Preventing a page from getting opened - ruby-on-rails

Question

When user clicks on a chart, I get some ID in the Javascript side of its onclick event and pass that as a query param to the page that I want to open and I say
window.open(go_to);
which goto will have that query param in it for exampel like "http://localhost:3000/myapp/people?provider=134"
so now it hits the index action method in the Rails side, in there I also get another variable for logged in user:
def index
cur_user_id = current_user.id
provider_id = params[:provider]
# call the REST service and pass those two params
# and get the appropriate JSON back from the service
if provider_id == cur_user_id
render nothing: true
end
end
The problem I have is with this logic:
if provider_id == cur_user_id
render nothing: true
end
So if logged in user is the same as the provider I don't want to open that page or show anything. Render Nothing is helping with not showing anything but still the window.open part of the code from Javascript is opening the page, blank tho
How can I tell it hey don't even open the new page?

Answer 1

You can use ruby code mixed with javascript:
var provider_id = $('#provider_id').val();
var go_to = '/path/to/somewhere?provider_id=' + provider_id;
if(provider_id == <%= current_user.id %>) {
alert('You cannot go there!');
} else {
window.open(go_to);
}
Remember that the ruby code will be executed first (on server-side), then your HTML/javascript will be generated, and finally be executed on the client-side. So <%= current_user.id %> inside the javascript will just print the value in there, like if it was hard-coded in JS.
It seems that you didn't know about the ruby code inside the javascript parts, to give you an example, try this in one of your view using Javascript:
# this is on the server-side, it will be generated:
<script type="text/javascript">
<%= "alert('hello Eric!');".html_safe %>
</script>
# on the client-side, you will receive this generated HTML content:
<script type="text/javascript">
alert('hello Eric!');
</script>
For HAML:
:javascript
#{"alert('hello Eric')".html_safe}
var hello = '#{"hello World!"}';
alert(hello);