xml_http_request.cljs

(ns ajax.xml-http-request
  (:require [ajax.protocols :refer [AjaxImpl AjaxRequest
                                    AjaxResponse Interceptor]]
            goog.string))

(defn ready-state [e]
  ({0 :not-initialized
    1 :connection-established
    2 :request-received
    3 :processing-request
    4 :response-ready} (.-readyState (.-target e))))

(defn append [current next]
  (if current
    (str current ", " next)
    next))

(defn process-headers [header-str]
  (if header-str
    (reduce (fn [headers header-line]
              (if (goog.string/isEmptyOrWhitespace header-line)
                headers
                (let [key-value (goog.string/splitLimit header-line ": " 2)]
                  (update headers (aget key-value 0) append (aget key-value 1)))))
            {}
            (.split header-str "\r\n"))
    {}))

(def xmlhttprequest
  (cond
    (exists? goog/global.XMLHttpRequest)
    goog/global.XMLHttpRequest
    (exists? js/require)
    (let [req js/require]
      (.-XMLHttpRequest (req "xmlhttprequest")))))

(extend-type xmlhttprequest
  AjaxImpl
  (-js-ajax-request
    [this
     {:keys [uri method body headers timeout with-credentials
             response-format]
      :or {with-credentials false
           timeout 0}}
     handler]
    (set! (.-withCredentials this) with-credentials)
    (set! (.-onreadystatechange this)
          #(when (= :response-ready (ready-state %))
             (handler this)))
    (.open this method uri true)
    (set! (.-timeout this) timeout)
;;; IE8 needs timeout to be set between open and send
;;; https://msdn.microsoft.com/en-us/library/cc304105(v=vs.85).aspx
    (when-let [response-type (:type response-format)]
      (set! (.-responseType this) (name response-type)))
    (doseq [[k v] headers]
      (.setRequestHeader this k v))
    (.send this (or body ""))
    this)
  AjaxRequest
  (-abort [this] (.abort this))
  AjaxResponse
  (-body [this] (.-response this))
  (-status [this] (.-status this))
  (-status-text [this] (.-statusText this))
  (-get-all-headers [this]
    (process-headers (.getAllResponseHeaders this)))
  (-get-response-header [this header]
    (.getResponseHeader this header))
  (-was-aborted [this] (= 0 (.-readyState this))))