Hooking into the OpenERP ORM

I’ve been hooking into the OpenERP ORM layer of a few of the models to add full text search via an external engine. Thanks to the way OpenERP is structured that appears to be quite a reliable approach. As I was doing it I found that I wanted a common set of hooks on several models. Doing that suggested I should refactor the hooks to a mixin or a base class. After playing about with my OpenERP module I’ve come to the conclusion that creating a base class seems to be the most reliable way to hook the methods. The one trick you need to be aware of is the _register flag that you want to set to False for your base class.

class search_base(osv.osv):

    _register = False

    def write(self, cr, user, ids, vals, context=None):
       success = super(search_base, self).write(cr, user, ids,
                                                    vals, context)
       … do stuff
       return success


class product_template_search(search_base):
    _name = "product.template"
    _inherit = "product.template"
    _register = True


class product_search(search_base):
    _name = "product.product"
    _inherit = "product.product"
    _register = True

product_search()
product_template_search()

Without that you’ll end up with the orm whining that the search_base class has no _name attribute as it tries to register it as a model.

openerp.osv.orm: The class search_base has to have a _name attribute
openerp.netsvc: ValueError
The class search_base has to have a _name attribute
> /usr/lib/pymodules/python2.7/openerp/osv/orm.py(967)__init__()
-> raise except_orm('ValueError', msg)
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2 thoughts on “Hooking into the OpenERP ORM

  1. To tell the truth I was going to do that, but it didn’t appear to work. I think I may have just realised why however. I’ll have to give it another go. Thanks for pointing that example out.

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