I am trying to understand how to extend Odoo. As first step I want to implement a new method named 'hello_world' for product.product class.

This methods does the mandatory 'Hello World', which according to other posts should be seen if odoo is launched in command line:

    print 'Hello World'

Then I set up an automated action which executes python code to launch that method every time a new product is created, so I will have my first new method in Odoo implemented.

I edit and add the following to addons/product/product.py:

class product_product(osv.osv):

[...]

    def hello_world():

        print 'Hello World'

And add the following server action:

Base model: Product

Action: Execute Python Code

Python Code:

self.hello_world()

And I try this flamboyant method by creating a new product through the GUI and getting the following error:

ValueError: "'product.product' object has no attribute 'hello_world'" while evaluating

u'# Available locals:\n# - time, datetime, dateutil: Python libraries\n# - env: Odoo Environement\n# - model: Model of the record on which the action is triggered\n# - object: Record on which the action is triggered if there is one, otherwise None\n# - workflow: Workflow engine\n# - Warning: Warning Exception to use with raise\n# To return an action, assign: action = {...}\nself.hello_world()'

Note: I am aware that the right way of doing this is extending Odoo through modules, but it is needed to understand this before moving forward.