REST response for empty XML elements incorrect

[nolsen311]

Describe the bug
A clear and concise description of what the bug is.

As I'm trying to modernize one of the pfsense integrations for home assistant, I've found a couple places where the rest API isn't returning correct data, relative to the existing XML api.

1. Firewall rules - enabled - is represented as an empty xml element when disabled (e.g., . Which is returned as an empty string by the rest api.
2. Firewall rules - statetype - also often represented as an empty xml element, and rest api may fail due to empty statetype during PATCH.

To Reproduce

1. PATCH method to /firewall/rule endpoint with "" as statetype (rule must have default statetype; if "keepstate" seems to work properly with empty string) attempting to toggle enabled/disabled on rule.

Expected behavior
expected rule to toggle enabled/disabled

Screenshots or Response
no screenshots at this time

pfSense Version & Package Version:

• pfSense Version: pfSense 26.07
• Package Version v2.10.2

Affected Endpoints:

• URL: /api/v2/firewall/rule

Additional context
Add any other context about the problem here.

[jaredhendrickson13]

I believe the field you're looking for is disabled, which should be set to true when the rule should be disabled, or false when it should be enabled. https://pfrest.org/api-docs/#/FIREWALL/patchFirewallRuleEndpoint

The schema for v2 is not always 1:1 with the XML or the webConfigurator. This was an intentional decision mostly to prevent unpredictable type and value mutation, which prevented strict-typed languages like Go from reliably integrating. This does however mean that the API treats empty values and null values as different values altogether, whereas the webConfigurator often treats empty and null values as the same. To assume the default value for an existing string field, null should be used instead of an empty string.