DownloadManager class

Manages concurrent file downloads with queuing, retries, progress reporting, cancellation, and strategies for handling existing files.

Provides methods to request files (getFile), add downloads to a queue (addToQueue, addAllToQueue), cancel downloads (cancelDownload, cancelAll), and manage downloaded files (deleteContentFile).

It uses a base directory and an optional subdirectory to store downloads. Concurrency limits and retry attempts are configurable. Logging can be enabled via the optional logger callback.

Constructors

DownloadManager.new({required String subDir, Directory? baseDirectory, int maxConcurrentDownloads = 3, int maxRetries = 3, LogCallback? logger, FileExistsStrategy fileExistsStrategy = FileExistsStrategy.resume, Duration delayBetweenRetries = Duration.zero})
Creates a DownloadManager instance.

Properties

delayBetweenRetries ↔ Duration
A duration representing the delay between retries when a download task fails.
getter/setter pair
fileExistsStrategy → FileExistsStrategy
The default strategy to use when a file already exists, applied if not specified per-download. Defaults to FileExistsStrategy.resume.
final
hashCode → int
The hash code for this object.
no setterinherited
logger → LogCallback?
An optional callback function for logging messages from the manager. Receives records with a message string and a LogLevel.
final
maxConcurrentDownloads → int
The maximum number of downloads that can run concurrently. Defaults to 3.
final
maxRetries → int
The maximum number of times a failed download will be automatically retried. Defaults to 3.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
subDir → String
The name of the subdirectory within the _baseDirectory where files will be stored.
final

Methods

addAllToQueue(List<QueueItem> downloadItems) → Future<void>
Iterates through the list of download configurations and calls addToQueue for each. Allows specifying individual progress callbacks per download. The strategy field in the input records is ignored.
addToQueue(QueueItem downloadItem) → Future<void>
Adds a URL to the download queue without waiting for completion. Honours the manager's configured default FileExistsStrategy. Note: This method currently does not support overriding the strategy per call.
cancelAll() → void
Cancels all active and queued downloads.
cancelDownload(String url) → Future<void>
Cancels a specific download (if active or queued).
deleteContentFile(QueueItem item) → Future<void>
Deletes the downloaded file corresponding to the URL, if it exists. Also attempts to delete the corresponding .tmp file.
dispose() → Future<void>
Disposes of the download manager, cancelling all downloads and releasing resources.
getFile(QueueItem downloadItem) → Future<File?>
Retrieves a file, downloading it if necessary, based on the manager's configured default strategy.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited