Several new things !

- General : syntax checking of the configuration file *(thanks to Micht69)*
- General : check PHP version (5.3+) *(thanks to Gilles)*
- General : add *check_updates* setting to the config file to enable or not the checking for updates
- General : add *auto_refresh* setting to the config file to automatically reload page each x seconds *(thanks to sebastienserre and Aranud)*

libs/Utils/Config.class.php

@@ -7,16 +7,25 @@ class Config
 
     public function __construct()
     {
+        $this->_checkPHPVersion(5.3);
+
         $this->file = __DIR__.'/../../esm.config.json';
 
-        if (file_exists($this->file))
-            $this->_readFile();
+        if (!file_exists($this->file))
+            throw new \Exception('Config file '.basename($this->file).' not found');
+
+        $this->_readFile();
     }
 
     private function _readFile()
     {
         $content = file_get_contents($this->file);
         $this->config = json_decode(utf8_encode($content), true);
+
+        if ($this->config == null && json_last_error() != JSON_ERROR_NONE)
+        {
+            throw new \LogicException(sprintf("Failed to parse config file '%s'. Error: '%s'", basename($this->file) , json_last_error_msg()));
+        }
     }
 
 
@@ -51,11 +60,26 @@ class Config
     }
 
 
+    /**
+     * Checks the PHP version compared to the required version
+     */
+    private function _checkPHPVersion($min)
+    {
+        if (!version_compare(phpversion(), $min, '>='))
+            throw new \Exception('Your PHP version is too old ! PHP '.$min.' is required.');
+
+        return true;
+    }
+
+
     /**
      * Checks if there is an eSM`Web update available
      */
     public function checkUpdate()
     {
+        if ($this->get('esm:check_updates') === false)
+            return false;
+        
         $response       = null;
         $this_version   = $this->get('esm:version');
         $update_url     = $this->get('esm:website').'/esm-web/update/'.$this_version;
@@ -91,4 +115,23 @@ class Config
             }
         }
     }
+}
+
+
+// PHP 5.5.0
+if (!function_exists('json_last_error_msg'))
+{
+    function json_last_error_msg()
+    {
+        static $errors = array(
+            JSON_ERROR_NONE             => null,
+            JSON_ERROR_DEPTH            => 'Maximum stack depth exceeded',
+            JSON_ERROR_STATE_MISMATCH   => 'Underflow or the modes mismatch',
+            JSON_ERROR_CTRL_CHAR        => 'Unexpected control character found',
+            JSON_ERROR_SYNTAX           => 'Syntax error, malformed JSON',
+            JSON_ERROR_UTF8             => 'Malformed UTF-8 characters, possibly incorrectly encoded'
+        );
+        $error = json_last_error();
+        return array_key_exists($error, $errors) ? $errors[$error] : "Unknown error ({$error})";
+    }
 }