Error Handling

Error handling is an integral part of software development. This article provides effective ways to handle LicenseSpring errors and keep your application secure.

Prerequisites

1

Completed the Getting Started tutorial

• Follow the Getting Started Tutorial, specifically:
• Initialized LicenseManager (or LicenseHandler) with your configuration using the appropriate settings.
• Created a LicenseID using either LicenseID::fromKey or LicenseID::fromUser function, depending on the activation method you prefer.
• Implemented basic license management, including license activations, deactivations, and both online and local license checks.

Handling Exceptions

Methods of License and LicenseManager classes throw exceptions if something went wrong. Put the methods that can produce exceptions in try...catch block.

LicenseSpringException is the base class of all SDK exceptions. The good practice is to implement separate logic for different types of exceptions. Below is the example of handling device id mismatch. Instead of closing the application, we can try to upgrade to a new device id algorithm. See: Hardware ID generation

C++

try
{
    license->localCheck();
}
catch(const DeviceNotLicensedException& ex)
{
    // Handling specific error: trying to upgrade to new device id algorithm
    license = m_licenseManager->relinkLicense(WinCryptographyId);
    return;
}
catch(const LicenseSpringException& ex)
{
    std::cout << "LicenseSpring exception encountered: " << ex.what();
}

C#

try
{
    license.LocalCheck();
}
catch( DeviceNotLicensedException ex )
{
    // Handling specific error: trying to upgrade to new device id algorithm
    license = manager.RelinkLicense( DeviceIDAlgorithm.Gen3 );
    return;
}
catch (LicenseSpringException ex )
{
    Console.WriteLine( "LicenseSpring exception encountered: {0}", ex.Message );
}

Java

try {
    license.LocalCheck();
} catch(LicenseExpiredException e) {
    // Handling specific error
} catch (LicenseSpringException ex ) {
    System.out.println("LicenseSpring exception encountered: " + ex.getMessage());
}

Common Exceptions

Below is the list of the exceptions that can occur on any SDK request:

Exception	Definition
LicenseStateException	License is disabled, was reset or expired
SignatureMismatchException	In case signature returned by LicenseSpring server is not valid. E.g. if the response data was changed.
NoInternetException NetworkTimeoutException LicenseServerException	Connection-related errors: if there's no Internet or an internal server error occured. See License Checks (Grace Period)
ApiKeyException	If provided api key cannot be used for the request( is invalid, readonly or revoked).
AuthorizationException	Authorization failed, please check your proxy settings.

Handling C++ Errors

The LicenseHandler class of C++ SDK is exception-free by default. It provides an alternative way to implement licensing without exceptions but C-style error codes. Make sure to put error checks after LicenseHandler calls.

To retrieve the error use the following methods:

bool LicenseHandler::wasError() const; //check if there was an error
LSErrorCode LicenseHandler::getLastError() const; //get code of the last error
const std::string& LicenseHandler::getLastErrorMsg() const; //get message of the last error

This class also contains several methods to check for error type, e.g. isLicenseStateError, isNoInternetError.

Example of handling LicenseHandler errors:

licenseHandler.checkLicenseLocal();
if(licenseHandler.wasError())
{
    if(licenseHandler.getLastError() == eDeviceError)
        licenseHandler.relinkLicense(WinCryptographyId);
    else
        std::cout << "LicenseSpring error encountered: " << licenseHandler.getLastErrorMsg();
}

Common Errors

Below is the list of the exceptions that can occur on any SDK request:

Error	Definition
eStdError	C++ standard exception encountered
eSignatureMismatchError	Server signature is not valid. E.g. if the response data was changed.
eNoInternetError eNetworkTimeoutError eServerError	Connection-related errors: if there's no Internet or an internal server error occured. See License Checks (Grace Period)
eInvalidApiKey eReadOnlyApiKey eRevokedApiKey eApiKeyProductNotAllowed	If provided api key cannot be used for the request( is invalid, readonly or revoked).
eAuthorizationError	Authorization failed, please check your proxy settings.

Handling Swift errors

Swift SDK uses LSError compatible with NSError for error reporting.

Any SDK method marked as throws produces LSError in case of error. Possible error codes described as enum LSErrorCode.

Swift

do {
    try license.fullCheck()
} catch let error as LSError {
    print("LicenseSpring error: \(error)")
} catch {
    print("Unknown error: \(error)")
}