Nextcloud configuration to automatically get the latest Bunny CDN IP addresses and add them to the trusted_proxies config value. It even supports caching for 1 week!

trusted_proxies.config.php

<?php

# Make sure to put this file in the same place as the regular config.php. 
# The trusted_proxies value here will override the value in config.php
# Change $trustedProxiesFilepath to wherever you want to temporarily store/cache the IP addresses from the Bunny server.

$trustedProxiesFilepath = "/config/www/nextcloud/config/trusted_proxies.json";

function download_page($path){
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL,$path);
    curl_setopt($ch, CURLOPT_FAILONERROR,1);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION,1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
    curl_setopt($ch, CURLOPT_TIMEOUT, 15);
    $retValue = curl_exec($ch);          
    return $retValue;
}

function getBunnyIPs() : array {
    $edgeServerListV4 = (string) str_replace("\"", "", download_page("https://api.bunny.net/system/edgeserverlist"));
    $edgeServerListV6 = (string) str_replace("\"", "", download_page("https://api.bunny.net/system/edgeserverlist/ipv6"));
    $ipv4List = explode(",", substr($edgeServerListV4, 1, strlen($edgeServerListV4) - 2));
    $ipv6List = explode(",", substr($edgeServerListV6, 1, strlen($edgeServerListV6) - 2));
    return array_merge($ipv4List, $ipv6List);
}

function getCachedIps(string $trustedProxiesFilepath) : array {
    if (!file_exists($trustedProxiesFilepath)) {
        return [];
    }
    $fileContents = file_get_contents($trustedProxiesFilepath);
    if (empty($fileContents)) {
        return [];
    }
    $jsonContents = json_decode($fileContents, true);
    if (array_key_exists("lastUpdated", $jsonContents) && array_key_exists("ipAddresses", $jsonContents)) {
        return $jsonContents;
    }
    return [];
}

function updateCache(string $trustedProxiesFilepath) : array {
    $bunnyIps = getBunnyIPs();
    $jsonContents = ["lastUpdated" => strtotime("now"), "ipAddresses" => $bunnyIps];
    file_put_contents($trustedProxiesFilepath, json_encode($jsonContents, JSON_PRETTY_PRINT|JSON_UNESCAPED_SLASHES|JSON_UNESCAPED_LINE_TERMINATORS|JSON_UNESCAPED_UNICODE));
    return $bunnyIps;
}

function getTrustedProxies(string $trustedProxiesFilepath) : array {
    $default = ['192.168.80.0/24', "127.0.0.1"];
    $cachedIps = getCachedIps($trustedProxiesFilepath);
    if (empty($cachedIps)) {
        $newBunnyIps = updateCache($trustedProxiesFilepath);
        return array_merge($default, $newBunnyIps);
    }
    $lastUpdated = new DateTime();
    $lastUpdated->setTimestamp($cachedIps["lastUpdated"]);
    $now = new DateTime();
    $difference = $lastUpdated->diff($now)->days;
    if ($difference > 7) {
        $newBunnyIps = updateCache($trustedProxiesFilepath);
        return array_merge($default, $newBunnyIps);
    }
    return array_merge($default, $cachedIps["ipAddresses"]);
}

$CONFIG = [
    'trusted_proxies' => getTrustedProxies($trustedProxiesFilepath),
];