ZRM Model Declaration Changes

Abstract

This enhancement proposal removes the Groovy declaration in favor of an equivalent JSON-based declaration.

Rationale

ZRM grew up Groovy oriented. As such, the model declaration is in Groovy which is not the best solution for a fairly language neutral platform. By replacing the Groovy model declaration with a JSON one, we allow the developers from both Java, Groovy, and PHP camps to have a single story that makes sense across all languages.

In addition to simplifying the implementation, moving to JSON will make ZRM better prepared for when model declarations are done over HTTP.

Proposed changes

The proposed changes can be summarized by:

1. Change valid type attribute values and introduce the format attribute
2. Change the model syntax to JSON instead of Groovy
3. Change the file suffix from *.groovy to *.json

Type and format attributes

The current field names are useful in abstracting higher level of functionality in terms of validation and encapsulating a framework to extend the system. However, in terms of a programming model, they are not necessarily the way developers think about their data.

This proposal changes the type attributes to more data type approach. For instance, rather than all the *Field strings used at field type values, replace them with boolean, string, date, date-time, time, and number.

The following table illustrates the changes made to the existing type attribute and how the introduction of the format attribute achieves the previous functionality of higher level field types:

Existing type	New type	Format
BooleanField	boolean
CharField	string
DateField	date
DateTimeField	date-time
DecimalField	number
EmailField	string	email
FloatField	number
IntegerField	number
TextField	string
TimeField	time
USStateField	string	region
USPhoneField	string	phone

JSON model declaration syntax

Currently, a simple model declaration in Groovy is as follows:

// /app/models/person.groovy
fields = [
    first_name: [type: 'CharField'],
    birth_date: [type: 'DateField'],
]

This proposal calls to change this Groovy-based data structure to JSON as follows:

// /app/models/person.json
fields = {
    "first_name" : {"type": "string"},
    "birth_date" : {"type": "date"}
}

Model file suffix

If the declaration syntax is changed to JSON, it only makes sense to change the file suffix to *.json as shown in the previous example.