Define UnknownFrameReceived event

Author: Lukasa

docs/source/api.rst

@@ -77,6 +77,9 @@ Events
 .. autoclass:: h2.events.AlternativeServiceAvailable
    :members:
 
+.. autoclass:: h2.events.UnknownFrameReceived
+   :members:
+
 
 Exceptions
 ----------

h2/events.py

@@ -574,6 +574,28 @@ def __repr__(self):
         )
 
 
+class UnknownFrameReceived(Event):
+    """
+    The UnknownFrameReceived event is fired when the remote peer sends a frame
+    that hyper-h2 does not understand. This occurs primarily when the remote
+    peer is employing HTTP/2 extensions that hyper-h2 doesn't know anything
+    about.
+
+    RFC 7540 requires that HTTP/2 implementations ignore these frames. hyper-h2
+    does so. However, this event is fired to allow implementations to perform
+    special processing on those frames if needed (e.g. if the implementation
+    is capable of handling the frame itself).
+
+    .. versionadded:: 2.7.0
+    """
+    def __init__(self):
+        #: The hyperframe Frame object that encapsulates the received frame.
+        self.frame = None
+
+    def __repr__(self):
+        return "<UnknownFrameReceived>"
+
+
 def _bytes_representation(data):
     """
     Converts a bytestring into something that is safe to print on all Python

test/test_events.py

@@ -323,6 +323,13 @@ def test_alternativeserviceavailable_repr(self):
             'field_value:h2=":8000"; ma=60>'
         )
 
+    def test_unknownframereceived_repr(self):
+        """
+        UnknownFrameReceived has a useful debug representation.
+        """
+        e = h2.events.UnknownFrameReceived()
+        assert repr(e) == '<UnknownFrameReceived>'
+
 
 def all_events():
     """