diff --git a/django_downloadview/middlewares.py b/django_downloadview/middlewares.py
index d0c2cbb..31b983f 100644
--- a/django_downloadview/middlewares.py
+++ b/django_downloadview/middlewares.py
@@ -16,6 +16,7 @@ class BaseDownloadMiddleware(object):
         """Call ``process_download_response()`` if ``response`` is download."""
         if self.is_download_response(response):
             return self.process_download_response(request, response)
+        return response
 
     def process_download_response(self, request, response):
         """Handle file download response."""
diff --git a/django_downloadview/nginx.py b/django_downloadview/nginx.py
index 2c8035b..8f69011 100644
--- a/django_downloadview/nginx.py
+++ b/django_downloadview/nginx.py
@@ -15,15 +15,22 @@ from django_downloadview.utils import content_type_to_charset
 
 
 #: Default value for X-Accel-Buffering header.
-DEFAULT_BUFFERING = None
-if not hasattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_BUFFERING'):
-    setattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_BUFFERING', DEFAULT_BUFFERING)
+DEFAULT_WITH_BUFFERING = None
+if not hasattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_WITH_BUFFERING'):
+    setattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_WITH_BUFFERING',
+            DEFAULT_WITH_BUFFERING)
 
 
 #: Default value for X-Accel-Limit-Rate header.
 DEFAULT_LIMIT_RATE = None
 if not hasattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_LIMIT_RATE'):
-    setattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_LIMIT', DEFAULT_LIMIT_RATE)
+    setattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_LIMIT_RATE', DEFAULT_LIMIT_RATE)
+
+
+#: Default value for X-Accel-Limit-Rate header.
+DEFAULT_EXPIRES = None
+if not hasattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_EXPIRES'):
+    setattr(settings, 'NGINX_DOWNLOAD_MIDDLEWARE_EXPIRES', DEFAULT_EXPIRES)
 
 
 class XAccelRedirectResponse(HttpResponse):
@@ -84,7 +91,7 @@ class BaseXAccelRedirectMiddleware(BaseDownloadMiddleware):
                                       limit_rate=self.limit_rate)
 
 
-class XAccelRedirectMiddleware():
+class XAccelRedirectMiddleware(BaseXAccelRedirectMiddleware):
     """Apply X-Accel-Redirect globally.
 
     XAccelRedirectResponseHandler with django settings.
diff --git a/docs/api/django_downloadview.txt b/docs/api/django_downloadview.txt
index cc5f612..c790b25 100644
--- a/docs/api/django_downloadview.txt
+++ b/docs/api/django_downloadview.txt
@@ -17,14 +17,6 @@ django_downloadview Package
     :undoc-members:
     :show-inheritance:
 
-:mod:`file` Module
-------------------
-
-.. automodule:: django_downloadview.file
-    :members:
-    :undoc-members:
-    :show-inheritance:
-
 :mod:`middlewares` Module
 -------------------------
 
diff --git a/docs/nginx.txt b/docs/nginx.txt
index 4b11147..6020f60 100644
--- a/docs/nginx.txt
+++ b/docs/nginx.txt
@@ -109,6 +109,131 @@ In some urls.py:
    # ... URL patterns using ``download`` 
 
 
+********************
+Sample configuration
+********************
+
+In this sample configuration...
+
+* we register files in some "myapp.models.Document" model
+* store files in :file:`/var/www/private/` folder
+* publish files at ``/download/<pk>/`` URL
+* restrict access to authenticated users with the ``login_required`` decorator
+* delegate file download to Nginx, via ``/private/`` internal URL.
+
+Nginx
+=====
+
+:file:`/etc/nginx/sites-available/default`:
+
+.. code-block:: nginx
+
+   charset utf-8;
+
+   # Django-powered service.
+   upstream frontend {
+       server 127.0.0.1:8000 fail_timeout=0;
+   }
+
+   server {
+       listen 80 default;
+
+       # File-download proxy.
+       # See http://wiki.nginx.org/X-accel
+       # and https://github.com/benoitbryon/django-downloadview
+       location /private/ {
+           internal;
+           # Location to files on disk.
+           # See Django's settings.NGINX_DOWNLOAD_MIDDLEWARE_MEDIA_ROOT
+           alias /var/www/private/;
+       }
+
+       # Proxy to Django-powered frontend.
+       location / {
+           proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+           proxy_set_header Host $http_host;
+           proxy_redirect off;
+           proxy_pass http://frontend;
+       }
+   }
+
+Django settings
+===============
+
+:file:`settings.py`:
+
+.. code-block:: python
+
+   MYAPP_STORAGE_LOCATION = '/var/www/private/'
+   NGINX_DOWNLOAD_MIDDLEWARE_MEDIA_ROOT = MYAPP_STORAGE_LOCATION
+   MIDDLEWARE_CLASSES = (
+       # ...
+       'django_downloadview.nginx.XAccelRedirectMiddleware',
+       # ...
+   ) 
+   INSTALLED_APPS = (
+       # ...
+       'myapp',
+       # ...
+   )
+
+In some model
+=============
+
+:file:`myapp/models.py`:
+
+.. code-block:: python
+
+   from django.conf import settings
+   from django.db import models
+   from django.core.files.storage import FileSystemStorage
+
+
+   storage = FileSystemStorage(location=settings.MYAPP_STORAGE_LOCATION)
+
+
+   class Document(models.Model):
+       file = models.ImageField(storage=storage)
+
+URL patterns
+============
+
+:file:`myapp/urls.py`:
+
+.. code-block:: python
+
+   from django.conf.urls import url, url_patterns
+   from django.contrib.auth.decorators import login_required
+
+   from django_downloadview import ObjectDownloadView
+
+   from myapp.models import Document
+
+
+   download = login_required(ObjectDownloadView.as_view(model=Document))
+
+   url_patterns = ('',
+       url('^download/(?P<pk>[0-9]+/$', download, name='download'),
+   )
+
+
+*************
+Common issues
+*************
+
+``Unknown charset "utf-8" to override``
+=======================================
+
+Add ``charset utf-8;`` in your nginx configuration file.
+
+``open() "path/to/something" failed (2: No such file or directory)``
+====================================================================
+
+Check your ``settings.NGINX_DOWNLOAD_MIDDLEWARE_MEDIA_ROOT`` in Django
+configuration VS ``alias`` in nginx configuration: in a standard configuration,
+they should be equal.
+
+
 **********
 References
 **********