Spec Driven Model

Intro

This module is a databinding framework for Odoo and XML data: it allows to go from XML to Odoo objects back and forth. While having no hard dependency with it, it has been designed to be used along with xsdata. So a good starting point is to read the xsdata documentation here.

But what if instead of only generating Python structures from XML files you could actually generate full blown Odoo objects or serialize Odoo objects back to XML? This is what this module is for!

First you should generate xsdata Python binding libraries you would generate for your specific XSD grammar, the Brazilian Electronic Invoicing for instance, or UBL or any XSD files...

Second you should generate Odoo abstract mixins for all these pure Python bindings. This can be achieved using xsdata-odoo. An example is OCA/l10n-brazil/l10n_br_nfe_spec for the Brazilian Electronic Invoicing.

SpecModel

Now that you have generated these Odoo abstract bindings you should tell Odoo how to use them. For instance you may want that your abstract model for the recipient of the electronic invoice matches the Odoo res.partner object. This is fairly easy, you mostly need to define an override like:

Notice you should inherit from spec_models.SpecModel and not the usual models.Model.

Field mapping: You can then define two ways mapping between fields by overriding fields from Odoo or from the binding using _compute= , _inverse= or simply related=.

Relational fields: simple fields are easily mapped this way. However what about relational fields? In your XSD schema, your electronic invoice is related to the partner.binding.mixin not to an Odoo res.partner. Don't worry, when SpecModel classes are instanciated for all relational fields, we look if their comodel have been injected into some existing Odoo model and if so we remap them to the proper Odoo model.

Field prefixes: to avoid field collision between the Odoo fields and the XSD fields, the XSD fields are prefixed with the name of the schema and a few digits representing the schema version (typically 2 digits). So if your schema get a minor version upgrade, the same fields and classes are used. For a major upgrade however new fields and classes may be used so data of several major versions could co-exist inside your Odoo database.

StackedModel

Sadly real life XML is a bit more complex than that. Often XML structures are deeply nested just because it makes it easier for XSD schemas to validate them! for instance an electronic invoice line can be a nested structure with lots of tax details and product details. In a relational model like Odoo however you often want flatter data structures instead. This is where StackedModel comes to the rescue! It inherits from SpecModel and when you inherit from StackedModel you can inherit from all the generated mixins corresponding to the nested XML tags below some tag (here invoice.line.binding.mixin). All the fields corresponding to these XML tag attributes will be collected in your model and the XML parsing and serialization will happen as expected. Here is an example inspired from the Brazilian Electronic Invoice where the schema is called nfe and where we use the 2 digits 40 for its short version:

All many2one fields that are required in the XSD (xsd_required=True) will get their model stacked automatically and recursively. You can also force non required many2one fields to be stacked using the stacking_force_paths attribute. On the contrary, you can avoid some required many2one fields to be stacked using the stacking_skip_paths attribute.

Initialization hook

Because XSD schemas can define lot's of different models, spec_driven_model comes with a handy _register_hook override (in spec.mixin) that will automatically make all XSD mixins turn into concrete Odoo model (eg with a table) if you didn't inject them into existing Odoo models already.