CODEWITHSUNDEEP
ruby-on-railscoffeescript
Andy Harvey
Andy Harvey

Reputation: 12663

How to generate a params array using coffeescript and data-attributes?

In a Rails 3.2 app I have a coffeescript function that returns an array of ID numbers from elements with a 'selected" data attribute.

#view (pseudo code!)
<table id='elems_container' data-url=<%= my_path(@object%) >
  <tr data-selected = 'true' data-id = '1'></tr>
  <tr data-selected = 'true' data-id = '2'></tr>
  <tr data-selected = 'false' data-id = '3'></tr>
  <tr data-selected = 'true' data-id = '4'></tr>
</table>

#coffeescript
elems = $("tr[data-selected='true']").map(->
  $(this).data "id"
).get()
$.ajax({ url: $('#elems_container').data('url'), dataType: "script", data: { 'selected_ids': elems } })

This returns the following in the logs

Started GET "/my/path?selected_ids%5B%5D=1&selected_ids%5B%5D=2&selected_ids%5B%5D=4

I now want to select these selected ids in the controller

@collection = Model.where('id = ?', params[:selected_ids])

Instead this is returning all Models, not just those listed in the params.

Is the get URL correct, or should a params array look different? What else am I doing wrong?

Upvotes: 1

Views: 225

Answers (1)

mu is too short
mu is too short

Reputation: 434785

If you URI-decode your query string, you'll see this:

selected_ids[]=1&selected_ids[]=2&selected_ids[]=4

When Rails sees the brackets, [], it will create an array in params[:selected_ids] holding the values from the query string and you'll have ['1','2','4'] in params[:selected_ids].

When you have multiple values to check, the SQL you want is:

where id in (1,2,4)

ActiveRecord is smart enough to use the in operator when you hand it an array like this:

where(:some_column => some_array)

so you should be able to say:

@collection = Model.where(:id => params[:selected_ids])

and get what you're looking for in @collection.

Upvotes: 2

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