com.nesscomputing.httpserver.jetty

Class TransparentCompressionFilter

java.lang.Object

com.nesscomputing.httpserver.jetty.TransparentCompressionFilter

All Implemented Interfaces:

javax.servlet.Filter

public class TransparentCompressionFilter
extends Object
implements javax.servlet.Filter

NOTE: this is a copy of the Jetty GzipFilter, updated to add LZ4 support! LZ4/GZIP Filter This filter will lz4 or gzip or deflate the content of a response if:

• The filter is mapped to a matching path
• accept-encoding header is set to any of lz4, gzip, deflate or a combination of those
• The response status code is >=200 and <300
• The content length is unknown or more than the minGzipSize initParameter or the minGzipSize is 0(default)
• The content-type is in the comma separated list of mimeTypes set in the mimeTypes initParameter or if no mimeTypes are defined the content-type is not "application/gzip"
• No content-encoding is specified by the resource

If multiple acceptable encodings are supplied, lz4 trumps gzip trumps deflate.

Compressing the content can greatly improve the network bandwidth usage, but at a cost of memory and CPU cycles. If this filter is mapped for static content, then use of efficient direct NIO may be prevented, thus use of the gzip mechanism of the DefaultServlet is advised instead.

This filter extends UserAgentFilter and if the the initParameter excludedAgents is set to a comma separated list of user agents, then these agents will be excluded from gzip content.

Init Parameters:

 bufferSize                 The output buffer size. Defaults to 8192. Be careful as values <= 0 will lead to an
                            IllegalArgumentException.

See Also:

GZIPOutputStream.GZIPOutputStream(java.io.OutputStream, int), minGzipSize Content will only be compressed if content length is either unknown or greater than minGzipSize. deflateCompressionLevel The compression level used for deflate compression. (0-9)., deflateNoWrap The noWrap setting for deflate compression. Defaults to true. (true/false), mimeTypes Comma separated list of mime types to compress. See description above. excludedAgents Comma separated list of user agents to exclude from compression. Does a {@link String#contains(CharSequence)} to check if the excluded agent occurs in the user-agent header. If it does -> no compression excludeAgentPatterns Same as excludedAgents, but accepts regex patterns for more complex matching. excludePaths Comma separated list of paths to exclude from compression. Does a {@link String#startsWith(String)} comparison to check if the path matches. If it does match -> no compression. To match subpaths use excludePathPatterns instead. excludePathPatterns Same as excludePath, but accepts regex patterns for more complex matching.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	_bufferSize
protected int	_deflateCompressionLevel
protected boolean	_deflateNoWrap
protected Set<Pattern>	_excludedPathPatterns
protected Set<String>	_excludedPaths
protected Set<String>	_mimeTypes
protected int	_minGzipSize

Constructor Summary

Constructors

Constructor and Description
TransparentCompressionFilter()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	configureWrappedResponse(org.eclipse.jetty.http.gzip.CompressedResponseWrapper wrappedResponse)
protected org.eclipse.jetty.http.gzip.CompressedResponseWrapper	createWrappedResponse(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, String compressionType)
void	destroy()
void	doFilter(javax.servlet.ServletRequest req, javax.servlet.ServletResponse res, javax.servlet.FilterChain chain)
void	init(javax.servlet.FilterConfig filterConfig)

Methods inherited from class java.lang.Object

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

Field Detail

_mimeTypes

protected Set<String> _mimeTypes

_bufferSize

protected int _bufferSize

_minGzipSize

protected int _minGzipSize

_deflateCompressionLevel

protected int _deflateCompressionLevel

_deflateNoWrap

protected boolean _deflateNoWrap

_excludedPaths

protected Set<String> _excludedPaths

_excludedPathPatterns

protected Set<Pattern> _excludedPathPatterns

Constructor Detail

TransparentCompressionFilter

public TransparentCompressionFilter()

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

See Also:

org.eclipse.jetty.servlets.UserAgentFilter#init(javax.servlet.FilterConfig)

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Filter

See Also:

org.eclipse.jetty.servlets.UserAgentFilter#destroy()

doFilter

public void doFilter(javax.servlet.ServletRequest req,
            javax.servlet.ServletResponse res,
            javax.servlet.FilterChain chain)
              throws IOException,
                     javax.servlet.ServletException

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

IOException

javax.servlet.ServletException

See Also:

org.eclipse.jetty.servlets.UserAgentFilter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)

createWrappedResponse

protected org.eclipse.jetty.http.gzip.CompressedResponseWrapper createWrappedResponse(javax.servlet.http.HttpServletRequest request,
                                                                          javax.servlet.http.HttpServletResponse response,
                                                                          String compressionType)

configureWrappedResponse

protected void configureWrappedResponse(org.eclipse.jetty.http.gzip.CompressedResponseWrapper wrappedResponse)