skjema

JSON Schema 2020-12 validation for Clojure.

com.blockether/skjema {:mvn/version "0.3.0"}

Use

(require '[com.blockether.skjema.core :as skjema]
         '[clojure.java.io :as io])

(def schema
  (skjema/read-schema (io/resource "user.schema.json")))

(skjema/validate schema {"name" "Ada"})
;; => true

(skjema/explain schema {"name" 42})
;; => {:valid false
;;     :errors [{:instanceLocation "/name"
;;               :keywordLocation "/properties/name/type"
;;               :keyword "type"
;;               :params {:type "string"}
;;               :error "expected string, got integer"}]}

Compile once and keep the function when the same schema validates repeatedly - that is the fast path, and it is what the benchmark measures:

(def valid? (skjema/validator schema))
(def why (skjema/explainer schema))

(valid? {"name" "Ada"})   ;; => true
(why {"name" "Ada"})      ;; => nil

read-schema takes JSON text, a Path, a File, a URL or classpath resource, an InputStream or a Reader. write-schema returns compact JSON text.

References resolve from an explicit registry; nothing is fetched over the network:

(skjema/compile-schema schema
  {:base "https://example.com/user.json"
   :registry {"https://example.com/tag.json" tag-schema}
   :format-assertion true})

Errors

explain answers nil, or BASIC output locations extended with keyword, keyword-specific params and a readable error. Reading, compiling and writing throw ExceptionInfo carrying a :skjema/error category and the original cause.

Verify

clojure -M:test    # official JSON-Schema-Test-Suite, required and optional 2020-12
clojure -M:bench   # against malli, schema compiled on both sides

License

MIT — see LICENSE and NOTICE.