/
server.clj
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server.clj
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(ns nrepl.server
"Default server implementations"
{:author "Chas Emerick"}
(:require
[nrepl.ack :as ack]
[nrepl.middleware.dynamic-loader :as dynamic-loader]
[nrepl.middleware :as middleware]
nrepl.middleware.completion
nrepl.middleware.interruptible-eval
nrepl.middleware.load-file
nrepl.middleware.lookup
nrepl.middleware.session
nrepl.middleware.sideloader
[nrepl.misc :refer [log response-for returning]]
[nrepl.transport :as t])
(:import
[java.net InetSocketAddress ServerSocket]))
(defn handle*
[msg handler transport]
(try
(handler (assoc msg :transport transport))
(catch Throwable t
(log t "Unhandled REPL handler exception processing message" msg))))
(defn- normalize-msg
"Normalize messages that are not quite in spec. This comes into effect with
The EDN transport, and other transports that allow more types/data structures
than bencode, as there's more opportunity to be out of specification."
[msg]
(cond-> msg
(keyword? (:op msg)) (update :op name)))
(defn handle
"Handles requests received via [transport] using [handler].
Returns nil when [recv] returns nil for the given transport."
[handler transport]
(when-let [msg (normalize-msg (t/recv transport))]
(future (handle* msg handler transport))
(recur handler transport)))
(defn- safe-close
[^java.io.Closeable x]
(try
(.close x)
(catch java.io.IOException e
(log e "Failed to close " x))))
(defn- accept-connection
[{:keys [^ServerSocket server-socket open-transports transport greeting handler]
:as server}]
(when-not (.isClosed server-socket)
(let [sock (.accept server-socket)]
(future (let [transport (transport sock)]
(try
(swap! open-transports conj transport)
(when greeting (greeting transport))
(handle handler transport)
(finally
(swap! open-transports disj transport)
(safe-close transport)))))
(future (accept-connection server)))))
(defn stop-server
"Stops a server started via `start-server`."
[{:keys [open-transports ^ServerSocket server-socket] :as server}]
(returning server
(.close server-socket)
(swap! open-transports
#(reduce
(fn [s t]
;; should always be true for the socket server...
(if (instance? java.io.Closeable t)
(do
(safe-close t)
(disj s t))
s))
% %))))
(defn unknown-op
"Sends an :unknown-op :error for the given message."
[{:keys [op transport] :as msg}]
(t/send transport (response-for msg :status #{:error :unknown-op :done} :op op)))
(def default-middleware
"Middleware vars that are implicitly merged with any additional
middleware provided to nrepl.server/default-handler."
[#'nrepl.middleware/wrap-describe
#'nrepl.middleware.completion/wrap-completion
#'nrepl.middleware.interruptible-eval/interruptible-eval
#'nrepl.middleware.load-file/wrap-load-file
#'nrepl.middleware.lookup/wrap-lookup
#'nrepl.middleware.session/add-stdin
#'nrepl.middleware.session/session
#'nrepl.middleware.sideloader/wrap-sideloader
#'nrepl.middleware.dynamic-loader/wrap-dynamic-loader])
(def built-in-ops
"Get all the op names from default middleware automatically"
(->> default-middleware
(map #(-> % meta :nrepl.middleware/descriptor :handles keys))
(reduce concat)
set))
(def ^{:deprecated "0.8.0"} default-middlewares
"Use `nrepl.server/default-middleware` instead. Middleware"
default-middleware)
(defn default-handler
"A default handler supporting interruptible evaluation, stdin, sessions,
readable representations of evaluated expressions via `pr`, sideloading, and
dynamic loading of middleware.
Additional middleware to mix into the default stack may be provided; these
should all be values (usually vars) that have an nREPL middleware descriptor
in their metadata (see `nrepl.middleware/set-descriptor!`).
This handler bootstraps by initiating with just the dynamic loader, then
using that to load the other middleware."
[& additional-middleware]
(let [initial-handler (dynamic-loader/wrap-dynamic-loader nil)
state (atom {:handler initial-handler
:stack [#'nrepl.middleware.dynamic-loader/wrap-dynamic-loader]})]
(binding [dynamic-loader/*state* state]
(initial-handler {:op "swap-middleware"
:state state
:middleware (concat default-middleware additional-middleware)}))
(fn [msg]
(binding [dynamic-loader/*state* state]
((:handler @state) msg)))))
(defrecord Server [server-socket port open-transports transport greeting handler]
java.io.Closeable
(close [this] (stop-server this)))
(defn start-server
"Starts a socket-based nREPL server. Configuration options include:
* :port — defaults to 0, which autoselects an open port
* :bind — bind address, by default \"127.0.0.1\"
* :handler — the nREPL message handler to use for each incoming connection;
defaults to the result of `(default-handler)`
* :transport-fn — a function that, given a java.net.Socket corresponding
to an incoming connection, will return a value satisfying the
nrepl.Transport protocol for that Socket.
* :ack-port — if specified, the port of an already-running server
that will be connected to inform of the new server's port.
Useful only by Clojure tooling implementations.
* :greeting-fn - called after a client connects, receives
a nrepl.transport/Transport. Usually, Clojure-aware client-side tooling
would provide this greeting upon connecting to the server, but telnet et
al. isn't that. See `nrepl.transport/tty-greeting` for an example of such
a function.
Returns a (record) handle to the server that is started, which may be stopped
either via `stop-server`, (.close server), or automatically via `with-open`.
The port that the server is open on is available in the :port slot of the
server map (useful if the :port option is 0 or was left unspecified."
[& {:keys [port bind transport-fn handler ack-port greeting-fn]}]
(let [port (or port 0)
addr (fn [^String bind ^Integer port] (InetSocketAddress. bind port))
transport-fn (or transport-fn t/bencode)
;; We fallback to 127.0.0.1 instead of to localhost to avoid
;; a dependency on the order of ipv4 and ipv6 records for
;; localhost in /etc/hosts
bind (or bind "127.0.0.1")
ss (doto (ServerSocket.)
(.setReuseAddress true)
(.bind (addr bind port)))
server (Server. ss
(.getLocalPort ss)
(atom #{})
transport-fn
greeting-fn
(or handler (default-handler)))]
(future (accept-connection server))
(when ack-port
(ack/send-ack (:port server) ack-port transport-fn))
server))