from django.http import HttpResponse
from django.test import RequestFactory, SimpleTestCase
from django.test.utils import override_settings


class SecurityMiddlewareTest(SimpleTestCase):
    def middleware(self, *args, **kwargs):
        from django.middleware.security import SecurityMiddleware
        return SecurityMiddleware(self.response(*args, **kwargs))

    @property
    def secure_request_kwargs(self):
        return {"wsgi.url_scheme": "https"}

    def response(self, *args, headers=None, **kwargs):
        def get_response(req):
            response = HttpResponse(*args, **kwargs)
            if headers:
                for k, v in headers.items():
                    response.headers[k] = v
            return response
        return get_response

    def process_response(self, *args, secure=False, request=None, **kwargs):
        request_kwargs = {}
        if secure:
            request_kwargs.update(self.secure_request_kwargs)
        if request is None:
            request = self.request.get("/some/url", **request_kwargs)
        ret = self.middleware(*args, **kwargs).process_request(request)
        if ret:
            return ret
        return self.middleware(*args, **kwargs)(request)

    request = RequestFactory()

    def process_request(self, method, *args, secure=False, **kwargs):
        if secure:
            kwargs.update(self.secure_request_kwargs)
        req = getattr(self.request, method.lower())(*args, **kwargs)
        return self.middleware().process_request(req)

    @override_settings(SECURE_HSTS_SECONDS=3600)
    def test_sts_on(self):
        """
        With SECURE_HSTS_SECONDS=3600, the middleware adds
        "Strict-Transport-Security: max-age=3600" to the response.
        """
        self.assertEqual(
            self.process_response(secure=True).headers['Strict-Transport-Security'],
            'max-age=3600',
        )

    @override_settings(SECURE_HSTS_SECONDS=3600)
    def test_sts_already_present(self):
        """
        The middleware will not override a "Strict-Transport-Security" header
        already present in the response.
        """
        response = self.process_response(
            secure=True,
            headers={"Strict-Transport-Security": "max-age=7200"})
        self.assertEqual(response.headers["Strict-Transport-Security"], "max-age=7200")

    @override_settings(SECURE_HSTS_SECONDS=3600)
    def test_sts_only_if_secure(self):
        """
        The "Strict-Transport-Security" header is not added to responses going
        over an insecure connection.
        """
        self.assertNotIn(
            'Strict-Transport-Security',
            self.process_response(secure=False).headers,
        )

    @override_settings(SECURE_HSTS_SECONDS=0)
    def test_sts_off(self):
        """
        With SECURE_HSTS_SECONDS=0, the middleware does not add a
        "Strict-Transport-Security" header to the response.
        """
        self.assertNotIn(
            'Strict-Transport-Security',
            self.process_response(secure=True).headers,
        )

    @override_settings(SECURE_HSTS_SECONDS=600, SECURE_HSTS_INCLUDE_SUBDOMAINS=True)
    def test_sts_include_subdomains(self):
        """
        With SECURE_HSTS_SECONDS non-zero and SECURE_HSTS_INCLUDE_SUBDOMAINS
        True, the middleware adds a "Strict-Transport-Security" header with the
        "includeSubDomains" directive to the response.
        """
        response = self.process_response(secure=True)
        self.assertEqual(
            response.headers['Strict-Transport-Security'],
            'max-age=600; includeSubDomains',
        )

    @override_settings(SECURE_HSTS_SECONDS=600, SECURE_HSTS_INCLUDE_SUBDOMAINS=False)
    def test_sts_no_include_subdomains(self):
        """
        With SECURE_HSTS_SECONDS non-zero and SECURE_HSTS_INCLUDE_SUBDOMAINS
        False, the middleware adds a "Strict-Transport-Security" header without
        the "includeSubDomains" directive to the response.
        """
        response = self.process_response(secure=True)
        self.assertEqual(response.headers["Strict-Transport-Security"], "max-age=600")

    @override_settings(SECURE_HSTS_SECONDS=10886400, SECURE_HSTS_PRELOAD=True)
    def test_sts_preload(self):
        """
        With SECURE_HSTS_SECONDS non-zero and SECURE_HSTS_PRELOAD True, the
        middleware adds a "Strict-Transport-Security" header with the "preload"
        directive to the response.
        """
        response = self.process_response(secure=True)
        self.assertEqual(
            response.headers['Strict-Transport-Security'],
            'max-age=10886400; preload',
        )

    @override_settings(SECURE_HSTS_SECONDS=10886400, SECURE_HSTS_INCLUDE_SUBDOMAINS=True, SECURE_HSTS_PRELOAD=True)
    def test_sts_subdomains_and_preload(self):
        """
        With SECURE_HSTS_SECONDS non-zero, SECURE_HSTS_INCLUDE_SUBDOMAINS and
        SECURE_HSTS_PRELOAD True, the middleware adds a "Strict-Transport-Security"
        header containing both the "includeSubDomains" and "preload" directives
        to the response.
        """
        response = self.process_response(secure=True)
        self.assertEqual(
            response.headers['Strict-Transport-Security'],
            'max-age=10886400; includeSubDomains; preload',
        )

    @override_settings(SECURE_HSTS_SECONDS=10886400, SECURE_HSTS_PRELOAD=False)
    def test_sts_no_preload(self):
        """
        With SECURE_HSTS_SECONDS non-zero and SECURE_HSTS_PRELOAD
        False, the middleware adds a "Strict-Transport-Security" header without
        the "preload" directive to the response.
        """
        response = self.process_response(secure=True)
        self.assertEqual(
            response.headers['Strict-Transport-Security'],
            'max-age=10886400',
        )

    @override_settings(SECURE_CONTENT_TYPE_NOSNIFF=True)
    def test_content_type_on(self):
        """
        With SECURE_CONTENT_TYPE_NOSNIFF set to True, the middleware adds
        "X-Content-Type-Options: nosniff" header to the response.
        """
        self.assertEqual(
            self.process_response().headers['X-Content-Type-Options'],
            'nosniff',
        )

    @override_settings(SECURE_CONTENT_TYPE_NOSNIFF=True)
    def test_content_type_already_present(self):
        """
        The middleware will not override an "X-Content-Type-Options" header
        already present in the response.
        """
        response = self.process_response(secure=True, headers={"X-Content-Type-Options": "foo"})
        self.assertEqual(response.headers["X-Content-Type-Options"], "foo")

    @override_settings(SECURE_CONTENT_TYPE_NOSNIFF=False)
    def test_content_type_off(self):
        """
        With SECURE_CONTENT_TYPE_NOSNIFF False, the middleware does not add an
        "X-Content-Type-Options" header to the response.
        """
        self.assertNotIn('X-Content-Type-Options', self.process_response().headers)

    @override_settings(SECURE_BROWSER_XSS_FILTER=True)
    def test_xss_filter_on(self):
        """
        With SECURE_BROWSER_XSS_FILTER set to True, the middleware adds
        "s-xss-protection: 1; mode=block" header to the response.
        """
        self.assertEqual(
            self.process_response().headers['X-XSS-Protection'],
            '1; mode=block',
        )

    @override_settings(SECURE_BROWSER_XSS_FILTER=True)
    def test_xss_filter_already_present(self):
        """
        The middleware will not override an "X-XSS-Protection" header
        already present in the response.
        """
        response = self.process_response(secure=True, headers={"X-XSS-Protection": "foo"})
        self.assertEqual(response.headers["X-XSS-Protection"], "foo")

    @override_settings(SECURE_BROWSER_XSS_FILTER=False)
    def test_xss_filter_off(self):
        """
        With SECURE_BROWSER_XSS_FILTER set to False, the middleware does not
        add an "X-XSS-Protection" header to the response.
        """
        self.assertNotIn('X-XSS-Protection', self.process_response().headers)

    @override_settings(SECURE_SSL_REDIRECT=True)
    def test_ssl_redirect_on(self):
        """
        With SECURE_SSL_REDIRECT True, the middleware redirects any non-secure
        requests to the https:// version of the same URL.
        """
        ret = self.process_request("get", "/some/url?query=string")
        self.assertEqual(ret.status_code, 301)
        self.assertEqual(ret["Location"], "https://testserver/some/url?query=string")

    @override_settings(SECURE_SSL_REDIRECT=True)
    def test_no_redirect_ssl(self):
        """
        The middleware does not redirect secure requests.
        """
        ret = self.process_request("get", "/some/url", secure=True)
        self.assertIsNone(ret)

    @override_settings(SECURE_SSL_REDIRECT=True, SECURE_REDIRECT_EXEMPT=["^insecure/"])
    def test_redirect_exempt(self):
        """
        The middleware does not redirect requests with URL path matching an
        exempt pattern.
        """
        ret = self.process_request("get", "/insecure/page")
        self.assertIsNone(ret)

    @override_settings(SECURE_SSL_REDIRECT=True, SECURE_SSL_HOST="secure.example.com")
    def test_redirect_ssl_host(self):
        """
        The middleware redirects to SECURE_SSL_HOST if given.
        """
        ret = self.process_request("get", "/some/url")
        self.assertEqual(ret.status_code, 301)
        self.assertEqual(ret["Location"], "https://secure.example.com/some/url")

    @override_settings(SECURE_SSL_REDIRECT=False)
    def test_ssl_redirect_off(self):
        """
        With SECURE_SSL_REDIRECT False, the middleware does not redirect.
        """
        ret = self.process_request("get", "/some/url")
        self.assertIsNone(ret)

    @override_settings(SECURE_REFERRER_POLICY=None)
    def test_referrer_policy_off(self):
        """
        With SECURE_REFERRER_POLICY set to None, the middleware does not add a
        "Referrer-Policy" header to the response.
        """
        self.assertNotIn('Referrer-Policy', self.process_response().headers)

    def test_referrer_policy_on(self):
        """
        With SECURE_REFERRER_POLICY set to a valid value, the middleware adds a
        "Referrer-Policy" header to the response.
        """
        tests = (
            ('strict-origin', 'strict-origin'),
            ('strict-origin,origin', 'strict-origin,origin'),
            ('strict-origin, origin', 'strict-origin,origin'),
            (['strict-origin', 'origin'], 'strict-origin,origin'),
            (('strict-origin', 'origin'), 'strict-origin,origin'),
        )
        for value, expected in tests:
            with self.subTest(value=value), override_settings(SECURE_REFERRER_POLICY=value):
                self.assertEqual(
                    self.process_response().headers['Referrer-Policy'],
                    expected,
                )

    @override_settings(SECURE_REFERRER_POLICY='strict-origin')
    def test_referrer_policy_already_present(self):
        """
        The middleware will not override a "Referrer-Policy" header already
        present in the response.
        """
        response = self.process_response(headers={'Referrer-Policy': 'unsafe-url'})
        self.assertEqual(response.headers['Referrer-Policy'], 'unsafe-url')
