Say you've got a Ramaze web application quite happily running at http://foo.com/ but you want to have the whole app running at http://foo.com/myapp/. It's not unusual to want to do this, for various reasons, and it's relatively easy to arrange by setting a single piece of Ramaze config.

The exact way to do this depends on the version of Ramaze you're using, as the options system changed between the 2009.03 and 2009.04 gem versions. Here's the syntax for Ramaze version 2009.03 and previous:

Ramaze::Global.prefix = '/myapp'

And here's the syntax for Ramaze 2009.04 and later, which requires setting the prefix for links (as before) and a routing rule for stripping it off incoming requests (since it no longer does it automatically):

app_prefix = '/myapp'

Ramaze.options.prefix = app_prefix

Ramaze::Route[ /^#{app_prefix}(.*)$/ ] = '%s'

The prefix will be automatically added onto the front of all URLs created by Ramaze's built-in URL and link creator methods (R, Rs and A from the link helper). It will also be stripped off the front of all incoming requests by the dispatcher (for Ramaze 2009.03) or by the routing rule (for later versions). So your own application code doesn't need to be aware that it's running with a prefix at all, unless you create absolute URLs via means other than the link helper methods. In that case you will need to use Ramaze::Global.prefix or Ramaze.options.prefix in your own link construction code to get them right.

One thing which might catch you out is forgetting to put the forward slash on the front of the prefix. If you set the prefix to 'myapp' it won't work – it has to be '/myapp'.

Update: Note that static files (those in your public directory) are not affected by any of the above changes. Furthermore, chances are that you refer to them with absolute paths from your HTML anyway – e.g. for images, CSS, JavaScript. So further thought will be required to handle these.