Merge pull request #22 from dotkernel/request-lifecycle

added request lifecycle page

Author: arhimede

docs/book/v1/introduction/request-lifecycle.md

@@ -0,0 +1,107 @@
+# Request Lifecycle for a Mezzio-Based Application
+
+The request lifecycle is the sequence of steps that happen from the moment a user makes an HTTP request until the server sends back a response.
+
+The graph below shows how the request is handled by Dotkernel Light.
+
+![Dotkernel Light Request Lifecycle!](https://docs.dotkernel.org/img/light/request-lifecycle.jpg)
+
+## Request Lifecycle Step-by-Step
+
+The following list describes what each of the steps from the graph does in Dotkernel Light.
+
+### 1. HTTP Request [public/index.php]
+
+- Bootstrap the application.
+- Load configuration.
+- Create the Mezzio application instance.
+
+### 2. Service Container
+
+Register:
+
+- Factories.
+- Aliases.
+- Delegators.
+
+All services are configured and ready to use.
+
+### 3. Route Registration
+
+Read all available routes with their allowed request methods and dynamically register them in the application.
+Routes are managed by FastRoute.
+
+#### Example
+
+| Item       | Value                             |
+|------------|-----------------------------------|
+| Match      | /page/about -> GetPageViewHandler |
+| Method     | GET                               |
+| Route name | page::about                       |
+
+### 4. Middleware Pipeline [config/pipeline.php]
+
+Loads the predefined order of middleware.
+It defines how incoming HTTP requests move through the application and how responses are generated.
+
+### 5. Routing
+
+FastRoute matches the URL and method against registered routes.
+
+#### Example
+
+| Item       | Value              |
+|------------|--------------------|
+| Match      | GET /page/about    |
+| Handler    | GetPageViewHandler |
+| Route name | page::about        |
+
+### 6. Handler Invocation
+
+Extract the matched route name from the request and pass it to the renderer.
+
+```php
+$template = $request->getAttribute(RouteResult::class)->getMatchedRouteName();
+// $template = 'page::about';
+```
+
+### 7. Custom Logic Execution in Handler
+
+Execute the business logic in the handler.
+The process can involve services and any custom logic.
+
+### 8. Template Rendering
+
+Twig loads the template, applies layout, renders blocks and includes partials.
+
+#### Example
+
+| Item             | Value                                   |
+|------------------|-----------------------------------------|
+| Load             | src/Page/templates/page/about.html.twig |
+| Extends          | @layout/default.html.twig               |
+| Render blocks    | title, content                          |
+| Include partials | alerts.html.twig, etc.                  |
+| Output           | Final HTML                              |
+
+### 9. Response Creation
+
+An HtmlResponse is created with status, headers and the rendered HTML body.
+
+#### Example
+
+| Item         | Value                    |
+|--------------|--------------------------|
+| Status       | 200 OK                   |
+| Content-Type | text/html; charset=utf-8 |
+| Body         | Rendered HTML            |
+
+### 10. Response Pipeline
+
+The response flows back through the middleware stack.
+Middleware can modify headers, cookies, compress content, etc.
+
+### 11. Response Emitter
+
+The final response is sent back to the browser.
+The page is rendered and sent to the user.

mkdocs.yml

@@ -10,6 +10,7 @@ nav:
   - v1:
       - Introduction: v1/introduction.md
       - Overview:
+          - "Request Lifecycle": v1/introduction/request-lifecycle.md
           - "Server Requirements": v1/introduction/server-requirements.md
           - "File Structure": v1/introduction/file-structure.md
           - "Packages": v1/introduction/packages.md