EDIT - The source code is on github if you're interested. Thanks
I am a bit confused as to how to access json data that has been posted to a url in clojure; I just can't seem to get it to work.
This is my route:
(cc/POST "/add"
request
(str ": " request))
I am not entirely sure what I have to put in place of request - I just saw some blog online and tried to follow it, but couldn't get it to work.
Here's how I'm trying to post: (from fiddler)
note: request header port is different in the image; it's a mistake, I was trying to mess with that data to see what it says so ignore that part in the above image please
In curl, I'm just doing this:
curl -X POST -H "Content-Type: application/json" -d '{"foo":"bar","baz":5}'
http://localhost:3005/add
It looks like clojure is not receiving the json data that I posted at all.
Here's what the request var contains:
: {:scheme :http, :query-params {}, :form-params {}, :request-method :post,
:query-string nil, :route-params {}, :content-type "\"application/json\"",
:uri "/event", :server-name "localhost", :params {},
:headers {"user-agent" "Fiddler", "content-type" "\"application/json\"",
"content-length" "23", "host" "localhost:3005"},
:content-length 23, :server-port 3005, :character-encoding nil, :body #}
As you can see, all params are empty...
I am using compojure and cheshire - and I can convert data into json and return them just fine for GET routes.. I need to figure out how to pass json and convert it into clojure data..
thanks
That's because :params is filled by a ring middleware which deals with "form-encoded" body.
You can use ring-json to wrap your application into this other middleware. It will parse the JSON body and fill :params accordingly. (https://github.com/ring-clojure/ring-json)
Here is an example that does what you want. The code was taken from this project. In the README you will see some of the access patterns that this supports. The code is a little messy, but it should illustrate how this can be done.
(ns poky.protocol.http.jdbc.text
(:require [poky.kv.core :as kv]
(compojure [core :refer :all]
[route :as route]
[handler :as handler])
[ring.util.response :refer [response not-found]]
(ring.middleware [format-response :as format-response ]
[format-params :as format-params])
[cheshire.core :as json]
[ring.middleware.stacktrace :as trace]))
;
; curl -d"some data" -H'Content-Type: application/text' -v -X PUT http://localhost:8080/xxx
; curl -d'{"bla":"bar"}' -H'Content-Type: application/json' -v -X PUT http://localhost:8080/bla
(def valid-key-regex #"[\d\w-_.,]+")
; FIXME: this should be split- one fn for get, one for mget
(defn- wrap-get
[kvstore ks params headers body]
(response
(let [eks (clojure.string/split ks #",")
nks (count eks)
multi (> nks 1)
ret (if multi (kv/mget* kvstore eks) (kv/get* kvstore ks))]
(condp = (get headers "accept")
"application/json" ret
"text/plain" (if multi (throw (Exception. "Multi get unsupported with Accept: text/plain")) (get ret ks))
ret))))
(defn- wrap-put
[kvstore ks params headers body]
(if (and
(= (get headers "content-type") "application/json")
(get params (keyword ks) nil))
(kv/set* kvstore ks (get params (keyword ks)))
(kv/set* kvstore ks body))
(response ""))
(defn api
[kvstore]
(let [api-routes
(routes
(GET ["/:ks" :ks valid-key-regex] {{:keys [ks] :as params} :params body :body headers :headers}
(wrap-get kvstore ks params headers body))
(PUT ["/:ks" :ks valid-key-regex] {{:keys [ks] :as params} :params
body :body body-params :body-params headers :headers}
(let [body (slurp body)
body (if (empty? body) body-params body)]
(wrap-put kvstore ks params headers body))))]
(-> (handler/api api-routes)
(format-params/wrap-format-params
:predicate format-params/json-request?
:decoder #(json/parse-string % true)
:charset format-params/get-or-guess-charset)
(format-response/wrap-format-response
:predicate format-response/serializable?
:encoders [(format-response/make-encoder json/encode "application/json")
(format-response/make-encoder identity "text/plain")]
:charset "utf-8")
trace/wrap-stacktrace)))
Hope this helps.
Just an update to a previous answers, now is enough to add formats key with list of formats which will be processed by Ring to your handler.
So something like
(def app (noir.util.middleware/app-handler
[your-routes]
:formats [:json-kw]))
Related
I've got a website that I'm the process of developing, the backend route which isn't working is /login with the compojure route as:
(POST login "/" [] check-admin-before-logging)
This is what the check-admin-before-logging function does:
(defn redirect-admin-to-page
[]
(-> (response/redirect "/admin/home")
(assoc :body "logging you in...")
(assoc :cookies {:token (token/sign-token)})))
;; function that checks whether credentials are in fact valid.
;; check-admin is a db func which compares hashed pswd with input.
(defn check-admin-before-logging-in
[request]
(let [username (:username (:params request))
password (:password (:params request))]
(if (check-admin username password)
(redirect-admin-to-page username)
(str "username : " username " and password " password " is not valid.\n" request))))
For the moment it just returns a string, as for testing purposes.
and for the app I have wrapped it in the following middleware:
(def app
(-> all-routes
(wrap-defaults (assoc-in site-defaults [:security :anti-forgery] false))
(wrap-json-body)
;; (wrap-json-params)
(wrap-json-response)
))
Now when I make an AJAX request with the following on the frontend:
(defn submit
[]
(let [username *grabbed from input field...*
password *grabbed from input field...*]
(POST "/login" {:params {:username username :password password}})))
But the problem arises when I actually click the button I get this. The console shows the result of the post request itself, with :params being empty and some mangled JSON in the :body key. If I was to try and include
(wrap-json-params)
within app, I would get nil in the :body and :params key. Moreover it seems there is a problem with the output, as cheshire has problems with parsing it. If I leave the ring-json library to the side and just have wrap-defaults over app, I just get this for the body key
:body #object[org.eclipse.jetty.server.HttpInputOverHTTP 0x6ef9a9e1 HttpInputOverHTTP#6ef9a9e1]
My question is how do I change the json so that it is able to be understood by wrap-json-params or cheshire? Any advice is much appreciated.
I am trying to implement AJAX POST in ClojureScript.
The following is the code i am using
(defn handler [response]
(.log js/console (str response)))
(defn test-post [name email]
(let [data {:name name :email email}]
(POST "http://localhost:5000/Add/"
{
:format {"Accept" :json}
:body (.stringify js/JSON (clj->js data))
:handler handler
:error-handler (fn [r] (prn r))
:response-format {"Content-Type" "application/json;charset=utf-8"}
}
)))
When do i call the Post method. On form Submit? Also the post request is hitting the url but the json data is not present.
I assume you're using cljs-ajax for sending data.
What you really need in something like this:
(let [data {:name name :email email}]
(POST "/Add"
{:format :json
:params data
:handler handler
:error-handler (fn [r] (prn r))})))
You can just pass a plain Clojure object as params, just set :json as data format (default is :transit).
The second question is rather open and depends on your setup. I think the simplest to use is reagent, here is a nice example with sending form data.
I have been writing a clojure application with ring and compojure. I am using the ring.middleware.json middleware for handling JSON so I don't have to serialise and deserialise it myself in my code.
This middleware only seems to correctly parse nested JSON when given in a flattened format, for example if I want to POST nested data to an API route I have to encode it as:
{"task" : 1,
"success" : false,
"files[0][type]" : "log",
"files[0][sha256]" : "adef5c",
"files[0][url]" : "s3://url"}
Instead of, what seems to me, more standard JSON:
{"task" : 1,
"success" : false,
"files" : [{"type" : "log", "sha256" : "adef5c", "url": "s3://url"}]}
Is this indented or a standard way of posting nested JSON? Here is my middleware stack:
(defn middleware [handler]
(-> handler
(wrap-json-response)
(wrap-with-logger)
(api)))
Here is a full Clojure example of post and get routes that handle JSON or return JSON:
(ns ring-app.core
(:require [ring.adapter.jetty :as jetty]
[compojure.core :as compojure]
[ring.middleware.keyword-params :refer [wrap-keyword-params]]
[ring.middleware.json :refer [wrap-json-response wrap-json-body]]
[ring.util.http-response :as response]
[clojure.pprint :refer [pprint]]
[ring.middleware.reload :refer [wrap-reload]]))
(defn json-get [request]
(response/ok
{"task" 1
"success" false
"files" [{"type" "log" "sha256" "adef5c" "url" "s3://url"}]}))
(defn json-post [request]
(let [bpdy (:body request)]
(prn bpdy)
(response/ok bpdy)))
(compojure/defroutes handler_
(compojure/GET "/get" request json-get)
(compojure/POST "/post" request json-post))
(defn wrap-nocache [handler]
(fn [request]
(-> request
handler
(assoc-in [:headers "Pragma"] "no-cache"))))
(def handler
(-> #'handler_ wrap-nocache wrap-reload wrap-json-response wrap-json-body ) )
The get endpoint returns the nested structure:
curl http://localhost:3000/get
; {"task":1,"success":false,"files":[{"type":"log","sha256":"adef5c","url":"s3://url"}]}
And the POST endpoint parses the json and create a Clojure data structure:
curl -X post -d '{"task":1,"success":false,"files":[{"type":"log","sha256":"adef5c","url":"s3://url"}]}' -H "Accept: application/json" -H "Content-type: application/json" http://localhost:3000/post
; {"task":1,"success":false,"files":[{"type":"log","sha256":"adef5c","url":"s3://url"}]}
This is roundtripping on JSON->CLJ->JSON
The json ring middleware expects the Content-type to be properly set so maybe that was why the structure was not parsed properly in your case ?
When defining a compojure handler e.g. by using the defroutes macro, I can do something like this:
(defroutes home-routes
(GET "/myhome/:id" [ id ] (home-page)))
(defn home-page [ id ]
( ... do something ... ))
So I know how to pass a piece of the path parameter. But imagine I want to return a HAL+JSON object with a selflink. How would I get defroutes to pass the whole URI to the home-page function?
The Ring request map contains all the necessary information to construct a "selflink". Specifically, :scheme, :server-name, :server-port, and :uri values can be assembled into full request URL. When I faced this problem I created Ring middleware that adds the assembled request URL to the Ring request map. I could then use the request URL in my handlers as long as I pass the request map (or some subset of it) into the handler. The following snippet shows one way of implementing this:
(defroutes app-routes
(GET "/myhome/:id" [id :as {:keys [self-link]}] (home-page id self-link))
(route/resources "/")
(route/not-found "Not Found"))
(defn wrap-request-add-self-link [handler]
(fn add-self-link [{:keys [scheme server-name server-port uri] :as r}]
(let [link (str (name scheme) "://" server-name ":" server-port uri)]
(handler (assoc r :self-link link)))))
(def app
(-> app-routes
handler/site
wrap-request-add-self-link))
I have a rather simple problem I thought. I have a luminus web project with clojurescript and cljs-ajax. What I do is an ajax request to my server and in my error-handler I want to parse a json string to display a specific error message. I just cannot get it working.
This is my code:
Clojurescript:
(defn error-handler [response]
(js/alert (aget response "message")))
; (js/alert (:message response ))) neither works here
(defn test-connection []
(POST "/url"
{:params (get-form-data)
:response-format :json
:handler succ-handler
:error-handler error-handler}))
And my serverside code:
(defn connect-jira []
{:body {:message "No connection to JIRA. Please check your details."}}
)
(defroutes jira-routes
(POST "url" []
(connect-jira)))
What is the idiomatic way to return a custom error message and parse that with clojurescript?
Update
I tracked my problem down some more. There is a difference between the success and the error handler of the POST request. Lets say my server side looks like this:
(defn connect-jira []
{:status 200 :body {:message "No connection to JIRA. Please check your details."}})
And my success handler like this:
(defn succ-handler [{:keys [message]}]
(.log js/console message))
Then its all fine, the correct messages is logged to the console.
But if my server side looks like this (different statu):
(defn connect-jira []
{:status 500 :body {:message "No connection to JIRA. Please check your details."}})
I call the error handler on cljs side
(defn err-handler [{:keys [message]}]
(.log js/console message))
But the message is "null"
I also tried to overwrite the status-text on server side, but did not succeed. So, how do I pass a message to the error handler from server side?
Are you using this library for your AJAX calls?
https://github.com/yogthos/cljs-ajax
If so, your error handler would need to look something more like this:
(defn err-handler [{:keys [response]}]
(.log js/console (:message response)))