Aws-cdk: API Gateway ModelOptions interface should require contentType

[Townsheriff]

Cloudformation requires contentType to be defined in ModelOptions, but in API it is marked as optional.

Reproduction Steps

    const model = new gateway.Model(this, 'Model', {
      restApi: props.resource.restApi,
      schema: {
        schema: gateway.JsonSchemaVersion.DRAFT4,
        type: gateway.JsonSchemaType.OBJECT,
        properties: {
          name: {
            type: gateway.JsonSchemaType.STRING,
          }
        }
      }
    });

Error Log

Environment

• CLI Version : 1.22.0 (build 309ac1b)
• Framework Version: 1.22.0
• OS : MacOS
• Language : Typescript

Other

Adding contentType property everything works fine.

---

This is :bug: Bug Report

[richardhboyd]

I was just independently exposed to this same bug.

[nija-at]

Thanks for filing this issue.

It seems that CF has also marked this property as optional. Internal reference: i/CFN-30792.

@richardhboyd & @Townsheriff - I think we should keep this property as optional in the CDK and set the default to application/json as per what I see in their API documentation.
What do you both think?

[richardhboyd]

I agree with that plan. I am about 84% certain that the Content Type on Models is never enforced/checked anywhere else.