Update functions.php for Caddy

[lilrags16]

This change gets the left most IP address from the X-Forward-For header. This is required to get the right IP easily from Caddy. Tested and working.

[github-actions]

Hello & Welcome! :)

Thanks for taking the time to help improve ITFlow. We're excited to review your contributions - we'll review this PR as soon as we can!

Whilst you're waiting, please feel free to check out the forum.

Just so you know, all contributions to ITFlow are licensed under the GNU GPL. By contributing you grant us a perpetual & irrevocable license to include your work in ITFlow.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[lilrags16]

@johnnyq what is the process for getting PRs included upstream?

[git-kup]

@johnnyq what is the process for getting PRs included upstream?

https://docs.itflow.org/contribute

[johnnyq]

how will this affect users not using Caddy?

[lilrags16]

If someone is using the CONST_GET_IP_METHOD == "HTTP_X_FORWARDED_FOR" value in there config, it will always set the IP that ITFlow logs as the leftmost IP presented in a list of comma separated IPs.

Case 1 - Not using config value, not using caddy- No changes to use
Case 2 - Using config value, but reverse proxy only passes on IP: No effective change as the left most of a list of one is still the same
Case 3 - Caddy w/ Value set: The actually client IP is passed through correctly.

[wrongecho]

@lilrags16 - Thanks for raising this, sorry it's taken so long to get some traction.
There's a merge conflict now but I've incluided your changes in #1222 amongst other things. We should always be grabbing the left-most IP if we're told there's a proxy in place.
@johnnyq I've raised it as a PR into develop rather than a straight commit just to make you aware of it - it's worth testing across a variety of deployments (including the develop branch when its merged). It works fine on my local box and on my dev Hestia which has HTTP_X_FORWARDED_FOR defined.