hub: move filename resolution to _streamed_log_response

... because it is only used by this function and we can't use file_path
on its own to reconstruct the name of the requested log.

kobo/hub/views.py

@@ -132,7 +132,11 @@ def _trim_log(text):
     return '<...trimmed, download required for full log>' + subtext
 
 
-def _streamed_log_response(file_path, offset, as_attachment):
+def _streamed_log_response(task, log_name, offset, as_attachment):
+    file_path = task.logs._get_absolute_log_path(log_name)
+    if not os.path.isfile(file_path) and not file_path.endswith(".gz"):
+        file_path = task.logs._get_absolute_log_path(log_name + ".gz")
+
     mimetype = mimetypes.guess_type(file_path)[0] or 'application/octet-stream'
 
     try:
@@ -191,16 +195,12 @@ def task_log(request, id, log_name):
 
     task = get_object_or_404(Task, id=id)
 
-    file_path = task.logs._get_absolute_log_path(log_name)
-    if not os.path.isfile(file_path) and not file_path.endswith(".gz"):
-        file_path = task.logs._get_absolute_log_path(log_name + ".gz")
-
     offset = int(request.GET.get("offset", 0))
 
     request_format = request.GET.get("format")
 
     if request_format == "raw" or log_name.endswith(".html") or log_name.endswith(".htm"):
-        return _streamed_log_response(file_path, offset, as_attachment=(request_format == 'raw'))
+        return _streamed_log_response(task, log_name, offset, as_attachment=(request_format == 'raw'))
 
     return _rendered_log_response(request, task, log_name)