feat: at_file_share demo

at_file_share/.gitignore

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+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/
+
+pubspec.lock
+
+at_file_share.iml

at_file_share/CHANGELOG.md

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+## 1.0.0
+
+- Initial version.

at_file_share/README.md

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+#TODO
+
+Prerequisite:
+1. Storj account and access grant
+   1. Login/signup to https://www.storj.io/
+   2. Create new project e.g acme_demo
+   3. Open the newly created project
+   4. Go to buckets https://us1.storj.io/buckets/management and create new bucket e.g demo-bucket
+   5. Go to access tab https://us1.storj.io/access-grants and click "create access grant"
+      6. Type --> "Access Grant" and give a name to identify the access e.g acme-access. Click continue
+      7. Under bucket select the bucket that you created i.e demo-bucket
+      8. Create/enter a passphrase and click "create access".Click confirm
+      9. Download the credentials file(acme-access.txt) by clicking "Download" 
+2. Configure uplink
+   1. Follow the instructions to install uplink tool - https://docs.storj.io/learn/tutorials/quickstart-uplink-cli
+   2. Run the below command with the credentials file downloaded 
+      3. uplink access import main acme-access.txt
+3. Run file sender on sending machine and file receiver on receiving machine. File receiver will receive notification through
+   atprotocol and download the storj file, decrypt using atClient SDK method.
+
+Usage: 
+1. File sender
+   1. dart bin/at_file_share.dart -m send -a <sender_atsign> -r <receiver_atsign> -k <path_to_sender_atKeys_file> -f <path_of_file_to_send> -b <storj_bucket_name> -n <namespace>
+   2. e.g. dart bin/at_file_share.dart -m send -s @alice -r @bob -k /home/user/@alice.atKeys -f /home/user/test_file.txt  -b demo-bucket -n acme
+2. File receiver 
+   1. dart bin/at_file_share.dart -m receive -k <path_to_receiver_atKeysFile> -a <current_atsign> -o <download_path> -n <namespace>
+   2. e.g dart bin/at_file_share.dart -m receive -k /home/user/@bob.atKeys -a @bob -o /home/user/downloads -n acme

at_file_share/analysis_options.yaml

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+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+# linter:
+#   rules:
+#     - camel_case_types
+
+# analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
+
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+# For additional information about configuring this file, see
+# https://dart.dev/guides/language/analysis-options

at_file_share/bin/at_file_share.dart

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+import 'package:args/args.dart';
+import 'package:at_client/at_client.dart';
+import 'package:at_file_share/src/file_send_params.dart';
+import 'package:at_file_share/src/service/file_receiver.dart';
+import 'package:at_file_share/src/service/file_sender.dart';
+import 'package:at_onboarding_cli/at_onboarding_cli.dart';
+import 'package:at_cli_commons/at_cli_commons.dart';
+
+const String version = '0.0.1';
+
+ArgParser buildParser() {
+  return CLIBase.argsParser
+    ..addOption('mode',
+        abbr: 'm', mandatory: true, help: 'File sharing mode - send or receive')
+    ..addOption('receiver',
+        abbr: 'r', mandatory: true, help: 'atsign receiving the shared file')
+    ..addOption('filePath',
+        abbr: 'f', mandatory: false, help: 'path of file in local to share')
+    ..addOption('downloadDir',
+        abbr: 'o', mandatory: false, help: 'download dir when receiving files')
+    ..addOption('bucketName',
+        abbr: 'b',
+        mandatory: false,
+        help: 'bucket name of storj to upload the file');
+}
+
+void printUsage(ArgParser argParser) {
+  print('Usage: dart at_file_share.dart <flags> [arguments]');
+  print(argParser.usage);
+}
+
+void main(List<String> arguments) async {
+  final ArgParser argParser = buildParser();
+  try {
+    final ArgResults results = argParser.parse(arguments);
+    // Process the parsed arguments.
+    if (results.wasParsed('help')) {
+      printUsage(argParser);
+      return;
+    }
+    String mode = results['mode'];
+    var atClient = (await CLIBase.fromCommandLineArgs(arguments)).atClient;
+    print('mode: $mode');
+    if (mode == 'send') {
+      String receiver = results['receiver'];
+      var params = FileSendParams()
+        ..receiverAtSign = receiver
+        ..filePath = results['filePath']
+        ..bucketName = results['bucketName'];
+
+      await FileSender(atClient).sendFile(params);
+    } else if (mode == 'receive') {
+      await FileReceiver(atClient).receiveFile(results['downloadDir']);
+    }
+  } on FormatException catch (e) {
+    // Print usage information if an invalid argument was provided.
+    print(e.message);
+    print('');
+    printUsage(argParser);
+  }
+}

at_file_share/lib/src/file_send_params.dart

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+class FileSendParams {
+  late String receiverAtSign;
+  int chunkSize = 1024;
+  late String filePath;
+  late String bucketName;
+}

at_file_share/lib/src/service/file_receiver.dart

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+import 'dart:convert';
+import 'dart:io';
+import 'dart:typed_data';
+import 'package:http/http.dart' as http;
+
+import 'package:at_client/at_client.dart';
+
+class FileReceiver {
+  final AtClient _atClient;
+
+  FileReceiver(this._atClient);
+
+  Future<void> receiveFile(String downloadPath) async {
+    _atClient.notificationService
+        .subscribe()
+        .listen((AtNotification atNotification) async {
+      if (atNotification.id != '-1') {
+        var fileName;
+        try {
+          print('notification Received: ${atNotification.toString()}');
+          var key = atNotification.key;
+          var atValue = await _atClient.get(AtKey.fromString(key));
+          print(atValue.toString());
+          var valueJson = jsonDecode(atValue.value);
+          var storjUrl = valueJson['fileUrl'];
+          fileName = valueJson['fileName'];
+          await downloadFileWithProgress(
+              storjUrl, downloadPath, fileName, valueJson);
+        } on Exception catch (e, trace) {
+          print(e);
+          print(trace);
+        } on Error catch (e, trace) {
+          print(e);
+          print(trace);
+        }
+      }
+    });
+  }
+
+  Future<void> _decryptFile(
+      String downloadPath, String fileName, dynamic valueJson) async {
+    try {
+      var startTime = DateTime.now();
+      var encryptionService = _atClient.encryptionService!;
+      var encryptedFile =
+          File('$downloadPath${Platform.pathSeparator}encrypted_$fileName');
+      await encryptionService.decryptFileInChunks(
+          encryptedFile, valueJson['fileEncryptionKey'], valueJson['chunkSize'],
+          ivBase64: valueJson['iv']);
+      var endTime = DateTime.now();
+      print(
+          'Time taken to decrypt file: ${endTime.difference(startTime).inSeconds}');
+      var decryptedFile = File(
+          "$downloadPath${Platform.pathSeparator}decrypted_encrypted_$fileName");
+      if (decryptedFile.existsSync()) {
+        decryptedFile
+            .renameSync(downloadPath + Platform.pathSeparator + fileName);
+      } else {
+        throw Exception('could not decrypt downloaded file');
+      }
+    } on Exception catch (e, trace) {
+      print(e);
+      print(trace);
+    } on Error catch (e, trace) {
+      print(e);
+      print(trace);
+    } finally {
+      var encryptedFile =
+          File("$downloadPath${Platform.pathSeparator}encrypted_$fileName");
+      if (encryptedFile.existsSync()) {
+        encryptedFile.deleteSync();
+      }
+    }
+  }
+
+  Future<void> downloadFileWithProgress(String fileUrl, String downloadPath,
+      String fileName, dynamic valueJson) async {
+    var httpClient = http.Client();
+    var request = http.Request('GET', Uri.parse('$fileUrl?download=1'));
+    var response = httpClient.send(request);
+
+    List<List<int>> chunks = [];
+    int downloaded = 0;
+
+    response.asStream().listen((http.StreamedResponse r) {
+      r.stream.listen((List<int> chunk) {
+        if (r.contentLength == null) {
+          print('content length is null.');
+          return;
+        }
+        // Display percentage of completion
+        var percentage = downloaded / r.contentLength! * 100;
+        int roundedPercent = percentage.round();
+        updateProgress(roundedPercent);
+
+        chunks.add(chunk);
+        downloaded += chunk.length;
+      }, onDone: () async {
+        // Display percentage of completion
+        // print('downloadPercentage: ${downloaded / r.contentLength! * 100}');
+
+        // Save the file
+        File file =
+            File('$downloadPath${Platform.pathSeparator}encrypted_$fileName');
+        final Uint8List bytes = Uint8List(r.contentLength!);
+        int offset = 0;
+        for (List<int> chunk in chunks) {
+          bytes.setRange(offset, offset + chunk.length, chunk);
+          offset += chunk.length;
+        }
+        await file.writeAsBytes(bytes);
+        await _decryptFile(downloadPath, fileName, valueJson);
+      });
+    });
+  }
+
+  void updateProgress(int progress) {
+    // Move cursor to the beginning of the line
+    stdout.write('\r');
+
+    // Print the progress in percentage
+    stdout.write('Download progress: $progress%');
+    stdout.flush();
+  }
+}