Ok, that's pretty easy to do as the information is already in every page. Probably won't need the php module either. There is a canonical url in the header if every page. This can be retrieved and the variable set for disqus using jquery and set to the this.page.url variable. For the this.page.identifier variable, you can use the pageData.nodeid variable that is embedded in the page.
Here is what the header code for the canonical url looks like.
Code:
<link rel="canonical" href="http://www.example.com/articles/1234-article-name"/>