Session.custom property AttributeError: 'com.inductiveautomation.perspective.gateway.script' object has no attribute

Ignition
,
1

I have this code in a view on the onStartUp action.

data = self.session.custom.rooms_data
if not data:
	self.session.custom.rooms_data = (
		perspective.get_rooms()
	)

For some reason I get this error:

Error running action 'system.onStartup' on pages/page@C: Traceback (most recent call last): File "<function:runAction>", line 2, in runAction AttributeError: 'com.inductiveautomation.perspective.gateway.script' object has no attribute 'rooms_data'
Full Error 
com.inductiveautomation.ignition.common.script.JythonExecException: Traceback (most recent call last): File "", line 2, in runAction AttributeError: 'com.inductiveautomation.perspective.gateway.script' object has no attribute 'rooms_data'
at org.python.core.Py.AttributeError(Py.java:176)
at org.python.core.PyObject.noAttributeError(PyObject.java:965)
at org.python.core.PyObject.__getattr__(PyObject.java:959)
at org.python.pycode._pyx11386.runAction$1(:3)
at org.python.pycode._pyx11386.call_function()
at org.python.core.PyTableCode.call(PyTableCode.java:173)
at org.python.core.PyBaseCode.call(PyBaseCode.java:306)
at org.python.core.PyFunction.function___call__(PyFunction.java:474)
at org.python.core.PyFunction.__call__(PyFunction.java:469)
at org.python.core.PyFunction.__call__(PyFunction.java:464)
at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:847)
at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:829)
at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle$TrackingProjectScriptManager.runFunction(ProjectScriptLifecycle.java:868)
at com.inductiveautomation.ignition.common.script.ScriptManager$ScriptFunctionImpl.invoke(ScriptManager.java:1010)
at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle$AutoRecompilingScriptFunction.invoke(ProjectScriptLifecycle.java:950)
at com.inductiveautomation.perspective.gateway.script.ScriptFunctionHelper.invoke(ScriptFunctionHelper.java:161)
at com.inductiveautomation.perspective.gateway.script.ScriptFunctionHelper.invoke(ScriptFunctionHelper.java:98)
at com.inductiveautomation.perspective.gateway.action.ScriptAction.runAction(ScriptAction.java:80)
at com.inductiveautomation.perspective.gateway.action.ActionDecorator.runAction(ActionDecorator.java:18)
at com.inductiveautomation.perspective.gateway.action.SecuredAction.runAction(SecuredAction.java:44)
at com.inductiveautomation.perspective.gateway.model.ActionCollection$ActionSequence$ExecuteActionsTask.lambda$call$0(ActionCollection.java:263)
at com.inductiveautomation.perspective.gateway.api.LoggingContext.mdc(LoggingContext.java:54)
at com.inductiveautomation.perspective.gateway.model.ActionCollection$ActionSequence$ExecuteActionsTask.call(ActionCollection.java:252)
at com.inductiveautomation.perspective.gateway.model.ActionCollection$ActionSequence$ExecuteActionsTask.call(ActionCollection.java:221)
at com.inductiveautomation.perspective.gateway.threading.BlockingTaskQueue$TaskWrapper.run(BlockingTaskQueue.java:154)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at com.inductiveautomation.perspective.gateway.threading.BlockingWork$BlockingWorkRunnable.run(BlockingWork.java:58)
at java.base/java.lang.Thread.run(Unknown Source)
Caused by: org.python.core.PyException: AttributeError: 'com.inductiveautomation.perspective.gateway.script' object has no attribute 'rooms_data'
... 31 common frames omitted

I'm missing something. Someone knows what it could be?

Thx in advance!

2

What is surprising? rooms_data won't exist until something assigns to it. Use if not hasattr(self.session.custom, 'rooms_data'): as your condition.

3

I thought that when you declare a custom session property even if is set to null it will "exists". I'll change the code.
I suppose that If I have a default value (as persistent) then it will work as I now have.

Thx pturmel!

4

In that case, you will never call perspective.get_rooms(). :man_shrugging: