContentTypeUnsupportedException(type)
+        }.removeDrmLicense(audiobook)
+    }
 }
diff --git a/Armadillo/src/main/java/com/scribd/armadillo/encryption/SecureStorage.kt b/Armadillo/src/main/java/com/scribd/armadillo/encryption/SecureStorage.kt
@@ -12,6 +12,7 @@ internal interface SecureStorage {
     fun downloadSecretKey(context: Context): ByteArray
     fun saveDrmKeyId(context: Context, audioUrl: String, drmType: String, drmKeyId: ByteArray)
     fun getDrmKeyId(context: Context, audioUrl: String, drmType: String): ByteArray?
+    fun removeDrmKeyId(context: Context, audioUrl: String, drmType: String)
 }
 
 @Singleton
@@ -64,6 +65,14 @@ internal class ArmadilloSecureStorage @Inject constructor() : SecureStorage {
             }
         }
 
+    override fun removeDrmKeyId(context: Context, audioUrl: String, drmType: String) {
+        context.getSharedPreferences(LOCATION, Context.MODE_PRIVATE).also { sharedPrefs ->
+            val key = Base64.encodeToString(audioUrl.toByteArray(StandardCharsets.UTF_8) + drmType.toByteArray(StandardCharsets.UTF_8),
+                Base64.NO_WRAP)
+            sharedPrefs.edit().remove(key).apply()
+        }
+    }
+
     private val String.toSecretByteArray: ByteArray
         get() {
             val keyBytes = ByteArray(16)
-Original file line number
+Diff line change
@@ Expand Up / @@ -13,4 +13,5 @@ internal interface DrmLicenseDownloader { @@
         }
         fun downloadDrmLicense(audiobook: AudioPlayable)
+        fun removeDrmLicense(audiobook: AudioPlayable)
     }