Redesign the ForbidMiddleware architecture (GH-17)

Author: ArtyomVancyan

README.md

@@ -1,14 +1,15 @@
 # Django Forbid <img src="https://github.com/pysnippet.png" align="right" height="64" />
 
-Secure your Django app by controlling the access - grant or deny user access based on device and location, including VPN
-detection.
-
 [![PyPI](https://img.shields.io/pypi/v/django-forbid.svg)](https://pypi.org/project/django-forbid/)
 [![Python](https://img.shields.io/pypi/pyversions/django-forbid.svg?logoColor=white)](https://pypi.org/project/django-forbid/)
 [![Django](https://img.shields.io/pypi/djversions/django-forbid.svg?color=0C4B33&label=django)](https://pypi.org/project/django-forbid/)
 [![License](https://img.shields.io/pypi/l/django-forbid.svg)](https://github.com/pysnippet/django-forbid/blob/master/LICENSE)
 [![Tests](https://github.com/pysnippet/django-forbid/actions/workflows/tests.yml/badge.svg)](https://github.com/pysnippet/django-forbid/actions/workflows/tests.yml)
 
+Django Forbid aims to make website access managed and secure for the maintainers. It provides a middleware to grant or
+deny user access based on device and/or location. It also supports VPN detection for banning users who want to lie about
+their country and geolocation. Also, users can use only the VPN detection feature or disable it.
+
 ## Install
 
 ```shell

src/django_forbid/__init__.py

@@ -1 +1 @@
-__version__ = "0.0.6"
+__version__ = "0.0.7"

src/django_forbid/detect.py

@@ -1,14 +1,12 @@
-from datetime import datetime
+from .skills.forbid_device import ForbidDeviceMiddleware
+from .skills.forbid_location import ForbidLocationMiddleware
+from .skills.forbid_network import ForbidNetworkMiddleware
 
-from django.http import HttpResponseForbidden
-from django.shortcuts import redirect
-from django.utils.timezone import utc
-
-from .access import grants_access
-from .config import Settings
-from .detect import detect_vpn
-from .device import detect_device
-from .device import device_forbidden
+__skills__ = (
+    ForbidDeviceMiddleware,
+    ForbidLocationMiddleware,
+    ForbidNetworkMiddleware,
+)
 
 
 class ForbidMiddleware:
@@ -18,35 +16,6 @@ def __init__(self, get_response):
         self.get_response = get_response
 
     def __call__(self, request):
-        address = request.META.get("REMOTE_ADDR")
-        address = request.META.get("HTTP_X_FORWARDED_FOR", address)
-
-        # Detects the user's device and saves it in the session.
-        if not request.session.get("DEVICE"):
-            http_ua = request.META.get("HTTP_USER_AGENT")
-            request.session["DEVICE"] = detect_device(http_ua)
-
-        if device_forbidden(request.session.get("DEVICE")):
-            if Settings.has("OPTIONS.URL.FORBIDDEN_KIT"):
-                return redirect(Settings.get("OPTIONS.URL.FORBIDDEN_KIT"))
-            return HttpResponseForbidden()
-
-        # Checks if the PERIOD attr is set and the user has been granted access.
-        if Settings.has("OPTIONS.PERIOD") and request.session.has_key("ACCESS"):
-            acss = datetime.utcnow().replace(tzinfo=utc).timestamp()
-
-            # Checks if access is not timed out yet.
-            if acss - request.session.get("ACCESS") < Settings.get("OPTIONS.PERIOD"):
-                return detect_vpn(self.get_response, request)
-
-        # Checks if access is granted when timeout is reached.
-        if grants_access(request, address.split(",")[0].strip()):
-            acss = datetime.utcnow().replace(tzinfo=utc)
-            request.session["ACCESS"] = acss.timestamp()
-            return detect_vpn(self.get_response, request)
-
-        # Redirects to the FORBIDDEN_LOC URL if set.
-        if Settings.has("OPTIONS.URL.FORBIDDEN_LOC"):
-            return redirect(Settings.get("OPTIONS.URL.FORBIDDEN_LOC"))
-
-        return HttpResponseForbidden()
+        for skill in __skills__:
+            self.get_response = skill(self.get_response)
+        return self.get_response(request)

src/django_forbid/device.py

@@ -0,0 +1,73 @@
+import re
+
+from device_detector import DeviceDetector
+from django.http import HttpResponseForbidden
+from django.shortcuts import redirect
+
+from ..config import Settings
+
+
+def normalize(device_type):
+    """Removes the "!" prefix from the device type."""
+    return device_type[1:]
+
+
+def forbidden(device_type):
+    """Checks if the device type is forbidden."""
+    return device_type.startswith("!")
+
+
+def permitted(device_type):
+    """Checks if the device type is permitted."""
+    return not forbidden(device_type)
+
+
+class ForbidDeviceMiddleware:
+    """Checks if the user device is forbidden."""
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        device_aliases = {
+            "portable media player": "player",
+            "smart display": "display",
+            "smart speaker": "speaker",
+            "feature phone": "phone",
+            "car browser": "car",
+        }
+
+        device_type = request.session.get("DEVICE")
+        devices = Settings.get("DEVICES", [])
+
+        # Permit all devices if the
+        # DEVICES setting is empty.
+        if not devices:
+            return self.get_response(request)
+
+        if not request.session.get("DEVICE"):
+            http_ua = request.META.get("HTTP_USER_AGENT")
+            device_detector = DeviceDetector(http_ua)
+            device_detector = device_detector.parse()
+            device = device_detector.device_type()
+            device_type = device_aliases.get(device, device)
+            request.session["DEVICE"] = device_type
+
+        # Creates a regular expression in the following form:
+        # ^(?=PERMITTED_DEVICES)(?:(?!FORBIDDEN_DEVICES)\w)+$
+        # where the list of forbidden and permitted devices are
+        # filtered from the DEVICES setting by the "!" prefix.
+        permit = r"|".join(filter(permitted, devices))
+        forbid = r"|".join(map(normalize, filter(forbidden, devices)))
+        forbid = r"(?!" + forbid + r")" if forbid else ""
+        regexp = r"^(?=" + permit + r")(?:" + forbid + r"\w)+$"
+
+        # Regexp designed to match the permitted devices.
+        if re.match(regexp, device_type):
+            return self.get_response(request)
+
+        # Redirects to the FORBIDDEN_KIT URL if set.
+        if Settings.has("OPTIONS.URL.FORBIDDEN_KIT"):
+            return redirect(Settings.get("OPTIONS.URL.FORBIDDEN_KIT"))
+
+        return HttpResponseForbidden()

src/django_forbid/middleware.py

@@ -1,8 +1,10 @@
 from django.conf import settings
 from django.contrib.gis.geoip2 import GeoIP2
+from django.http import HttpResponseForbidden
+from django.shortcuts import redirect
 from geoip2.errors import AddressNotFoundError
 
-from .config import Settings
+from ..config import Settings
 
 
 class Rule:
@@ -77,27 +79,46 @@ def create_access(cls, action):
         return getattr(cls, action)()
 
 
-def grants_access(request, ip_address):
-    """Checks if the IP address is in the white zone."""
-    try:
-        city = Access.geoip.city(ip_address)
-
-        # Saves the timezone in the session for
-        # comparing it with the timezone in the
-        # POST request sent from user's browser
-        # to detect if the user is using VPN.
-        timezone = city.get("time_zone")
-        request.session["tz"] = timezone
-
-        # Creates an instance of the Access class
-        # and checks if the IP address is granted.
-        action = Settings.get("OPTIONS.ACTION", "FORBID")
-        return Factory.create_access(action).grants(city)
-    except (AddressNotFoundError, Exception):
-        # This happens when the IP address is not
-        # in  the  GeoIP2 database. Usually, this
-        # happens when the IP address is a local.
-        return not any([
-            Settings.has(Access.countries),
-            Settings.has(Access.territories),
-        ]) or getattr(settings, "DEBUG", False)
+class ForbidLocationMiddleware:
+    """Checks if the user location is forbidden."""
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        city = dict()
+        address = request.META.get("REMOTE_ADDR")
+        address = request.META.get("HTTP_X_FORWARDED_FOR", address)
+        ip_address = address.split(",")[0].strip()
+
+        try:
+            city = Access.geoip.city(ip_address)
+
+            # Creates an instance of the Access class
+            # and checks if the IP address is granted.
+            action = Settings.get("OPTIONS.ACTION", "FORBID")
+            granted = Factory.create_access(action).grants(city)
+        except (AddressNotFoundError, Exception):
+            # This happens when the IP address is not
+            # in  the  GeoIP2 database. Usually, this
+            # happens when the IP address is a local.
+            granted = not any([
+                Settings.has(Access.countries),
+                Settings.has(Access.territories),
+            ]) or getattr(settings, "DEBUG", False)
+        finally:
+            # Saves the timezone in the session for
+            # comparing it with the timezone in the
+            # POST request sent from user's browser
+            # to detect if the user is using VPN.
+            timezone = city.get("time_zone", "N/A")
+            request.session["tz"] = timezone
+
+        if granted:
+            return self.get_response(request)
+
+        # Redirects to the FORBIDDEN_LOC URL if set.
+        if Settings.has("OPTIONS.URL.FORBIDDEN_LOC"):
+            return redirect(Settings.get("OPTIONS.URL.FORBIDDEN_LOC"))
+
+        return HttpResponseForbidden()