Improve error handling

wrapper.php

@@ -21,9 +21,6 @@ function render_results($input_array){
   print $w->toXML($results);
 }
 
-// Store argument in variable
-$input = strtolower($argv[1]);
-
 // Find out which cache file should be used
 if (file_exists($_SERVER['HOME']."/.alfred-dongers.cache")) {
   $donger_cache = $_SERVER['HOME']."/.alfred-dongers.cache";
@@ -46,7 +43,9 @@ function render_results($input_array){
 $dongers = array();
 
 // Check for arguments (show only specified category or list categories)
-if (isset($input)) {
+if (isset($argv[1])) {
+  // Store argument in variable
+  $input = strtolower($argv[1]);
   // If argument is "list" => list categories
   if ($input == "list") {
     foreach (array_keys(get_object_vars($donger_raw)) as $category) {
@@ -55,10 +54,15 @@ function render_results($input_array){
     render_results(array_unique($catgories));
   // If argument is "category" => show dongers of specific category
   } else {
-    foreach ($donger_raw->$input as $donger) {
-      $dongers[] = $donger;
+    if (isset($donger_raw->$input)) {
+      foreach ($donger_raw->$input as $donger) {
+        $dongers[] = $donger;
+      }
+      render_results($dongers);
+    } else {
+      $errors[] = 'Warning: Couldn\'t find category "'.$input.'"!';
+      render_results($errors);
     }
-    render_results($dongers);
   }
 } else {
   // No arguments => show all dongers