New task: socket-repl

Exposes the Socket Server functionality available in Clojure 1.8 or
above as a task. By default, the handler function is
clojure.core.server/repl, but a different handler can be specified.

boot/core/src/boot/task/built_in.clj

@@ -479,6 +479,28 @@
           (core/with-post-wrap [_]
             (when (or client (not server)) @repl-cli)))))
 
+(core/deftask socket-server
+  "Start a socket server.
+
+  The default behavior is to serve a simple Clojure REPL. To serve a different
+  handler function, specify a symbol using `--accept'.
+
+  If no bind address is specified, the socket server will listen on 127.0.0.1.
+
+  If no port is specified, an open port will be chosen automatically. The port
+  number is written to .socket-port in the current directory.
+
+  The REPL can be accessed with the command
+
+     $ nc localhost $(cat .server-port)"
+
+  [b bind ADDR      str    "The address server listens on."
+   p port PORT      int    "The port to listen to."
+   a accept ACCEPT  sym    "Namespaced symbol of the accept function to invoke."]
+  (let [repl-soc (delay (repl/launch-socket-server *opts*))]
+    (core/with-pass-thru [fs]
+      @repl-soc)))
+
 (core/deftask pom
   "Create project pom.xml file.
 

boot/pod/src/boot/repl.clj

@@ -58,3 +58,21 @@
   [{:keys [bind port init-ns middleware handler] :as options}]
   (let [opts (->> options setup-nrepl-env!)]
     (@start-server opts)))
+
+(defn launch-socket-server
+  "See #boot.task.built-in/socket-server for explanation of options."
+  [{:keys [bind port accept]}]
+  (let [opts {:host (or bind "127.0.0.1")
+              :port (or port 0)
+              :name (gensym "socket-server")
+              :accept (or accept 'clojure.core.server/repl)}]
+    (try
+      (require 'clojure.core.server)
+      (catch java.io.FileNotFoundException e
+        (throw (ex-info "Socket server requires Clojure version 1.8.0 or above"
+                        {:version (clojure-version)}
+                        e))))
+    (let [effective-port (-> ((resolve 'clojure.core.server/start-server) opts)
+                             (.getLocalPort))]
+      (doto (io/file ".socket-port") .deleteOnExit (spit effective-port))
+      (util/info "Socket server started on port %s on host %s.\n" effective-port (:host opts)))))