Multi-threaded development

[Shark-with-Blue-Shoes]

I'm currently developing a plugin that allows for concurrent editing of CAD databases between multiple users. The current component I'm working on listens to events (object modified, object appended) and sends those logs to a server.

My first approach was to just send the proper log synchronously once the event was triggered. However, it would look like this.

1. User Action (Create Yellow Line)
2. Events Triggered (about 6)
3. Send Logs to server through http (takes a couple seconds as it is a highly unoptimized prototype)
4. Line renders (very delayed due to the main thread being too busy sending logs)

My second approach was to use a background process that sent the logs using http. It looked something like this

1. User Action (Create Yellow Line)
2. Events Triggered
3. Logs added to a queue.Queue()
4. Line renders and background process takes elements from queue one at a time and sends it to the server

This removed rendering delay on the user end! However, sending the logs synchronously was really slow. Using httpx, async, or a WebSocket also crashed the background process.

Instead of waiting for each http request to finish one at a time, I'll bunch the 6 http requests into 1!

So, I'll take each JSON log {"event_type": log.event_type, "object_id": log.object_id}
And append it to a list!

[
{"event_type": log.event_type, "object_id": log.object_id},
{"event_type": log.event_type, "object_id": log.object_id},
{"event_type": log.event_type, "object_id": log.object_id}
]

Which will be sent to the server.

However, it seems that the list data type is giving me some issues that may have to do with it's lack of thread safety. I'm not sure what the exact issue is, so I'd appreciate better documentation on how to debug. I will be opening an issue.

I also noticed that @CEXT-Dan's samples that concern multithreading did not include the list data type. I think that if possible, creating a sample that uses the list data type would be a great reference.

[CEXT-Dan]

1, Please check that this is not a violation of the AutoCAD EULA, pretty sure it is, my answers may be limited as not to put my ADN membership at risk

Hypothetically, you could have a long running thread that handles the network traffic. This thread adds commands to a queue.
Use the OnIdle event to query the queue and run the items inside beginExecuteInCommandContext.

I think this approach could potentially have a lot of flaws, especially when it comes to undo, erase, etc.
For a multiuser environment, I might setup a GIT repository, have everyone work in xrefs, poll for changes and send notifications to update.

2, there’s a sample for debugging, testPyRxDebug.py and some notes here https://www.theswamp.org/index.php?topic=58821
Debugging works really good, though I have not tested stepping through threads.

[Shark-with-Blue-Shoes]

I contacted support and they are going to let me know whether it would infringe on the EULA in 24-48 hours.

I was able to figure out how to bunch up the logs, though now that you mentioned xrefs and git, I think that is a better approach.

[CEXT-Dan]

2025 has the drawing compare tool where its possible to merge or import drawings.
https://help.autodesk.com/view/ACD/2025/ENU/?guid=GUID-2D69E78D-5C82-464F-B864-CD29D5720EB9

I don’t see anything in the API yet, but a cool idea is to have an event somehow hooked up to a git repository that automatically merges DWG files.

[Shark-with-Blue-Shoes]

Actually, I think a much simpler approach would be to use Windows's native network shared drive functionality that'll allow users to directly collaborate P2P. Windows will automatically prevent 2 users from editing the same file, but at the same time allow them to xref the files that are being edited. When one user makes a change, it is automatically saved, and all I have to do is reload the relevant xrefs in each session!