Initial application.yml support

documentation/index.markdown

@@ -6,6 +6,7 @@ Midgard MVC applications are written in the PHP language, and consist of a colle
 Basic building blocks:
 ----------------------
 
+* Application: a configuration file describing the components and other settings used in a Midgard MVC website
 * Component: a PHP module intended to run as part of a web application. For example: a news listing. Provides routes, controllers and templates
 * Library: a PHP module that can be called by other modules to perform some task. Does not run as part of a website. For example: a form validation library
 * Service: a standardized interface to access a given functionality. For example: authentication
@@ -21,6 +22,21 @@ Installation
   - Enable the Midgard2 extension in your `php.ini` with an `extension=midgard2.so`
   - Copy Midgard MVC database definitions (`midgardmvc_core/configuration/mgdschema.xml`) to the Midgard schema directory (by default `/usr/share/midgard2/schema/`)
 
+Application configuration
+-------------------------
+
+Application configuration is a configuration file read before Midgard MVC starts where you can define application-wide shared configuration settings, including overriding Midgard MVC default configurations. The components used with an application are defined in the application configuration file.
+
+The application configuration is by default located in the root of your Midgard MVC installation directory in a YAML file called `application.yml`. Example:
+
+    name: Example Blog
+    components:
+        midgardmvc_core
+            source: git://github.com/midgardproject/midgardmvc_core.git
+        midgardmvc_create
+    services_dispatcher: midgard3
+    providers_component: midgardmvc
+
 Running Midgard MVC
 -------------------
 

interface.php

@@ -329,19 +329,42 @@ public static function get_instance($local_configuration = null)
             return self::$instance;
         }
 
-        if (   !is_null($local_configuration)
-            && !is_array($local_configuration))
+        if (is_null($local_configuration))
         {
-            // Ratatoskr-style dispatcher selection fallback
-            $local_configuration = array
-            (
-                'services_dispatcher' => $local_configuration,
-            );
+            $configuration = array();
+        }
+        else
+        {
+            if (is_array($local_configuration))
+            {
+                // Configuration passed as a PHP array
+                $configuration = $local_configuration;
+            }
+            elseif (is_string($local_configuration))
+            {
+                if (substr($local_configuration, 0, 1) == '/')
+                {
+                    // Application YAML file provided, load configuration from it
+                    $configuration = yaml_parse_file($local_configuration);
+                }
+                else
+                {
+                    // Ratatoskr-style dispatcher selection fallback
+                    $configuration = array
+                    (
+                        'services_dispatcher' => $local_configuration,
+                    );
+                }
+            }
+            else
+            {
+                throw new Exception('Unrecognized configuration given for Midgard MVC initialization');
+            }
         }
 
         // Load and return MVC instance
         self::$instance = new midgardmvc_core();
-        self::$instance->load_base_services($local_configuration);
+        self::$instance->load_base_services($configuration);
         return self::$instance;
     }
 }