WSDL to Apex Generation Guide

WSDL to Apex Generation Guide

Overview

Salesforce can automatically generate Apex classes from WSDL (Web Services Description Language) files, enabling integration with SOAP-based web services.

Step-by-Step Process

1. Obtain the WSDL File

Get the WSDL from your external system. Common sources:

• API documentation portal
• Endpoint URL with ?wsdl suffix (e.g., https://api.example.com/service?wsdl)
• Direct download from vendor

2. Review WSDL for Compatibility

Salesforce WSDL2Apex has limitations. Check for:

Supported:

• Document/literal and RPC/encoded styles
• Simple types (string, integer, boolean, date, etc.)
• Complex types (objects with properties)
• Arrays and lists
• Basic SOAP headers

Not Supported / Problematic:

• Very large WSDLs (may hit Apex class size limits)
• Certain complex inheritance patterns
• Some advanced XSD features
• WS-Security (requires manual implementation)

3. Generate Apex Classes

1. Navigate to Setup → Apex Classes
2. Click Generate from WSDL
3. Click Choose File and upload the WSDL
4. Review the parse results
5. Modify class names if needed (keep them short to avoid limits)
6. Click Generate Apex code

4. Generated Class Structure

For a WSDL defining CustomerService with operation getCustomer:

AsyncCustomerService.cls         - Async version of service
CustomerService.cls              - Main stub class with methods
GetCustomerRequest.cls           - Request wrapper
GetCustomerResponse.cls          - Response wrapper
Customer.cls                     - Data type from schema
Address.cls                      - Nested data type

5. Configure Endpoint Access

Option A: Named Credential (Recommended)

1. Create Named Credential in Setup
2. Set endpoint to SOAP service URL
3. Configure authentication (Basic, Certificate, OAuth)
4. In Apex: stub.endpoint_x = 'callout:MyNamedCredential';

Option B: Remote Site Setting

1. Create Remote Site Setting with domain
2. In Apex: stub.endpoint_x = 'https://api.example.com/service';

6. Basic Usage Example

public class CustomerServiceCaller {

    public static Customer getCustomer(String customerId) {
        // Instantiate the generated stub
        CustomerService.CustomerServicePort stub = new CustomerService.CustomerServicePort();

        // Configure endpoint (Named Credential)
        stub.endpoint_x = 'callout:CustomerServiceNC';

        // Set timeout (max 120 seconds)
        stub.timeout_x = 120000;

        // Create request
        GetCustomerRequest request = new GetCustomerRequest();
        request.customerId = customerId;

        // Make the call
        GetCustomerResponse response = stub.getCustomer(request);

        return response.customer;
    }
}

7. Error Handling

try {
    GetCustomerResponse response = stub.getCustomer(request);
    // Process response

} catch (CalloutException e) {
    // Network error, timeout, SSL issues
    System.debug('Callout failed: ' + e.getMessage());

} catch (Exception e) {
    // SOAP fault (error from service)
    // The exception message contains SOAP fault details
    System.debug('SOAP error: ' + e.getMessage());
}

8. Common Issues and Solutions

9. Testing SOAP Callouts

Use Test.setMock() with WebServiceMock:

@isTest
public class CustomerServiceTest {

    @isTest
    static void testGetCustomer() {
        // Set mock
        Test.setMock(WebServiceMock.class, new CustomerServiceMock());

        // Call service
        Test.startTest();
        Customer result = CustomerServiceCaller.getCustomer('CUST001');
        Test.stopTest();

        // Assert
        System.assertEquals('Test Customer', result.name);
    }

    // Mock implementation
    public class CustomerServiceMock implements WebServiceMock {
        public void doInvoke(
            Object stub,
            Object request,
            Map<String, Object> response,
            String endpoint,
            String soapAction,
            String requestName,
            String responseNS,
            String responseName,
            String responseType
        ) {
            // Create mock response
            GetCustomerResponse mockResponse = new GetCustomerResponse();
            mockResponse.customer = new Customer();
            mockResponse.customer.name = 'Test Customer';

            response.put('response_x', mockResponse);
        }
    }
}

10. Async SOAP Calls

For calls from triggers or after DML:

public class CustomerSyncQueueable implements Queueable, Database.AllowsCallouts {

    private String customerId;

    public CustomerSyncQueueable(String customerId) {
        this.customerId = customerId;
    }

    public void execute(QueueableContext context) {
        try {
            Customer customer = CustomerServiceCaller.getCustomer(customerId);
            // Process result
        } catch (Exception e) {
            // Log error
        }
    }
}

// Usage in trigger:
System.enqueueJob(new CustomerSyncQueueable(accountId));

Best Practices

1. Always use Named Credentials for authentication instead of hardcoding credentials
2. Set appropriate timeouts - default may be too short
3. Implement error handling - SOAP services can fail in many ways
4. Log requests and responses for debugging
5. Use async patterns when calling from DML contexts
6. Test with mocks - don't call real services in tests
7. Monitor governor limits - especially for large responses

Limitations

• Maximum 100 callouts per transaction
• Maximum 120 second timeout per callout
• Response body limit: 6MB
• Apex code size limits may prevent large WSDL imports
• Some WSDL features not supported (WS-Security, MTOM, etc.)