How to Run Jetty Example with Ring in Clojure -

i following along this example on creating simple web service in clojure using ring , jetty.

i have in project.clj:

(defproject ws-example "0.0.1"   :description "rest datastore interface."   :dependencies     [[org.clojure/clojure "1.5.1"]      [ring/ring-jetty-adapter "0.2.5"]      [ring-json-params "0.1.0"]      [compojure "0.4.0"]      [clj-json "0.5.3"]]    :dev-dependencies      [[lein-run "1.0.0-snapshot"]]) 

this in script/run.clj

(use 'ring.adapter.jetty) (require '[ws-example.web :as web])  (run-jetty #'web/app {:port 8080}) 

and in src/ws_example/web.clj

(ns ws-example.web   (:use compojure.core)   (:use ring.middleware.json-params)   (:require [clj-json.core :as json]))  (defn json-response [data & [status]]   {:status (or status 200)    :headers {"content-type" "application/json"}    :body (json/generate-string data)})  (defroutes handler   (get "/" []     (json-response {"hello" "world"}))    (put "/" [name]     (json-response {"hello" name})))  (def app   (-> handler     wrap-json-params)) 

however, when execute:

lein run script/run.clj 

i error:

no :main namespace specified in project.clj. 

why getting , how fix it?

you're getting error because purpose of lein run (according lein run) "run project's -main function." don't have -main function in ws-example.web namespace, nor have :main specified in project.clj file, lein run complaining about.

to fix this, have few options. move run-jetty code new -main function of ws-example.web function , lein run -m ws-example.web. or , add line :main ws-example.web project.clj , lein run. or try using lein exec plugin execute file, rather namespace.

for more info, check out leiningen tutorial.