Question

I want to create a handler function which takes two inputs. One is a parameter taken from the url /name, and second is a param from the query string /name?x=3

(def my-app (app
               [page-name] (handler page-name)))

(defn handler
  [{:keys [params]} page-name]
  (let [x (params "x")]
    (-> (page-templ page-name x) response constantly)))

The above fails because the handler is expecting 2 params, however I am only passing one.

How do I get hold of the request map, and pass it to the handler ?

The request map in the above case contains a param named x.

Answer 1

It is best if you could dispatch on the page name, like that:

(app
 [""] (index-page)
 ["login"] (serve-login))

Here functions index-page and serve-login return function of one argument.

(defn index-page[]
  (fn [req] ..))

req is the request that will contain all the url parameters in key/value map. To get parameter value do this:

(-> req (get :params) (get :x))

So the full solution would look something like this:

(def my-app (app
               ["page1-name"] (handler)))

(defn handler []
  (fn [req]
    (let [x (-> req :params :x)]
      (-> (page-templ page-name x) response))))

EDIT: Don’t forget to wrap you application into (wrap-keyword-params) and (wrap-params), here’s how you can do it:

(def my-wrapped-app
  (-> my-app
   (wrap-keyword-params)
   (wrap-params))