I'm using compojure for a basic web app, I have this code in core.clj:
(defroutes routes
(GET "/" [] (layout/application "Home" (contents/index)))
(route/resources "/"))
(def application (handler/site routes))
(defn -main []
(let [port (Integer/parseInt (or (System/getenv "PORT") "8090"))]
(jetty/run-jetty application {:port port :join? false})))
When I access the 0.0.0.0:8090 everything is loading ok, but I keep seeing this error:
java.lang.NullPointerException: Response map is nil
at ring.util.servlet$update_servlet_response.invokeStatic(servlet.clj:100)
at ring.util.servlet$update_servlet_response.invoke(servlet.clj:91)
at ring.util.servlet$update_servlet_response.invokeStatic(servlet.clj:95)
at ring.util.servlet$update_servlet_response.invoke(servlet.clj:91)
at ring.adapter.jetty$proxy_handler$fn__337.invoke(jetty.clj:27)
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:132)
at org.eclipse.jetty.server.Server.handle(Server.java:503)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)
at java.base/java.lang.Thread.run(Thread.java:844)
Any idea what's going on?
#Svante is almost certainly correct. An easy way to verify is to use the spyx function from the Tupelo library:
(ns demo.core
(:use tupelo.core))
(defroutes routes
(GET "/" [] (spyx (layout/application "Home" (contents/index))))
(route/resources "/"))
which will print something like:
(layout/application "Home" (contents/index))) => nil
when run. spyx ("spy explicit") prints the expression you give it, an arrow, and the expression value. spy, spyx, spy-pretty, etc also return the value printed (unlike println which always returns nil) so you can insert a spy printout anywhere without disrupting the processing chain. Thus, you don't need to write something like:
(defroutes routes
(GET "/" [] (let [tmp-1 (layout/application "Home" (contents/index))]
(println "layout/application result => " tmp-1)
tmp-1)))
(route/resources "/"))
in order to get a debug message printed. In order to spy & friends, add this to the :dependencies in your project.clj:
[tupelo "0.9.138"]
Update
Hmmmm.... Not sure what could be the problem. I made a simple demo app from lein new compojure demo-compojure with the following:
(ns demo-compojure.handler
(:use tupelo.core)
(:require [compojure.core :refer :all]
[compojure.route :as route]
[ring.middleware.defaults :refer [wrap-defaults site-defaults]]))
(defn index []
(spy :index--result "Hello World"))
(defroutes app-routes
(GET "/" [] (spyx (index)))
(route/not-found "Not Found"))
(def app
(wrap-defaults app-routes site-defaults))
and results:
~/expr/demo-compojure > lein ring server
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Started server on port 3000
:index--result => "Hello World"
(index) => "Hello World"
So that is working. Also, int? is a basic Clojure function, so that is puzzling. Perhaps make a clean demo project like the above and take it from there?
Related
I have a (routes (route/not-found)) definition with value derived from an (atom). Though I've updated the atom, the routing retains the initial value. This is similiar to Dynamic handler update in Clojure Ring/Compojure REPL but I'm having a hard time understanding what needs to be de/referenced where.
(ns mveroute
(:require
[org.httpkit.server :as srv]
[compojure.core :as cmpj]
[compojure.route :as route]
[clj-http.client :as client])
(:gen-class))
(def my-atom (atom "foobar"))
(def app
(cmpj/routes
(route/not-found {:status 400 :body #my-atom})))
(defn -main [& args]
(reset! my-atom "hello world")
(srv/run-server #'app {:port 8005})
;; "hello world" as expected
(println #my-atom)
;; still "foobar" but wanted "hello world"
(-> "http://localhost:8005"
(client/get {:throw-exceptions? false})
:body
println))
I thought warp-routes might have come to the rescue. But not how I've used it.
(defn atom-body [] {:status 200 :body #my-atom})
(cmpj/defroutes wrap-found
(route/not-found (atom-body)))
(def app
(cmpj/wrap-routes #'wrap-found {}))
The ultimate goal is a simple cli application that can set the resource/html root directory with command line arguments.
Try something like the following:
(defn not-found-fn
[req]
{:status 400 :body "not found again!"})
(def app
(cmpj/routes
(route/not-found not-found-fn)))
So inside of not-found-fn, you can construct the :body string any way you like. You could also have the string stored in an atom which is dereferenced by not-found-fn.
Side note:
Please see the following to clarify when you should use a Var object instead of just a symbol in your code:
When to use a Var instead of a function?
I am having a little trouble starting my app.
Here is my core.clj
(ns myapp.core
(:require [yada.yada :as yada :refer [resource as-resource]]
[yada.resources.file-resource :refer [new-directory-resource]]
[aero.core :refer [read-config]]
[web.view :as view]
[web.routes :as routes]
[clojure.java.io :as io]
[aero.core :refer [read-config]]
[com.stuartsierra.component :as component]
[clojure.java.jdbc :as jdbc]
[clojure.tools.namespace.repl :refer (refresh)]
[ring.adapter.jetty :as jetty]
[environ.core :refer [env]]))
(defrecord Listener [listener]
component/Lifecycle
(start [component]
(assoc component :listener (yada/listener
["/"
[(view/view-route)
routes/route-handler
["public/" (new-directory-resource (io/file "target/cljsbuild/public") {})]
[true (as-resource nil)]]] )))
(stop [component]
(when-let [close (-> component :listener :close)]
(close))
(assoc component :listener nil)))
(defn new-system []
(component/system-map
:listener (map->Listener {})
))
(def system nil)
(defn init []
(alter-var-root #'system
(constantly (new-system))))
(defn start []
(alter-var-root #'system component/start))
(defn stop []
(alter-var-root #'system
(fn [s] (when s (component/stop s)))))
(defn go []
(init)
(start))
(defn reset []
(stop)
(refresh :after 'web.core/go))
(defn -main
[& [port]]
(let [port (Integer. (or port (env :port) 3300))]
(jetty/run-jetty (component/start (new-system)) {:port port :join? false})))
I am testing out Stuart Sierra's library, component.
I can start the app if I do lein repl and (go) but I am trying to start my app by running lein run (to see what the app is like if I deployed it in production). When I do lein run in the browser I get the error
HTTP ERROR: 500
Problem accessing /view. Reason:
com.stuartsierra.component.SystemMap cannot be cast to clojure.lang.IFn
I am confused because I don't know why the system-map (in new-system) is the error. I'm also not sure what the error means so I don't know how to fix it
Could someone please help. Thanks
Your -main function calls jetty/run-jetty function first argument of which must be a Ring handler - function which accepts request map and produces response map. You're passing a system instead which leads to the exception. Exception means that jetty adapter tries to call passed system as a function, but can't, because system is actually a record and doesn't implement function interface IFn.
I'm not that familiar with yada, but it looks like yada/listener starts the (Aleph) server, so there's no need to explicitly call the jetty adapter. Your main should look something like this:
(defn -main [& [port]]
(component/start (new-system)))
Port (or any other config) could be passed as an argument to the new-system and then forwarded to components requiring it (in your case port should be passed down to the Listener and then to yada/listener call in start implementation).
I am running Lein 2 and cider 0.7.0. I made a sample ring app that uses ring/run-jetty to start.
(ns nimbus-admin.handler
(:require [compojure.core :refer :all]
[compojure.handler :as handler]
[clojure.tools.nrepl.server :as nrepl-server]
[cider.nrepl :refer (cider-nrepl-handler)]
[ring.adapter.jetty :as ring]
[clojure.tools.trace :refer [trace]]
[ring.util.response :refer [resource-response response redirect content-type]]
[compojure.route :as route])
(:gen-class))
(defroutes app-routes
(GET "/blah" req "blah")
(route/resources "/")
(route/not-found (trace "not-found" "Not Found")))
(def app (handler/site app-routes))
(defn start-nrepl-server []
(nrepl-server/start-server :port 7888 :handler cider-nrepl-handler))
(defn start-jetty [ip port]
(ring/run-jetty app {:port port :ip ip}))
(defn -main
([] (-main 8080 "0.0.0.0"))
([port ip & args]
(let [port (Integer. port)]
(start-nrepl-server)
(start-jetty ip port))))
then connect to it with cider like:
cider-connect 127.0.0.1 7888
I can navigate to my site and eval forms in emacs and it will update what is running live in my nrepl session, so that is great.
I cannot see output, either with (print "test") (println "test") (trace "out" 1)
Finally, my project file:
(defproject nimbus-admin "0.1.0"
:description ""
:url ""
:min-lein-version "2.0.0"
:dependencies [[org.clojure/clojure "1.6.0"]
[com.climate/clj-newrelic "0.1.1"]
[com.ashafa/clutch "0.4.0-RC1"]
[ring "1.3.1"]
[clj-time "0.8.0"]
[midje "1.6.3"]
[org.clojure/tools.nrepl "0.2.6"]
[ring/ring-json "0.3.1"]
[org.clojure/tools.trace "0.7.8"]
[compojure "1.1.9"]
[org.clojure/data.json "0.2.5"]
[org.clojure/core.async "0.1.346.0-17112a-alpha"]
]
:plugins [[lein-environ "1.0.0"]
[cider/cider-nrepl "0.7.0"]]
:main nimbus-admin.handler)
I start the site with lein run
Edit
I CAN see output, ONLY when using (.println System/out msg)
Have you tried (.println System/out msg)? I had the same problem and this worked for me.
It's possible to just put print statements in your code manually.
If you want to print information about each request, you can add middleware.
The handler you pass to jetty is a function from Ring requests to Ring responses.
Ring request and responses are just maps, see the Ring spec for more which keys they should contain.
Middleware is just a function that takes a handler as its first argument and returns a handler.
Example of a middleware function to print basic info about requests and responses:
(defn log-middleware [handler]
(fn [request]
(let [response (handler request)]
(println "=>" (name (:request-method request)) ":" (:uri request))
(println "<=" (:status request))
response)))
This middleware should print to the cider repl buffer, but cider behaves strangely
sometimes and send output to *Messages* or the nrepl server buffer.
You use this middleware by applying it to your handlers:
(def application (log-middleware (handler/site routes)))
Headers could be printed this way to: just get the :headers field form the request map and print it.
The Prone library may help you out. It is has a ring middleware for better exception reporting that also has the ability for debugging. When debugging, you can inspect any local bindings as well as the Ring request.
Here is a video that demonstrates how it works
Use (flush) after your print expressions to force output.
I copied a very basic sample from https://github.com/cgrand/enlive, but it doesn't compile:
(ns web.handler
(:require
[compojure.core :refer :all]
[compojure.handler]
[compojure.route :as route]
[net.cgrand.enlive-html :as html]))
;; Compiler throws in the next line, see the message below.
(html/deftemplate main-template "templates/index.html"
[]
[:head :title] (html/content "Enlive starter kit"))
(defroutes app-routes
(GET "/" [] "Hello")
(GET "/ping/:what" [what] (str "<h1>Ping '" what "'</h1>"))
(route/resources "/")
(route/not-found "Not Found"))
(def app
(compojure.handler/site app-routes))
Error I get:
java.lang.NullPointerException, compiling:(handler.clj:9:1)
I run with command:
lein ring server-headless
How to make it work?
EDIT
My investigation so far: error throw from enlive-html.clj:54:
(defn tagsoup-parser
"Loads and parse an HTML resource and closes the stream."
[stream]
(filter map?
(with-open [^java.io.Closeable stream stream]
(xml/parse (org.xml.sax.InputSource. stream) startparse-tagsoup)))) ; #54
Probably org.xml.sax is not referenced? How can I do this with lein?
That error normally happens when the template file is not found. With templates/index.html, it is looking in the resources/templates directory or in the src/templates directory.
I'm writing a Compojure application and am using clj-webdriver to graphically test it. I'm trying to use with-redefs to mock out the function that pulls out data from persistence to just return canned values, but it's ignoring my function overwrite. I know with-redefs works in terms of vars, but it's still not working:
project.clj relevant pieces:
(defproject run-hub "0.1.0-SNAPSHOT"
:main run-hub.handler/start-server)
handler.clj:
(ns run-hub.handler
(:require [compojure.core :refer :all]
[compojure.handler :as handler]
[compojure.route :as route]
[ring.adapter.jetty :refer :all]
[run-hub.controllers.log-controller :as log-controller]))
(defroutes app-routes
(GET "/MikeDrogalis/log" [] (log-controller/mikes-log))
(route/resources "/")
(route/not-found "Not Found"))
(def app (handler/site #'app-routes))
log-controller.clj:
(ns run-hub.controllers.log-controller
(:require [run-hub.views.log :as views]
[run-hub.persistence :as persistence]))
(defn mikes-log []
(views/mikes-log (persistence/mikes-log)))
persistence.clj
(ns run-hub.persistence
(require [clj-time.core :as time]
[run-hub.models.log :as log]))
(defn mikes-log [] [])
And finally, my graphical test - which tries to override mikes-log and fails:
(fact
"It has the first date of training as August 19, 2012"
(with-redefs [persistence/mikes-log (fn [] (one-week-snippet))]
(to (local "/MikeDrogalis/log"))
(.contains (text "#training-log") "August 19, 2012"))
=> true)
Where one-week-snippet is a function that returns some sample data.
(defn start-server []
(run-jetty (var app) {:port 3000 :join? false}))
I am able to use with-redefs in a clj-webdriver test doing the following:
(defn with-server
[f]
(let [server (run-jetty #'APP {:port 0 :join? false})
port (-> server .getConnectors first .getLocalPort)]
(binding [test-port port]
(try
(println "Started jetty on port " test-port)
(f)
(finally
(.stop server))))))
(use-fixtures :once with-server)
Then the whole bunch of tests gets its own jetty and this seems to run in
such a manner that with-redefs works.