Using LexActivator with Flutter

Adding licensing to your app

After you've added a product for your app in the admin portal, you will need to do the following things:

• Note the product id for the product (from the actions menu in the table).

• Download the Product.dat for the product (from the actions menu in the table).

• Download the example project from Github.

Product.dat contains product data that is used by LexActivator. The product id is the identifier of your product that is to be used in the code.

Adding the library to your app

LexActivator wrapper for Dart can be easily installed using Flutter's package manager:

flutter pub add lexactivator

LexActivator has a dependency on VS2015 runtime on Windows. On the target machines where you will deploy your app, you can install the VS2015 runtime, if not present, using the link: https://www.microsoft.com/en-in/download/details.aspx?id=48145

Setting product.dat file and product Id

The first thing you need to do is either embed the Product.dat file in your app using 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);
}

If your app requires admin (root) privileges to run (e.g. services, daemons etc.), instead of passing PermissionFlags.LA_USER flag, you need to pass PermissionFlags.LA_SYSTEM flag.

If your app requires a single activation to be shared across all OS users (system-wide activation), pass the PermissionFlags.LA_ALL_USERS flag before activation. This flag is compatible with Windows OS only.

In case your app doesn't have write access to the disk, you can use PermissionFlags.LA_IN_MEMORY flag instead, which causes all the data to be stored in the memory. But this would require you to activate the license every time you restart the app.

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() {
  try {
    LexActivator.SetLicenseKey(licenseKey: 'PASTE_LICENSE_KEY');
    LexActivator.SetActivationMetadata(key: 'Metadata 1', value: 'Value 1');
    final status = LexActivator.ActivateLicense();
    
    switch (status) {
      case LexStatusCodes.LA_OK:
        print('License activated successfully!');
        break;
      case LexStatusCodes.LA_EXPIRED:
        print('License activated successfully but has expired!');
        break;
      case LexStatusCodes.LA_SUSPENDED:
        print('License activated successfully but has been suspended!');
        break;
    }
  } on LexActivatorException catch (e) {
    print('License activated failed: $e');
  }
}
 

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 {
    LexActivator.SetProductData(productData: 'PASTE_PRODUCT_DATA');
    LexActivator.SetProductId(productId: 'PASTE_PRODUCT_ID', flags: LexActivator.LA_USER);
    LexActivator.SetReleaseVersion(releaseVersion: 'PASTE_YOUR_RELEASE_VERSION');
    
    final status = LexActivator.IsLicenseGenuine();
    switch (status) {
      case LexStatusCodes.LA_OK:
        print('License is genuinely activated!');
        break;
      case LexStatusCodes.LA_EXPIRED:
        print('License is genuinely activated but has expired!');
        break;
      case LexStatusCodes.LA_SUSPENDED:
        print('License is genuinely activated but has been suspended!');
        break;
      case LexStatusCodes.LA_GRACE_PERIOD_OVER:
        print('License is genuinely activated but grace period is over!');
        break;
      default:
        print('License is not activated');
    }
  } on LexActivatorException catch (e) {
    print('Error: $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.

Limitations

The application you are building with the plugin will only build for the host architecture on Linux and Windows i.e. if you are building your application on a Linux x64, it will build for Linux x64 and not for Linux ARM.

Need more help

In case you need more help for adding LexActivator to your app, we'll be glad to help you make the integration. You can either post your questions on our support forum or can contact us through email.