Tim,
Your middleware never sends a response. Each request message can produce
multiple response messages, sent at some later time (i.e. the request/response
cycle is fundamentally asynchronous). Handler return values are ignored.
So, assoc'ing the "result" into the request message as the return value of the
handler function won't do anything. You need to construct a response message
and send it on the transport hanging off of the request message; here's a
concise real-world example from ritz:
https://github.com/pallet/ritz/blob/develop/nrepl-middleware/src/ritz/nrepl/middleware/doc.clj
And, be a mensch, and send a "done" status in the response, too, so
message-scoped response seqs terminate properly without waiting for the read
timeout to expire. :-)
Cheers,
- Chas
On Dec 26, 2012, at 5:55 PM, Timothy Washington wrote:
> Hi all,
>
> I'm trying to put together some nrepl middleware. To get a basic
> understanding, I thought I would implement some simple nrepl middleware in a
> test project as seen in A). I can execute `M-x nrepl-jack-in`. But executing
> the client, gives me an empty result (`repl/response-values` pulls nil out of
> ()). So I tried a bare bones communication example in the middleware page
> (see B), but am still getting an error.
>
> I like the example given in the leiningen sample project. But it seems I need
> to get the basics working in A) and B), first.
>
> Any insights here? Ultimately, I would like to create nrepl middleware for i)
> Clojurescript compilation (cljsbuild auto (yes, I've already looked at
> hiredman/nrepl-cljs-middleware)) and ii) a browser-connected repl (cljsbuild
> repl-listen). I want to have these facilities in a `M-x nrepl-jack-in`
> session.
>
>
> A) basic nrepl middleware
>
> project.clj (https://www.refheap.com/paste/7875)
> middleware.clj (https://www.refheap.com/paste/7874)
> client.clj (https://www.refheap.com/paste/7876)
>
> B) lein repl
>
> $ lein new thing
> ...
> $ cd thing/
> $ lein repl
>
> nREPL server started on port 38789
> ...
> user=> (require '[clojure.tools.nrepl :as repl])
> nil
>
> user=>
> user=> (with-open [conn (repl/connect :port 38789)]
> #_=> (-> (repl/client conn 1000)
> #_=> (repl/message {:op "eval" :code "(+ 2 3)"})
> #_=> repl/response-values))
>
> Exception in thread "nREPL-worker-2" nil
> user=> java.net.SocketException: Broken pipe
> at java.net.SocketOutputStream.socketWrite0(Native Method)
> at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
> at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
> at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
> at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
> at clojure.tools.nrepl.transport$bencode$fn__214.invoke(transport.clj:81)
> at clojure.tools.nrepl.transport.FnTransport.send(transport.clj:27)
> at
> clojure.tools.nrepl.middleware.pr_values$pr_values$fn$reify__479.send(pr_values.clj:23)
> at
> clojure.tools.nrepl.middleware.interruptible_eval$interruptible_eval$fn__536$fn__538.invoke(interruptible_eval.clj:171)
> at clojure.core$comp$fn__4034.invoke(core.clj:2278)
> at
> clojure.tools.nrepl.middleware.interruptible_eval$run_next$fn__529.invoke(interruptible_eval.clj:137)
> at clojure.lang.AFn.run(AFn.java:24)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:619)
>
>
>
> Thanks in advance
>
> Tim Washington
> Interruptsoftware.ca
>
>
>
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