I am trying to run Aleph on top of Ring and use lein ring server for shorter feedback loop.
When I'm invoking lein ring server everything seems to be fine but when I point my browser to an url I get a nasty NullPointerException with the stack trace below.
However, when I run (al.app/start 3006) then no NLP shows up.
The whole project is available on GitHub.
What am I doing wrong?
core.clj:107 lamina.core/enqueue
app.clj:39 al.app/hello-handler
http.clj:79 aleph.http/wrap-aleph-handler[fn]
response.clj:27 compojure.response/eval1328[fn]
response.clj:10 compojure.response/eval1289[fn]
core.clj:93 compojure.core/make-route[fn]
core.clj:39 compojure.core/if-route[fn]
...
I am using aleph 0.3.2 and that's my code:
(ns al.app
(:use
aleph.http
lamina.core
compojure.core
ring.middleware.keyword-params)
(:require [compojure.route :as route]))
(defn hello-handler
"Our handler for the /hello path"
[ch request]
(let [params (:route-params request)
name (params :name)]
(enqueue ch
{:status 200
:headers {}
:body (str "Hello " name)})))
(defroutes my-routes
(GET ["/hello/:name", :name #"[a-zA-Z]+"] {} (wrap-aleph-handler hello-handler))
(route/not-found "Page not found"))
(defn start
"Start our server in the specified port"
[port]
(start-http-server (wrap-ring-handler my-routes) {:port port}))
The Lein-Ring plugin uses an embedded Jetty web server, while Aleph uses the asynchronous Netty web server. The aleph.http/wrap-aleph-handler middleware is designed only to work with a Netty server started with aleph.http/start-http-server function.
Related
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?
I keep getting "Invalid anti-forgery token" when wrapping specific routes created with metosin/reitit reitit.ring/ring-router. I've also tried reitit's middleware registry, but it didn't work too. Although I could just wrap the entire handler with wrap-session and wrap-anti-forgery, that defeats the reitit's advantage on allowing route-specific middleware.
(ns t.core
(:require [immutant.web :as web]
[reitit.ring :as ring]
[ring.middleware.anti-forgery :refer [wrap-anti-forgery]]
[ring.middleware.content-type :refer [wrap-content-type]]
[ring.middleware.params :refer [wrap-params]]
[ring.middleware.keyword-params :refer [wrap-keyword-params]]
[ring.middleware.session :refer [wrap-session]]
[ring.util.anti-forgery :refer [anti-forgery-field]]
[ring.util.response :as res]))
(defn render-index [_req]
(res/response (str "<form action='/sign-in' method='post'>"
(anti-forgery-field)
"<button>Sign In</button></form>")))
(defn sign-in [{:keys [params session]}]
(println "params: " params
"session:" session)
(res/redirect "/index.html"))
(defn wrap-af [handler]
(-> handler
wrap-anti-forgery
wrap-session
wrap-keyword-params
wrap-params))
(def app
(ring/ring-handler
(ring/router [["/index.html" {:get render-index
:middleware [[wrap-content-type]
[wrap-af]]}]
["/sign-in" {:post sign-in
:middleware [wrap-af]}]])))
(defn -main [& args]
(web/run app {:host "localhost" :port 7777}))
It turns out that metosin/reitit creates one session store for each route (refer to issue 205 for more information); in other words, ring-anti-forgery is not working because reitit does not use the same session store for each route.
As of the time of this answer, the maintainer suggests the following (copied from the issue for ease of reference within Stack Overflow):
mount the wrap-session outside of the router so there is only one instance of the mw for the whole app. There is :middleware option in ring-handler for this:
(require '[reitit.ring :as ring])
(require '[ring.middleware.session :as session])
(defn handler [{session :session}]
(let [counter (inc (:counter session 0))]
{:status 200
:body {:counter counter}
:session {:counter counter}}))
(def app
(ring/ring-handler
(ring/router
["/api"
["/ping" handler]
["/pong" handler]])
(ring/create-default-handler)
;; the middleware on ring-handler runs before routing
{:middleware [session/wrap-session]}))
create a single session store and use it within the routing table (all instances of the session middleware will share the single store).
(require '[ring.middleware.session.memory :as memory])
;; single instance
(def store (memory/memory-store))
;; inside, with shared store
(def app
(ring/ring-handler
(ring/router
["/api"
{:middleware [[session/wrap-session {:store store}]]}
["/ping" handler]
["/pong" handler]])))
Not shown in this answer is the third option that the maintainer calls for PR.
How to get the content of an incoming POST http request's :body #object[org.eclipse.jetty.server.HttpInputOverHTTP 0x42c3599b "HttpInputOverHTTP#42c3599b"] in a Compojure/Ring project?
I know that this :body is composed of a part named data whose MIME-type is text-plain and another part named excel whose MIME-type is application/excel.
I slurped the content of :body and it shows:
Parsing a binary stream manually would be difficult. Wrap your handler as follows:
(wrap-multipart-params handler options)
This middleware parses the body and populates :params parameters with parsed data as well.
See ring.middleware.multipart-params documentation for more details.
I was seeing it in Reitit, what fixed for me was to change the order of the middlewares so the exception-middleware is after the multipart/multipart-middleware.
:middleware [;; multipart
multipart/multipart-middleware
;; exception handling
exception-middleware]
You can find a basic example in the Clojure Cookbook (O'Reilly), which I highly recommend:
(ns ringtest
(:require
[ring.adapter.jetty :as jetty]
clojure.pprint))
;; Echo (with pretty-print) the request received
(defn handler [request]
{:status 200
:headers {"content-type" "text/clojure"}
:body (with-out-str (clojure.pprint/pprint request))})
(defn -main []
;; Run the server on port 3000
(jetty/run-jetty handler {:port 3000}))
When I try and request a resource from a cljs app (running on http://localhost:3000) to my Pedestal server (running on http://localhost:8080) I get the below error. I would like to allow CORS from http://localhost:3000:
XMLHttpRequest cannot load http://localhost:8080/db/query. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access.
I am using cljs-http to send the request from the client. The request looks something like this:
(defn load-server-data
[]
(go
(let [q (<! (http/post "http://localhost:8080/db/query"
{:edn-params {:query '[:find ?rep ?last
:where
[?rep :sales-rep/first-name ?last]]}}))]
(println "q" q))))
The route for /db/query looks like this:
(defroutes routes
[[["/db"
{:post handlers/db-post}
["/query" {:post handlers/db-query}
^:interceptors [interceptors/edn-interceptor]]]]])
This is the handler for /db/query:
(defn db-query
[req]
(let [edn-params (:edn-params req)
q (:query edn-params)
args (:args edn-params)
q-result (apply d/q q (d/db conn) args)]
{:status 200
:body (pr-str q-result)}))
To run the server I execute this function in the REPL.
(defn run-dev
"The entry-point for 'lein run-dev'"
[& args]
(println "\nCreating your [DEV] server...")
(-> service/service
(merge {:env :dev
::server/join? false
::server/routes #(deref #'service/routes)
::server/allowed-origins {:creds true :allowed-origins (constantly true)}})
server/default-interceptors
server/dev-interceptors
server/create-server
server/start))
There does not seem to be much information around CORS for Pedestal. I have looked at the cors example but it seems to just work while mine does not. Is there another interceptor I need to add to my routes or some sort of configuration setting that I am missing here?
I have figured out the problem. It turns out that an error was being thrown, however, it was getting swallowed and hidden from my debugger. Simply adding a try catch around my handler function fixes the problem.
(defn db-query
[req]
(try
(let [edn-params (:edn-params req)
q (:query edn-params)
args (:args edn-params)
q-result (apply d/q q (d/db conn) args)]
{:status 200
:body (pr-str q-result)})
(catch Exception ex
{:status 400
:body "Not authorized"})))
My original response:
The purpose of CORS is to limit the origin of the requests. You have
to purposely tell it where requests can come from. This will fix it.
(def service {;other config stuff
io.pedestal.http/allowed-origins ["http://localhost:3000"]}
It appears this is a duplicate question. Apparently javascript ajax requests are by definition limited to single origin. That code would work in production only if the GET request is made by clj-http or http-kit on the ring server that spawn http://localhost:3000 and then a cljs-http ajax request is made to that same ring server on port 3000. I still don't know why your run-dev doesn't work, but if you're calling lein with run, this is definitely what's happening.
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.