Snippet

Parametrized View Decorator for Dynamic Request Control Flow

Higher-order functions in Python can alter control flow before reaching Django views. By creating closure-based decorators, request execution is gated or rejected early based on custom conditions such as request headers or access tokens.

snippet.py

python

from functools import wraps
from django.http import HttpResponseForbidden, HttpRequest
from typing import Callable, Any
 
def require_header_flag(header_name: str, expected_value: str):
    """Higher-order decorator controlling view execution flow based on request headers."""
    def decorator(view_func: Callable[..., Any]) -> Callable[..., Any]:
        @wraps(view_func)
        def _wrapped_view(request: HttpRequest, *args: Any, **kwargs: Any):
            header_val = request.headers.get(header_name)
            if header_val != expected_value:
                return HttpResponseForbidden(f"Missing or invalid header: {header_name}")
            return view_func(request, *args, **kwargs)
        return _wrapped_view
    return decorator

django

Breakdown

def require_header_flag(header_name: str, expected_value: str):

Outer factory function accepting parameters to customize decorator behavior.

def decorator(view_func: Callable[..., Any]) -> Callable[..., Any]:

Intermediate decorator accepting the target Django view function.

@wraps(view_func)

Preserves docstrings, function names, and metadata of the original view function.

if header_val != expected_value: return HttpResponseForbidden(...)

Branching control flow that halts view execution and returns an HTTP 403 response if header validation fails.

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Parametrized View Decorator for Dynamic Request Control Flow

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