Support Custom Meta-schemas

[dszier]

I ran into the same issue with custom keywords as #16, but attempted to fix it by creating my own meta-schema that defines the keywords we use. Following the example of the hyper meta-schema, and the spec, I created a new meta-schema that defined my custom keywords. It referenced it's own id as $schema and incorporated draft-07 of the core meta-schema. However, when I try to read the schema, even withSchemaValidation(false), I get Unsuppoted metaschema: "http://my.company.com/meta-schemas/draft-01/schema#".

My thinking would be that I should be able to read the meta-schema itself without having to do anything special, and then when reading schemas that make use of the meta-schema, read them withSchemaResolver(new MyMetaSchemaResolver()). However, my schema resolver doesn't even have a chance to resolve the meta-schema because it seems that the exception bubbles up before calling resolve().

Am I doing something wrong and custom meta-schemas are already supported? Will this be a feature that Justify supports?

I took a look under the hood at how Justify creates JsonSchema objects for the core meta-schemas, and while I think I can get past the exception and read the meta-schema as a JsonSchema, it doesn't look like the internal schema catalog was really meant to be extended by having custom meta-schemas injected into it.

[leadpony]

Hello @dszier. Thank you for contacting me.
Unfortunately the library does not support custom meta-schema. Justify internally contains the official meta-schemas for the JSON Schema specification Draft-04, -06 and -07. Using thsese internal meta-schemas, the library automatically validates all JSON schemas while reading them if withSchemaValidation is set to true . Also the value of $schema keyword is used to detect the version of the JSON Schema specification between 3 drafts.
The JsonSchemaResolver interface is for resolving external schemas referenced by $ref keywords and not for resolving meta-schemas.
If the feature of cutsom meta-schema is really needed, we must start from designing the concept and the API.

[dszier]

I think it would be great if custom meta-schemas were supported. If so, I could turn on strict validation of schemas against my own meta-schema.

However, with #16 fixed and a new version released, my needs will be met.

Thanks for the response and for maintaining this great library :)

[leadpony]

Hello @dszier
I have released 0.17.0 and it solved the issue #16 partially. Please see my comment in #16.
Also the support of custom meta-schema will be added in future release. I believe it is not so difficult to implement it.
Thank you so much for your nice suggestion of enhancement.

[leadpony]

The new release 1.0.0 is now available, which supports custom metaschema feature. Please refer to the changelog.