Unable to parse out EDN in this server request - clojure

Question

I think I'm doing things right but I can't get my EDN out of the :body input stream. The Ring and Compojure handler is this:
dependencies:
[ring.middleware.params :as params]
[ring.middleware.edn :as edn]; https://github.com/tailrecursion/ring-edn
Handler:
(defroutes ajax-example
(PUT "/ajax-example" r
(println r)
{:status 200
:headers {"Content-Type" "application/edn"}
:body "yo"}))
I wrap it like:
(def ajax-wrapped
(-> ajax-example
edn/wrap-edn-params
params/wrap-params))
The println'd response correctly reveals that it is EDN and the content length is correct based on the simple test map I send in, but the map itself is nowhere to be found, it is forever trapped in the input stream of the :body... how to get at it?
Here is the response println:
{:ssl-client-cert nil, :remote-addr 0:0:0:0:0:0:0:1, :params {}, :route-params {}, :headers {origin http://localhost:6542, host localhost:6542, user-agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36, content-type application/edn, cookie _ga=GA1.1.1354518981.1429622648; content-length 20, referer http://localhost:6542/, connection keep-alive, accept /, accept-language en-US,en;q=0.8,sq;q=0.6, accept-encoding gzip, deflate, sdch, cache-control max-age=0}, :server-port 6542, :content-length 20, :form-params {}, :query-params {}, :content-type application/edn, :character-encoding nil, :uri /ajax-example, :server-name localhost, :query-string nil, :body #, :edn-params nil, :scheme :http, :request-method :put}
The :body is not pasting correctly above, it looks like this:
[open corner bracket] HttpInput org.eclipse.jetty.server.HttpInput#5d969109 [end corner bracket]
The client-side code sent from the browser using cljs-ajax lib is:
(defn ajax-send
[]
(let [push {:adder1 2 :add2 3}]
(PUT "/ajax-example"
{:format :edn
:params push
:handler ajax-result
:error-handler error-handler})))
Here is the output of a test suggested by one of the answers:
hf.examples> ((-> ajax-example params/wrap-params edn/wrap-edn-params) (-> (mock/request :put "/ajax-example")
(mock/content-type "application/edn")
(mock/body "{:hello \"there\"}")))
{:status 200,
:headers {"Content-Type" "application/edn"},
:body
"{:remote-addr \"localhost\", :params {:hello \"there\"}, :route-params {}, :headers {\"content-length\" \"16\", \"content-type\" \"application/edn\", \"host\" \"localhost\"}, :server-port 80, :content-length 16, :form-params {}, :query-params {}, :content-type \"application/edn\", :uri \"/ajax-example\", :server-name \"localhost\", :query-string nil, :edn-params {:hello \"there\"}, :scheme :http, :request-method :put}"}
hf.examples>
I also tried this:
(defroutes ajax-example
(PUT "/ajax-example" r
{:status 200
:headers {"Content-Type" "application/edn"}
:body (pr-str (dissoc r :body))}))
Curl result independent of the front end:
curl -X PUT -H "Content-Type: application/edn" -d '{:name :barnabas}' http://localhost:6542/ajax-example
{:ssl-client-cert nil, :remote-addr "0:0:0:0:0:0:0:1", :params {}, :route-params {}, :headers {"host" "localhost:6542", "content-length" "17", "content-type" "application/edn", "user-agent" "curl/7.37.1", "accept" "*/*"}, :server-port 6542, :content-length 17, :content-type "application/edn", :character-encoding nil, :uri "/ajax-example", :server-name "localhost", :query-string nil, :edn-params nil, :scheme :http, :request-method
The content-length of 17 matches the number of characters in the map passed via Curl. But the edn-params is nil! Where is the content?

Answer 1

EDIT: As an answer to the updated question, the wrap-edn-params function consumes the body of the request by fully reading the :body InputStream. Compojure routes passes the request to each parameter handler until a non nil value is returned. In this case, whichever handler is passed to routes as the first handler will consume :body and there will be no :body value for the 2nd handler to consume, resulting in a nil body value read by wrap-edn-params.
The request that is being passed to the ring handler probably does not have its content-type set to edn. The wrap-edn-params function will only parse the edn if the request content-type is set to edn.
In addition the parsed edn parameters will only be placed in the :params and :edn-params keys of the request map by the wrap-edn-params function, and therefore :body should not be used to access the parsed edn.
(require '[ring.mock.request :as mock])
(require '[ring.middleware.edn :as edn])
((-> ajax-example params/wrap-params edn/wrap-edn-params) (-> (mock/request :put "/ajax-example")
(mock/content-type "application/edn")
(mock/body "{:hello \"there\"}")))
{:remote-addr "localhost",
:params {:hello "there"},
:route-params {},
:headers
{"content-length" "16",
"content-type" "application/edn",
"host" "localhost"},
:server-port 80,
:content-length 16,
:form-params {},
:query-params {},
:content-type "application/edn",
:uri "/ajax-example",
:server-name "localhost",
:query-string nil,
:body #<ByteArrayInputStream java.io.ByteArrayInputStream#171788d8>,
:edn-params {:hello "there"},
:scheme :http,
:request-method :put}

Answer 2

I have fixed this but I do not know why the problem exists. I had another independent route that also wrapped EDN middle ware. Here is the reproducible example:
(defroutes example-routes2
(PUT "/test-edn" r
(println r)
{:status 200
:headers {"Content-Type" "application/edn"}
:body (pr-str (str "request is: " r))}))
(defroutes ajax-example
(PUT "/ajax-example" r
(println r)
{:status 200
:headers {"Content-Type" "application/edn"}
:body (pr-str (str "request is: " r))}))
(def edn-routes
(-> example-routes2
edn/wrap-edn-params))
(def ajax-wrapped
(-> ajax-example
edn/wrap-edn-params))
;;combining all routes on this page into a single handler
(def example-routes (routes example-routes1 ajax-wrapped edn-routes))
Note that these two routes are essentially identical and are being wrapped identically. The one that fails to parse EDN into edn-params is the one listed second in the example-routes def!
curl -X PUT -H "Content-Type: application/edn" -d '{:name :barnabasss}' http://localhost:6542/test-edn
returns:
"request is: {:ssl-client-cert nil, :remote-addr \"0:0:0:0:0:0:0:1\", :params {}, :route-params {}, :headers {\"host\" \"localhost:6542\", \"content-length\" \"19\", \"content-type\" \"application/edn\", \"user-agent\" \"curl/7.37.1\", \"accept\" \"/\"}, :server-port 6542, :content-length 19, :content-type \"application/edn\", :character-encoding nil, :uri \"/test-edn\", :server-name \"localhost\", :query-string nil, :body #, :edn-params nil, :scheme :http, :request-method :put}"
curl -X PUT -H "Content-Type: application/edn" -d '{:name :barnabasss}' http://localhost:6542/ajax-example
returns:
"request is: {:ssl-client-cert nil, :remote-addr \"0:0:0:0:0:0:0:1\", :params {:name :barnabasss}, :route-params {}, :headers {\"host\" \"localhost:6542\", \"content-length\" \"19\", \"content-type\" \"application/edn\", \"user-agent\" \"curl/7.37.1\", \"accept\" \"/\"}, :server-port 6542, :content-length 19, :content-type \"application/edn\", :character-encoding nil, :uri \"/ajax-example\", :server-name \"localhost\", :query-string nil, :body #, :edn-params {:name :barnabasss}, :scheme :http, :request-method :put}"
Switching their order in the example-routes switches which one works. Can anyone explain?