RoR Class vs Instance variables, and relaying a value to partial

Question

I have a controller "mainpage", with a correspondingly named view. The controller creates a @myLocalSuites variable, and the view includes the following line:

<li class="active"><%= link_to "Perforce", :action =>  'renderp4', :remote => true, :localSuites => @myLocalSuites %></a></li>

Routing is defined such that clicking this link_to calls renderp4.js.erb to render a partial within the mainpage view:

$('#MainPage').replaceWith('<%= escape_javascript render "perforce_sync/perforceSync" %>')

where _perforceSync partial includes:

<%= select_tag "perforceSuites", options_for_select(*MYOPTIONSVARIABLE*), {:class => 'form-control', :size => "20", :multiple => true} %>

Where *MYOPTIONSVARIABLE* needs to be myLocalSuites as cascaded down from the mainpage view/controller.

Having tried everything I can think of, and failed - can someone please show how to modify the above snippets to use the required variable in the PerforceSync partial? Everything I've tried seems to produce something along the lines of:

 ActionView::Template::Error (undefined method `map' for nil:NilClass):

An example of what I've tried. I don't think I'm a million miles off, but...

<li class="active"><%= link_to "Perforce", :action =>  'renderp4', :remote => true, :localSuites => @myLocalSuites %></a></li>

$('#MainPage').replaceWith('<%= escape_javascript render "perforce_sync/perforceSync", :suitesLocally => params[:localSuites]%>')

<%= select_tag "perforceSuites", options_for_select(params[:suitesLocally]), {:class => 'form-control', :size => "20", :multiple => true} %>

Thanks! :)

Let me see if I have this right, you want the link to call the javascript function `$('#MainPage').replaceWith()`, and then dynamically generate the argument to this function with some data based on a select tag on the page? This will require ajax, since you will have to send the selected option(s) to the server, then use that response in your javascript code. — Slicedpan, Mar 26 '14 at 11:10
Ummm not quite (I don't think at least!)... The argument in question (an array of strings - @myLocalSuites) exists in the parent "mainpage" view. I want to pass this to the replaceWith, and then pass it on from there to the partial that gets rendered within mainpage, to populate the select_tag with the contents of that array... — Steve Hall, Mar 26 '14 at 11:20
That's what I had expected to work - but for some reason, the value get's lost.... `<%= puts @myLocalSuites %>
Are you expecting the `perforceSync` partial to be rendered immediately on page load? — Slicedpan, Mar 26 '14 at 12:06
No - I have a navbar at the top of the mainpage, and it is one of the links on this navbar that is the above `

Slicedpan · Accepted Answer · 2014-03-26T13:05:12.080

In response to your comment, there are two things you can do here. One way is to simply render some dynamic JS on page load, and then use javascript to show that data at a later point.

If this data however is to depend on user actions after the page has loaded, you must make another request to the server using AJAX.

The first way might look like this:

<script>
  var my_data = "<%= @some_data %>";   
    //@some_data could be set by the controller action for example
  $('button').click(function() {
    $('div.content_container').text(my_data);
  });
</script>

The second way would look like this:

<script>
  $('button').click(function() {
    $.ajax({
      url: '/some_resource/id.json',
      data: {param1: 'some_user_data'}
    }).done(function(data) {
      $('div.content_container').text(data);
    });
  });
</script>

The data option for the ajax call allows you to pass parameters back to the server, so you can send some data provided by the client. Documentation for jquery ajax is here if you want to see other options.

The .done callback gets fired when the client receives a response from the server, and the function parameter is the data returned.

Thanks Slicedpan. I think the AJAX route is gonna make most sense. Logically, when my mainpage navbar has several buttons on, it makes sense that when the user "comes back" to the Perforce page, it refreshes the select_tag contents... So I'll gratefully accept your answer for now, and leave you in peace - until I get confused to the point of banging my head against the wall with the AJAX implementation :) THANK YOU :) — Steve Hall, Mar 26 '14 at 13:15

RoR Class vs Instance variables, and relaying a value to partial

1 Answers1