Question

My JavaScript serializes view fields and add waypoints array to post data, in controller each parameter separately add to Geo object encounters a waypoint parameter and it parse to array. Whether can be done a filter that would get these parameter and parse it so that I can use normal approach? Now in normal approach that is Geo.new(params[:geo]) rails returns (Field was defined as a(n) Array, but received a String with the value “[\”Paris, France\”,\”Stuttgart, Deutschland\”]”.).

Controller:

def create
  @geo = Geo.new
  @geo.waypoints = JSON.parse params[:geo][:waypoints] if params[:geo][:waypoints].is_a? String
  @geo.description = params[:geo][:description]
  @geo.start = params[:geo][:start]
  @geo.end = params[:geo][:end]
  @geo.save
  redirect_to geo_path(@geo), :notice => "Geo successfully submitted."
end

JS:

$('form').submit(function () {
    var waypoints = ["Paris, France", "Stuttgart, Deutschland"]
    var url = $(this).attr('action');
    var waypoints_temp_field = $('<input type="hidden" name="geo[waypoints]" />').val(JSON.stringify(waypoints)).appendTo(this);
    var postdata = $(this).serialize();

    $.post(url, postdata, function (callback) {
        // callback
    }, "json");
    return false;
});

Answer 1

Well, couldn’t you change the waypoints_temp_field to post to something other than geo? For example:

var waypoints_temp_field = $('<input type="hidden" name="waypoints" />')
                           .val(JSON.stringify(waypoints)).appendTo(this);

Then in your controller, you could have:

@geo = Geo.new(params[:geo])
@geo.waypoints = JSON.parse(params[:waypoints]) if params[:waypoints])

This way, you can process waypoints separately from everything else.