CLOJURE

Alphabetical index of projects in Clojure:

A	B	C	D	E	F	G
H	I	J	K	L	M	N
O	P	Q	R	S	T	U
V	W	X	Y	Z

A

Aleph exposes data from the network as a Manifold stream, which can easily be transformed into a java.io.InputStream, core.async channel, Clojure sequence, or many other byte representations. It exposes simple default wrappers for HTTP, TCP, and UDP, but allows access to full performance and flexibility of the underlying Netty library.

aleph

C

Cheshire is fast JSON encoding, based off of clj-json and clojure-json, with additional features like Date/UUID/Set/Symbol encoding and SMILE support.

Encoding example:

;; generate some json
(generate-string {:foo "bar" :baz 5})

;; write some json to a stream
(generate-stream {:foo "bar" :baz 5} (clojure.java.io/writer "/tmp/foo"))

;; generate some SMILE
(generate-smile {:foo "bar" :baz 5})

;; generate some JSON with Dates
;; the Date will be encoded as a string using
;; the default date format: yyyy-MM-dd'T'HH:mm:ss'Z'
(generate-string {:foo "bar" :baz (java.util.Date. 0)})

;; generate some JSON with Dates with custom Date encoding
(generate-string {:baz (java.util.Date. 0)} {:date-format "yyyy-MM-dd"})

;; generate some JSON with pretty formatting
(generate-string {:foo "bar" :baz {:eggplant [1 2 3]}} {:pretty true})
;; {
;;   "foo" : "bar",
;;   "baz" : {
;;     "eggplant" : [ 1, 2, 3 ]
;;   }
;; }

;; generate JSON escaping UTF-8
(generate-string {:foo "It costs £100"} {:escape-non-ascii true})
;; => "{\"foo\":\"It costs \\u00A3100\"}"

;; generate JSON and munge keys with a custom function
(generate-string {:foo "bar"} {:key-fn (fn [k] (.toUpperCase (name k)))})
;; => "{\"FOO\":\"bar\"}"

Clojurecademy is an interactive platform that provides Clojure based courses. It's like Codecademy for Clojure.

Clojurecademy Homepage

Clojure News is Hacker News clone for Clojurists.Entirely written in Clojure & ClojureScript.

Clojure News Demo

compojure — a small routing library for Ring that allows web applications to be composed of small, independent parts.

This small Compojure application demonstrates creating a Ring handler from two routes:

(ns hello-world.core
  (:require [compojure.core :refer :all]
            [compojure.route :as route]))
(defroutes app
  (GET "/" [] "<h1>Hello World</h1>")
  (route/not-found "<h1>Page not found</h1>"))

Cryogen is a simple static site generator built with Clojure. It's shipped on Leiningen so setup is fuss free and there's no need to mess with databases or other CMS systems.

Cryogen Logo

D

Datascript — an immutable in-memory database and Datalog query engine in Clojure and ClojureScript.

datascript

H

http-kit is a minimalist, event-driven, high-performance Clojure HTTP server/client library with WebSocket and asynchronous support.

Server:

(defn async-handler [ring-request]
  ;; unified API for WebSocket and HTTP long polling/streaming
  (with-channel ring-request channel    ; get the channel
    (if (websocket? channel)            ; if you want to distinguish them
      (on-receive channel (fn [data]     ; two way communication
                            (send! channel data)))
      (send! channel {:status 200
                      :headers {"Content-Type" "text/plain"}
                      :body    "Long polling?"}))))

(run-server async-handler {:port 8080}) ; Ring server

Client:

;; start concurrent requests, get promise, half the waiting time
(let [response1 (http-kit/get "http://http-kit.org/")
      response2 (http-kit/get "http://clojure.org/")]
  ;; Handle responses one-by-one, blocking as necessary
  ;; Other keys :headers :body :error :opts
  (println "response1's status: " (:status @response1))
  (println "response2's status: " (:status @response2)))

J

Jepsen is a Clojure library. A test is a Clojure program which uses the Jepsen library to set up a distributed system, run a bunch of operations against that system, and verify that the history of those operations makes sense. Jepsen has been used to verify everything from eventually-consistent commutative databases to linearizable coordination systems to distributed task schedulers. It can also generate graphs of performance and availability, helping you characterize how a system responds to different faults. See aphyr.com for examples of the sorts of analyses you can carry out with Jepsen.

K

Klipse is a simple client-side code evaluator pluggable on any web page: clojure, ruby, javascript, python, scheme, es2017, jsx, brainfuck, c++, reagent and a clojure[script] web repl.

Checkout Klipse blog with interactive code snippets and the KLIPSE clojure web repl.

L

Liberator is a Clojure library for building RESTful applications.

Example:

(ns example
  (:use [liberator.core :only [defresource]]))

(defresource hello-world
  :available-media-types ["text/plain"]
  :handle-ok "Hello, world!")

Luminus is a Clojure micro-framework based on a set of lightweight libraries. It aims to provide a robust, scalable, and easy to use platform.

Luminus Logo

M

Metabase is the easy, open source way for everyone in your company to ask questions and learn from data.

metabase

O

Overtone is an Open Source toolkit for designing synthesizers and collaborating with music.

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   `Y8b._            _o88P
     `Y888oo.____ooo888P'
        '"PP888888PP''

P

Pedestal is a set of libraries written in Clojure that aims to bring both the language and its principles (Simplicity, Power and Focus) to server-side development.

Here you can find samples.

Q

Quil is a Clojure/ClojureScript library for creating interactive drawings and animations.

S

Selmer. A fast, Django inspired template system for Clojure.

Selmer templates consist of plain text that contains embedded expression and filter tags. While Selmer is primarily meant for HTML generation, it can be used for templating any text.

Selmer compiles the template files and replaces any tags with the corresponding functions for handling dynamic content. The compiled template can then be rendered given a context map.

For example, if we wanted to render a string containing a name variable we could write the following:

(use 'selmer.parser)

(render "Hello {{name}}!" {:name "Yogthos"})
=>"Hello Yogthos!"

To render a file we can call render-file instead:

(use 'selmer.parser)

(render-file "home.html" {:name "Yogthos"})

Specter. Advanced data navigator. Specter rejects Clojure's restrictive approach to immutable data structure manipulation, instead exposing an elegant API to allow any sort of manipulation imaginable. Specter especially excels at querying and transforming nested and recursive data, important use cases that are very complex to handle with vanilla Clojure.

(def data {:a [{:aa 1 :bb 2}
               {:cc 3}]
           :b [{:dd 4}]})

;; Manual Clojure
(defn map-vals [m afn]
  (->> m (map (fn [[k v]] [k (afn v)])) (into (empty m))))

(map-vals data
  (fn [v]
    (mapv
      (fn [m]
        (map-vals
          m
          (fn [v] (if (even? v) (inc v) v))))
      v)))

;; Specter
(transform [MAP-VALS ALL MAP-VALS even?] inc data)

Y

yada — a web library for Clojure, designed to support the creation of production services via HTTP.

Typically, yada handlers are created from a configuation expressed in data.

(require '[yada.yada :as yada])

(yada/handler
  {:methods
    {:get
      {:produces "text/html"
       :response "<h1>Hello World!</h1>"}}})