Prevent lookup of undefined key in header array while parsing. Respon…

…se parsing logic priority tweak.

restclient.php

@@ -209,26 +209,26 @@ public function parse_response($response){
         $this->response_status_lines = [];
         $line = strtok($response, "\n");
         do {
-            if(strpos($line, 'HTTP') === 0){
-                // One or more HTTP status lines
-                $this->response_status_lines[] = trim($line);
-            }
-            elseif(strlen(trim($line)) == 0){
+            if(strlen(trim($line)) == 0){
                 // Since we tokenize on \n, use the remaining \r to detect empty lines.
                 if(count($headers) > 0) break; // Must be the newline after headers, move on to response body
             }
+            elseif(strpos($line, 'HTTP') === 0){
+                // One or more HTTP status lines
+                $this->response_status_lines[] = trim($line);
+            }
             else { 
                 // Has to be a header
                 list($key, $value) = explode(':', $line, 2);
                 $key = trim(strtolower(str_replace('-', '_', $key)));
                 $value = trim($value);
 
-                if(is_array($headers[$key]))
+                if(empty($headers[$key]))
+                    $headers[$key] = $value;
+                elseif(is_array($headers[$key]))
                     $headers[$key][] = $value;
-                elseif(!empty($headers[$key]))
-                    $headers[$key] = [$headers[$key], $value];
                 else
-                    $headers[$key] = $value;
+                    $headers[$key] = [$headers[$key], $value];
             }
         } while($line = strtok("\n"));