Added functionality to validate Paysera Delivery API credentials (project_id and password) for use during initial setup or configuration changes

[alexleopnet]

What's Changed

New Features

• ✅ validateCredentials() method in DeliveryFacade for credential validation
• ✅ Public getPublicMerchantClient() method for unauthenticated requests
• ✅ New CredentialsValidationException exception class for error handling
• ✅ Rate limiting support (HTTP 429) with proper error handling

Documentation

• 📚 Comprehensive documentation in docs/VALIDATING_CREDENTIALS.md:
  • Usage examples in configuration forms
  • Setup wizard examples
  • Handling different response types (valid/invalid/rate limit)
  • Architectural flow description
  • Best practices and security notes

Technical Implementation

Code Changes:

• DeliveryFacade.php - added entry point validateCredentials() method
• DeliveryOrderService.php - business logic with logging
• DeliveryApiClient.php - error handling
• DeliveryOrderApiClient.php - API communication
• MerchantClientProvider.php - new public client without MAC authentication
• CredentialsValidationException.php - new exception class
• BaseException.php - added E_CREDENTIALS_VALIDATION_FAILED constant

Tests:

• ✅ DeliveryFacadeTest.php - tests for facade layer
• ✅ DeliveryOrderServiceTest.php - tests for service layer
• ✅ DeliveryApiClientTest.php - tests for api client
• ✅ DeliveryOrderApiClientTest.php - tests for order api client
• ✅ MerchantClientProviderTest.php - tests for public client

Dependencies:

• Updated paysera/lib-delivery-api-merchant-client to dev-master with validateProjectCredentials() support

How It Works

The validation uses a public (unauthenticated) API endpoint /rest/v1/projects/validate-credentials:

• HTTP 204 - credentials are valid
• HTTP 401 - credentials are invalid
• HTTP 429 - rate limit exceeded

Usage Example

try {
    $isValid = $deliveryFacade->validateCredentials($projectId, $password);

    if ($isValid) {
        // Save credentials and continue
    } else {
        // Show error: invalid credentials
    }
} catch (CredentialsValidationException $exception) {
    // Handle rate limit or connection errors
}

Important Notes

⚠️ Purpose: This method is intended only for one-time validation during setup. DO NOT use before regular operations (creating orders, etc.)

🔒 Security: Validation is performed server-side, without MAC authentication for the public endpoint

📝 Logging: All validation attempts (successful and failed) are logged via DeliveryLoggerInterface

[dankovalenko-paysera]

It's not good, it should be a stable version

[alexleopnet]

This change is temporary and for testing purposes only. I will revert it back after the pull request has been tested.

[dankovalenko-paysera]

It is also not okay when an official package has a dependency on the employee's own repos

[alexleopnet]

This change is temporary and for testing purposes only. I will revert it back after the pull request has been tested.

[dankovalenko-paysera]

Why?

[alexleopnet]

This change is temporary and for testing purposes only. I will revert it back after the pull request has been tested.

[dankovalenko-paysera]

Too many responsibilities for one method. Move the whole block to a private method

[dankovalenko-paysera]

Let's refactor this method: move each logger call into its own private method. It'll look much comprehensive