validation - Prismatic schema: removing unanticipated keys -

my api receiving json data client.

i use schema perform validation , coercion on data receive, 1 additional requirement: if there map key not described in schema, ignore , remove instead of failing validation (this because client may send me "garbage" properties along ones care about. want tolerant that.).

so in nutshell, perform "deep select-keys" on input data using schema, before validation/coercion.

example of need:

(require '[schema.core :as sc]) (def myschema {:a sc/int                :b {:c sc/str                    (sc/optional-key :d) sc/bool}                :e [{:f sc/inst}]})  (sanitize-and-validate   myschema   {:a 2    :b {:c "hello"        :$$garbage-key 32}    :e [{:f #inst "2015-07-23t12:29:51.822-00:00" :garbage-key 42}]    :_garbage-key1 "woot"}) => {:a 2     :b {:c "hello"}     :e [{:f #inst "2015-07-23t12:29:51.822-00:00"}]} 

i haven't yet found reliable way of doing this:

1. i can't seem in custom transformation, because seems walker not give access keys.
2. i haven't had luck trying walk schema hand, because it's hard differentiate map schemas , scalar schemas in generic way; difficult account possible shapes schema can have.

is there obvious way i'm not seeing?

thanks!

a third solution, credits abp: use schema.coerce/coercer matcher remove unknown keys maps.

(require '[schema.core :as s]) (require '[schema.coerce :as coerce]) (require '[schema.utils :as utils])  (defn filter-schema-keys   [m schema-keys extra-keys-walker]   (reduce-kv (fn [m k v]                (if (or (contains? schema-keys k)                        (and extra-keys-walker                             (not (utils/error? (extra-keys-walker k)))))                  m                  (dissoc m k)))              m              m))  (defn map-filter-matcher   [s]   (when (or (instance? clojure.lang.persistentarraymap s)             (instance? clojure.lang.persistenthashmap s))     (let [extra-keys-schema (#'s/find-extra-keys-schema s)           extra-keys-walker (when extra-keys-schema (s/walker extra-keys-schema))           explicit-keys (some->> (dissoc s extra-keys-schema)                                  keys                                  (mapv s/explicit-schema-key)                                  (into #{}))]       (when (or extra-keys-walker (seq explicit-keys))         (fn [x]           (if (map? x)             (filter-schema-keys x explicit-keys extra-keys-walker)             x)))))) 

this was described cleanest solution primary author of schema, not require change schema work. it's way go.

usage example:

(def data {:a 2            :b {:c "hello"                :$$garbage-key 32}            :e [{:f #inst "2015-07-23t12:29:51.822-00:00" :garbage-key 42}]            :_garbage-key1 "woot"}) ((coerce/coercer myschema map-filter-matcher) data) ;=> {:a 2, :b {:c "hello"}, :e [{:f #inst "2015-07-23t12:29:51.822-00:00"}]}