Ended up adding the request-handler.md and request-response.md too

flash/request-handler.md

@@ -0,0 +1,57 @@
+---
+banner_title: "Flash - Request Handler"
+banner_description: "Learn how to create and manage Request Handlers in Flash."
+---
+
+# ⚙️ Request Handler
+
+In this section, we illustrate the powerful concept of `RequestHandler` in Flash, which are used to handle incoming requests and generate responses.
+
+## Creating a Request Handler
+
+To create a custom request handler, you need to extend the `RequestHandler` class and annotate the class with the `RouteInfo` annotation,
+specifying the HTTP method that the handler will respond to and the relative path that the handler will be registered to.
+The `enforceNonNullBody` attribute is used to specify whether the handler expects a non-null request body: by default, it is set to `false`.
+After that, you must override the `handle` method;
+The `handle` method is where you define the logic for processing the request and generating the response.
+The `req` (request) and `res` (response) objects are available in the handler to access the request data and send the response back to the client.
+
+You must call the super constructor with the `req` and `res` objects to initialize the handler.
+
+```java{5,8}
+import flash.Request;
+import flash.Response;
+import flash.RequestHandler;
+
+@RouteInfo(method = HttpMethod.GET, path = "/hello", enforceNonNullBody = false)
+public class MyHandler extends RequestHandler {
+    public MyHandler(Request req, Response res) {
+        super(req, res);
+    }
+
+    @Override
+    public Object handle() {
+        String response = "Hello, world!";
+        return response;
+    }
+}
+```
+
+::: warning
+Any logic that needs to be executed before the request handler is registered must be done within the constructor.
+:::
+
+## Request Handler methods
+
+The `RequestHandler` class provides several methods that can be used to interact with the request and response objects easily and safely.
+Following are listed the methods available in the `RequestHandler` class, with a brief description of their purpose:
+
+| Method                       | Params                     | Description                                                                                          |
+|------------------------------|----------------------------|------------------------------------------------------------------------------------------------------|
+| `getRequestBody()`           | `none`                     | Returns a `JSONObject` representation of the request body.                                           |
+| `getSpecification()`         | `none`                     | Returns an instance of `HandlerSpecification` containing all sorts of information about the handler. |
+| `expectedRequestParameter()` | `String name, description` | Returns an instance of `ExpectedRequestParameter` for the specified parameter name.                  |
+| `expectedBodyField()`        | `String name, description` | Returns an instance of `ExpectedBodyField` for the specified field name.                             |
+| `expectedBodyFile()`         | `String name, description` | Returns an instance of `ExpectedBodyFile` for the specified file name.                               |
+
+(More on the `ExpectedRequestParameter`, `ExpectedBodyField`, and `ExpectedBodyFile` classes in the next section).