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;;;; Demo Clojure IRC server
;;;; Limitations:
;;;; No server-server connect
;;;; Only partially implemented basic commands (channel and private messages)
;;;; no channel modes, no ops, no bans
;;;; Straightforward algorithms, no optimisation
;;;; User-id is lowercased nickname. It changes and it is exposed to user instead of nickname.
;;;; Implemented by Vitaly "_Vi" Shukela; 2010; MIT License.
(ns irc
(:import ( BufferedReader InputStreamReader OutputStreamWriter))
(:use server.socket)
(:use [clojure.string :only [split join upper-case lower-case trim blank?]])
;; state
(def users (ref {}))
(def channels (ref {}))
(def channel-topics (ref {}))
;; print info to stdout (*out* is overridden)
(defn log [& args] (. java.lang.System/out println (apply str (interpose "|\t" args))))
;; server to client communication
(defn irc-reply [user code text & args] "Prints text like \":irc.clj 251 q :There are 2 users on the server\""
(locking *out* (print (format ":irc.clj %s %s %s\r\n" code user (apply format text args)))))
(defn ^{:private true} ircmsg2-impl [from cmd msg]
(locking *out* (print (format ":%s %s %s\r\n" from cmd msg)) (flush) ))
(defn irc-event "Print text like \":_Vi JOIN #qqq :User joined the channel\""
([from cmd solearg] (ircmsg2-impl from cmd (str ":" solearg)))
([from cmd arg & args] (ircmsg2-impl from cmd (str (join " " (cons arg (butlast args))) " :" (last args)))))
(defn greet [newuser] "Welcome message for user (after \"NICK\" command)"
(irc-reply newuser "001" "Welcome to _Vi's Clojure IRC \"server\"")
(irc-reply newuser "002" "I don't know what your host is")
(irc-reply newuser "003" "I don't know when this server was created")
(irc-reply newuser "004" "irc.clj 0.1 ")
(irc-reply newuser "005" "PREFIX=(ov)@+ NETWORK=demo CHANTYPES=# : are supported by this demo")
(irc-reply newuser "251" ":There are %d users on the server." (count (dosync @users)))
(irc-reply newuser "254" "%d :channels formed" (count (dosync @channels)))
(irc-reply newuser "375" "MoTH")
(irc-reply newuser "376" "End of MoTH"))
(defmacro try-output-to [writer# & code]
(binding [*out* ~writer#]
(catch Exception e# (.printStackTrace e#))))
(defn broadcast [function] "Send message to all users. Argument is closure to execute."
(doall (map #(try-output-to (get (second %1) :out)
(function)) (dosync @users))))
(defn channel-multicast "Send message to all channel participants (except of ignore-user). Argument is closure to execute"
([channel function ignore-user]
(doall (map #(when (not= %1 ignore-user)
(try-output-to (get (get (dosync @users) %1) :out)
([channel function] (channel-multicast channel function nil)))
;; state update functions
(defn remove-user! [user-id]
(dosync (alter users #(dissoc %1 user-id))))
(defn add-user! [user-id nick] "Add user. If already exists returns true"
(if (contains? @users user-id)
(do (alter users #(conj %1 {user-id {:nick nick, :out *out*, :user-id user-id}})) false)
(defn change-nick-on-all-channels! [old-user-id new-user-id]
(dosync (alter channels #(into {} (for [[k v] %1] [k (if (contains? v old-user-id) (conj (disj v old-user-id) new-user-id) v)])))))
(defn remove-user-from-channels [user-id]
(dosync (alter channels #(into {} (for [[k v] %1] [k (disj v user-id)])))))
(defn join-channel! [user-id channel] "Create channel or add user to it"
(alter channel-topics (fn [chs] (update-in chs [channel] #(if %1 %1 ""))))
(alter channels (fn[chs] (update-in chs [channel] #(conj (set %1) user-id))))))
(defn part-channel! [user-id channel] "Remove user from channel. Returns false if channel does not exist"
(if (contains? @channels channel)
(do (alter channels (fn[chs] (update-in chs [channel] #(disj %1 user-id)))) true)
(defn update-channel-topic! [channel new-topic] "Update topic on channel. Returns false if no such channel"
(if (contains? @channels channel)
(do (alter channel-topics (fn[chs] (update-in chs [channel] (fn[_]new-topic)))) true)
(defn get-user-id [nick] (lower-case (trim nick)))
;; IRC command handlers
(defmulti command (fn [^String user command-name & args] command-name))
(defmethod command "NICK"
([user _] (irc-reply user "431" ":No nickname given") user)
([user _ nick & args] (irc-reply user "431" ":Extra arguments for NICK") user)
([user _ nick]
(if (re-find #"^[\]\[{}\\|_^a-zA-Z][\]\[{}\\|_^a-zA-Z0-9\-]{0,255}$" nick)
(let [user-id (get-user-id nick)
already-present (add-user! user-id nick)]
(if already-present
(irc-reply user "433" "%s :Nickname already in use." nick)
(if (= user "*")
(greet nick) ; if it is the first "NICK" command in this session then greet user
(let [old-user-id (get-user-id user)] ; else it is renaming
(remove-user! old-user-id)
(broadcast #(irc-event user "NICK" nick))
(change-nick-on-all-channels! old-user-id user-id)))
(irc-reply user "432" "%s :Erroneous Nickname: Nickname should match [][{}\\|_^a-zA-Z][][{}\\|_^a-zA-Z0-9-]{0,255}" nick)
(defmethod command "PRIVMSG"
([user _ recepient message]
(let [ruser-id (get-user-id recepient)]
(if (= (first ruser-id) \#)
(let [chs (dosync @channels)]
(if (contains? chs ruser-id)
(channel-multicast (get chs ruser-id) #(irc-event user "PRIVMSG" recepient message) (get-user-id user))
(irc-reply user "401" "%s :No such nick/channel" recepient)))
(let [usrs (dosync @users)]
(if (contains? usrs ruser-id)
(try-output-to (get (get usrs ruser-id) :out)
(irc-event user "PRIVMSG" recepient message))
(irc-reply user "401" "%s :No such nick/channel" recepient))))))
([user _] (irc-reply user "412" ":Not enought arguments for PRIVMSG"))
([user _ recepient] (irc-reply user "412" ":Not enought arguments for PRIVMSG"))
([user _ recepient message & args] (irc-reply user "412" ":Extra arguments for PRIVMSG")))
(defmethod command "JOIN"
([user _ channel-name]
(let [channel (get-user-id channel-name)]
(if (re-find #"^#[\#\]\[{}\\|_^a-z0-9]{0,29}$" channel)
(join-channel! (get-user-id user) channel)
(let [chs (dosync @channels), ch (get chs channel)]
(channel-multicast ch #(irc-event user "JOIN" channel "User joined the channel"))
(irc-reply user "332" "%s :%s" channel (dosync (get @channel-topics channel)))
;(irc-reply user "333" "%s :none 0" channel)
(irc-reply user "353" "@ %s :%s" channel (join " " ch))
(irc-reply user "366" "%s :End of /NAMES list." channel)
(irc-reply user "479" "%s :Illegal channel name" channel) )))
([user _] (irc-reply user "412" ":Not enought arguments for JOIN"))
([user _ channel & args] (irc-reply user "412" ":Extra arguments for JOIN")))
(defmethod command "PART"
([user _ channel-name message]
(let [channel (get-user-id channel-name), user-id (get-user-id user)]
(if(part-channel! user-id channel)
(broadcast #(irc-event user "PART" channel message))
(irc-reply user "403" "%s :No such channel" channel))))
([user _] (irc-reply user "412" ":Not enought arguments for PART"))
([user _ channel message & args] (irc-reply user "412" ":Extra arguments for PART"))
([user _ channel] (command user "PART" channel "User have left this channel")))
(defmethod command "TOPIC"
([user _ channel-name new-topic]
(let [channel (get-user-id channel-name)]
(if (update-channel-topic! channel new-topic)
(broadcast #(irc-event user "TOPIC" channel new-topic))
(irc-reply user "403" (format "%s :No such channel" channel)))))
([user _] (irc-reply user "412" ":Not enought arguments for TOPIC"))
([user _ channel] (irc-reply user "332" "%s :%s" channel (dosync (get @channel-topics channel))))
([user _ channel topic & args] (irc-reply user "412" ":Extra arguments for TOPIC")))
(defmethod command :default [user cmd-name & args]
(irc-reply user "421" "%s: Unknown command" cmd-name))
(defmethod command "TEST" [user & args]
(doall (map #(irc-reply user "421" "TEST :Parameter is \"%s\"" %) args)))
(defmethod command "PING" [user _ & args]
(println ":irc.clj PONG irc.lcj :irc.clj"))
(defmethod command "LIST" [user _ & args]
(doall (for [[k v] (dosync @channels)] (irc-reply user "322" (format "%s %d :%s" k (count v) (dosync (get @channel-topics k)))) ))
(irc-reply user "323" ":End of /LIST"))
(defmethod command "DEBUG" [user _ & args]
(irc-reply user "000" (format ": Debug %s" (dosync [@users @channels @channel-topics]))))
(defmethod command "USER" [user _ & args])
(defmethod command "QUIT" [user _ & args])
(defmethod command "MODE" [user _ & args])
(defmethod command "" [user _ & args])
(defn unregister-user [user]
(let [user-id (get-user-id user)]
(remove-user! user-id)
(broadcast #(irc-event user "QUIT" user "Connection closed"))
(remove-user-from-channels user-id)))
(defn parse-irc-command-line [^String line] "Returns vector: command name and it's arguments, all strings. Sole empty string on empty input"
(let [
colon-search-result (re-find #"(.*):(.*)" line)
; the list of splittable parameters (including the command name) we need to split by ' ' and the final parameter after ':' (it may be nil)
[splittable-parameters final-parameter-as-vector]
(if colon-search-result
#_"example: TOPIC #qqq :Qqq qq!" [(nth colon-search-result 1) [(nth colon-search-result 2)]]
#_"example: TOPIC #qqq Qqq" [line nil]) ]
(into (into [] (split (trim splittable-parameters) #"\s+")) final-parameter-as-vector)))
(defn execute-irc-command-line [user ^String line] "Returns nick (possibly updated by \"NICK\" command)"
(let [[command-name-pre & args] (parse-irc-command-line line)
command-name (upper-case command-name-pre)]
(if (and (= user "*") (not (contains? #{"NICK" "DEBUG" "QUIT" "PING" ""} command-name)))
(do (irc-reply user "451" ":You are not registered") user)
(let [new-user (apply command user command-name args)]
(case command-name
"NICK" new-user
"QUIT" (str "~" user)
(defn irc-server [port]
(letfn [(irc [in out]
(binding [*in* (BufferedReader. (InputStreamReader. in))
*out* (OutputStreamWriter. out)]
(irc-reply "*" "439" ":Supply your NICK to procceed")
(loop [user "*"]
(if (not= (first user) \~); User becomes "~User" on QUIT command
(let [line (read-line)]
(if line
(log user line)
(recur (try
(let [user (execute-irc-command-line user line)]
(catch Exception e (.printStackTrace e) (irc-reply user "400" ":Error") (flush) user))))
(recur (str "~" user))))
(unregister-user (#_"removes the first character" apply str (next user)))))))]
(create-server port irc)))
(defn -main []
(let [
envport (System/getenv "IRC_PORT")
port (if envport (Integer. envport) 6667)
(log (str "IRC_PORT=" envport " ; using port " port))
(irc-server port)))