🛡️ Duck Middlewares

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Duck middlewares allow you to intercept, process, and modify HTTP requests and responses.
They provide a flexible mechanism for logging, validation, authentication, and more.

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🏗️ Base Middleware Class

All custom middlewares in Duck inherit from BaseMiddleware:

from duck.http.middlewares import BaseMiddleware
from duck.http.request import HttpRequest
from duck.http.response import HttpBadRequestResponse, HttpResponse


class MyMiddleware(BaseMiddleware):
    @classmethod
    def process_request(cls, request: HttpRequest) -> int:
        # Custom request processing logic
        return cls.request_ok  # or cls.request_bad

    @classmethod
    def process_response(cls, response: HttpResponse, request: HttpRequest) -> None:
        # Modify response before sending
        pass

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⚡ Key Attributes

Attribute	Type	Description
debug_message	str	Message for debugging errors in middleware (default: "Middleware error")
request_ok	int	Indicates request is valid (default: 1)
request_bad	int	Indicates request has issues (default: 0)

Each middleware subclass manages its own attributes independently.
Middleware class names must be unique to behave independently.

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🔧 Class Methods

process_request(request: HttpRequest) -> int

• Implement this method to inspect incoming requests.

• Return BaseMiddleware.request_ok if valid or BaseMiddleware.request_bad to indicate an error.

get_error_response(request: HttpRequest) -> HttpResponse

• Returns the default error response when process_request returns request_bad.

HttpBadRequestResponse("Sorry there is an error in Request, that's all we know!")

process_response(response: HttpResponse, request: HttpRequest) -> None

• Modify the outgoing response before it is sent to the client.

• Optional to override depending on your middleware logic.

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💡 Notes

• You can return request_bad even if the request has no errors to override the final response from get_error_response.

• Use middlewares for authentication, logging, validation, rate-limiting, or any cross-cutting concerns.

• Duck middlewares are class-based, so no instance creation is required.

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✨ Duck’s middleware system gives you powerful control over request/response flow while keeping the API simple and flexible.