How to change the location where license information is stored

Overview

This guide explains how to migrate your end-users' license keys from one storage location to another when you decide to change where your application stores QLM license keys. The provided MyLicenseValidator class demonstrates a best-practice implementation for seamless key migration.

When to Use This

You should implement key migration when: • Changing from Windows Registry to file-based storage (or vice versa) • Moving from per-user storage to machine-level storage (or vice versa) • Switching between different EStoreKeysTo locations in your application

How It Works

Key Features:

1. Non-destructive: Original keys remain in the old location

2. One-time operation: Uses a cookie flag to prevent repeated migrations

3. Transparent: Runs automatically on application startup

4. Fallback logic: Checks new location first, then old location Migration Flow

5. Check Migration Status: Reads a cookie named "keyLocationMigrated" to determine if migration has already occurred.

6. Attempt Current Location: Tries to read keys from your newly configured storage location.

7. Fallback to Old Location: If no keys found, temporarily switches to the old storage configuration and attempts to read keys there.

8. Copy Keys Forward: If keys are found in the old location, stores them in the new location using StoreKeys().

9. Set Migration Flag: Writes a timestamp cookie to prevent future migration attempts.

Implementation Steps

1. Customize Migration Parameters Modify these variables in MigrateKeys() to match your specific migration scenario:

// Configure where to migrate FROM
EStoreKeysTo migrateFromLocation = EStoreKeysTo.ERegistry;
EStoreKeysOptions migrateFromOptions = EStoreKeysOptions.EStoreKeysPerUserAndMachine;

1. Configure Your New Storage Location Set your desired storage location in your QLM settings file or during LicenseValidator initialization:

license.StoreKeysLocation = EStoreKeysTo.EFileCommonData;
license.StoreKeysOptions = EStoreKeysOptions.EStoreKeysPerUserAndMachine;

1. Integrate into Your License Validator

Instead of using the default LicenseValidator class, update your code to use MyLicenseValidator which inherits from LicenseValidator and adds the migration code.

public MyLicenseValidator() : base()
{
    MigrateKeys();  // Runs on every instantiation, but cookie prevents re-execution
}
public MyLicenseValidator(string settingsFile) : base(settingsFile)
{
    MigrateKeys();  // Runs on every instantiation, but cookie prevents re-execution
}

MyLicenseValidator.cs

4KB

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