cuts: don't crash when retrieving header of a non-existent response

2 files changed, 7 insertions, 0 deletions

diff --git a/mitmproxy/addons/cut.py b/mitmproxy/addons/cut.py
index b90df549..f4b560e8 100644
--- a/mitmproxy/addons/cut.py
+++ b/mitmproxy/addons/cut.py
@@ -36,6 +36,8 @@ def extract(cut: str, f: flow.Flow) -> typing.Union[str, bytes]:
             if spec == "host" and is_addr(current):
                 return str(current[0])
             elif spec.startswith("header["):
+                if not current:
+                    return ""
                 return current.headers.get(headername(spec), "")
             elif isinstance(part, bytes):
                 return part
diff --git a/test/mitmproxy/addons/test_cut.py b/test/mitmproxy/addons/test_cut.py
index 0a523fff..71e699db 100644
--- a/test/mitmproxy/addons/test_cut.py
+++ b/test/mitmproxy/addons/test_cut.py
@@ -135,6 +135,11 @@ def test_cut():
         with pytest.raises(exceptions.CommandError):
             assert c.cut(tflows, ["__dict__"]) == [[""]]
 
+    with taddons.context():
+        tflows = [tflow.tflow(resp=False)]
+        assert c.cut(tflows, ["response.reason"]) == [[""]]
+        assert c.cut(tflows, ["response.header[key]"]) == [[""]]
+
     c = cut.Cut()
     with taddons.context():
         tflows = [tflow.ttcpflow()]