# Django 4.2.11 documentation

# Source code for django.middleware.security

    import re

    from django.conf import settings
    from django.http import HttpResponsePermanentRedirect
    from django.utils.deprecation import MiddlewareMixin

    class SecurityMiddleware(MiddlewareMixin):
        def __init__(self, get_response):
            super().__init__(get_response)
            self.sts_seconds = settings.SECURE_HSTS_SECONDS
            self.sts_include_subdomains = settings.SECURE_HSTS_INCLUDE_SUBDOMAINS
            self.sts_preload = settings.SECURE_HSTS_PRELOAD
            self.content_type_nosniff = settings.SECURE_CONTENT_TYPE_NOSNIFF
            self.redirect = settings.SECURE_SSL_REDIRECT
            self.redirect_host = settings.SECURE_SSL_HOST
            self.redirect_exempt = [re.compile(r) for r in settings.SECURE_REDIRECT_EXEMPT]
            self.referrer_policy = settings.SECURE_REFERRER_POLICY
            self.cross_origin_opener_policy = settings.SECURE_CROSS_ORIGIN_OPENER_POLICY

        def process_request(self, request):
            path = request.path.lstrip("/")
            if (
                self.redirect
                and not request.is_secure()
                and not any(pattern.search(path) for pattern in self.redirect_exempt)
            ):
                host = self.redirect_host or request.get_host()
                return HttpResponsePermanentRedirect(
                    "https://%s%s" % (host, request.get_full_path())
                )

        def process_response(self, request, response):
            if (
                self.sts_seconds
                and request.is_secure()
                and "Strict-Transport-Security" not in response
            ):
                sts_header = "max-age=%s" % self.sts_seconds
                if self.sts_include_subdomains:
                    sts_header += "; includeSubDomains"
                if self.sts_preload:
                    sts_header += "; preload"
                response.headers["Strict-Transport-Security"] = sts_header

            if self.content_type_nosniff:
                response.headers.setdefault("X-Content-Type-Options", "nosniff")

            if self.referrer_policy:
                # Support a comma-separated string or iterable of values to allow
                # fallback.
                response.headers.setdefault(
                    "Referrer-Policy",
                    ",".join(
                        [v.strip() for v in self.referrer_policy.split(",")]
                        if isinstance(self.referrer_policy, str)
                        else self.referrer_policy
                    ),
                )

            if self.cross_origin_opener_policy:
                response.setdefault(
                    "Cross-Origin-Opener-Policy",
                    self.cross_origin_opener_policy,
                )
            return response