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Flutter Downloader – A plugin for creating and managing download tasks

Flutter Downloader

A plugin for creating and managing download tasks. Supports iOS and Android.

This plugin is based on WorkManager in Android and NSURLSessionDownloadTask in iOS to run download task in background mode.

iOS integration

Required configuration:

Note: following steps requires to open your ios project in Xcode.

Objective-C:

/// AppDelegate.h
#import <Flutter/Flutter.h>
#import <UIKit/UIKit.h>

@interface AppDelegate : FlutterAppDelegate

@end
// AppDelegate.m
#include "AppDelegate.h"
#include "GeneratedPluginRegistrant.h"
#include "FlutterDownloaderPlugin.h"

@implementation AppDelegate

void registerPlugins(NSObject<FlutterPluginRegistry>* registry) {   
  if (![registry hasPlugin:@"FlutterDownloaderPlugin"]) {
     [FlutterDownloaderPlugin registerWithRegistrar:[registry registrarForPlugin:@"FlutterDownloaderPlugin"]];
  }
}

- (BOOL)application:(UIApplication *)application
    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  [GeneratedPluginRegistrant registerWithRegistry:self];
  [FlutterDownloaderPlugin setPluginRegistrantCallback:registerPlugins];
  // Override point for customization after application launch.
  return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

@end

Or Swift:

import UIKit
import Flutter
import flutter_downloader

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
    FlutterDownloaderPlugin.setPluginRegistrantCallback(registerPlugins)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

private func registerPlugins(registry: FlutterPluginRegistry) { 
    if (!registry.hasPlugin("FlutterDownloaderPlugin")) {
       FlutterDownloaderPlugin.register(with: registry.registrar(forPlugin: "FlutterDownloaderPlugin")!)
    }
}

Optional configuration:

  1. Disable ATS for a specific domain only: (add following codes to your Info.plist file)
<key>NSAppTransportSecurity</key>
<dict>
  <key>NSExceptionDomains</key>
  <dict>
    <key>www.yourserver.com</key>
    <dict>
      <!-- add this key to enable subdomains such as sub.yourserver.com -->
      <key>NSIncludesSubdomains</key>
      <true/>
      <!-- add this key to allow standard HTTP requests, thus negating the ATS -->
      <key>NSTemporaryExceptionAllowsInsecureHTTPLoads</key>
      <true/>
      <!-- add this key to specify the minimum TLS version to accept -->
      <key>NSTemporaryExceptionMinimumTLSVersion</key>
      <string>TLSv1.1</string>
    </dict>
  </dict>
</dict>
  1. Completely disable ATS: (add following codes to your Info.plist file)
<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key><true/>
</dict>
<!-- changes this number to configure the maximum number of concurrent tasks -->
<key>FDMaximumConcurrentTasks</key>
<integer>5</integer>
<key>FDAllFilesDownloadedMessage</key>
<string>All files have been downloaded</string>

Note:

Android integration

Required configuration:

<provider
    android:name="vn.hunghd.flutterdownloader.DownloadedFileProvider"
    android:authorities="${applicationId}.flutter_downloader.provider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/provider_paths"/>
</provider>

Note:

Optional configuration:

 <provider
     android:name="androidx.work.impl.WorkManagerInitializer"
     android:authorities="${applicationId}.workmanager-init"
     tools:node="remove" />

 <provider
     android:name="vn.hunghd.flutterdownloader.FlutterDownloaderInitializer"
     android:authorities="${applicationId}.flutter-downloader-init"
     android:exported="false">
     <!-- changes this number to configure the maximum number of concurrent tasks -->
     <meta-data
         android:name="vn.hunghd.flutterdownloader.MAX_CONCURRENT_TASKS"
         android:value="5" />
 </provider>
<string name="flutter_downloader_notification_started">Download started</string>
<string name="flutter_downloader_notification_in_progress">Download in progress</string>
<string name="flutter_downloader_notification_canceled">Download canceled</string>
<string name="flutter_downloader_notification_failed">Download failed</string>
<string name="flutter_downloader_notification_complete">Download complete</string>
<string name="flutter_downloader_notification_paused">Download paused</string>
<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />

Usage

Import package:

import 'package:flutter_downloader/flutter_downloader.dart';

Initialize

WidgetsFlutterBinding.ensureInitialized();
await FlutterDownloader.initialize(
  debug: true // optional: set false to disable printing logs to console
);

Create new download task:

final taskId = await FlutterDownloader.enqueue(
  url: 'your download link',
  savedDir: 'the path of directory where you want to save downloaded files',
  showNotification: true, // show download progress in status bar (for Android)
  openFileFromNotification: true, // click on notification to open downloaded file (for Android)
);

Update download progress:

FlutterDownloader.registerCallback(callback); // callback is a top-level or static function

Important note: your UI is rendered in the main isolate, while download events come from a background isolate (in other words, codes in callback are run in the background isolate), so you have to handle the communication between two isolates. For example:

ReceivePort _port = ReceivePort();

@override
void initState() {
	super.initState();

	IsolateNameServer.registerPortWithName(_port.sendPort, 'downloader_send_port');
	_port.listen((dynamic data) {
		String id = data[0];
		DownloadTaskStatus status = data[1];
		int progress = data[2];
		setState((){ });
	});

	FlutterDownloader.registerCallback(downloadCallback);
}

@override
void dispose() {
	IsolateNameServer.removePortNameMapping('downloader_send_port');
	super.dispose();
}

static void downloadCallback(String id, DownloadTaskStatus status, int progress) {
	final SendPort send = IsolateNameServer.lookupPortByName('downloader_send_port');
	send.send([id, status, progress]);
}

Load all tasks:

final tasks = await FlutterDownloader.loadTasks();

Load tasks with conditions:

final tasks = await FlutterDownloader.loadTasksWithRawQuery(query: query);
SELECT * FROM task WHERE status=3
CREATE TABLE `task` (
	`id`	INTEGER PRIMARY KEY AUTOINCREMENT,
	`task_id`	VARCHAR ( 256 ),
	`url`	TEXT,
	`status`	INTEGER DEFAULT 0,
	`progress`	INTEGER DEFAULT 0,
	`file_name`	TEXT,
	`saved_dir`	TEXT,
	`resumable`	TINYINT DEFAULT 0,
	`headers`	TEXT,
	`show_notification`	TINYINT DEFAULT 0,
	`open_file_from_notification`	TINYINT DEFAULT 0,
	`time_created`	INTEGER DEFAULT 0
);

Cancel a task:

FlutterDownloader.cancel(taskId: taskId);

Cancel all tasks:

FlutterDownloader.cancelAll();

Pause a task:

FlutterDownloader.pause(taskId: taskId);

Resume a task:

FlutterDownloader.resume(taskId: taskId);

Retry a failed task:

FlutterDownloader.retry(taskId: taskId);

Remove a task:

FlutterDownloader.remove(taskId: taskId, shouldDeleteContent:false);

Open and preview a downloaded file:

FlutterDownloader.open(taskId: taskId);

Bugs/Requests

If you encounter any problems feel free to open an issue. If you feel the library is missing a feature, please raise a ticket on Github. Pull request are also welcome.

Download Flutter Downloader package source code on GitHub

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