Polymorphic schema validation in Clojure

clojure, schema

Solution

You can use prismatic.schema's `conditional` to accomplish this:

(s/conditional #(= (:type %) :bird) {:type (s/eq :bird) :chirping s/Bool}
               #(= (:type %) :fish) {:type (s/eq :fish) :swimming s/Bool}
               ...
               :default  {:type (s/eq :animal) :existing s/Bool})

Problem

I want to use a schema to validate a request object. One of the values in the map determines which other fields are valid. For example, these would all be valid: ``` { :name "jane" :type :dog :barking true } { :name "alan" :type :bird :cheeping true } { :name "bert" :type :fish :swimming true } ``` Some fields are common. But others depend upon the value of `:type`. For example, this would be invalid: ``` { :name "phil" :type :bird :barking false } ``` How can such schema be expressed? I'm happy to use either clj-schema or Prismatic schema.

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