Removal of the Model instance reduce and APIBuilder.Model.reduce functions

3 minute read

Beginning with the Cairo release, Reducing a Model instance (i.e. Model.prototype.reduce) and APIBuilder.Model.reduce are deprecated and will be removed in a future version of the product.

Why we are making this change

The Model instance reduce and APIBuilder.Model.reduce functions were designed to achieve three basic features:

1. Reduce (remove) fields from a parent model
2. Rename fields of a parent model
3. Add fields to a parent model

On review of these features, it was determined that all of these features could be achieved with Model.extend, and because of that Model instance reduce and APIBuilder.Model.reduce are redundant. For clarity and ease of use, these functions are deprecated.

How does this impact my service

The API Builder v3.x UI only uses Model.extend, so unless you manually code your Models, then this change will not impact your service. However, if you manually create Models, you should check your Models in the ./models directory to see if they use Model.reduce. If you are using Model.reduce, then this feature will be removed in the next major version of the product, and you should migrate your models to use Model.extend instead.

There are two ways to reduce a Model: one way is calling APIBuilder.Model.reduce.

// Employee - APIBuilder.Model.reduce example

var APIBuilder = require('@axway/api-builder-runtime');
var Model = APIBuilder.Model.reduce('Friend', 'Person', {
    "fields": {
        "name": {
            "type": "string"
        }
    },
    "connector": "memory",
    "actions": [
        "create",
        "read",
        "update",
        "delete",
        "deleteAll"
    ]
});
module.exports = Model;

The other way is to call the reduce function on a Model instance (for example, Person.reduce).

// Employee - Model.reduce example

var APIBuilder = require('@axway/api-builder-runtime');
var Model = APIBuilder.Model;
var Person = Model.getModel('Person');
var Model = Person.reduce('Friend', {
    "fields": {
        "name": {
            "type": "string"
        }
    },
    "connector": "memory",
    "actions": [
        "create",
        "read",
        "update",
        "delete",
        "deleteAll"
    ]
});
module.exports = Model;

If your application reduces Models in this way, then your application will be impacted by this change.

Upgrading models using the UI

The easiest way to upgrade a reduced model is with the UI. You will have to use a different model name temporarily. In this example, the parent model is Employee, and your existing reduced model is Friend. Select the menu on Person -> Compose into new.

This opens a dialog to generate a new composite model. We will give this model a different name, Friend2.

You now have an opportunity to edit the model. In this screen, you can remove or rename fields that are sourced from the Person model. Make the changes to Friend2 so that it has equivalent fields to the Friend model.

Click “Next >” to save and generate API for Friend2.

At this point, exit your application, delete the original model/Friend.js, and rename the new model/Friend2.js file to model/Friend.js.

Finally, open the model/Friend.js file, and rename “Friend2” to “Friend” in APIBuilder.createModel.

Restart your application.