Ring: Web Apps in Idiomatic Clojure

Ring Web Apps in Idiomatic Clojure Mark McGranaghan January 23, 2010

About Mark Bowdoin College ’10 Clojure user since 2008 Open source: http://github.com/mmcgrana

Motivation for Ring

Motivation for Ring Abstract HTTP

Motivation for Ring Abstract HTTP Write apps in idiomatic Clojure

Motivation for Ring Abstract HTTP Write apps in idiomatic Clojure Share code across web frameworks

Motivation for Ring Abstract HTTP Write apps in idiomatic Clojure Share code across web frameworks Deploy on a variety of web servers

Motivation for Ring Abstract HTTP Write apps in idiomatic Clojure Share code across web frameworks Deploy on a variety of web servers WSGI & Rack

The Ring Project

The Ring Project Spec

The Ring Project Spec Library

The Ring Project Spec Library Ecosystem

Overview of Ring

Overview of Ring Handlers are functions

Overview of Ring Handlers are functions that take requests as Clojure maps

Overview of Ring Handlers are functions that take requests as Clojure maps and return responses as Clojure map

Overview of Ring Handlers are functions that take requests as Clojure maps and return responses as Clojure map Adapters run handlers on a web server

Overview of Ring Handlers are functions that take requests as Clojure maps and return responses as Clojure map Adapters run handlers on a web server Middleware augments handlers

“Ring”

Request Map {:uri <String> :query-string <String> :request-method <Keyword> :headers <IPersistentMap> :body <InputStream> ... ...}

Response Map {:status <Integer> :headers <IPersistentMap> :body <String, ISeq, File, InputStream>}

Example: Hello World (defn app [req] {:status 200 :headers {"Content-Type" "text/html"} :body (str "Hi from " (:server-name req))})

Example: Hello World (defn app [req] {:status 200 :headers {"Content-Type" "text/html"} :body (str "Hi from " (:server-name req))}) (use ’ring.adapter.jetty) (run-jetty app {:port 8080})

Example: Hello World

Example: Stacktraces (defn app [req] ("o noes"))

Example: Stacktraces (defn app [req] ("o noes")) (use ’ring.adapter.jetty) (use ’ring.middleware.stacktrace) (run-jetty (wrap-stacktrace app) {:port 8080})

Example: Stacktraces

Example: Static Files (defn dynamic-app [req] (...))

Example: Static Files (defn dynamic-app [req] (...)) (use ’ring.middleware.file) (use ’ring.middleware.file-info) (def app (-> dynamic-app (wrap-file "public") (wrap-file-info)))

Example: Testability

Example: Testability (defn my-app [req] (...))

Example: Testability (defn my-app [req] (...)) (deftest not-found-error (let [req {:uri "/bogus/uri"} resp (my-app req)] (is (= 404 (:status resp)))))

Ring and Web Frameworks

Ring and Web Frameworks Foundation, not replacement

Ring and Web Frameworks Foundation, not replacement Avoid duplication and share code

Ring and Web Frameworks Foundation, not replacement Avoid duplication and share code Compojure, Conjure, Weld all targeting Ring

Ring and Web Frameworks Foundation, not replacement Avoid duplication and share code Compojure, Conjure, Weld all targeting Ring Compojure case study

Ring Middleware

Ring Middleware ring.middleware.reload: Automatically reload namespaces

Ring Middleware ring.middleware.reload: Automatically reload namespaces ring.middleware.params: Get request params as a map

Ring Middleware ring.middleware.reload: Automatically reload namespaces ring.middleware.params: Get request params as a map ring.middleware.cookies: Cookie jar abstraction

Other Components

Other Components ring.util.servlet: If you really want a Servlet

Other Components ring.util.servlet: If you really want a Servlet ring.adapter.httpcore: Adapter for HTTP Core library

Other Components ring.util.servlet: If you really want a Servlet ring.adapter.httpcore: Adapter for HTTP Core library ring.handler.dump: See the request map

Other Components ring.util.servlet: If you really want a Servlet ring.adapter.httpcore: Adapter for HTTP Core library ring.handler.dump: See the request map ring.examples.*: Runnable examples

Future Work

Future Work Middleware and utility extraction from frameworks

Future Work Middleware and utility extraction from frameworks Not a framework itself

Future Work Middleware and utility extraction from frameworks Not a framework itself More use in production?

Future Work Middleware and utility extraction from frameworks Not a framework itself More use in production? User needs?

Learn More http://github.com/mmcgrana/ring ring/example/*.clj ring/SPEC

Ring: Web Apps in Idiomatic Clojure

by Mark McGranaghan on Jan 23, 2010

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