Add middleware for range request

backend/api/middleware.py

@@ -0,0 +1,35 @@
+import os
+
+from django.utils.deprecation import MiddlewareMixin
+
+
+class RangesMiddleware(MiddlewareMixin):
+    """Quick solution. See:
+    https://stackoverflow.com/questions/14324250/byte-ranges-in-django/35928017#35928017
+    """
+
+    def process_response(self, request, response):
+        if response.status_code != 200 or not hasattr(response, 'file_to_stream'):
+            return response
+        http_range = request.META.get('HTTP_RANGE')
+        if not (http_range and http_range.startswith('bytes=') and http_range.count('-') == 1):
+            return response
+        if_range = request.META.get('HTTP_IF_RANGE')
+        if if_range and if_range != response.get('Last-Modified') and if_range != response.get('ETag'):
+            return response
+        f = response.file_to_stream
+        statobj = os.fstat(f.fileno())
+        start, end = http_range.split('=')[1].split('-')
+        if not start:  # requesting the last N bytes
+            start = max(0, statobj.st_size - int(end))
+            end = ''
+        start, end = int(start or 0), int(end or statobj.st_size - 1)
+        assert 0 <= start < statobj.st_size, (start, statobj.st_size)
+        end = min(end, statobj.st_size - 1)
+        f.seek(start)
+        old_read = f.read
+        f.read = lambda n: old_read(min(n, end + 1 - f.tell()))
+        response.status_code = 206
+        response['Content-Length'] = end + 1 - start
+        response['Content-Range'] = 'bytes %d-%d/%d' % (start, end, statobj.st_size)
+        return response

backend/app/settings.py

@@ -88,6 +88,9 @@ MIDDLEWARE = [
     'corsheaders.middleware.CorsMiddleware',
 ]
 
+if DEBUG:
+    MIDDLEWARE.append('api.middleware.RangesMiddleware')
+
 ROOT_URLCONF = 'app.urls'
 
 TEMPLATES = [