Inconsistent API requests

Hello! I have been using AJAX in the front end of my phoenix app to give flickerless updates when text is edited and rendered (see AJAX code below). The fields of data in the Ajax code are available in the reply to Phoenix in params, e.g., params["title"].

I would like to use the api server more generally and have been testing it with Postman. I do this by creating a key-value pair for the headers section, e.g., key=‘data’ value = {“title”: “TEST”, content: 'YADA YADA", …}. The info in the api server reply is in conn.req_headers, which is a list of key-value pairs as listed further down.

I can handle either case, but would like to formulate my requests and replies in a uniform manner – What do you advise?

AJAX CODE

$.ajax({
        url: "/api/notes/" + note_id,
        type: "put",
        data: {
            title: title,
            username: username,
            user_id: user_id,
            token : token,
            content: content,
            tag_string: tag_string,
            identifier: identifier,
        },
        headers: {
            "X-CSRF-TOKEN": csrf
        },
        dataType: "json",
        success: function (data) {

          console.log("OKKKK!");
          console.log(data);
          document.getElementById("rendered_text3a").innerHTML = data.rendered_text;

          newTypeset();

        }
    });

API REPLY TO POSTMAN REQUEST

[{"cache-control", "no-cache"},
 {"postman-token", "cee52325-1811-43b0-bd9c-413068e6b9d6"}, {"user_id", "9"},
 {"data",
  "{\"username\":\"jxxcarlson\",\"content\":\"This *is* a test\",\"tag_string\":\"foo,bar\",\"title\":\"Magick\"}"},
 {"token",
  "\"eyYADA_YADA_YADA_pPcVyg\""},
 {"username", "jxxcarlson"}, {"content", "This *is* a test"},
 {"title", "Magick"}, {"id", "1114"},
 {"user-agent", "PostmanRuntime/3.0.11-hotfix.2"}, {"accept", "*/*"},
 {"host", "localhost:4001"}, {"accept-encoding", "gzip, deflate"},
 {"content-length", "0"}, {"connection", "keep-alive"}]

NOTE added I extract info from conn.req_headers using the code below. Surely there is a better way!

   {:ok, data} = Poison.Parser.parse conn2value(conn, "data")

    defp key2value(list, key) do
      pair =  Enum.filter(list, fn(pair) -> {k, v} = pair; k == key end)
      [{_,value}] = pair
      value
    end

    defp conn2value(conn, key) do
      key2value(conn.req_headers, key)
    end