How can I set a session variable from a js inside haml in ruby on rails?

Question

I have table row shading (for groups of row) via js.
I want to make it so that the shading is remembered through a session variable.

The haml partial I am using has:

Group Shading: 
  %a{:href => '#', :id => 'row_colors_on'}
    On
  %a{:href => '#', :id => 'row_colors_off'}
    Off

the js has:

$(function(){
$("a#row_colors_on").click(function(){
$(".row_color_group_1").addClass("color_group_1");
$(".row_color_group_2").addClass("color_group_2");
$(".row_color_group_3").addClass("color_group_3");
<%- session.group_shading = 'true' %>
event.preventDefault();
});
});
$(function(){
$("a#row_colors_off").click(function(){
$(".row_color_group_1").removeClass("color_group_1");
$(".row_color_group_2").removeClass("color_group_2");
$(".row_color_group_3").removeClass("color_group_3");
<%- session.group_shading = 'false' %>
});
});

the main page then uses:

- row_bg_color_group = 'row_color_group_1'
- for link in @links
  - construct_hyperlink(link.url_address, link.alt_text)
  - if link.group.group_name != (current_group ||= '') 
    - display_group = current_group = link.group.group_name
    - row_bg_color_group = rotate_rows_color_group
  - else
    - display_group = ''
   %tr{:class => "#{row_bg_color_group}"}

The code to change the background color of rows does do it but it is not remembered after a page refresh through the session variable ?

with the helper:

def rotate_rows_color_group
  if session[:group_shading] == 'true'
    cycle('row_color_group_1', 'row_color_group_2', 'row_color_group_3')
  else
   'row_color_group_1'
  end 
end

but I always get the 'else' condition, i.e. session[:group_shading] is not being either set or recognized

The css is

.color_group_1 { background-color: #133333; }
.color_group_2 { background-color: #122222; }
.color_group_3 { background-color: #111111; }

BroiSatse · Accepted Answer · 2015-09-10 14:40:27Z

3

You can't use erb statements within javascript, it is parsed before it is send to a client. Instead use javascript sessionStorage:

$(function(){
$("a#row_colors_on").click(function(){
$(".row_color_group_1").addClass("color_group_1");
$(".row_color_group_2").addClass("color_group_2");
$(".row_color_group_3").addClass("color_group_3");
sessionStore.setItem('group_shading', true);
event.preventDefault();
});
});
$(function(){
$("a#row_colors_off").click(function(){
$(".row_color_group_1").removeClass("color_group_1");
$(".row_color_group_2").removeClass("color_group_2");
$(".row_color_group_3").removeClass("color_group_3");
sessionStorage.setItem('group_shading', false);
});
});

$(document).ready(function() {
  if (sessionStorage.getItem('group_shading'))
    $("a#row_colors_on").click();
});

Important note:

Note however that js session is sth else than your rails session. Rails session can be stored in various places and javascript has no access to it. This means you can't access those values on the server side. There are two solutions:

1) Use sessionStorage and execute some javascript depending on stored value after the page has loaded (as above).

2) Instead of using sessionStorage, send an ajax request to server to populate rails session (recommended).

edited Sep 10, 2015 at 14:40

answered May 24, 2014 at 14:44

BroiSatse

44.8k8 gold badges63 silver badges89 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

BroiSatse Over a year ago

@MichaelDurrant - This is a long story to tell. you need to create a new action in your controller to handle the request and then send a request. Youc an find examples of jquery AJAX at the botom of api.jquery.com/jquery.ajax

Michael Durrant Over a year ago

k thanks. I am trying the above method but page refresh still removes shading currently.

BroiSatse Over a year ago

Could you create a fiddle for those changes?

deprecated Over a year ago

where does the sessionStore function come from?

deprecated Over a year ago

@BroiSatse then you meant sessionStorage. that was confusing as there is Rails class called SessionStore!

|

Barrett Clark · Accepted Answer · 2016-12-30 15:12:55Z

1

You can share state between Javascript (client-side) and Rails (server-side) with cookies. You can set a cookie in the view via Javascript (check out the js-cookie library), and read the cookies in a Rails controller.

Using the js-cookie library, you could set a cookie: (Cookie.set('awesome', 'sauce')) and then read it in the Rails controller: (puts cookies['awesome']).

answered Dec 30, 2016 at 15:12

Barrett Clark

2622 silver badges5 bronze badges

Collectives™ on Stack Overflow

How can I set a session variable from a js inside haml in ruby on rails?

2 Answers 2

Important note:

9 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Important note:

9 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related