Post process HTML with a Rewriter

Jease allows to post-process the resulting HTML for a page with a so called JEASE_SITE_REWRITER. A Rewriter is mostly a function which transforms a given input string into a modified output string.

Go to "CMS » System » Parameter" and create a new Parameter with key=JEASE_SITE_REWRITER and paste the following code into it:

import jfix.functor.Function;

public class Rewriter implements Function<String, String> {

  public String evaluate(String input) {
    return input.replace("Jease", "Cheese");
  }

}

This is a very simple solution to rebrand your website.

Another use of the JEASE_SITE_REWRITER is to rewrite all internal links into their final representation on server-side. Jease uses a special prefix (.​/​~) to store internal references which are resolved at request time via appropriate redirects. In order to avoid additional redirects, Jease uses a jQuery-Link-Rewriter at the client, which works fine, but if you have a good reason to rewrite all internal links at server side, you can do it with a JEASE_SITE_REWRITER like the following:

import jfix.functor.*;
import jease.cms.web.servlet.*;

public class LinkRewriter implements Function<String, String> { 
 public String evaluate(String input) { 
  return input.replace("."+"/"+"~", JeaseController.getContextPath()); 
 } 
}

Obfuscate email-addresses with JEASE_SITE_REWRITER

A more serious approach for using the JEASE_SITE_REWRITER is to parse your resulting HTML for special expressions with the following format and replace them via obfuscated mailto-links:

${mailto=email@somedomain.org}

So putting an expression like above somewhere in your content (e.g. in a Text or Wiki) should result in a proper mailto link which is obfuscated against Spam-bots.

Here's the code which does the magic:

// Parse input for ${mailto=mail@domain.org}-expressions
// and replace them with Javascript obfuscated mailto-links.

import jfix.functor.Function;
import jfix.util.Regexps;

public class Rewriter implements Function<String, String> {

  public String evaluate(String content) {
    return Regexps.parseExpressions(content, PARSER);
  }

  private static final Function<String, String> PARSER = new Function<String, String>() {
    public String evaluate(String input) {
      try {
        int idx = input.indexOf("=");
        if (idx != -1) {
          String key = input.substring(0, idx).toLowerCase();
          String value = input.substring(idx + 1).trim();
          if ("mailto".equals(key)) {
            String address = value.replace("@", "&#64;").replace(".", "&#46;");
            String mailto = String.format("<a href=\"mailto:%1$s\">%1$s</a>", address);
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < mailto.length(); i++) {
              if (sb.length() != 0) {
                sb.append("+");
              }
              sb.append("'" + mailto.charAt(i) + "'");
            }
            return String.format("<script>document.write(%s);</script>", sb.toString());
          }
        }
      } catch (Throwable e) {
        // pass
      }
      return input;
    }
  };

}

The output in the final HTML will be as follows:

<script>
document.write(
'<'+'a'+' '+'h'+'r'+'e'+'f'+'='+'"'+'m'+'a'+'i'+'l'+'t'+'o'+':'+'e'+'m'+'a'+'i'+
'l'+'&'+'#'+'6'+'4'+';'+'s'+'o'+'m'+'e'+'d'+'o'+'m'+'a'+'i'+'n'+'&'+'#'+'4'+
'6'+';'+'o'+'r'+'g'+'"'+'>'+'e'+'m'+'a'+'i'+'l'+'&'+'#'+'6'+'4'+';'+'s'+'o'+
'm'+'e'+'d'+'o'+'m'+'a'+'i'+'n'+'&'+'#'+'4'+'6'+';'+'o'+'r'+'g'+'<'+'/'+'a'+'>'
);
</script>

And finally...

...the result will look like the following in your browser:

Maybe you can come up with more ideas what can be done with a rewriter. Just let us know...

Last modified on 2012-04-05 by Maik Jablonski

Java with Ease

1970-01-01

Java is a very productive development environment if you choose and combine the right tools and patterns.

Jease is the result of my personal quest bringing tools and patterns together which make the life of a web-developer as simple as it can be.