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package com.sun.jersey.api.container.filter;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
import javax.ws.rs.core.EntityTag;
import javax.ws.rs.core.HttpHeaders;
import com.sun.jersey.api.container.ContainerException;
import com.sun.jersey.spi.container.ContainerRequest;
import com.sun.jersey.spi.container.ContainerRequestFilter;
import com.sun.jersey.spi.container.ContainerResponse;
import com.sun.jersey.spi.container.ContainerResponseFilter;
import com.sun.jersey.spi.container.ContainerResponseWriter;
/**
* A GZIP content encoding filter.
* <p/>
* If the request contains a Content-Encoding header of "gzip"
* then the request entity (if any) is uncompressed using gzip.
* If the request contains an Accept-Encoding header containing "gzip" and an "If-None-Match" Header, entitytag value is checked:
* if it contains the -gzip suffix, remove this suffix, otherwise, completely remove the "if-none-match" header.
* <p/>
* If the request contains a Accept-Encoding header that contains
* "gzip" then the response entity (if any) is compressed using gzip and a
* Content-Encoding header of "gzip" is added to the response.
* As this filter is active, the resource representation can be compressed. the value "Accept-Encoding" is so added to the Vary header.
* If any entityTag is used and content may be gzipped, the "-gzip" suffix is added to entitytag value.
* <p/>
* When an application is deployed as a Servlet or Filter this Jersey filter can be
* registered using the following initialization parameters:
* <blockquote><pre>
* <init-param>
* <param-name>com.sun.jersey.spi.container.ContainerRequestFilters</param-name>
* <param-value>com.sun.jersey.api.container.filter.GZIPContentEncodingFilter</param-value>
* </init-param>
* <init-param>
* <param-name>com.sun.jersey.spi.container.ContainerResponseFilters</param-name>
* <param-value>com.sun.jersey.api.container.filter.GZIPContentEncodingFilter</param-value>
* </init-param>
* </pre></blockquote>
* Note that if you're using Entitag for cache control and want to use this filter, you shoud add this filter to both ContainerFilters (Request and Response).
*
* @author Paul Sandoz
* @author Edouard Chevalier
* @see com.sun.jersey.api.container.filter
*/
public class GZIPContentEncodingFilter implements ContainerRequestFilter, ContainerResponseFilter {
private static final String ENTITY_TAG_GZIP_SUFFIX_VALUE = "-gzip";
private static final String ENTITY_TAG_GZIP_SUFFIX_HEADER_VALUE = "-gzip\""; // Entity tag raw values always finish with a quotation mark within http headers.
public ContainerRequest filter(ContainerRequest request) {
String contentEncoding = request.getRequestHeaders().getFirst(HttpHeaders.CONTENT_ENCODING);
if (contentEncoding != null && contentEncoding.trim().equals("gzip")) {
request.getRequestHeaders().remove(HttpHeaders.CONTENT_ENCODING);
try {
request.setEntityInputStream(
new GZIPInputStream(request.getEntityInputStream()));
} catch (IOException ex) {
throw new ContainerException(ex);
}
}
// Check for entity tag header 'If-None-Match' in case of accept-encoding = gzip
String acceptEncoding = request.getRequestHeaders().getFirst(HttpHeaders.ACCEPT_ENCODING);
String entityTag = request.getRequestHeaders().getFirst(HttpHeaders.IF_NONE_MATCH);
if (acceptEncoding != null && acceptEncoding.contains("gzip") && entityTag != null) {
// normalize entitytag (Note: maybe it should check whether it ends with a quotation mark ?)
if (entityTag.endsWith(ENTITY_TAG_GZIP_SUFFIX_HEADER_VALUE)) {
final int gzipsuffixbeginIndex = entityTag.lastIndexOf(ENTITY_TAG_GZIP_SUFFIX_HEADER_VALUE);
final StringBuilder sb = new StringBuilder();
sb.append(entityTag.substring(0, gzipsuffixbeginIndex));
sb.append('\"');
request.getRequestHeaders().putSingle(HttpHeaders.IF_NONE_MATCH, sb.toString());
} else {
// otherwise, remove if-none-match header
request.getRequestHeaders().remove(HttpHeaders.IF_NONE_MATCH);
}
}
return request;
}
private static final class Adapter implements ContainerResponseWriter {
private final ContainerResponseWriter crw;
private GZIPOutputStream gos;
Adapter(ContainerResponseWriter crw) {
this.crw = crw;
}
public OutputStream writeStatusAndHeaders(long contentLength, ContainerResponse response) throws IOException {
gos = new GZIPOutputStream(crw.writeStatusAndHeaders(-1, response));
return gos;
}
public void finish() throws IOException {
gos.finish();
crw.finish();
}
}
public ContainerResponse filter(ContainerRequest request, ContainerResponse response) {
response.getHttpHeaders().add(HttpHeaders.VARY, HttpHeaders.ACCEPT_ENCODING); // add vary header
String acceptEncoding = request.getRequestHeaders().getFirst(HttpHeaders.ACCEPT_ENCODING);
String contentEncoding = (String) response.getHttpHeaders().getFirst(HttpHeaders.CONTENT_ENCODING);
if (acceptEncoding != null && contentEncoding == null && acceptEncoding.contains("gzip")) {
// Check EntityTag header
if (response.getHttpHeaders().containsKey(HttpHeaders.ETAG)) {
EntityTag entityTag = (EntityTag) response.getHttpHeaders().getFirst(HttpHeaders.ETAG);
if (entityTag != null) {
response.getHttpHeaders().putSingle(HttpHeaders.ETAG, new EntityTag(entityTag.getValue()
+ ENTITY_TAG_GZIP_SUFFIX_VALUE, entityTag.isWeak()));
}
}
// wrap entity with gzip
if (response.getEntity() != null) {
response.getHttpHeaders().add(HttpHeaders.CONTENT_ENCODING, "gzip");
response.setContainerResponseWriter(new Adapter(response.getContainerResponseWriter()));
}
}
return response;
}
}