How to use definitions in JSON schema (draft-04)

Question

The rest service response I am working with is similar to following example, I have only included 3 fields here but there are many more:

{     "results": [         {             "type": "Person",             "name": "Mr Bean",             "dateOfBirth": "14 Dec 1981"         },         {             "type": "Company",             "name": "Pi",             "tradingName": "Pi Engineering Limited"         }     ] } 

I want to write a JSON schema file for above (draft-04) which will explicitly specify that:

if type == Person then list of required properties is ["type", "name", "dateOfBirth", etc]  OR if type == "Company" then list of required properties is ["type", "name", "tradingName", etc] 

However am unable to find any documentation or example of how to do it.

Currently my JSON schema looks like following:

{     "$schema": "http://json-schema.org/draft-04/schema",     "type": "object",     "required": ["results" ],     "properties": {         "results": {             "type": "array",             "items": {                 "type": "object",                 "required": ["type", "name"],                 "properties": {                     "type": { "type": "string" },                     "name": { "type": "string" },                     "dateOfBirth": { "type": "string" },                     "tradingName": { "type": "string" }                 }             }         }     } } 

Any pointers/examples of how I should handle this.

Answer 1

I think the recommended approach is the one shown in Json-Schema web, Example2. You need to use an enum to select schemas "by value". In your case it would be something like:

{     "type": "object",     "required": [ "results" ],     "properties": {         "results": {             "type": "array",             "items": {                 "oneOf": [                     { "$ref": "#/definitions/person" },                     { "$ref": "#/definitions/company" }                 ]             }         }     },     "definitions": {         "person": {             "properties": {                 "type": { "enum": [ "person" ] },                 "name": {"type": "string" },                 "dateOfBirth": {"type":"string"}             },             "required": [ "type", "name", "dateOfBirth" ],             "additionalProperties": false         },         "company": {             "properties": {                 "type": { "enum": [ "company" ] },                 . . .              }                 }     } }