fix: fetch ETag via PROPFIND after TUS chunked upload

TUS PATCH responses from openCloud do not include ETag headers.
This caused large file uploads (>10MB) to have null ETags in the
local database, breaking thumbnail preview URLs and caching.

Changes:
- TusUploadHelper: after TUS upload completes, perform a PROPFIND
  to fetch the file's ETag from the server
- PatchTusUploadChunkRemoteOperation: extract ETag from PATCH
  response header (for future backend support)
- UploadFileFromFileSystemWorker: persist ETag to database for both
  overwrite and non-overwrite uploads
- ThumbnailsRequester: use .orEmpty() for null-safe ETag formatting

Author: zerox80

opencloudApp/src/main/java/eu/opencloud/android/presentation/thumbnails/ThumbnailsRequester.kt

@@ -97,7 +97,7 @@ object ThumbnailsRequester : KoinComponent {
         val path = if (remotePath?.startsWith("/") == true) remotePath else "/$remotePath"
         val encodedPath = Uri.encode(path, "/")
 
-        return String.format(Locale.US, FILE_PREVIEW_URI, baseUrl, encodedPath, width, height, etag)
+        return String.format(Locale.US, FILE_PREVIEW_URI, baseUrl, encodedPath, width, height, etag.orEmpty())
     }
 
     fun getCoilImageLoader(): ImageLoader {

opencloudApp/src/main/java/eu/opencloud/android/workers/TusUploadHelper.kt

@@ -50,7 +50,7 @@ class TusUploadHelper(
         progressListener: OnDatatransferProgressListener?,
         progressCallback: ((Long, Long) -> Unit)? = null,
         spaceWebDavUrl: String? = null,
-    ) {
+    ) : String? {
         // Reset cancelled state for new upload
         cancelled = false
         Timber.d("TUS: starting upload for %s size=%d", remotePath, fileSize)
@@ -135,7 +135,7 @@ class TusUploadHelper(
         Timber.d("TUS: resume offset %d / %d", offset, fileSize)
         progressCallback?.invoke(offset, fileSize)
 
-        offset = performUploadLoop(
+        val loopResult = performUploadLoop(
             client = client,
             resolvedTusUrl = resolvedTusUrl,
             localPath = localPath,
@@ -146,6 +146,8 @@ class TusUploadHelper(
             initialOffset = offset,
             uploadId = uploadId,
         )
+        offset = loopResult.first
+        val finalEtag = loopResult.second
 
         // Verify upload is actually complete
         if (offset != fileSize) {
@@ -162,7 +164,30 @@ class TusUploadHelper(
             tusUploadExpires = null,
             tusUploadConcat = null,
         )
-        Timber.i("TUS: upload completed for %s (size=%d)", remotePath, fileSize)
+        // If TUS PATCH didn't return an ETag (which is normal for openCloud's TUS implementation),
+        // fetch it via a PROPFIND request on the newly uploaded file.
+        var resultEtag = finalEtag
+        if (resultEtag.isNullOrBlank()) {
+            Timber.d("TUS: no etag from PATCH, attempting PROPFIND for %s (spaceWebDavUrl=%s)", remotePath, spaceWebDavUrl)
+            try {
+                val readOp = eu.opencloud.android.lib.resources.files.ReadRemoteFileOperation(
+                    remotePath = remotePath,
+                    spaceWebDavUrl = spaceWebDavUrl,
+                )
+                val readResult = readOp.execute(client)
+                if (readResult.isSuccess && readResult.data != null) {
+                    resultEtag = readResult.data!!.etag
+                    Timber.d("TUS: fetched ETag via PROPFIND: %s", resultEtag)
+                } else {
+                    Timber.w("TUS PROPFIND failed. code=%s, httpCode=%d", readResult.code, readResult.httpCode)
+                }
+            } catch (e: Throwable) {
+                Timber.e(e, "TUS: exception during PROPFIND for ETag")
+            }
+        }
+
+        Timber.i("TUS: upload completed for %s (size=%d) resulting etag=%s", remotePath, fileSize, resultEtag)
+        return resultEtag
     }
 
     private fun performUploadLoop(
@@ -175,8 +200,9 @@ class TusUploadHelper(
         progressCallback: ((Long, Long) -> Unit)?,
         initialOffset: Long,
         uploadId: Long,
-    ): Long {
+    ): Pair<Long, String?> {
         var offset = initialOffset
+        var lastEtag: String? = null
         val serverMaxChunk = tusSupport?.maxChunkSize?.takeIf { it > 0 }?.toLong()
         val httpOverride = tusSupport?.httpMethodOverride
         var consecutiveFailures = 0
@@ -203,6 +229,7 @@ class TusUploadHelper(
             activePatchOperation = patchOperation
 
             val patchResult = patchOperation.execute(client)
+            lastEtag = patchOperation.etag.takeIf { it.isNotBlank() }
             activePatchOperation = null
             if (!patchResult.isSuccess || patchResult.data == null || patchResult.data!! < offset) {
                 consecutiveFailures++
@@ -281,7 +308,7 @@ class TusUploadHelper(
             progressCallback?.invoke(offset, fileSize)
             consecutiveFailures = 0
         }
-        return offset
+        return Pair(offset, lastEtag)
     }
 
     private fun resolveTusCollectionUrl(

opencloudApp/src/main/java/eu/opencloud/android/workers/UploadFileFromFileSystemWorker.kt

@@ -101,6 +101,8 @@ class UploadFileFromFileSystemWorker(
     private val transferRepository: TransferRepository by inject()
     private val tusUploadHelper by lazy { TusUploadHelper(transferRepository) }
 
+    private var finalEtag: String = ""
+
     private val foregroundJob = SupervisorJob()
     private val foregroundScope = CoroutineScope(Dispatchers.Default + foregroundJob)
     @Volatile
@@ -262,17 +264,15 @@ class UploadFileFromFileSystemWorker(
         val hasPendingTusSession = !ocTransfer.tusUploadUrl.isNullOrBlank()
         val shouldTryTus = hasPendingTusSession || (supportsTus && fileSize >= TusUploadHelper.DEFAULT_CHUNK_SIZE)
 
-        var attemptedTus = false
         if (shouldTryTus) {
-            attemptedTus = true
             Timber.d(
                 "Attempting TUS upload (size=%d, threshold=%d, resume=%s)",
                 fileSize,
                 TusUploadHelper.DEFAULT_CHUNK_SIZE,
                 hasPendingTusSession
             )
             val tusSucceeded = try {
-                tusUploadHelper.upload(
+                val returnedEtag = tusUploadHelper.upload(
                     client = client,
                     transfer = ocTransfer,
                     uploadId = uploadIdInStorageManager,
@@ -286,6 +286,9 @@ class UploadFileFromFileSystemWorker(
                     progressCallback = ::updateProgressFromTus,
                     spaceWebDavUrl = spaceWebDavUrl,
                 )
+                if (!returnedEtag.isNullOrBlank()) {
+                    finalEtag = returnedEtag
+                }
                 true
             } catch (throwable: Throwable) {
                 Timber.w(throwable, "TUS upload failed, falling back to single PUT")
@@ -299,7 +302,6 @@ class UploadFileFromFileSystemWorker(
                 if (removeLocal) {
                     removeLocalFile()
                 }
-                Timber.d("TUS upload completed for %s", uploadPath)
                 return
             }
         } else {
@@ -330,6 +332,7 @@ class UploadFileFromFileSystemWorker(
         val result = executeRemoteOperation { uploadFileOperation.execute(client) }
 
         if (result == Unit) {
+            finalEtag = uploadFileOperation.etag
             clearTusState()
             if (removeLocal) {
                 removeLocalFile() // Removed file from tmp folder
@@ -412,15 +415,20 @@ class UploadFileFromFileSystemWorker(
                 if (ocTransfer.forceOverwrite) {
                     ocFile.copy(
                         needsToUpdateThumbnail = true,
-                        etag = uploadFileOperation.etag,
+                        etag = finalEtag,
                         length = fileSize,
                         lastSyncDateForData = currentTime,
                         modifiedAtLastSyncForData = currentTime,
                     )
                 } else {
-                    // Uploading a file should remove any conflicts on the file.
+                    // Uploading a file should remove any conflicts and update etag.
                     ocFile.copy(
                         storagePath = null,
+                        needsToUpdateThumbnail = true,
+                        etag = finalEtag.ifBlank { ocFile.etag },
+                        length = fileSize,
+                        lastSyncDateForData = currentTime,
+                        modifiedAtLastSyncForData = currentTime,
                     )
                 }
             saveFileOrFolderUseCase(SaveFileOrFolderUseCase.Params(fileWithNewDetails))

opencloudComLibrary/src/main/java/eu/opencloud/android/lib/resources/files/tus/PatchTusUploadChunkRemoteOperation.kt

@@ -38,6 +38,8 @@ class PatchTusUploadChunkRemoteOperation(
     private val dataTransferListeners: MutableSet<OnDatatransferProgressListener> = HashSet()
     private var activeMethod: HttpBaseMethod? = null
 
+    var etag: String = ""
+
     @Suppress("ExpressionBodySyntax")
     override fun run(client: OpenCloudClient): RemoteOperationResult<Long> {
         // Fast-path: if caller requested cancellation before execution, honour it without hitting the network.
@@ -85,6 +87,10 @@ class PatchTusUploadChunkRemoteOperation(
                 )
 
                 if (isSuccess(status)) {
+                    val rawEtag = eu.opencloud.android.lib.common.network.WebdavUtils.getEtagFromResponse(method)
+                    if (rawEtag != null) {
+                        this@PatchTusUploadChunkRemoteOperation.etag = rawEtag.replace("\"", "")
+                    }
                     val newOffset = method.getResponseHeader(HttpConstants.UPLOAD_OFFSET)?.toLongOrNull()
                     if (newOffset != null) {
                         RemoteOperationResult<Long>(ResultCode.OK).apply { data = newOffset }