core.clj

(ns snapper.core
  (:require [ring.adapter.jetty :as jetty]
            [clojure.java.io    :as io]
            [ring.util.io       :as ringio])
  (:gen-class))


(defn handler
  "Respond with a stream"
  [request]

  (let [input-stream
        (ringio/piped-input-stream
          (fn [output-stream]
            (try
              (.write output-stream 97)
              (Thread/sleep 500)
              (.write output-stream 97)
              (.close output-stream)
            (catch Exception e
              (println "Caught" (.getMessage e)) "failure")
            )
        ))]
    {
     :status 200
     :headers {}
     :body input-stream
    }
  )
)

(defn -main
  [& args]
  (jetty/run-jetty handler {:port 8081})
)

curl-out.txt

oration ~/C/snapper  (master*) ➜  curl -v localhost:8081
* About to connect() to localhost port 8081 (#0)
*   Trying ::1...
* connected
* Connected to localhost (::1) port 8081 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8r zlib/1.2.5
> Host: localhost:8081
> Accept: */*
> 
< HTTP/1.1 200 OK
< Date: Thu, 03 Jan 2013 21:10:41 GMT
< Content-Length: 0
< Server: Jetty(7.6.1.v20120215)
< 
* Connection #0 to host localhost left intact
* Closing connection #0