Query parameter declared as array cannot contain only one value

[leflamm]

Hi,

a query parameter that is declared as type: array isn't allowed to contain only one value.

#%RAML 1.0
title: foo
version: v0.0.1

/bar:
  get:
    queryParameters:
      q:
        type: array
        items: string
    responses:
      200:
        body:
          application/json:
            example: |
              OK

Providing one query parameter causes an error...

$ curl "localhost:3333/bar?q=narf"

{
   "errors":[
      {
         "type":"query",
         "dataPath":"q",
         "keyword":"type",
         "schema":"array",
         "data":"narf",
         "message":"Invalid type, expected array"
      }
   ],
   "stack":"BadRequestError: Request failed to validate against RAML definition\n    at createValidationError (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/osprey-method-handler/osprey-method-handler.js:746:14)\n    at ospreyQuery (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/osprey-method-handler/osprey-method-handler.js:210:19)\n    at handle (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/compose-middleware/lib/index.js:56:16)\n    at dispatch (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/compose-middleware/lib/index.js:39:20)\n    at next (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/compose-middleware/lib/index.js:37:24)\n    at ospreyAccepts (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/osprey-method-handler/osprey-method-handler.js:187:12)\n    at handle (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/compose-middleware/lib/index.js:56:16)\n    at dispatch (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/compose-middleware/lib/index.js:39:20)\n    at IncomingMessage.next (/home/cf/.nvm/versions/node/v6.9.4/lib/node_modules/osprey-mock-service/node_modules/compose-middleware/lib/index.js:37:24)\n    at emitNone (events.js:86:13)"
}

... providing two or more works fine

$ curl "localhost:3333/bar?q=narf&q=poit"
OK

$ curl "localhost:3333/bar?q=narf&q=poit&q=zort"
OK

[jstoiko]

The issue is that a single q is passed as a string to the validator, and hence it does not validate against type: array. For reference, the RAML spec has a section about this scenario:

RAML does not define validation when a query parameter declaration specifies any of the following types for the value of the query parameter: an object type, a union of non-scalar types, or an array type if the underlying type of the array is an object type or union of non-scalar types. Processors MAY default to treating the format of the query parameter value as JSON in applying the type to instances of that query parameter, or they MAY allow other treatments based on annotations.

Have you tried declaring q as type: array | string? wouldn't it be a more accurate definition in your case?