ruby on rails update page with ajax - ruby-on-rails

Question

I am using below button_to tag inside view file (index.html.erb)
<textarea rows="2" cols="20"><%=#write_date%></textarea>
<%= button_to t(:get_date_write_new),channel_get_dates_path(#channel, :write => 1) %>
when i click the button it will get date from device and prints it on screen.
my question is that how do i make call to function "channel_get_dates_path(#channel, :write => 1)" continuously, and display the date in textarea without refreshing the page. by pressing the button only once?
my controller file:
class GetDatesController < ApplicationController
include DateUtilities
before_filter :require_user, :set_channels_menu
def index
#channel = current_user.channels.find(params[:channel_id])
#write_date = #channel.get_dates.write_dates.first
end
def create
#channel = current_user.channels.find(params[:channel_id])
#get_date = #channel.get_dates.write_dates.first
if (#get_date.nil?)
#get_date = GetDate.new
#get_date.channel_id = #channel.id
#get_date.user_id = current_user.id
#get_date.write_flag = params[:write]
end
#get_date.get_date = generate_get_date
#get_date.save
redirect_to channel_get_dates_path(#channel)
end
end
and i have date generation file(myapp/lib) as:
module DateUtilities
def generate_get_date
require 'rubygems'
require 'socket'
hostname = '127.0.0.1'
port = 2000
streamSock = TCPSocket.new( hostname, port )
streamSock.write "ON"
while line = streamSock.gets
k = line
end
k
end
end

Answer 1

In order to change the page without refreshing it, you need AJAX.
This can be done quite easily in rails by passing a :remote => true attribute in a form :
<%= form_tag(myupdate_path, :remote => true) do %>
<%= form_tag(channel_get_dates_path(#channel, :write => 1), :remote => true) do %>
<input type="submit" value="Get Today's Date">
<input id="thedate" type="text" value="<%=#write_date%>">
<% end %>
<% end %>
The remote option will call the myupdate method in your controller, and tell it to render a javascript view instead of a html view. Let's say you have in your controller :
def myupdate
#thedate = params['wathever'] # get the params from the form
end
Then you can add your javascript method in myController/myupdate.js.erb ( instead of myupdate.html.erb). Assuming you're using jquery, this would be
$("#thedate").val("<%= #thedate %>") # dynamically update
By doing this you're able to get the params from the form, process it as you want with a controller, and tell javascript to update your page according to whathever you just put in your instance variable.
Edit : I used your form as the example. Hopefully the javascript is now more clear : the idea of the javascript view is to get the "thedate" html element in your page, and set its value according to the updated instance variable #thedate. This is where you tell javascript to dynamically update your page.
Hope this helps

Answer 2

#Aurel,thanks for your suggestions. i followed your steps.
in my view file changed the code as:
<%= form_tag(channel_get_dates_path(#channel, :write => 1), :remote => true) do %>
<input type="submit" value="Get Today's Date">
<input type="text" value="<%=#write_date%>">
<% end %>
after this when i press the submit button the update method is called(and i can see that device is sending the date), but the date is not displaying in text field. when i refresh the page the last obtained date from device is displayed in text field.
Is it possible to display the date every time when press submit button?