Using LexActivator with Delphi

First of all, login to your Cryptlex account and download LexActivator library for Windows or MacOS:

The above download package contains the library which you will be using to add licensing to your app.

Adding licensing to your app

After you've added a product for your app in the dashboard, go to the product page of the product you will be adding licensing to. You will need to do two things:

  • Note the product id for the product.

  • Download the Product.dat for the product.

  • Download the example project from Github

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

Adding library to your app

LexActivator example project for Delphi (7 or newer) contains the LexActivator.pas unit file. In addition to that it includes LexActivator.DelphiFeatures.pas unit file used internally.

You need to add these files to your app in order to use LexActivator API in your app. Both units must be added, but only LexActivator unit must be added to uses list. Depending on the OS you are targeting you need to copy the respective LexActivator.dll, libLexActivator.so or libLexActivator.dylib to your project.

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 LexActivator.SetProductData function or set the absolute path of the file using LexActivator.SetProductFile function.

The next thing you need to do is to set the product id of your application in your code using LexActivator.SetProductId function. It sets the id of the product you will be adding licensing to.

SetProductData('PASTE_CONTENT_OF_PRODUCT.DAT_FILE');
SetProductId('PASTE_PRODUCT_ID', lfUser);

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

In case your app doesn't have write access to the disk, you can use lfInMemory 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 LexActivator.ActivateLicense LexActivator API function. It invokes the /v3/activations Cryptlex Web API endpoint, verifies the encrypted and digitally signed response to validate the license.

var
Step: string;
Status: TLAKeyStatus;
begin
try
Step := 'SetLicenseKey'; SetLicenseKey('PASTE_LICENSE_KEY');
Step := 'ActivateLicense'; Status := ActivateLicense;
case Status of
lkOK: ShowMessage('Activation successful!');
lkExpired: ShowMessage('Activation successful, but license validity has expired!');
else
ShowMessage('Error activating the product: ' + LAKeyStatusToString(Status));
end;
except
on E: Exception do
begin
ShowMessage('Exception from ' + Step + ': ' + E.ClassName + ': ' + E.Message);
end;
end;
end;

The above code should be executed at the time of license activation, ideally on a button click.

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 LexActivator.IsLicenseGenuine LexActivator API function.

var
Step: string;
Status: TLAKeyStatus;
begin
try
Step := 'SetProductData'; SetProductData('PASTE_CONTENT_OF_PRODUCT.DAT_FILE');
Step := 'SetProductId'; SetProductId('PASTE_PRODUCT_ID', lfUser);
Step := 'IsLicenseGenuine'; Status := IsLicenseGenuine;
case Status of
lkOK: ShowMessage('License is genuinely activated!');
lkExpired: ShowMessage('License is genuinely activated, but has validity has expired!');
lkGracePeriodOver: ShowMessage('License is genuinely activated, but grace period is over!');
else
ShowMessage('Error code: ' + LAKeyStatusToString(Status));
end;
except
on E: Exception do
begin
ShowMessage('Exception from ' + Step + ': ' + E.ClassName + ': ' + E.Message);
end;
end;
end;

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. LexActivator.SetLicenseCallback can be used to set notification callback.

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.