Calling a function via button but also when saving .blend

Coding Python Support
1

Beginner here.
I have a function which is called by an operator which is connected to a UI button.

def actuallyDoIt(caller):
    caller.report({'INFO'}, 'Button clicked.')

class DoThatStuff(bpy.types.Operator):
    bl_idname = 'mything.dothatstuff'
    bl_label = 'Click this'
    def execute(self, context): 
        actuallyDoIt(self)
        return {'FINISHED'}

At least Google taught me that that’s how it’s done. It might be completely wrong.
Next I want to make it so that this function is also called when saving the .blend, so I registered it as follows:

bpy.app.handlers.save_pre.append(actuallyDoIt)

But obviously when the function is not called by the operator, it doesn’t know what the caller is, and instead of it executing the caller.report I am getting this error:

AttributeError: 'NoneType' object has no attribute 'report'

Any kind of advice is welcome.

2

Okay, after some googling I think that executing a report from outside a class is really not supported by Blender at the moment.
Apparently about a year ago, there was an attempt to add this functionality, but it never actually happened. That’s too bad.
I’ll have to stick with regular print commands then.

3

You can achieve this by calling the operator from the save_pre handler. Example:


import bpy


def actuallyDoIt(caller):
    caller.report({'INFO'}, 'Button clicked.')


class DoThatStuff(bpy.types.Operator):
    bl_idname = 'mything.dothatstuff'
    bl_label = 'Click this'
    def execute(self, context): 
        actuallyDoIt(self)
        return {'FINISHED'}
    

def CallDoThatStuffOperator(none):
    bpy.ops.mything.dothatstuff()
    

bpy.utils.register_class(DoThatStuff)
bpy.app.handlers.save_pre.append(CallDoThatStuffOperator)

Hope this helps!

4

Wow, thank you. I didn’t know I could call operators like that. That’s really helpful.

The only issue I’m having now is that my report message is not being displayed as a green line in the Info bar, but only appears in the system console. I wanted some kind of confirmation message for the average user.
So far I’ve only been able to get that via press of a UI button.