Access controller action variable in jquery and display it in ruby on rails

Question

I m new in Jquery and Ajax.... What i want to do is.. I have a controller action which reads a file content and stores it in a variable. I want to pass file name from jquery and want to access that file content through variable in jquery and display it in a div tag. For this i have used this code in controller...

requests_controller.rb

def download
   IO.foreach "#{RAILS_ROOT}/Backend/History/#{params[:filename]}" do |line|
      @file_content << line
      @file_content << '<br/>'
   end 
end

Code in Jquery is...

jQuery("#play").click(function() {
    jQuery.get("/requests/download_log", { filename: filename});
});

Answer 1

Its not clear what you are trying to do. Do you want to access the controller variable into the jquery view, or do you want from an ajax jquery function request a controller action and get some data from the response?

I think you want to do the first thing, so you can do on the controller:

class MyController < ApplicationController
  def my_action
    @file_content = some_content
  end
end

On the view my_action.html.erb

<script type="text/javascript">
  $(document).ready(function() {
    $("#play").click(function() {
      $.get("/requests/download_log", { filename: <%= j @file_content %> });
    });
  });
</script>

---

Now if by chance you want to do the second thing I said, you can do

class MyController < ApplicationController
  def download_log
    @file_content = some_content
    respond_to do |format|
      format.json { render json: @file_content.to_json }
    end
  end
end

and on the view

success_handler = function(json_data) {
  // Do any operation with the json_data 
}

error_handler = function(jqXHR, textStatus, errorThrown) {
  // Handle ajax errors here
} 

$("#play").click(function() {
  $.ajax("/requests/download_log.json", dataType: "json",  success: success_handler, error: error_handler);
});