Fix #1: handle invalid JSON and missing fields in Porkbun ping response

pb-dydns.php

@@ -23,7 +23,7 @@
 //
 // Append this line as many times as domains you want to automatically update:
 //
-// */10 * * * *    php /path/to/pb-dydns.php domain_name > /dev/null
+// */10 * * * *	php /path/to/pb-dydns.php domain_name > /dev/null
 //
 // And restart cron (I'm not sure if this is necessary):
 //
@@ -41,7 +41,7 @@ $config_filename = __DIR__ . "/pb-dydns.json";
 
 if (!file_exists($config_filename))
 {
-    echo "The config file $config_filename does not exist." . PHP_EOL;
+	echo "The config file $config_filename does not exist." . PHP_EOL;
 
 	$config = json_encode(array
 	(
@@ -75,15 +75,35 @@ $myDomain = $argv[1];
 $pbapi = new PorkbunAPI($config_filename);
 
 // Test connection to Porkbun API in order to get the public IP:
-$result = json_decode($pbapi->ping());
+$raw = $pbapi->ping();
-if ($result->status == "SUCCESS") $myIp = $result->yourIp;
+$result = json_decode($raw);
-else
+
+if ($result === null)
 {
-	echo_to_cli("There was an error trying to ping Porkbun." . PHP_EOL);
+	echo_to_cli("Invalid JSON returned by Porkbun API:\n$raw\n");
-	var_dump($result);
 	exit(3);
 }
 
+if (!isset($result->status))
+{
+	echo_to_cli("Porkbun API response missing 'status' field:\n$raw\n");
+	exit(3);
+}
+
+if ($result->status !== "SUCCESS") 
+{
+	echo_to_cli("Porkbun API returned an error:\n$raw\n");
+	exit(3);
+}
+
+if (!isset($result->yourIp))
+{
+	echo_to_cli("Porkbun API did not return your public IP.\n");
+	exit(3);
+}
+
+$myIp = $result->yourIp;
+
 echo_to_cli("Your public IP address is $myIp" . PHP_EOL);
 
 // Retrieve all DNS records associated with user's domain: