Add service and entry script docs

guide/en/README.md

@@ -26,17 +26,17 @@ Application Structure
 ---------------------
 
 * [Application Structure Overview](structure/overview.md)
-* [Entry Scripts](structure/entry-scripts.md)
-* [Applications](structure/applications.md)
-* [Services](structure/services.md)
-* [Controllers](structure/controllers.md)
+* [Entry Scripts](structure/entry-script.md)
+* [Applications](structure/application.md)
+* [Service components](structure/service.md)
+* [Actions](structure/action.md)
 * [Domain](structure/domain.md)
-* [Views](structure/views.md)
-* [Modules](structure/modules.md)
+* [Views](structure/view.md)
+* [Modules](structure/module.md)
 * [Middleware](structure/middleware.md)
-* [Widgets](structure/widgets.md)
-* [Assets](structure/assets.md)
-* [Extensions](structure/extensions.md)
+* [Widgets](structure/widget.md)
+* [Assets](structure/asset.md)
+* [Extensions](structure/extension.md)
 
 
 Handling Requests

guide/en/structure/entry-script.md

@@ -0,0 +1,93 @@
+# Entry Scripts
+
+Entry scripts are the first step in the application bootstrapping process. An application (either
+Web application or console application) has a single entry script. End users make requests to
+entry scripts which instantiate application instances and forward the requests to them.
+
+Entry scripts for Web applications must be stored under Web accessible directories so that they
+can be accessed by end users. They are often named as `index.php`, but can also use any other names,
+provided Web servers can locate them.
+
+Entry script for console application is `./vendor/bin/yii`.
+
+Entry scripts mainly do the following work:
+
+
+* Register [Composer autoloader](https://getcomposer.org/doc/01-basic-usage.md#autoloading);
+* Obtain configuration;
+* Use configuration to initialize dependency injection container;
+* Call `Application::run()` to process the incoming request.
+
+
+## Web Applications <span id="web-applications"></span>
+
+The following is the code in the entry script for the application template:
+
+```php
+<?php
+use hiqdev\composer\config\Builder;
+use Yiisoft\Di\Container;
+use Yiisoft\Yii\Web\Application;
+use Yiisoft\Yii\Web\ServerRequestFactory;
+
+require_once dirname(__DIR__) . '/vendor/autoload.php';
+
+// Don't do it in production, assembling takes it's time
+Builder::rebuild();
+
+$container = new Container(require Builder::path('web'));
+
+$request = $container->get(ServerRequestFactory::class)->createFromGlobals();
+$container->get(Application::class)->handle($request);
+```
+
+
+## Console Applications <span id="console-applications"></span>
+
+Similarly, the following is the code for the entry script of a console application:
+
+```php
+#!/usr/bin/env php
+<?php
+
+use hiqdev\composer\config\Builder;
+use Yiisoft\Di\Container;
+use Yiisoft\Yii\Console\Application;
+
+(static function () {
+    $cwd = getcwd();
+
+    $possibleAutoloadPaths = [
+        // running from project root
+        $cwd . '/vendor/autoload.php',
+        // running from project bin
+        dirname($cwd) . '/autoload.php',
+        // local dev repository
+        dirname(__DIR__) . '/vendor/autoload.php',
+        // dependency
+        dirname(__DIR__, 4) . '/vendor/autoload.php',
+    ];
+    $autoloadPath = null;
+    foreach ($possibleAutoloadPaths as $possibleAutoloadPath) {
+        if (file_exists($possibleAutoloadPath)) {
+            $autoloadPath = $possibleAutoloadPath;
+            break;
+        }
+    }
+
+    if ($autoloadPath === null) {
+        $message = "Unable to find vendor/autoload.php in the following paths:\n\n";
+        $message .= '- ' . implode("\n- ", $possibleAutoloadPaths) . "\n\n";
+        $message .= "Possible fixes:\n";
+        $message .= "- Install yiisoft/console via Composer.\n";
+        $message .= "- Run ./yii either from project root or from vendor/bin.\n";
+        fwrite(STDERR, $message);
+        exit(1);
+    }
+    require_once $autoloadPath;
+
+    $container = new Container(require Builder::path('console'));
+
+    $container->get(Application::class)->run();
+})();
+```

guide/en/structure/service.md

@@ -0,0 +1,28 @@
+# Service components
+
+Application may get complicated so it makes sense to extract focused parts of business logic
+or infrastructure into service components. These components are typically instantiated
+once and put into dependency injection container.
+
+These components are typically accessed either from other components or from controller.
+It is typically done via autowiring:
+
+```php
+public function actionIndex(ServerRequestInterface $request, MyService $myService): ResponseInterface
+{
+    $id = $request->getAttribute('id');
+
+    // ...
+    $extraData = $myService->getExtraData($id);
+
+    // ...
+}
+```
+
+Note that in many cases it makes sense to choose more specific class to place your code into.
+Check:
+
+- Repository
+- Widget
+- Middleware
+- Entity