Content-Type Enforcement Middleware

# middleware.py

from django.conf import settings

class EnforceContentTypeMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response
        self.default_ct = getattr(settings, 'DEFAULT_CONTENT_TYPE', 'application/json')
        self.only_api_prefixes = getattr(settings, 'CONTENT_TYPE_ONLY_PREFIXES', ['/api/'])

    def __call__(self, request):
        response = self.get_response(request)

        path = request.path
        is_api = any(path.startswith(p) for p in self.only_api_prefixes)

        if is_api:
            # Respect explicit content type already set by views
            current = response.get('Content-Type')
            if not current:
                response['Content-Type'] = self.default_ct
        return response
  

# settings.py

MIDDLEWARE = [
    # ...
    'your_app.middleware.EnforceContentTypeMiddleware',
]

# Default Content-Type for API responses
DEFAULT_CONTENT_TYPE = 'application/json'

# Apply only to these URL prefixes (avoid forcing admin/static pages)
CONTENT_TYPE_ONLY_PREFIXES = ['/api/']
  

# views.py (examples)

from django.http import JsonResponse, HttpResponse

def api_ok(request):
    return JsonResponse({'status': 'ok'})  # already sets application/json

def api_text(request):
    return HttpResponse('hello')  # middleware will enforce application/json
  

# Example curl tests

$ curl -i http://localhost:8000/api/ok/
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
...

$ curl -i http://localhost:8000/api/text/
HTTP/1.1 200 OK
Content-Type: application/json
...
hello