Referring to redirect URL in Velocity template - velocity

Question

So I'm trying to render a page's URL in the head of the document, for use with rel=canonical. This is on a site running off Velocity templates. The type of content I'm talking about is specifically a quiz -- which has multiple pages, one for each question, not to mention different URL paramters reflecting how many answers the user has gotten correct.
The site has redirect rules in place to generate the URL for the quiz. They look like this:
<rule>
<from>^/([a-zA-Z_0-9\-]*)/(quiz_[a-zA-Z_0-9\-]*)/(\d*).htm$</from>
<to>/contentdata/quiz.htm?path=/$1/$2.xml&qnum=$3</to>
</rule>
All this is by way of explaining that I'm using this Velocity code:
<link rel="canonical" href="$link.self" />
On the template for this page:
http://example.com/fun/quiz_best_quiz_ever/1.htm
Which produces this HTML:
<link rel="canonical" href="/contentdata/quiz.htm" />
But what I want is this HTML:
<link rel="canonical" href="http://example.com/fun/quiz_best_quiz_ever/" />
Is that clear enough? I know this is complicated, but does anyone have any idea as to how I may be able to accomplish it?

Answer 1

Your Velocity template needs to know what the rest of the URL is. You didn't explain how you are rendering the Velocity. Is it Spring? Velocity Servlet? Some other system?
The basic idea is that you need another reference called $baseUrl. Set this in your java code before the Velocity template is merged
(in Java)
context.put("baseUrl", "http://example.com/fun/quiz_best_quiz_ever");
(in Velocity)
<link rel="canonical" href="$baseUrl/$link.self" />