io.pedestal.interceptor.component — io.pedestal/pedestal.interceptor 0.8.0-alpha-5

Streamline the use of Components as interceptors.

The definterceptor macro is used to implement a record that extends [[IntoInterceptor]] and so can be used an interceptor.

component->interceptor clj

(component->interceptor interceptor-name component)

Converts a component into an interceptor. The component must implement at least one of the Handler, OnEnter, OnLeave, or OnError protocols.

A component can implement the [[IntoInterceptor]] protocol and base the -interceptor method on this function.

Returns an interceptor record.

definterceptor clj macro

(definterceptor record-name fields & opts+specs)

Defines an interceptor component, as a Clojure record. The interceptor's name will be the record's name as a namespace qualified keyword.

After the optional options map, and before the normal protocol/method specs, additional methods may be added:

• (handle [this context])
• (enter [this context])
• (leave [this context])
• (error [this context exception])

For each of these, definterceptor will provide the matching protocol.

Example:

(definteceptor upcase []

  (enter [_ context] (update-in context [:request :query-params :id] string/upper-case)))

The class name will match the record-name (which is typically kebab-cased). That is (definterceptor foo-bar ...) will generate the same class name as (defrecord foo-bar ...) even though this is not the normal Pascal Case naming convention for most records.

The record implements the [[IntoInterceptor]] protocol; see component->interceptor.

The normal map->record and ->record construction functions are generated.

Handler clj protocol

handle clj

(handle _ request)

Handles a request map and returns a response map, or a channel that conveys the response map.

OnEnter clj protocol

enter clj

(enter _ context)

Corresponds to the :enter phase of a standard interceptor; passed the context and returns the (new) context, or a core.async channel that will convey the new context.

OnError clj protocol

error clj

(error _ context exception)

Corresponds to the :error phase of a standard interceptor; passed the context and an exception, and returns the (new) context, or a core.async channel that will convey the new context.

OnLeave clj protocol

leave clj

(leave _ context)

Corresponds to the :leave phase of a standard interceptor; passed the context and returns the (new) context, or a core.async channel that will convey the new context.