Split out add_file_headers

synapse/rest/media/v1/_base.py

@@ -70,6 +70,32 @@ def respond_with_file(request, media_type, file_path,
     logger.debug("Responding with %r", file_path)
 
     if os.path.isfile(file_path):
+        if file_size is None:
+            stat = os.stat(file_path)
+            file_size = stat.st_size
+
+        add_file_headers(request, media_type, file_size, upload_name)
+
+        with open(file_path, "rb") as f:
+            yield logcontext.make_deferred_yieldable(
+                FileSender().beginFileTransfer(f, request)
+            )
+
+        finish_request(request)
+    else:
+        respond_404(request)
+
+
+def add_file_headers(request, media_type, file_size, upload_name):
+    """Adds the correct response headers in preparation for responding with the
+    media.
+
+    Args:
+        request (twisted.web.http.Request)
+        media_type (str): The media/content type.
+        file_size (int): Size in bytes of the media, if known.
+        upload_name (str): The name of the requested file, if any.
+    """
     request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
     if upload_name:
         if is_ascii(upload_name):
@@ -95,19 +121,7 @@ def respond_with_file(request, media_type, file_path,
     request.setHeader(
         b"Cache-Control", b"public,max-age=86400,s-maxage=86400"
     )
-        if file_size is None:
-            stat = os.stat(file_path)
-            file_size = stat.st_size
 
     request.setHeader(
         b"Content-Length", b"%d" % (file_size,)
     )
-
-        with open(file_path, "rb") as f:
-            yield logcontext.make_deferred_yieldable(
-                FileSender().beginFileTransfer(f, request)
-            )
-
-        finish_request(request)
-    else:
-        respond_404(request)