Handling geojson validation issue in 2.0

[bquinn]

We have a problem with ninjs 2.0 whereby the geojson validation doesn't work properly.

Currently we set additionalProperties in the wrong place here:

        "places": {
            "title": "Places",
            "description": "An array of named locations. nar:subject",
            "additionalProperties": false,   # this doesn't do anything
            "type": "array",
            "items": {
                "type": "object",
                "anyOf": [
                    {
                        "properties": {
                            "name": {
                                "title": "Name",
                                "description": "The name of the place",
                                "type": "string"
                            },
                            "rel": {
                                "title": "Relationship",
                                "description": "The relationship of the content of the news object to the place",
                                "type": "string"
                            },
                            "uri": {
                                "title": "URI",
                                "description": "The identifier for the place as a complete uri",
                                "type": "string",
                                "format": "uri"
                            },
                            "literal": {
                                "title": "Literal",
                                "description": "The code for the place as a literal",
                                "type": "string"
                            }
                        }
                       # we should be setting additionalProperties: true here to make it work
                    },
                    {"$ref": "https://json.schemastore.org/geojson"} 
                ]
            }
        },

Because this additionalProperties line is set in the wrong place, it means that any property is allowed in a "places" object.

We have two options:

Option 1: We can add additionalProperties: true in the place indicated above, which would allow geoJSON properties to be inter-mixed with the defined name, rel, uri and literal properties that we define in the schema.

So a valid instance would look like this:

"places": [
  {
     "name": "London, UK",
     "rel": "mentioned",
    "type": "Point",
    "coordinates": [ 51.509865, -0.118092 ]
 },
 {
    "name": "Paris, France",
    "rel": "describes",
    "type": "Polygon",
    "coordinates": [0.0, 0.1, 0.2, 0.3]
  }
]

Pros:

• Compatible with the intent of the existing ninjs 2.0 schema Cons:
• Mixes ninjs and geojson properties in a way that might be confusing for some

Option 2: Add a new property as a child in the places array object

So the schema would look like this:

        "places": {
            "title": "Places",
            "description": "An array of named locations. nar:subject", 
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "name": {
                        "title": "Name",
                        "description": "The name of the place",
                        "type": "string"
                    },
                    "rel": {
                        "title": "Relationship",
                        "description": "The relationship of the content of the news object to the place",
                        "type": "string"
                    },
                    "uri": {
                        "title": "URI",
                        "description": "The identifier for the place as a complete uri",
                        "type": "string",
                        "format": "uri"
                    },
                    "literal": {
                        "title": "Literal",
                        "description": "An identifier for the place as a free-text string.",
                        "type": "string"
                    },
                    "geojson": {
                        "$ref": "https://json.schemastore.org/geojson"
                    }
                },
                "additionalProperties": false
            }

Pros:

• The schema is simpler and it's clear which parts are from ninjs and which parts are from geojson

Cons:

• It's different from what we describe in the existing ninjs 2.0 schema, so it would require a breaking change

Related issues that don't directly affect the decision above:

1. The geojson schema that we point to is not the latest version. But the new version at https://geojson.org/schema/GeoJSON.json uses JSON Schema draft-07 format, and a draft-04 schema can't include a draft-07 schema, so we can't change the reference without updating our schema to dfraft-07. We can do this in a future version but it will require at least a minor version update, it can't be pushed through as an errata change..
2. the examples for "places" are incorrect but passed validation due to this bug. So whichever approach we choose, we need to fix the examples accordingly.)

[bquinn]

@iyoung @jolla56 please check and see if this accurately reflects our discussion today...?

[jolla56]

Yes it does, I did some more testing today because I was afraid that adding geojson as in alternative 1 would force the mandatory properties in geojson, but it seems to be ok. You could further show that, even if we do not suggest such usage, the construction in alt 1 could lead to instances like this:

"places": [ { "name": "London, UK", "rel": "mentioned" }, { "name": "Paris, France", "rel": "describes", "type": "Polygon", "coordinates": [0.0, 0.1, 0.2, 0.3] }, { "type": "Point", "coordinates": [1.45,3.67] } ]

But it then become unclear what the last point refers to.

[jolla56]

Alternative 2 could be as confusing if not used properly because we do not require any of the first four properties in the place object:

"places": [ { "name": "London, UK", "rel": "mentioned" }, { "name": "Paris, France", "rel": "describes", "geojson": { "type": "Polygon", "coordinates": [0.0, 0.1, 0.2, 0.3] } }, { "geojson": { "type": "Point", "coordinates": [1.45,3.67] } } ]

[bquinn]

fixed in #128