Question

I think this has been asked before but even though I searched Google I haven t come up with a solution.

So this is what I m trying to do in Rails 2.3.5:

layouts/application.html.erb:
<html>
  <head>
    ... some other stuff
    <%= yield :head %>
  </head>
  <body>
    <% content_for :head, "something that belongs in the head" %>
  </body>
</html>

Notice the yield before the content_for.

I know that Rails - by default - doesn t allow the content of :head to be defined after yield has been used - makes sense.

I even tried hooking into the template render process but no success so far.

So my goal is to be able to define content_for inside partials/templates and have the "yield" somehow delayed and executed just before the response is send to the browser.

Has somebody come up with a solution?

Greetings and thanks, Frank

Update I ll go with weppos s idea and try myself on rack middleware. thanks

Answer 1

The rendering process first loads and executes the action template, then decorates the template with the selected layout. The layout is rendered from top to botton, thus you can t add more content to :head after :head is already rendered.

You need to change your strategy. Either place the fragment in a partial and attach it to your action views or use a post-processing strategy such as a Rack module/after_filter to alter the html code directly.

I probably would try to find a better solution based on what I actually need. If you are encountering this issue, chances are the error is somewhere else, perhaps in the app architecture.

Answer 2

There shouldn t be an equals sign in your content_for statement. It should be:

<% content_for :head, "Something that belongs in the head" %>

If you define the content within your templates and partials then it should work. This technique was covered in Railscast episode 8.

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