Rapildy moving figure betwen pads leads to TypeError

[Dave247]

In the process of testing reproductions for another bug I discovered this one. If you rapidly move a figure from one pad to another and back again it will lead to the following error in the terminal. Resyncing is required to fix it otherwise it will stay bugged with the same message.

I suppose as this isn't typical behaviour (rapidly switching figures) this might not be considered a bug in the traditional sense. but it's not really ideal either.

<<Syncing tags, one moment...>>
Initialized toytags.JSON
<<Tags are synced!>>
Placing tag: 1
Character tag: 1
Planning to set UID: 0409BB7F57DE80 to index 2
Set UID: 0409BB7F57DE80 to index 2
EVENT: Event { pad: 1, index: 2, dir: 0, uid: '0409BB7F57DE80' }
Removing item: 2
Item removed: 2
Planning to set UID: 0409BB7F57DE80 to index -1
Set UID: 0409BB7F57DE80 to index -1
EVENT: Event { pad: 1, index: 2, dir: 1, uid: '0409BB7F57DE80' }
Removing item: 5
TypeError: Cannot read properties of undefined (reading 'pad')
    at new Event (/app/node_modules/node-ld/dist/lib/Event.js:23:19)
    at ToyPadEmu.tagRemoveEvent (/app/node_modules/node-ld/dist/lib/ToyPadEmu.js:133:13)
    at ToyPadEmu.remove (/app/node_modules/node-ld/dist/lib/ToyPadEmu.js:121:9)
    at /app/index.js:622:6
    at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
    at next (/app/node_modules/express/lib/router/route.js:149:13)
    at Route.dispatch (/app/node_modules/express/lib/router/route.js:119:3)
    at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
    at /app/node_modules/express/lib/router/index.js:284:15
    at Function.process_params (/app/node_modules/express/lib/router/index.js:346:12)
Placing tag: 1
Character tag: 1
Planning to set UID: 0409BB7F57DE80 to index 5
Set UID: 0409BB7F57DE80 to index 5
EVENT: Event { pad: 2, index: 5, dir: 0, uid: '0409BB7F57DE80' }
Removing item: 2
TypeError: Cannot read properties of undefined (reading 'pad')
    at new Event (/app/node_modules/node-ld/dist/lib/Event.js:23:19)
    at ToyPadEmu.tagRemoveEvent (/app/node_modules/node-ld/dist/lib/ToyPadEmu.js:133:13)
    at ToyPadEmu.remove (/app/node_modules/node-ld/dist/lib/ToyPadEmu.js:121:9)
    at /app/index.js:622:6
    at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
    at next (/app/node_modules/express/lib/router/route.js:149:13)
    at Route.dispatch (/app/node_modules/express/lib/router/route.js:119:3)
    at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
    at /app/node_modules/express/lib/router/index.js:284:15
    at Function.process_params (/app/node_modules/express/lib/router/index.js:346:12)
<<Syncing tags, one moment...>>
Initialized toytags.JSON
<<Tags are synced!>>
Placing tag: 1
Character tag: 1
Planning to set UID: 0409BB7F57DE80 to index 2
Set UID: 0409BB7F57DE80 to index 2
EVENT: Event { pad: 1, index: 2, dir: 0, uid: '0409BB7F57DE80' }
Removing item: 2
Item removed: 2
Planning to set UID: 0409BB7F57DE80 to index -1
Set UID: 0409BB7F57DE80 to index -1
EVENT: Event { pad: 1, index: 2, dir: 1, uid: '0409BB7F57DE80' }
Removing item: 5
TypeError: Cannot read properties of undefined (reading 'pad')
    at new Event (/app/node_modules/node-ld/dist/lib/Event.js:23:19)
    at ToyPadEmu.tagRemoveEvent (/app/node_modules/node-ld/dist/lib/ToyPadEmu.js:133:13)
    at ToyPadEmu.remove (/app/node_modules/node-ld/dist/lib/ToyPadEmu.js:121:9)
    at /app/index.js:622:6
    at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
    at next (/app/node_modules/express/lib/router/route.js:149:13)
    at Route.dispatch (/app/node_modules/express/lib/router/route.js:119:3)
    at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
    at /app/node_modules/express/lib/router/index.js:284:15
    at Function.process_params (/app/node_modules/express/lib/router/index.js:346:12)
Placing tag: 1
Character tag: 1
Planning to set UID: 0409BB7F57DE80 to index 5
Set UID: 0409BB7F57DE80 to index 5
EVENT: Event { pad: 2, index: 5, dir: 0, uid: '0409BB7F57DE80' }

[Tivertoni]

Haven‘t looked into this yet, I think the bottleneck might be that we read and write to disk everytime, I think we should keep the state in memory and store snapshots of it to disk every set interval.
Also some changes we should consider that would also generally improve performance:

We should create a request queue on the client side, it would allow us to specify the interval between requests.

We should update the state on the Ui even if the request wasn‘t send yet and just revert it when the backend doesn’t confirm the changes.

We should not always reload the page on some changes.

These changes could eliminate the problems your describing.

[Tivertoni]

I will look into this when I get home.

[aurarius1]

I guess the part of moving in the frontend and reverting back if the api fails is something I am already doing in my frontend rewrite, though I don't know if it is sufficient.

If @Berny23 is okay with it I would create a draft pull request today evening with the updated frontend, an updated README (hinting about storage recommendations and updated for the use of the prebuilt images) and (maybe cannot promise this yet) a more space optimized dockerfile (which should result in a smaller end image). Then you guys could be the judge of if it makes sense or not, do follow this route.