lexactivator

LexActivator API wrapper for Dart (licensing library)

Getting Started

The first thing you need to do is either embed the Product.dat file in your app using the SetProductData() function or set the absolute path of the file using SetProductFile() function. The next thing you need to do is to set the product id of your application in your code using SetProductId() function. It sets the id of the product you will be adding licensing to.

void initializeLexActivator() {
  LexActivator.SetProductData(productData: "PASTE_CONTENT_OF_PRODUCT.DAT_FILE");

  LexActivator.SetProductId(
      productId: "PASTE_PRODUCT_ID", flags: LexActivator.LA_USER);
}

License activation

To activate the license in your app using the license key, you will use ActivateLicense() LexActivator API function. It invokes the /v3/activations Cryptlex Web API endpoint, verifies the encrypted and digitally signed response to validate the license.

void activateLicense() {
  LexActivator.SetLicenseKey(licenseKey: 'PASTE_LICENSE_KEY');
  LexActivator.SetActivationMetadata(key: 'Metadata 1', value: 'Value 1');
  final status = LexActivator.ActivateLicense();
  if (LexStatusCodes.LA_OK == status) {
    print('License activated successfully!');
  } else if (LexStatusCodes.LA_EXPIRED == status) {
    print('License activated successfully but has expired!');
  } else if (LexStatusCodes.LA_SUSPENDED == status) {
    print('License activated successfully but has been suspended!');
  }
}

The above code should be executed at the time of license activation.

Verifying license activation

Each time, your app starts, you need to verify whether your license is already activated or not. This verification should occur locally by verifying the cryptographic digital signature of activation. Ideally, it should also asynchronously contact Cryptlex servers to validate and sync the license activation periodically. For this you need to use IsLicenseGenuine() LexActivator API function.

void main() {
  try {
    
    initializeLexActivator();
    activateLicense(); //Run once, during first run.

    final status = LexActivator.IsLicenseGenuine();
    if (LexStatusCodes.LA_OK == status) {
      print('License is genuinely activated!');

      final expiryDate = LexActivator.GetLicenseExpiryDate();
      final daysLeft = DateTime.fromMillisecondsSinceEpoch(expiryDate)
          .difference(DateTime.now());
      print('Days left: $daysLeft');

      final userName = LexActivator.GetLicenseUserName();
      print('License user name: $userName');
    } else if (LexStatusCodes.LA_EXPIRED == status) {
      print('License is genuinely activated but has expired!');
    } else if (LexStatusCodes.LA_SUSPENDED == status) {
      print('License is genuinely activated but has been suspended!');
    } else if (LexStatusCodes.LA_GRACE_PERIOD_OVER == status) {
      print('License is genuinely activated but grace period is over!');
    } else {
      final trialStatus = LexActivator.IsTrialGenuine();
      if (LexStatusCodes.LA_OK == trialStatus) {
        final expiryDate = LexActivator.GetTrialExpiryDate();
        final daysLeft = DateTime.fromMillisecondsSinceEpoch(expiryDate)
            .difference(DateTime.now());
        print('Trial days left: $daysLeft');
      } else if (LexStatusCodes.LA_TRIAL_EXPIRED == trialStatus) {
        print('Trial has expired!');
        // Time to buy the license and activate the app
        activateLicense();
      } else {
        print('Either trial has not started or has been tampered!');
        // Activating the trial
        activateTrial();
      }
    }
  } on LexActivatorException catch (e) {
    print(e);
  }
}

The above code should be executed every time user starts the app. After verifying locally, it schedules a periodic server check in a separate thread.

Libraries

lexactivator

LexActivator wrapper for Dart and Flutter. The library lex_activator is part of the lex_activator package.