interface cobalt

For those of you who use the excellent Url Rewrite Filter, a Java Web Filter which allows you to rewrite URLs before they get to your code, here are a couple of more-or-less useful rewrite rules that I’ve created.

The first rule redirects access made through a non-preferred domain or subdomain name to the preferred one. For example, if you’re using the example.com domain name for your website, you might want to redirect http://example.com/page.jsp to http://www.example.com/page.jsp.

<rule>
 <name>Domain Name Check</name>
 <condition name="host"
  operator="notequal">www.example.com</condition>
 <!–
     Needed if using a version prior to 2.0-alpha:
     <condition name=”host”
      operator=”notequal”>www.example.com</condition>
 –>
 <from>(.*)</from>
 <to type=”redirect”>http://www.example.com/context$1</to>
</rule>

Obviously, just replace www.example.com with the domain name that you prefer, and context with the context which your webapp is deployed at, or if using the root context, remove /context altogether.

I should mention that I didn’t write the same condition twice by mistake. There seems to be a bug in UrlRewriteFilter (version 1.2) which causes such conditions to be ignored unless written twice. If somebody hasn’t filed a report on that one already, I guess I better do it. Update: Paul Tuckey, the creator of Url Rewrite Filter, emailed me to let me know that this problem has been fixed in version 2.0-alpha.

The second rule blocks access to JSPs (or anything you want) that you don’t want to be accessible by anyone, and shows the 403: Forbidden error page which you’ve configured in your web.xml file.

<rule>
 <name>JSP block</name>
 <from>^/jsp/.*$</from>
 <set type="request" name="status_code">403</set>
 <to>/jsp/sendError.jsp</to>
</rule>

Where /jsp/sendError.jsp contains the following:

<%
 response.sendError(Integer.parseInt(
  (String)request.getAttribute("status_code")));
%>

Note that you could use any status code you want; if you want to give the user a 404: Not Found error, just write 404 instead of 403 in the rule configuration.

Now, what’s the best RegExp to find out whether a given user-agent is from a cell phone? Hmm.

This entry was posted on Tuesday, July 27th, 2004 at 8:26 pm CEST (July 27th, 2004 6:26 pm UTC) and is filed under Development, Java. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.