Support min and max length for a string property in CTO

[ragi-dayananda]

Support min and max length for a string property in CTO

[dselman]

We should only use decorators for things that are external/opaque to Concerto. In this case we'd be using these facets to validate string properties so I think the meta model should be extended to support this. 'length' seems like a good name, and we could implement it similar to range for numbers, with an optional lower and upper bound, or we could add 'maxLength' and 'minLength' as explicit meta properties.

[mttrbrts]

The range property modifier syntax includes an = so we should mirror that. e.g.

concept Contact {
   o String firstName length=[0,100]
}

We could also make lower and upper bounds optional (like with range), e.g.

concept Contact {
   o String firstName length=[1,] // only non-empty strings are allowed
   o String lastName length=[,100] // syntactic sugar for [0,100]
}

Also note that with range, the upper-bound is inclusive, i.e. range=[3,10] means 3 >= x <= 10

concerto/packages/concerto-core/lib/introspect/numbervalidator.js

Lines 92 to 102 in 9009e82

	validate(identifier, value) {
	if(value !== null) {
	if(this.lowerBound !== null && value < this.lowerBound) {
	this.reportError(identifier, `Value ${value} is outside lower bound ${this.lowerBound}`);
	}
	if(this.upperBound !== null && value > this.upperBound) {
	this.reportError(identifier, `Value ${value} is outside upper bound ${this.upperBound}`);
	}
	}
	}

[mttrbrts]

As discussed on today's working group call, we should give this modifier precedence over the regex modifier if both are used.

Validating against length is the simpler, faster, and less-general operation.

[f5th-dimensional]

For translating these field constraints/modifiers into things such as OpenAPI, would using common labels such as those in JSON schema be practical? For example, as @dselman suggested, maxLength and minLength to describe character limits in a string, or minimum maximum to describe the range of possible values. Also, should distinguishing between inclusive and exclusive range values be considered, such as in the use of exclusiveMinimum and exclusiveMaximum?

-Steven

[mttrbrts]

For translating these field constraints/modifiers into things such as OpenAPI, would using common labels such as those in JSON schema be practical?

@f5th-dimensional
Are you suggesting using the same keywords from OpenAPI in Concerto, or just declaring an equivalence when converting to/from OpenAPI.

[dselman]

Please ensure that the latest metamodel is publish to the public model repo: https://models.accordproject.org/concerto/[email protected]