If I am on a view, how can I access the ID of the ruby object that is currently represented by that view?
E.g. If I am on blah.com/jobs/1 how do I get 1?
I thought about trimming the current URL but that seems way too brittle, especially given I have nested resources. The only other easy way I can think of is to have a hidden field but it seems silly to have a hidden input on a show page where there aren't any forms.
You're right that parsing the URL is a bad idea, you're better off explicitly supplying it somewhere.
You could attach a data-job-id attribute to a standard element in the HTML, perhaps even <body>. Then your JavaScript could do things like this:
var id;
var $body = $('body');
if(id = $body.data('job-id'))
// Do some job things.
else if(id = $body('user-id'))
// Do some user things.
and you'd still be HTML5 compliant and you wouldn't have to muck about with hidden inputs.
You don't have to use <body> of course, your HTML probably has some top level container with a known id so you could use that instead.
I'd suggest one of the following:
As Jamsi suggested, include <%= params[:id] %> or <%= @job[:id] %> directly in your javascript:
var id = <%= @job[:id] %>
If your javascript is in a separate file, follow Mu's advice. Add the <%= @job[:id] %> to one of your view's html tags, and query it.
Wouldn't just <%= params[:id] %> do the trick?
Here is a complete example, combining from the answers already provided.
Using the params[:id] and the body element, the following inline statement will produce a data-params-id attribute, that can be used generically in a layout file:
<body <%= "data-params-id=#{params[:id]}" if params.has_key?(:id) %> >
This can then be accessed with the following:
JavaScript:
var dataId = document.body.getAttribute('data-params-id');
jQuery:
var dataId = $('body').data('params-id');
