[CLK-323] CompressionServletResponseWrapper throws NPE in Jetty

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 1.4
• Fix Version/s: 1.4
• Environment: Jetty 5.1.4, Websphere 6
• Assignee: Malcolm Edgar
• Reporter: Bob Schellink
• Created: 26/Feb/08 10:35
• Updated: 06/Mar/08 05:55
• Resolved: 06/Mar/08 05:55

Description

Ricardo reported a compression issue while using PerformanceFilter in Jetty 5.1.4.

Here is the stack trace:

java.lang.NullPointerException
at net.sf.click.extras.filter.CompressionServletResponseWrapper.flushBuffer(CompressionServletResponseWrapper.java:149)
at org.mortbay.jetty.servlet.Default.passConditionalHeaders(Default.java:501)
at org.mortbay.jetty.servlet.Default.handleGet(Default.java:327)
at org.mortbay.jetty.servlet.Default.service(Default.java:232)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:427)
at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:832)
at net.sf.click.extras.filter.PerformanceFilter.doFilter(PerformanceFilter.java:378)

Source info:

#1 http://www.servlets.com/archive/servlet/ReadMsg?msgId=498901&listName=jetty-support
#2 http://www.servlets.com/archive/servlet/ReadMsg?msgId=196252&listName=tomcat-dev

it sounds like the problem comes from a null stream when the serving a 304 (not modified) response.

The following change needs to be applied to CompressionServletResponseWrapper#flushBuffer:

public void flushBuffer() throws IOException {
if (writer != null)

{ writer.flush(); }

else if (stream != null)

{ ((CompressionResponseStream) stream).flush(); }

}

We should also flush the writer according to #2