(executor {:keys [schema query mutation subscription engine env scalars directives], :as opts})

Creates a function that takes a query string, as well as an option map, returning the result of running the query.

(def run-query
    {:schema (io/resource "Schema.gql")
     :query  QueryRoot}))

(run-query "{ person { name } }")
;; => {:status :success, :data {"person" {"name" ...}}}

Allowed options are:

  • :operation-name: for multi-operation queries, sets the one to execute,
  • :variables: a map of variable name strings to their value,
  • :context: a context map to-be-merged into the resolution environment.

All handler options (except :context-fn) are suppored.


(handler {:keys [schema query mutation subscription engine env context-fn scalars directives], :as opts})

Generate a Ring handler for GraphQL execution based on the given GraphQL :schema.

type Person {
  id: ID!,
  name: String!

type QueryRoot {
  person(id: ID!): Person
  me: Person

schema {
  query: QueryRoot

The root types defined in the schema have to be given within opts:

  • :query (required)
  • :mutation
  • :subscription

Each root type has to be a map associating field names with claro resolvables:

(def QueryRoot
  {:person (map->Person {})
   :me     (map->Me {})

A basic GraphQL handler thus consists of at least:

  {:schema (io/resource "Schema.gql")
   :query  QueryRoot})

Schemas can be given as strings, File or URI values. Multiple schemas can be supplied and will be merged in-order.

A claro resolution environment can be supplied using :env. The environment can be extended using a request-specific :context-fn function, e.g.:

(defn context-fn
  {:locale  (read-locale request)
   :db      (select-db-for request)
   :session (read-session request)})

The claro engine to-be-used for resolution can be specified using :engine, allowing for custom engine middlewares to be attached.

Custom directive handlers can be defined in :directives. They’ll take a claro projection and the respective directive arguments, allowing a new projection to be generated. For example, the @skip handler is defined as:

{"skip" (fn [projection arguments]
            (when-not (:if arguments)

Custom scalar handlers can be defined in :scalars, as :encode/:decode pairs.

{"NumericalID" {:encode str, :decode #(Long. %)}}

Note that, for both directives and scalars, the respective schema definitions have to exist.


(string-validator schema)

Generate a validator function that takes GraphQL query document strings as input.

(def validate
    "type Person { id: ID!, name: String!, friends: [Person!] }
     type QueryRoot { person(id: ID!): Person }
     schema { query: QueryRoot }"))

On successful validation, the validator returns nil.