strojure.ring-control.handler — com.github.strojure/ring-control 1.0.59

Functions for building Ring handler from configuration.

build clj

(build handler xs)

(build handler xs {:keys [async ignored-deps]})

Returns ring handler wrapped with middleware configurations xs in direct order.

Default type of ring handler is sync handler. To produce async ring handler use either :async option or {:async true} in handler's meta.

Every middleware is a map with keys:

• {:keys [wrap]}

  • :wrap – a function (fn [handler] new-handler) to wrap handler.

• {:keys [enter leave]}

  • :enter — a function (fn [request] new-request) to transform request.
  • :leave – a function (fn [response request] new-response) to transform response.

• Optional middleware keys:

  • :name – a name symbol/keyword as middleware description, also used as reference in :deps key.
  • :deps — a map of required middleware names with value :before/:after, see validate-deps.
  • :meta — middleware specific data which can be used to distinguish middlewares with same name but different options, i.e. :root-path in wrap-resource.

Maps with :wrap and :enter/:leave causes exception.

Only middlewares with :wrap can short-circuit, :enter/:leave just modify request/response.

The middlewares are applied in the order:

• Request flows from first to last.
• Response flows from last to first.
• Every middleware receives request from previous :wrap/:enter middlewares only.
• Every :leave/:wrap receives response from next middlewares.

The xs is validating for dependencies with validate-deps. The option :ignored-deps contains dependency names to ignore in validation.

validate-deps clj

(validate-deps xs)

(validate-deps xs ignored)

Throws exception if xs contains middleware with :deps and corresponding dependency is missing. The :deps is a map of required middleware names with value :before/:after:

[{:name `name1}
 {:name `name2 :deps {`name1 :before, `name3 :after}}
 {:name `name3}]