JSONSchema validation failure with $ref (Draft v7)

Question

I have created a JSON schema following the draft v7 specifications. Schema looks like this:

{
  "type": "object",

  "properties": {

        "songs": {
            "type": "array",
            "items": {
                "type": "object",      
                "properties": {

                    "composition": {
                        "type": "object",

                        "properties": {
                            "title": {
                                "type": "string"
                            },
                            "publishing": {
                                "type": "array",

                                "items": {
                                    "type": "object",
                                    "required": ["publisherId","territory"],

                                    "definitions": {
                                        "categoryList": {
                                            "type": "object",
                                            "properties": {
                                                "BR": {
                                                "type": "number"
                                                }
                                            }
                                        }
                                    },
                                    "properties": {
                                        "publisherId": {
                                            "type": "integer"
                                        },
                                        "territory": {
                                            "$ref": "#/definitions/categoryList"
                                        }
                                    }
                                }
                            }
                        }
                    },
                    "recordings": {
                        "type": "array",
                        "items": {
                            "type": "object",
                            "properties": {
                                "songVersion": {
                                    "type": "string"
                                },
                                "album": {
                                    "type": "object",
                                    "properties": {
                                        "title": {
                                        "type": "string"
                                        }                    
                                    }
                                }                  
                            }              
                        }         
                    }

                }

            }
        }
    }
}

but got error Could not resolve schema reference '#/definitions/categoryList'. Path 'properties.songs.items.properties.composition.properties.publishing.items.properties.territory', line 40, position 24. If I omit the definitionpart it works perfectly

It's expecting to see definitions at the root level based on the reference you have provided. Your reference URI is relative to the document root, not the current object. — Relequestual
"URI is relative to the document root, not the current object "- could you please explain? — naqwe

Relequestual Relequestual · Accepted Answer · 2020-03-23T10:06:30

The easiest way to explain why the reference resolution doesn't work as you expect is to talk about a modified example from the draft-07 core specification itself.

   {
       "definitions": {
           "A": { },
           "B": {
               "definitions": {
                   "X": { },
                   "Y": { }
               }
           }
       }
   }

The document root is an object which has a definitions property.

To access #/definitions/A, you can use a reference of #/definitions/A.

To access #/definitions/B/definitions/X, you can use a reference of #/definitions/B/definitions/X.

The reference in your schema needs to know the FULL path to the subschema from the document root.

I would guess you've assumed the URI is relative to the closest subschema or the subschema which it's used in, but that is not the case.

Reference: https://tools.ietf.org/html/draft-handrews-json-schema-01#section-8.2.4

The example includes a more exhaustive set of examples. Think of URI referencing like you would an anchor tag in HTML. When a domain part of the URI isn't included, one is "imagined" in it's place in order to do URI resolution.

Let me know if you have any follow up questions.

JSONSchema validation failure with $ref (Draft v7)

1 Answers