diff --git a/inc/functions.php b/inc/functions.php
index 6df52894..014c7be1 100644
--- a/inc/functions.php
+++ b/inc/functions.php
@@ -1823,40 +1823,46 @@ function buildJavascript() {
 	file_write($config['file_script'], $script);
 }
 
-function checkIPAPI() {
+/**
+ * @param string $ip The IP to check.
+ * @return bool True if the IP should be blocked.
+ */
+function checkIPAPI(string $ip): bool {
 	global $config;
 
-	// query IPHub's database with the poster's IP
-	if (isset($config['iphub_key']) && $config['iphub_key'] !== "") {
-		if (isset($config['iphub_whitelisted_ips']) && array_search($_SERVER['REMOTE_ADDR'], $config['iphub_whitelisted_ips']) !== false) {
-			// IP is whitelisted, don't bother querying
-			error("return true;");
+	// Query IPHub's database with the poster's IP.
+	if ($config['iphub_key'] && !empty($config['iphub_key'])) {
+		if (array_search($ip, $config['iphub_whitelisted_ips']) !== false) {
+			// IP is whitelisted, don't bother querying.
+			return false;
 		}
 
 		$ch = curl_init();
-		curl_setopt($ch, CURLOPT_URL, "http://v2.api.iphub.info/ip/" . $_SERVER['REMOTE_ADDR']);
+		curl_setopt($ch, CURLOPT_URL, "http://v2.api.iphub.info/ip/$ip");
 		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
-		curl_setopt($ch, CURLOPT_HTTPHEADER, array("X-Key: " . $config['iphub_key']));
+		curl_setopt($ch, CURLOPT_HTTPHEADER, [ "X-Key: {$config['iphub_key']}" ]);
 		$reply = curl_exec($ch);
-		if ($reply == "") {
+		if ($reply === false) {
+			$curl_err = curl_error($ch);
+			curl_close($ch);
+			error_log("IPHub query failed: api call failed with curl error $curl_err");
+			return false;
+		}
+		curl_close($ch);
+		if (empty($reply)) {
+			error_log('IPHub query failed: api returned an empty response');
 			return false;
 		}
 
 		$json = json_decode($reply);
 		if (isset($json->error)) {
-			$logdata = array();
-			$logdata['time'] = date(DATE_ATOM);
-			$logdata['action'] = 'iphub_query';
-			$logdata['msg'] = $json->error;
-
-			$logline = json_encode($logdata);
-			error_log($logline);
+			error_log("IPHub query failed: $json->error");
 			return false;
 		}
 
 		if ($json->block == 1
-		  || (isset($config['iphub_banned_asns']) && array_search($json->asn, $config['iphub_banned_asns']) !== false)
-		  || (isset($config['iphub_banned_isps']) && array_search($json->isp, $config['iphub_banned_isps']) !== false)) {
+		 || array_search($json->asn, $config['iphub_banned_asns']) !== false
+		 || array_search($json->isp, $config['iphub_banned_isps']) !== false) {
 			error($config['error']['proxy']);
 			return true;
 		}