--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/patchsink.py	Fri Nov 25 20:58:08 2022 -0800
@@ -0,0 +1,43 @@
+import time
+from typing import Dict
+
+import cyclone.sse
+import cyclone.web
+
+class PatchSink(cyclone.sse.SSEHandler):
+    _handlerSerial = 0
+
+    def __init__(self, application: cyclone.web.Application, request):
+        cyclone.sse.SSEHandler.__init__(self, application, request)
+        self.bound = False
+        self.created = time.time()
+        self.graphClients = self.settings.graphClients
+
+        self._serial = PatchSink._handlerSerial
+        PatchSink._handlerSerial += 1
+        self.lastPatchSentTime: float = 0.0
+
+    def __repr__(self) -> str:
+        return '<Handler #%s>' % self._serial
+
+    def state(self) -> Dict:
+        return {
+            'created': round(self.created, 2),
+            'ageHours': round((time.time() - self.created) / 3600, 2),
+            'streamId': self.streamId,
+            'remoteIp': self.request.remote_ip,  # wrong, need some forwarded-for thing
+            'foafAgent': self.request.headers.get('X-Foaf-Agent'),
+            'userAgent': self.request.headers.get('user-agent'),
+        }
+
+    def bind(self, *args, **kwargs):
+        self.streamId = args[0]
+
+        self.graphClients.addSseHandler(self)
+        # If something goes wrong with addSseHandler, I don't want to
+        # try removeSseHandler.
+        self.bound = True
+
+    def unbind(self) -> None:
+        if self.bound:
+            self.graphClients.removeSseHandler(self)