Setting ISO-8859-1 encoding for a single Tapestry 4 page in application that is otherwise totally UTF-8

Question

I have a Tapestry application that is serving its page as UTF-8. That is, server responses have header:

Content-type: text/html;charset=UTF-8

Now within this application there is a single page that should be served with ISO-8859-1 encoding. That is, server response should have this header:

Content-type: text/html;charset=ISO-8859-1

How to do this? I don't want to change default encoding for whole application.

Based on google searching I have tried following:

 @Meta({    "org.apache.tapestry.output-encoding=ISO-8859-1", 
 "org.apache.tapestry.response-encoding=ISO-8859-1", 
 "org.apache.tapestry.template-encoding=ISO-8859-1",
 "tapestry.response-encoding=ISO-8859-1"})
 abstract class MyPage extends BasePage {

    @Override
    protected String getOutputEncoding() {
        return "ISO-8859-1";
    }
 }

But neither setting those values with @Meta annotation or overriding getOutputEncoding method works.

I am using Tapestry 4.0.2.

EDIT: I ended up doing this with a Servlet filter with subclassed HttpServletResposeWrapper. The wrapper overrides setContentType() to force required encoding for the response.

Answer 1

Have you considered a Filter? Maybe not as elegant as something within Tapestry, but using a plain Filter, that registers the url mapping(s) of interest. One of its init parameters would be the encoding your after. Example:

public class EncodingFilter implements Filter {
private String encoding;
private FilterConfig filterConfig;

/**
* @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
*/
public void init(FilterConfig fc) throws ServletException {
this.filterConfig = fc;
this.encoding = filterConfig.getInitParameter("encoding");
}

/**
* @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain chain) throws IOException, ServletException {
req.setCharacterEncoding(encoding);
chain.doFilter(req, resp);
}

/**
* @see javax.servlet.Filter#destroy()
*/
public void destroy() {
}

}

Answer 2

The filter suggestion is good. You can also mix servlets with Tapestry. For instance, we have servlets for serving displaying XML documents and dynamically generated Excel files. Just make sure that correctly set the mappings in web.xml so that that the servlets do not go through Tapestry.

Answer 3

Tapestry has the concept of filters that can be applied to the request/response pipeline, but with the advantage that you can access the T5 IoC Container & Services.

http://tapestry.apache.org/tapestry5/tapestry-core/guide/request.html

Answer 4

You could have done:

    @Override
public ContentType getResponseContentType() {
        return new ContentType("text/html;charset=" + someCharEncoding);
}