Support streaming responses from the storage class

This is needed to fetch content from S3 without needing a full_path

private_storage/models.py

 import mimetypes
-import os
+from django.core.files.storage import Storage, File
 
 from django.utils.functional import cached_property
 
@@ -11,7 +11,7 @@ class PrivateFile(object):
 
     def __init__(self, request, storage, relative_name):
         self.request = request
-        self.storage = storage
+        self.storage = storage  # type: Storage
         self.relative_name = relative_name
 
     @cached_property
@@ -19,13 +19,38 @@ class PrivateFile(object):
         # Not using self.storage.open() as the X-Sendfile needs a normal path.
         return self.storage.path(self.relative_name)
 
+    def open(self, mode='rb'):
+        """
+        Open the file for reading.
+        :rtype: django.core.files.storage.File
+        """
+        file = self.storage.open(self.relative_name, mode=mode)  # type: File
+        return file
+
     def exists(self):
-        return os.path.exists(self.full_path)
+        """
+        Check whether the file exists.
+        """
+        return self.storage.exists(self.relative_name)
 
     @cached_property
     def content_type(self):
         """
         Return the HTTP ``Content-Type`` header value for a filename.
         """
-        mimetype, encoding = mimetypes.guess_type(self.full_path)
+        mimetype, encoding = mimetypes.guess_type(self.relative_name)
         return mimetype or 'application/octet-stream'
+
+    @cached_property
+    def size(self):
+        """
+        Return the size of the file in bytes.
+        """
+        return self.storage.size(self.relative_name)
+
+    @cached_property
+    def modified_time(self):
+        """
+        Return the last-modified time
+        """
+        return self.storage.get_modified_time(self.relative_name)

private_storage/servers.py

@@ -5,7 +5,8 @@ import os
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
-from django.http import HttpResponse
+from django.http import FileResponse, HttpResponse
+from django.utils.http import http_date
 from django.utils.lru_cache import lru_cache
 from django.utils.module_loading import import_string
 from django.views.static import serve
@@ -15,6 +16,8 @@ from django.views.static import serve
 def get_server_class(path):
     if '.' in path:
         return import_string(path)
+    elif path == 'streaming':
+        return DjangoStreamingServer
     elif path == 'django':
         return DjangoServer
     elif path == 'apache':
@@ -27,7 +30,22 @@ def get_server_class(path):
         )
 
 
-class DjangoServer(object):
+class DjangoStreamingServer(object):
+    """
+    Serve static files as streaming chunks in Django.
+    """
+
+    @staticmethod
+    def serve(private_file):
+        # FileResponse will submit the file in 8KB chunks
+        response = FileResponse(private_file.open())
+        response['Content-Type'] = private_file.content_type
+        response['Content-Length'] = private_file.size
+        response["Last-Modified"] = http_date(private_file.modified_time.timestamp())
+        return response
+
+
+class DjangoServer(DjangoStreamingServer):
     """
     Serve static files from the local filesystem through Django.
     This is a bad idea for most situations other than testing.
@@ -38,7 +56,14 @@ class DjangoServer(object):
     @staticmethod
     def serve(private_file):
         # This supports If-Modified-Since and sends the file in 8KB chunks
-        return serve(private_file.request, private_file.full_path, document_root='/', show_indexes=False)
+        try:
+            full_path = private_file.full_path
+        except NotImplementedError:
+            # S3 files, fall back to streaming server
+            return DjangoStreamingServer.serve(private_file)
+        else:
+            # Using Django's serve gives If-Modified-Since support out of the box.
+            return serve(private_file.request, full_path, document_root='/', show_indexes=False)
 
 
 class ApacheXSendfileServer(object):

private_storage/views.py

@@ -85,7 +85,7 @@ class PrivateStorageDetailView(SingleObjectMixin, PrivateStorageView):
 
     def get_path(self):
         file = getattr(self.object, 'file')
-        return file.path
+        return file.name
 
     def can_access_file(self, private_file):
         """

setup.py

@@ -40,7 +40,7 @@ setup(
 
     install_requires=[],
     requires=[
-        'Django (>=1.7)',
+        'Django (>=1.7.4)',
     ],
 
     description='Private media file storage for Django projects',