Hi Ray, I don't entirely understand why you expected this to work. Channels aren't a valid Ring response body. The error message is essentially telling you that Compojure has no way of turning the channel object you've returned into a valid response.
The other problem you have is that the Ring Jetty adapter doesn't have any support for asynchronous operations. Another small point. You're using "*" as an argument name, but this isn't really recommended. This only works by coincidence, and it may be removed in future versions. Instead use something like: (GET ["/:brand/:country/:resource" :resource #".*"] [brand country resource] ...) - James On 27 September 2014 00:14, mond <r...@mcdermott.be> wrote: > My first core.async program ... all works outside of the web app but barfs > once I put the functions inside a web container. I hope somebody in the > group can point to my obvious mistake... > > The idea is that the function 'respond-within-sla' will give back a result > or a come back later message after N milliseconds. It is passed a number of > ms, three functions and the arguments for the final function ... which is > the one that should operate within the SLA. > > (defn respond-within-sla [expected-result-milliseconds respond-ok > respond-later data-fetcher & args] > (let [data-channel (timeout expected-result-milliseconds)] > (go (if-let [data (<!! data-channel)] > ((async/close! data-channel) > (respond-ok data)) > (respond-later))) > (go > (>! data-channel (apply data-fetcher args))))) > > To keep the volume of code to parse to a minimum I have made a few toy > functions that demonstrate the failure... > > ; test funcs > > (defn ok [data] > (prn (str "send HTTP 200 ... got data " data))) > > (defn later [] > (prn (str "send HTTP 202 ... request received, come back later"))) > > (defn fetcher [arg1 arg2 arg3] > (prn (str "fetching data with args " arg1 " " arg2 " " arg3)) > "response-data") > > (defn failer [& args] > (Thread/sleep 1000) > (str "never gets here " args)) > > ; test funcs > > (defn ok [data] > (prn (str "send HTTP 200 ... got data " data))) > > (defn later [] > (prn (str "send HTTP 202 ... request received, come back later"))) > > (defn fetcher [arg1 arg2 arg3] > (prn (str "fetching data with args " arg1 " " arg2 " " arg3)) > "response-data") > > (defn failer [& args] > (Thread/sleep 1000) > (str "never gets here " args)) > > (defn generate-response [brand country resource] > (let [sla (or (env :sla-milliseconds) 100)] > (respond-within-sla sla ok later fetcher brand country resource))) > > (defn generate-fail [brand country resource] > (let [sla (or (env :sla-milliseconds) 100)] > (respond-within-sla sla ok later failer brand country resource))) > > From within the REPL it all works fine... > > (generate-response "A" "B" "C") > => #<ManyToManyChannel > clojure.core.async.impl.channels.ManyToManyChannel@4b7ae3f7> > "fetching data with args A B C" > "send HTTP 200 ... got data response-data" > (generate-fail "A" "B" "C") > => #<ManyToManyChannel > clojure.core.async.impl.channels.ManyToManyChannel@4eb8b5a9> > "send HTTP 202 ... request received, come back later" > > Here is the compojure route.. > > (defroutes app > (GET "/:brand/:country/*" [brand country *] > (generate-response brand country *)) > > (ANY "*" [] > (route/not-found "You must use a REST style to specify > brand and country keys in the URL"))) > > If I now start it up 'lein run' and try to exercise the functions from the > web server... > > $ curl -I http://localhost:5000/A/B/D.jpg > HTTP/1.1 500 Server Error > Date: Fri, 26 Sep 2014 23:02:03 GMT > Content-Length: 0 > Connection: close > Server: Jetty(7.6.8.v20121106) > > And on the server I see this: > > $ lein run > Compiling redirector.web > 2014-09-27 01:01:48.426:INFO:oejs.Server:jetty-7.6.8.v20121106 > 2014-09-27 01:01:48.458:INFO:oejs.AbstractConnector:Started > SelectChannelConnector@0.0.0.0:5000 > 2014-09-27 01:02:03.535:WARN:oejs.AbstractHttpConnection:/A/B/D.jpg > java.lang.IllegalArgumentException: No implementation of method: :render > of protocol: #'compojure.response/Renderable found for class: > clojure.core.async.impl.channels.ManyToManyChannel > at clojure.core$_cache_protocol_fn.invoke(core_deftype.clj:544) > at compojure.response$fn__213$G__208__220.invoke(response.clj:9) > at compojure.core$make_route$fn__332.invoke(core.clj:100) > at compojure.core$if_route$fn__320.invoke(core.clj:46) > at compojure.core$if_method$fn__313.invoke(core.clj:33) > at compojure.core$routing$fn__338.invoke(core.clj:113) > at clojure.core$some.invoke(core.clj:2515) > at compojure.core$routing.doInvoke(core.clj:113) > at clojure.lang.RestFn.applyTo(RestFn.java:139) > at clojure.core$apply.invoke(core.clj:626) > at compojure.core$routes$fn__342.invoke(core.clj:118) > at clojure.lang.Var.invoke(Var.java:379) > at > ring.middleware.keyword_params$wrap_keyword_params$fn__534.invoke(keyword_params.clj:35) > at > ring.middleware.nested_params$wrap_nested_params$fn__576.invoke(nested_params.clj:84) > at ring.middleware.params$wrap_params$fn__507.invoke(params.clj:64) > at > ring.middleware.multipart_params$wrap_multipart_params$fn__612.invoke(multipart_params.clj:118) > at ring.middleware.flash$wrap_flash$fn__1286.invoke(flash.clj:35) > at ring.middleware.session$wrap_session$fn__1273.invoke(session.clj:98) > at ring.adapter.jetty$proxy_handler$fn__1426.invoke(jetty.clj:18) > at > ring.adapter.jetty.proxy$org.eclipse.jetty.server.handler.AbstractHandler$ff19274a.handle(Unknown > Source) > at > org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116) > at org.eclipse.jetty.server.Server.handle(Server.java:363) > at > org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:483) > at > org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:920) > at > org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:982) > at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:635) > "fetching data with args A B D.jpg" > at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235) > at > org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82) > at > org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:628) > at > org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52) > at > org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608) > at > org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543) > at java.lang.Thread.run(Thread.java:744) > "send HTTP 200 ... got data response-data" > > FYI I have tested the functions prior to adding the core.async code and > they all work fine from within Jetty and on Heroku. > > It seems like somehow I am getting the wrong thing put into my response. > > I am guessing that I have configured something wrong so here is my > project.clj > > (defproject redirector "1.0.0-SNAPSHOT" > :description "Clojure HTTP redirector" > :url "http://redirector.herokuapp.com"; > :license {:name "Eclipse Public License v1.0" > :url "http://www.eclipse.org/legal/epl-v10.html"} > :dependencies [[org.clojure/clojure "1.6.0"] > [compojure "1.1.9"] > [ring/ring-jetty-adapter "1.2.2"] > [com.novemberain/monger "2.0.0"] > [com.taoensso/carmine "2.7.0"] > [environ "0.5.0"] > [org.clojure/core.async "0.1.346.0-17112a-alpha"]] > :min-lein-version "2.0.0" > :plugins [[environ/environ.lein "0.2.1"]] > :hooks [environ.leiningen.hooks] > :main "redirector.web" > :aot :all > :uberjar-name "redirector-standalone.jar" > :profiles {:production {:env {:production true}}}) > > Any ideas, help would be greatly appreciated. > > Thanks > > Ray > > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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