PowerSync Core/com.powersync.attachments/AttachmentQueue

AttachmentQueue

open class AttachmentQueue(val db: PowerSyncDatabase, val remoteStorage: RemoteStorage, attachmentsDirectory: String, watchAttachments: () -> Flow<List<WatchedAttachmentItem>>, val localStorage: LocalStorage = IOLocalStorageAdapter(), attachmentsQueueTableName: String = DEFAULT_TABLE_NAME, errorHandler: SyncErrorHandler? = null, syncInterval: Duration = 30.seconds, archivedCacheLimit: Long = 100, syncThrottleDuration: Duration = 1.seconds, subdirectories: List<String>? = null, downloadAttachments: Boolean = true, val logger: Logger = Logger, coroutineScope: CoroutineScope? = null)

Class used to implement the attachment queue. Requires a PowerSyncDatabase, an implementation of AbstractRemoteStorageAdapter, and an attachment directory name which will determine which folder attachments are stored into.

Constructors

AttachmentQueue

constructor(db: PowerSyncDatabase, remoteStorage: RemoteStorage, attachmentsDirectory: String, watchAttachments: () -> Flow<List<WatchedAttachmentItem>>, localStorage: LocalStorage = IOLocalStorageAdapter(), attachmentsQueueTableName: String = DEFAULT_TABLE_NAME, errorHandler: SyncErrorHandler? = null, syncInterval: Duration = 30.seconds, archivedCacheLimit: Long = 100, syncThrottleDuration: Duration = 1.seconds, subdirectories: List<String>? = null, downloadAttachments: Boolean = true, logger: Logger = Logger, coroutineScope: CoroutineScope? = null)

Types

Companion

object Companion

Properties

attachmentsService

val attachmentsService: AttachmentService

Service which provides access to attachment records. Use this to:

closed

var closed: Boolean

val db: PowerSyncDatabase

PowerSync database client.

localStorage

val localStorage: LocalStorage

Provides access to local filesystem storage methods.

logger

val logger: Logger

Logging interface used for all log operations.

remoteStorage

val remoteStorage: RemoteStorage

Adapter which interfaces with the remote storage backend.

Functions

clearQueue

suspend fun clearQueue()

Clears the attachment queue and deletes all attachment files.

suspend fun close()

Closes the queue. The queue cannot be used after closing. A new queue should be created.

deleteFile

open suspend fun deleteFile(attachmentId: String, updateHook: (context: ConnectionContext, attachment: Attachment) -> Unit): Attachment

A function which creates an attachment delete operation locally. This operation is queued for delete. The default implementation assumes the attachment record already exists locally. An exception is thrown if the record does not exist locally. This method can be overridden for custom behavior.

expireCache

suspend fun expireCache()

Removes all archived items.

getLocalUri

open fun getLocalUri(filename: String): String

Returns the user's storage directory with the attachment path used to load the file. Example: filePath: "attachment-1.jpg" returns "/data/user/0/com.yourdomain.app/files/attachments/attachment-1.jpg".

processWatchedAttachments

open suspend fun processWatchedAttachments(items: List<WatchedAttachmentItem>)

Processes attachment items returned from watchAttachments. The default implementation asserts the items returned from watchAttachments as the definitive state for local attachments.

resolveNewAttachmentFilename

open suspend fun resolveNewAttachmentFilename(attachmentId: String, fileExtension: String?): String

Resolves the filename for new attachment items. A new attachment from watchAttachments might not include a filename. Concatenates the attachment ID and extension by default. This method can be overridden for custom behavior.

saveFile

open suspend fun saveFile(data: Flow<ByteArray>, mediaType: String, fileExtension: String? = null, metaData: String? = null, updateHook: (context: ConnectionContext, attachment: Attachment) -> Unit): Attachment

A function which creates a new attachment locally. This new attachment is queued for upload after creation.

startSync

suspend fun startSync()

Initialize the attachment queue by:

stopSyncing

suspend fun stopSyncing()

Stops syncing. Syncing may be resumed with startSync.