horse-middlewares

Horse Middlewares

Core Middleware Pipeline

Middlewares intercept and process HTTP requests/responses before reaching the endpoint handlers.

Required Registration Order

The registration order of middlewares in THorse is highly critical. Middlewares must be registered before defining any routes:

begin
  // 1. Logging and Error Handling (FIRST)
  THorse.Use(HandleException);
  
  // 2. Security and Headers
  THorse.Use(CORS);
  
  // 3. Payload Compression and Formatting
  THorse.Use(OctetStream);
  THorse.Use(Jhonson); // Parse JSON body and format JSON response
  
  // 4. Register Routes (AFTER all global middlewares)
  TProductController.RegisterRoutes;
  
  THorse.Listen(9000);
end;

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Middleware Scope & Execution Flow

Middlewares can be declared at three levels:

1. Global (via THorse.Use): Runs on every request.
2. Group-level (via THorseGroup.Use): Runs on all routes inside a specific group prefix.
3. Route-level (Local): Runs only on that specific route (defined as an array [Middleware1, Middleware2] in the verb method).

Execution Flow:

The execution order follows the nested onion pattern:

Global Middlewares → Group Middlewares → Route-level Middlewares → Final Route Handler

Always design middlewares to call Next() to pass control, or skip it to short-circuit the request (e.g., unauthorized requests).

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The Johnson Middleware (Critical)

The Jhonson middleware automatically handles JSON parsing (TJSONObject / TJSONArray) for requests and responses.

• Ownership Transfer: When you call Res.Send<TJSONObject>(LJson) or Res.Send<TJSONArray>(LArray), the Johnson middleware takes ownership of that object and will automatically destroy it after sending.
• Safety Rule: NEVER call .Free or FreeAndNil on a JSON object after sending it through Res.Send<T>. Doing so will cause a Double-Free memory corruption (Access Violation) when the middleware attempts to clean it up.