Add a way to listen on next synchronization #85
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ypy_websocket/websocket_provider.py
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| if self._synced is not None: | ||
| self._synced.set() | ||
| self._synced = None |
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Synchronization is done after a SYNC_STEP2 message is processed.
Also, I don't understand why you set _synced back to None. Shouldn't it be just self.synced.set()? Something like:
| if self._synced is not None: | |
| self._synced.set() | |
| self._synced = None | |
| if message[1] == YSyncMessageType.SYNC_STEP2: | |
| self.synced.set() |
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For my intended use case, either will work, but I figured that to mirror the flexibility of the JS (which IIUC can be triggered on every sync), the semantics should be that the event fire on the next synchronization even if the initial sync has already happened. This way if you wanted to listen for each synchronization in a loop, you could, but it's still a useful interface if you only care about the first sync event.
I'm not committed to this, I would also be fine with the event firing only after the initial synchronization.
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Why would there be multiple synchronizations?
ypy_websocket/websocket_provider.py
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| @property | ||
| def synced(self) -> Event: | ||
| """An async event that is set when the WebSocket provider has initially synced with the server.""" |
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| """An async event that is set when the WebSocket provider has initially synced with the server.""" | |
| """An async event that is set when the WebSocket provider has synchronized with the server.""" |
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Thanks @paulgb, I think this can be useful.
I left some comments.
I wanted a clean way to wait for the initial data to be synchronized down to the client, similar to
y-websocket's.on('sync')(docs), except that to be consistent withstarted(self), it uses ananyio.Eventinstead of a callback function.Calling
await provider.synced.wait()will resolve when the next synchronization message from the server is received and processed.I'm not deep into async Python stuff -- I think this is a reasonable way to do this, but if there's another approach you'd prefer I'd be glad to update the PR.