Additional filter outside Seam-filter messes up encoding

[toby451]

I added a very innocent looking request timing filter outside the Seam Filter like this:

 <filter>
 <filter-name>Timing Filter</filter-name>
 <filter-class>foo.bar.TimingFilter</filter-class>
 </filter>

 <filter>
 <filter-name>Seam Filter</filter-name>
 <filter-class>org.jboss.seam.servlet.SeamFilter</filter-class>
 </filter>

 <filter-mapping>
 <filter-name>Timing Filter</filter-name>
 <url-pattern>/*</url-pattern>
 </filter-mapping>

 <filter-mapping>
 <filter-name>Seam Filter</filter-name>
 <url-pattern>/*</url-pattern>
 </filter-mapping>

All of a sudden the UTF-8 encoding on our pages is broken. Scandinavian characters looking like "ö" instead of "ö" for instance (double encoded?).

This is strange since the filter I am using does nothing with the actual content, it merely times the call like this:

 long t0 = System.nanoTime();
 chain.doFilter(req, res);
 long dt = System.nanoTime() - t0;

What is going on here?

Best Regards,
Tobias

[shane.bryzak]

No idea.. could you post the full code for your filter?

[toby451]

Here it is (I can't see that it interfers with encoding in any way).
Application is being deployed on JBoss 4.2.1.GA.

import org.apache.commons.lang.StringUtils;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;

/**
 * TimingFilter messures requests times and should be placed
 * outside (in the filter/servlet chain) the thing to be meassured.
 */
public class TimingFilter implements Filter {

 private FilterConfig config;
 private static final int MAX_ARRAYITEMS_PRINTED = 5;

 public void init(FilterConfig config) throws ServletException {
 this.config = config;
 }

 public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
 String name = "<non http request>";
 String method = "?";
 if (req instanceof HttpServletRequest) {
 HttpServletRequest servletRequest = (HttpServletRequest) req;
 name = servletRequest.getRequestURI();
 method = servletRequest.getMethod();
 }
 Map requestMap = req.getParameterMap();

 long t0 = System.nanoTime();
 chain.doFilter(req, res);
 long dt = System.nanoTime() - t0;

 config.getServletContext().log(
 StringUtils.leftPad(formatTime(dt), 10) +
 StringUtils.leftPad(method + " ", 6) +
 StringUtils.rightPad(name, 26) +
 StringUtils.rightPad(prettify(requestMap), 100)
 );
 }


 /**
 * Will format a nanosecond value as milliseconds with one decimal.
 */
 private String formatTime(long ns) {
 String ms = String.valueOf(ns / 100000);
 int pointPos = ms.length() - 1;
 return ms.substring(0, pointPos) + "." + ms.substring(pointPos) + " ms";
 }


 /**
 * Will convert the map into something readable
 */
 private String prettify(Map map) {
 StringBuilder sb = new StringBuilder();

 //noinspection unchecked
 List<String> keys = new ArrayList(map.keySet());
 Collections.sort(keys);

 for (String key : keys)
 sb.append(key).append("=").append(prettifyValue(map.get(key))).append(" ");

 return sb.length() > 0 ? sb.toString() : "<no parameters>";
 }


 /**
 * Will loop through array values and give pretty output.
 * (i.e. some widgets (grouped checkboxes) give multiple values)
 */
 private String prettifyValue(Object o) {

 // Non arrays we just convert to String.
 if (!(o instanceof Object[]))
 return o.toString();

 // For arrays we build a comma separated list.
 StringBuilder sb = new StringBuilder("");
 Object[] arr = (Object[]) o;
 int itemsToPrint = Math.min(arr.length, MAX_ARRAYITEMS_PRINTED);
 for (int i = 0; i < itemsToPrint; i++)
 sb.append(arr).append(i < (itemsToPrint - 1) ? ", " : "");

 if (itemsToPrint == 1)
 return sb.toString();
 else
 return "[" + sb.toString() + "]";
 }

 public void destroy() {
 config = null;
 }
 }

[manuelpalacio]

How are you UTF-8 encoding your pages? I tried the filter and it didn't mess up the öåä, etc

[toby451]

Ok ... the scandinavian characters åäöÅÄÖ got scrambled when they where part of a post-data.

Adding this (below) filter in front of the timing seems to solve it!

 <filter>
 <filter-name>Character Encoding</filter-name>
 <filter-class>
 org.jboss.seam.servlet.SeamCharacterEncodingFilter
 </filter-class>
 <init-param>
 <param-name>encoding</param-name>
 <param-value>UTF-8</param-value>
 </init-param>
 <init-param>
 <param-name>overrideClient</param-name>
 <param-value>true</param-value>
 </init-param>
 </filter>

[pmuir]

N.B. if you make your filter a Seam filter (see the configuration chapter) you can order the filters using @Filter.