Extend the supported data types using types option

[subeeshcbabu-zz]

It would be really cool to provide an option to extend the default and supported types.
This types option can be an easy fix/feature for anyone wanting to extend capabilities of the validator to - either define custom types for schema or trying to extend features of the existing validations.

One example of such a use case, would be Swagger file type.

[LinusU]

I don't think this is valid according to JSON schema? JSON doesn't have any "file" type so it seems strange to add it. I might be missing something though, but why not use { type: 'string', format: 'file' }?

[subeeshcbabu-zz]

The idea is to use this module to validate response data for any specification that extends json schema. I really like this module and would love to use this for specs like swagger also. This option could be used by any spec that is extending json schema, not only swagger.

Adding an option to extend the supported types without changing the existing module is what I am proposing.

To answer your question on why I can't use a format file because swagger spec 2 has defined file as a type rather than a format.

[subeeshcbabu-zz]

@LinusU - sorry to bug you with this, however any update on this?

[subeeshcbabu-zz]

@LinusU any idea, if this PR would be accepted?

[LinusU]

Ultimately, it's up to mafintosh, but I think that the developers has misunderstood how json-schema works. "type": "file" should really be "type": "string", "format": "file". It doesn't make sense to extend json-schema with more types, because there aren't any more types in JSON.

I would really like to see a discussion with the Swagger people on why they chose to do this, because to me it seems wrong, and as far as I know, they aren't following the json schema specification.

For these reasons I'm not a big fan of merging this, I hope you can understand my point of view...

[subeeshcbabu-zz]

Completely understand, why you have concerns supporting this. Agree that, Swagger should not have deviated from the json schema to define a type like file.
However, talking more about the context of this PR, the extension support clearly separates the Implementation to the user-land or to any one trying to wrap (to bridge the swagger to json schema gap) the is-my-json-valid module. I really want to use the awesome features of this module, and at the same time keep the additions out of this module.

[LinusU]

It would probably be quite easy to make a small function that "fixes" the schema before passing it to is-my-json-valid though. Look for type: 'file' and replace with type: 'string', format: 'file'