Fix issue #49: Add null checks to prevent errors in domain mapping

[marcusquinn]

Fix issue #49: Add null checks to prevent errors in domain mapping

Description

This PR addresses issue #49 where domain mapping is broken in 2.4.0-beta. The error occurs when trying to call get_path() on a site object that doesn't exist, resulting in a fatal error:

PHP Fatal error: Uncaught Error: Call to a member function get_path() on false in inc/class-domain-mapping.php:476

Changes Made

• Added null checks in the replace_url method to verify that both the mapping and site objects exist before trying to use them
• Added similar checks in the mangle_url method to prevent errors when the site doesn't exist
• Added checks in the fix_srcset method to ensure we have a valid mapping before processing
• Improved code organization by storing the site object in a variable for better readability

Benefits

• Prevents fatal errors when a domain mapping exists but the associated site doesn't
• Gracefully falls back to the original URL when a mapping is invalid
• Improves overall stability of the domain mapping functionality

Testing

1. Set up a domain mapping for a site
2. Delete the site but keep the domain mapping
3. Try to access the mapped domain
4. Verify that no fatal errors occur

Fixes #49

[superdav42]

Works for me