Package org.kohsuke.stapler.compression

Class CompressionFilter

java.lang.Object

org.kohsuke.stapler.compression.CompressionFilter

All Implemented Interfaces:

javax.servlet.Filter

public class CompressionFilter
extends Object
implements javax.servlet.Filter

Pimps up HttpServletResponse so that it understands "Content-Encoding: gzip" and compress the response.

When exceptions are processed within web applications, different unrelated parts of the webapp can end up calling ServletResponse.getOutputStream(). This fundamentally doesn't work with the notion that the application needs to process "Content-Encoding:gzip" on its own. Such app has to maintain a GZIP output stream on its own, since HttpServletResponse doesn't know that its output is written through a compressed stream.

Another place this break-down can be seen is when a servlet throws an exception that the container handles. It tries to render an error page, but of course it wouldn't know that "Content-Encoding:gzip" is set, so it will fail to write in the correct format.

The only way to properly fix this is to make HttpServletResponse smart enough that it returns the compression-transparent stream from ServletResponse.getOutputStream() (and it would also have to process the exception thrown from the app.) This filter does exactly that.

Author:

Kohsuke Kawaguchi

Field Summary

Fields

Modifier and Type	Field	Description
static boolean	DISABLED	Disables the effect of setUncaughtExceptionHandler(javax.servlet.ServletContext, org.kohsuke.stapler.compression.UncaughtExceptionHandler), letting all errors be rethrown.

Constructor Summary

Constructors

Constructor	Description
CompressionFilter()

Method Summary

Modifier and Type	Method	Description
static boolean	activate(javax.servlet.ServletRequest req)	Is this request already wrapped into CompressionFilter, activate that, so that ServletResponse.getOutputStream() will return a stream that automatically handles compression.
void	destroy()
void	doFilter(javax.servlet.ServletRequest _req, javax.servlet.ServletResponse _rsp, javax.servlet.FilterChain filterChain)
static UncaughtExceptionHandler	getUncaughtExceptionHandler(javax.servlet.ServletContext context)
static boolean	has(javax.servlet.ServletRequest req)	Is this request already wrapped into CompressionFilter?
void	init(javax.servlet.FilterConfig filterConfig)
static void	setUncaughtExceptionHandler(javax.servlet.ServletContext context, UncaughtExceptionHandler handler)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DISABLED

public static boolean DISABLED

Disables the effect of setUncaughtExceptionHandler(javax.servlet.ServletContext, org.kohsuke.stapler.compression.UncaughtExceptionHandler), letting all errors be rethrown. Despite its name, this flag does not disable CompressionFilter itself! Rather use DefaultScriptInvoker.COMPRESS_BY_DEFAULT.

Constructor Detail

CompressionFilter

public CompressionFilter()

Method Detail

init

public void init(javax.servlet.FilterConfig filterConfig)
          throws javax.servlet.ServletException

Specified by:

init in interface javax.servlet.Filter

Throws:

javax.servlet.ServletException

doFilter

public void doFilter(javax.servlet.ServletRequest _req,
                     javax.servlet.ServletResponse _rsp,
                     javax.servlet.FilterChain filterChain)
              throws IOException,
                     javax.servlet.ServletException

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

IOException

javax.servlet.ServletException

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Filter

setUncaughtExceptionHandler

public static void setUncaughtExceptionHandler(javax.servlet.ServletContext context,
                                               UncaughtExceptionHandler handler)

getUncaughtExceptionHandler

public static UncaughtExceptionHandler getUncaughtExceptionHandler(javax.servlet.ServletContext context)

has

public static boolean has(javax.servlet.ServletRequest req)

Is this request already wrapped into CompressionFilter?

activate

public static boolean activate(javax.servlet.ServletRequest req)
                        throws IOException

Is this request already wrapped into CompressionFilter, activate that, so that ServletResponse.getOutputStream() will return a stream that automatically handles compression.

Throws:

IOException