From d505e79be82acb24a87e6bab080a5e06c93017e7 Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Sat, 4 Apr 2020 23:29:05 +1100
Subject: [PATCH] Allow token-based access to /media/ and /static/

- The InvenTree app needs to access the images, but currently token auth only works for the /api/ endpoint
- The app cannot use csrf tokens!
- So, borrow the tokens which are already created per-user in the DRF framework
- If a user is not authed, then check for a token!
- See InvenTree/middleware.py for further documentation
---
 InvenTree/InvenTree/middleware.py | 49 +++++++++++++++++++++++++++++--
 InvenTree/InvenTree/urls.py       |  5 ++--
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/InvenTree/InvenTree/middleware.py b/InvenTree/InvenTree/middleware.py
index d6d40e85b6..1f8fcf7830 100644
--- a/InvenTree/InvenTree/middleware.py
+++ b/InvenTree/InvenTree/middleware.py
@@ -5,6 +5,8 @@ import logging
 import time
 import operator
 
+from rest_framework.authtoken.models import Token
+
 logger = logging.getLogger(__name__)
 
 
@@ -20,10 +22,49 @@ class AuthRequiredMiddleware(object):
 
         response = self.get_response(request)
 
-        # Redirect any unauthorized HTTP requests to the login page
         if not request.user.is_authenticated:
-            if not request.path_info == reverse_lazy('login') and not request.path_info.startswith('/api/'):
-                return HttpResponseRedirect(reverse_lazy('login'))
+            """
+            Normally, a web-based session would use csrftoken based authentication.
+            However when running an external application (e.g. the InvenTree app),
+            we wish to use token-based auth to grab media files.
+
+            So, we will allow token-based authentication but ONLY for the /media/ directory.
+
+            What problem is this solving?
+            - The InvenTree mobile app does not use csrf token auth
+            - Token auth is used by the Django REST framework, but that is under the /api/ endpoint
+            - Media files (e.g. Part images) are required to be served to the app
+            - We do not want to make /media/ files accessible without login!
+
+            There is PROBABLY a better way of going about this?
+            a) Allow token-based authentication against a user?
+            b) Serve /media/ files in a duplicate location e.g. /api/media/ ?
+            c) Is there a "standard" way of solving this problem?
+
+            My [google|stackoverflow]-fu has failed me. So this hack has been created.
+            """
+
+            authorized = False
+
+            if 'Authorization' in request.headers.keys():
+                auth = request.headers['Authorization'].strip()
+
+                if auth.startswith('Token') and len(auth.split()) == 2:
+                    token = auth.split()[1]
+
+                    # Does the provided token match a valid user?
+                    if Token.objects.filter(key=token).exists():
+
+                        allowed = ['/media/', '/static/']
+
+                        # Only allow token-auth for /media/ or /static/ dirs!
+                        if any([request.path_info.startswith(a) for a in allowed]):
+                            authorized = True
+
+            # No authorization was found for the request
+            if not authorized:
+                if not request.path_info == reverse_lazy('login') and not request.path_info == '/api/':
+                    return HttpResponseRedirect(reverse_lazy('login'))
 
         # Code to be executed for each request/response after
         # the view is called.
@@ -38,6 +79,8 @@ class QueryCountMiddleware(object):
     status code of 200). It does not currently support
     multi-db setups.
 
+    To enable this middleware, set 'log_queries: True' in the local InvenTree config file.
+
     Reference: https://www.dabapps.com/blog/logging-sql-queries-django-13/
     """
 
diff --git a/InvenTree/InvenTree/urls.py b/InvenTree/InvenTree/urls.py
index 4b18916828..fd36fa9112 100644
--- a/InvenTree/InvenTree/urls.py
+++ b/InvenTree/InvenTree/urls.py
@@ -109,9 +109,8 @@ urlpatterns = [
 # Static file access
 urlpatterns += static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
 
-if settings.DEBUG:
-    # Media file access
-    urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)
+# Media file access
+urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)
 
 # Send any unknown URLs to the parts page
 urlpatterns += [url(r'^.*$', RedirectView.as_view(url='/index/', permanent=False), name='index')]