jquery ajax post application/json to luci openwrt lua web admin

controller-jquery.lua

module("luci.controller.rme.jquery", package.seeall)
local http = require("luci.http")
local protocol = require("luci.http.protocol")
local json = require("luci.json")

function index()
    entry({'karl', 'modbus_devices'}, call("action_modbus_devices"), "Modbus Devices", 20).dependent=false
end

function kkdumpt(tt, label)
    if tt then
        if label then io.stderr:write(string.format("dumping table: %s\n", label)) end
        for k,v in pairs(tt) do
            io.stderr:write(string.format("k=%s\n", tostring(k)))
        end
    else
        io.stderr:write(string.format("table was nil: %s\n", label))
    end
end

function action_modbus_devices()
    local http_method = http.getenv("REQUEST_METHOD")
    kkdumpt(http.getenv(), "http.getenv")
    if http_method == "POST" then
        local hc = http.content()
        io.stderr:write(string.format("karl early post content = %s\n", tostring(hc)))
        io.stderr:write(string.format("posted content type = %s\n", tostring(http.getenv("CONTENT_TYPE"))))
        if (http.getenv("CONTENT_TYPE") == "application/json") then
            io.stderr:write("karl got posted app/json as expected\n")
            -- TODO - do something useful with "hc""
            --modbus_devices_save(hc)
            local rdata = { message = "it sort of maybe worked..."}
            http.prepare_content("application/json")
            http.write(json.encode(rdata))
            http.close()
            return
        end
    end
    -- fall through if invalid post
    luci.template.render("rme/karl")
    return
end

uhttpd-stderr

-- errors here are from luci prior to r10531
-- current versions of luci in trunk and AA work as expected.

dumping table: http.getenv
k=SERVER_NAME
k=SCRIPT_NAME
k=QUERY_STRING
k=HTTP_ACCEPT_ENCODING
k=SERVER_ADDR
k=GATEWAY_INTERFACE
k=REMOTE_ADDR
k=CONTENT_LENGTH
k=SERVER_PORT
k=SCRIPT_FILENAME
k=REQUEST_URI
k=SERVER_PROTOCOL
k=REMOTE_HOST
k=HTTP_HOST
k=HTTP_ACCEPT_LANGUAGE
k=HTTP_REFERER
k=REDIRECT_STATUS
k=PATH
k=CONTENT_TYPE
k=SERVER_SOFTWARE
k=HTTP_COOKIE
k=DOCUMENT_ROOT
k=HTTP_ACCEPT
k=HTTP_CONNECTION
k=PATH_INFO
k=HTTP_USER_AGENT
k=REMOTE_PORT
k=REQUEST_METHOD
karl early post content = nil  <<<<===== :(
posted content type = application/json
karl got posted app/json as expected

view-rme-karl.htm

<%+header%>
<h2><%:Modbus Devices%></h2>
<input id="klicky" class="cbi-button cbi-input-apply" type="submit" data-bind="click: save" value="save"/>

<script type="text/javascript" src="/resources/jquery-2.1.1.min.js"></script>

<script type="text/javascript">
function clicky() {
            console.log("saving....");
            var dataToSave = {
                something: "asdfasd asdfa asdf",
                klist: [ "item1", "item2"],
                knum: 456
            };

            //alert("Could now send this to server: " + JSON.stringify(dataToSave));
            var pdata = JSON.stringify(dataToSave);
            console.log("posting: " + pdata);
            $.ajax({
                url: location.href,
                contentType: "application/json",
                data: pdata,
                type: "POST"
            })
}

$(function() {
    $("#klicky").click(clicky);
});


</script>
<%+footer%>