Refactored generic download views. Added storage argument to DownloadView. Renamed DownloadView's 'file' argument to 'filename'.

demo/demoproject/download/tests.py

@@ -71,7 +71,7 @@ class DownloadViewTestCase(DownloadTestCase):
         """Download_hello_world view returns hello-world.txt as attachement."""
         response = self.client.get(self.download_hello_world_url)
         self.assertEquals(response.status_code, 200)
-        self.assertEquals(response['Content-Type'], 'application/octet-stream')
+        self.assertEquals(response['Content-Type'], 'text/plain')
         self.assertEquals(response['Content-Disposition'],
                           'attachment; filename=hello-world.txt')
         self.assertEqual(open(self.files['hello-world.txt']).read(),
@@ -89,7 +89,7 @@ class ObjectDownloadViewTestCase(DownloadTestCase):
         )
         response = self.client.get(self.download_document_url)
         self.assertEquals(response.status_code, 200)
-        self.assertEquals(response['Content-Type'], 'application/octet-stream')
+        self.assertEquals(response['Content-Type'], 'text/plain')
         self.assertEquals(response['Content-Disposition'],
                           'attachment; filename=hello-world.txt')
         self.assertEqual(open(self.files['hello-world.txt']).read(),

demo/demoproject/download/views.py

@@ -10,7 +10,7 @@ fixtures_dir = join(app_dir, 'fixtures')
 hello_world_file = join(fixtures_dir, 'hello-world.txt')
 
 
-download_hello_world = DownloadView.as_view(file=hello_world_file)
-
+download_hello_world = DownloadView.as_view(filename=hello_world_file,
+                                            storage=None)
 
 download_document = ObjectDownloadView.as_view(model=Document)

django_downloadview/views.py

@@ -1,43 +1,117 @@
+import mimetypes
 import os
 import shutil
 from wsgiref.util import FileWrapper
 
 from django.core.files import File
+from django.core.files.storage import DefaultStorage
 from django.http import HttpResponse
 from django.views.generic.base import View
 from django.views.generic.detail import BaseDetailView
+from django.views.static import was_modified_since
 
 
 class DownloadMixin(object):
-    file = None
     response_class = HttpResponse
 
+    def get_file(self):
+        """Return a django.core.files.File object, which is to be served."""
+        raise NotImplementedError()
+
+    def get_filename(self):
+        """Return absolute filename."""
+        file_obj = self.get_file()
+        return file_obj.name
+
+    def get_file_wrapper(self):
+        """Return a wsgiref.util.FileWrapper instance for the file to serve."""
+        try:
+            return self.file_wrapper
+        except AttributeError:
+            self.file_wrapper = FileWrapper(self.get_file())
+            return self.file_wrapper
+
     def get_mime_type(self):
-        """Return mime-type of self.file."""
-        return 'application/octet-stream'
+        """Return mime-type."""
+        try:
+            return self.mime_type
+        except AttributeError:
+            filename = self.get_filename()
+            self.mime_type, self.encoding = mimetypes.guess_type(filename)
+            if not self.mime_type:
+                self.mime_type = 'application/octet-stream'
+            return self.mime_type
+
+    def get_encoding(self):
+        """Return encoding of self.file."""
+        try:
+            return self.encoding
+        except AttributeError:
+            filename = self.get_filename()
+            self.mime_type, self.encoding = mimetypes.guess_type(filename)
+            return self.encoding
+
+    def get_modification_time(self):
+        """Return last modification time of self.file."""
+        try:
+            return self.modification_time
+        except AttributeError:
+            self.stat = os.stat(self.get_filename())
+            self.modification_time = self.stat.st_mtime
+            return self.modification_time
+
+    def get_size(self):
+        """Return the size (in bytes) of the file to serve."""
+        try:
+            return self.size
+        except AttributeError:
+            try:
+                self.size = self.stat.st_size
+            except AttributeError:              
+                self.size = os.path.getsize(self.get_filename())
+            return self.size
 
     def render_to_response(self, **response_kwargs):
         """Returns a response with a file as attachment."""
         mime_type = self.get_mime_type()
-        if isinstance(self.file, File):
-            absolute_filename = self.file.path
-            wrapper = FileWrapper(self.file.file)
-            size = self.file.size
-        else:
-            absolute_filename = os.path.abspath(self.file)
-            wrapper = FileWrapper(file(absolute_filename))
-            size = os.path.getsize(absolute_filename)
-        basename = os.path.basename(absolute_filename)
+        modification_time = self.get_modification_time()
+        size = self.get_size()
+        # Respect the If-Modified-Since header.
+        if_modified_since = self.request.META.get('HTTP_IF_MODIFIED_SINCE', None)
+        if not was_modified_since(if_modified_since, modification_time, size):
+            return HttpResponseNotModified(mimetype=mime_type)
+        # Stream the file.
+        filename = self.get_filename()
+        basename = os.path.basename(filename)
+        encoding = self.get_encoding()
+        wrapper = self.get_file_wrapper()
         response = self.response_class(wrapper, content_type=mime_type,
                                        mimetype=mime_type)
         response['Content-Length'] = size
-        # Do not call fsock.close() as  HttpResponse needs it open
-        # Garbage collector will close it
+        # Do not call fsock.close() as HttpResponse needs it open.
+        # Garbage collector will close it.
         response['Content-Disposition'] = 'attachment; filename=%s' % basename
         return response
 
 
 class DownloadView(DownloadMixin, View):
+    filename = None
+    storage = DefaultStorage()
+
+    def get_file(self):
+        """Return a file object for the file to serve."""
+        try:
+            return self._file
+        except AttributeError:
+            try:
+                if self.storage:
+                    self._file = self.storage.open(self.filename)
+                else:
+                    self._file = File(open(self.filename))
+                return self._file
+            except IOError:
+                raise Http404
+
     def get(self, request, *args, **kwargs):
         return self.render_to_response()
 
@@ -45,7 +119,19 @@ class DownloadView(DownloadMixin, View):
 class ObjectDownloadView(DownloadMixin, BaseDetailView):
     file_field = 'file'
 
-    def get(self, request, *args, **kwargs):
+    def get_fieldfile(self):
         self.object = self.get_object()
-        self.file = getattr(self.object, self.file_field)
+        try:
+            return self.fieldfile
+        except AttributeError:
+            self.fieldfile = getattr(self.object, self.file_field)
+            return self.fieldfile
+
+    def get_file(self):
+        return self.get_fieldfile().file
+
+    def get_size(self):
+        return self.get_fieldfile().size
+
+    def get(self, request, *args, **kwargs):
         return self.render_to_response()