Tethys Async Websocket Consumer with Permission Checks #1012
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…mentation also stubbed out other custom methods just in case they are needed in the future
not uses the decorator for permissions added additional args for login_required and permissions_use_or
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I updated this PR after reviewing some feedback. The main thing was keeping user experience consistent with regards to decorators. Users can now use the new capabilities just like a controller by supplying arguments in the decorator. An example is below:
The methods for connecting and disconnecting have now been separated according to user authorization. So there is now a "authorized_connect", "unauthorized_connect", "authorized_disconnect", and "unauthorized_disconnect" so that developers can handle whatever use case they experience. For the backend, the solution was using a mixin and dynamically adding new methods from the mixin to the decorated class. This works for both async and sync websockets as well. |
tethys_apps/utilities.py
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| """ | ||
| base_class_name = inspect.getmro(function_or_class)[1].__name__.lower() | ||
| function_or_class_name = function_or_class.__name__.lower() | ||
| if "async" in function_or_class_name or "async" in base_class_name: |
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While it is not very likely to be a problem, there is a small chance that checking for "async" in the function_or_class_name could be miss-leading. Suppose someone were to create a function called: do_something_in_a_non_async_way that was not an async function?
I think it might be safer to just check all of the base classes:
async_base_classes = [cls for cls in inspect.getmro(function_or_class)[1:]. if "async" in cls.__name__.lower()]
if async_base_classes:
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I suppose this approach isn't foolproof either. Someone could do something like:
from channels.consumer import SyncConsumer, AsyncConsumer
class AnAsyncConsumer(AsyncConsumer):
pass
class ASyncConsumer(SyncConsumer):
passYou never know! 🤷
According to the Tethys Docs:
The consumer decorator functions largely the same way as the controller decorator except that it is used to decorate a consumer class, which must be a subclass of either channels.consumer.AsyncConsumer or channels.consumer.SyncConsumer
I'm hoping that I was smarter when I wrote that than I am now. If it is indeed true that a consumer class must be a subclass of channels.consumer.AsyncConsumer then:
if issubclass(function_or_class, channels.consumer.AsyncConsumer):
consumer_mixin = TethysAsyncWebsocketConsumerMixinThere was a problem hiding this comment.
Thanks Scott. Those are valid points. I like the final proposed solution. Simple and clean for sure.
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Although, maybe that won't work. I just looked at my implementation and I am using the
AsyncWebsocketConsumer class from channels.generic.websocket. That is also what is suggested in the tutorials for the websockets.
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The AsyncWebsocketConsumer is a subclass of AsyncConsumer. I think the issubclass will look at the whole parent chain, but I'm not sure.
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from channels.generic.websocket import AsyncWebsocketConsumer
class MyConsumer(AsyncWebsocketConsumer):
groups = ["broadcast"]
from channels.consumer import AsyncConsumer
issubclass(MyConsumer, AsyncConsumer)
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just implemented this. I had to do it the opposite way and checked if it is a subclass of SyncConsumer because the WebsocketConsumer and AsyncWebsocketConsumer are both subclasses of AsyncConsumer apparently.
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@swainn It looks like the Docker build is failing because the |
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I think we decided that the docker build won't work because this is being merged from a fork. Once other checks pass then I approve merging. |
This PR is to resolve issue #1009.
The newly created TethysAsyncWebsocketConsumer class will replace the AsyncWebsocketConsumer class. The new TethysAsyncWebsocketConsumer class has the following capabilities:
The websocket tutorial docs have been updated as well to show the new capabilities.