Class-Based Views

Class-Based Views in Nexios offer a structured and modular approach to handling HTTP requests. By encapsulating request logic within a class, developers can easily manage middleware, request preprocessing, error handling, and response formatting. The APIHandler class serves as the base class for creating class-based handlers, providing hooks for handling requests before execution, after execution, and error handling.

Basic Usage

from nexios.views import APIHandler
from nexios import NexiosApp
app = NexiosApp()
class UserView(APIHandler):
    async def get(self, request, response):
        user_id = request.state.user_id  # Retrieve stored state
        return response.json({"user_id": user_id})

app.add_route(UserView.as_route("/user"))

💡Tip

.as_route can also take same argument as route decorators or Nexios Route class

Middleware Support

Class-Based Views in Nexios also support middleware functions. Middleware functions are executed in order, before the request reaches the handler method.

from nexios.views import APIHandler
from nexios import NexiosApp
app = NexiosApp()
class UserView(APIHandler):
    async def get(self, request, response):
        user_id = request.state.user_id  # Retrieve stored state
        return response.json({"user_id": user_id})

    middlewares = [auth_middleware, logging_middleware]  # Pass middleware as a list

app.add_route(UserView.as_route("/user"))

Middleware Execution Flow

When a request is made to a class-based view with middleware, the execution flow is as follows:

• Middleware Execution: Each middleware function in the middleware list is executed in sequence. Each middleware can modify the request or short-circuit the request by returning a response early.

• Handler Execution: Once all middleware functions have been executed, the request is passed to the appropriate handler method (get, post, etc.).

• Response Return: The response from the handler is returned to the client.