Chilkat for Dart and Flutter

The Chilkat class library for Dart: HTTP, REST, email (SMTP/POP3/IMAP), FTP, SFTP, SSH, zip, encryption, digital signatures, certificates, XML, JSON and more — the same classes and methods Chilkat offers in 30+ other languages, with a Dart-native surface.

import 'package:chilkat/chilkat.dart';

void main() {
  Chilkat.unlockBundle('Anything for 30-day trial');

  final http = CkHttp();
  http.connectTimeout = 30;
  http.setRequestHeader('Accept', 'application/json');

  final body = http.quickGetStr('https://api.example.com/items');
  print('status ${http.lastStatus}');

  final json = CkJsonObject();
  json.load(body);
  for (var i = 0; i < json.size; i++) {
    final name = json.nameAt(i);
    print('$name = ${json.stringOf(name)}');
  }
}

Install

dart pub add chilkat      # or: flutter pub add chilkat

The native Chilkat library is a prebuilt shared library that the package's build hook downloads for your target the first time you build, verifies (SHA-256) and caches. Requires Dart 3.10 / Flutter 3.38 or later (build hooks). Supported targets: Android (arm64-v8a, armeabi-v7a, x86_64), iOS (device and simulator), macOS, Windows (x64, arm64), Linux (x64, arm64). Web is not supported.

Offline or air-gapped builds: point the build hook at a directory containing the library for your target (libchilkat_c_bridge.so, libchilkat_c_bridge.dylib or chilkat_c_bridge.dll) with a user-define in your application's pubspec.yaml, and nothing is downloaded:

hooks:
  user_defines:
    chilkat:
      lib_dir: /path/to/chilkat/lib    # relative paths resolve against this pubspec

How the API maps to Dart

Chilkat	Dart
class `Http`, `JsonObject`, `CkDateTime`	`CkHttp`, `CkJsonObject`, `CkDateTime` — every class has a `Ck` prefix
property `ConnectTimeout`	`http.connectTimeout` getter/setter
method `QuickGetStr`	`http.quickGetStr(url)` — lowerCamelCase, same arguments
a method returning a success `bool`	returns `void`; throws ChilkatException on failure
a method returning a `String` or object	returns it; throws ChilkatException when Chilkat returns null
a method returning a `bool` that is the answer (`HasMember`, `IsUnlocked`, ...)	returns `bool`
byte data	`Uint8List`
`LastErrorText`	`obj.lastErrorText`, and `e.lastErrorText` on the exception

try {
  final html = http.quickGetStr(url);
} on ChilkatException catch (e) {
  print(e);                // CkHttp.quickGetStr failed: <reason>
  print(e.lastErrorText);  // the full Chilkat log of the failed call
}

Objects release their native resources when garbage collected; call dispose() to release them immediately (large CkBinData, open sockets).

Flutter: long-running calls

Every call is synchronous and blocks the calling isolate. Quick operations (JSON, XML, hashing, encoding) are fine on the UI isolate; network and large file operations belong in a worker isolate. Chilkat objects cannot be sent between isolates, so the worker creates its own:

final body = await Isolate.run(() {
  final http = CkHttp()..connectTimeout = 30;
  return http.quickGetStr(url);
});

Progress and cancellation: the 40 event-capable classes (CkHttp, CkFtp2, CkSFtp, CkZip, CkBz2, ...) have onPercentDone, onProgressInfo and onAbortCheck callback properties. They fire on the calling thread, inside the method call; return true from onPercentDone or onAbortCheck to abort. From a worker isolate, forward progress through a SendPort:

final progress = ReceivePort();
progress.listen((pct) => setState(() => _pct = pct as int));
await Isolate.run(() {
  final ftp = CkFtp2()..hostname = host ..username = user ..password = pw;
  ftp.onPercentDone = (pct) { progress.sendPort.send(pct); return _cancelRequested; };
  ftp.connect();
  ftp.getFile('remote.dat', localPath);
});

Reference

Every class and member carries the Chilkat reference documentation as dartdoc. Online reference: www.chilkatsoft.com/refdoc/dart.asp. Examples for every class: www.example-code.com/dart/.

License

Chilkat is commercial software. The 30-day trial is fully functional; see LICENSE and www.chilkatsoft.com/purchase2.asp.