/**
* Copyright 2005-2014 Restlet
*
* The contents of this file are subject to the terms of one of the following
* open source licenses: Apache 2.0 or or EPL 1.0 (the "Licenses"). You can
* select the license that you prefer but you may not use this file except in
* compliance with one of these Licenses.
*
* You can obtain a copy of the Apache 2.0 license at
* http://www.opensource.org/licenses/apache-2.0
*
* You can obtain a copy of the EPL 1.0 license at
* http://www.opensource.org/licenses/eclipse-1.0
*
* See the Licenses for the specific language governing permissions and
* limitations under the Licenses.
*
* Alternatively, you can obtain a royalty free commercial license with less
* limitations, transferable or non-transferable, directly at
* http://restlet.com/products/restlet-framework
*
* Restlet is a registered trademark of Restlet S.A.S.
*/
package org.restlet.engine.application;
import java.util.Iterator;
import java.util.List;
import org.restlet.Context;
import org.restlet.Request;
import org.restlet.Response;
import org.restlet.data.ClientInfo;
import org.restlet.data.Encoding;
import org.restlet.data.Preference;
import org.restlet.representation.Representation;
import org.restlet.routing.Filter;
import org.restlet.service.EncoderService;
// [excludes gwt]
/**
* Filter compressing entities. The best encoding is automatically selected
* based on the preferences of the client and on the encoding supported by NRE:
* GZip, Zip and Deflate.<br>
* If the {@link org.restlet.representation.Representation} has an unknown size,
* it will always be a candidate for encoding. Candidate representations need to
* respect media type criteria by the lists of accepted and ignored media types.
*
* Concurrency note: instances of this class or its subclasses can be invoked by
* several threads at the same time and therefore must be thread-safe. You
* should be especially careful when storing state in member variables.
*
* @author Lars Heuer (heuer[at]semagia.com) <a
* href="http://semagia.com/">Semagia</a>
* @author Jerome Louvel
*/
public class Encoder extends Filter {
/** Indicates if the request entity should be encoded. */
private final boolean encodingRequest;
/** Indicates if the response entity should be encoded. */
private final boolean encodingResponse;
/** The parent encoder service. */
private final EncoderService encoderService;
/**
* Constructor.
*
* @param context
* The context.
* @param encodingRequest
* Indicates if the request entities should be encoded.
* @param encodingResponse
* Indicates if the response entities should be encoded.
* @param encoderService
* The parent encoder service.
*/
public Encoder(Context context, boolean encodingRequest,
boolean encodingResponse, EncoderService encoderService) {
super(context);
this.encodingRequest = encodingRequest;
this.encodingResponse = encodingResponse;
this.encoderService = encoderService;
}
/**
* Allows filtering after its handling by the target Restlet. Does nothing
* by default.
*
* @param request
* The request to filter.
* @param response
* The response to filter.
*/
@Override
public void afterHandle(Request request, Response response) {
// Check if encoding of the response entity is needed
if (isEncodingResponse()
&& getEncoderService().canEncode(response.getEntity())) {
response.setEntity(encode(request.getClientInfo(),
response.getEntity()));
}
}
/**
* Allows filtering before its handling by the target Restlet. Does nothing
* by default.
*
* @param request
* The request to filter.
* @param response
* The response to filter.
* @return The continuation status.
*/
@Override
public int beforeHandle(Request request, Response response) {
// Check if encoding of the request entity is needed
if (isEncodingRequest()
&& getEncoderService().canEncode(request.getEntity())) {
request.setEntity(encode(request.getClientInfo(),
request.getEntity()));
}
return CONTINUE;
}
/**
* Encodes a given representation if an encoding is supported by the client.
*
* @param client
* The client preferences to use.
* @param representation
* The representation to encode.
* @return The encoded representation or the original one if no encoding
* supported by the client.
*/
public Representation encode(ClientInfo client,
Representation representation) {
Representation result = representation;
Encoding bestEncoding = getBestEncoding(client);
if (bestEncoding != null) {
result = new EncodeRepresentation(bestEncoding, representation);
}
return result;
}
/**
* Returns the best supported encoding for a given client.
*
* @param client
* The client preferences to use.
* @return The best supported encoding for the given call.
*/
public Encoding getBestEncoding(ClientInfo client) {
Encoding bestEncoding = null;
Encoding currentEncoding = null;
Preference<Encoding> currentPref = null;
float bestScore = 0F;
for (Iterator<Encoding> iter = getSupportedEncodings().iterator(); iter
.hasNext();) {
currentEncoding = iter.next();
for (Iterator<Preference<Encoding>> iter2 = client
.getAcceptedEncodings().iterator(); iter2.hasNext();) {
currentPref = iter2.next();
if (currentPref.getMetadata().equals(Encoding.ALL)
|| currentPref.getMetadata().equals(currentEncoding)) {
// A match was found, compute its score
if (currentPref.getQuality() > bestScore) {
bestScore = currentPref.getQuality();
bestEncoding = currentEncoding;
}
}
}
}
return bestEncoding;
}
/**
* Returns the parent encoder service.
*
* @return The parent encoder service.
*/
public EncoderService getEncoderService() {
return encoderService;
}
/**
* Returns the list of supported encodings. By default it calls
* {@link EncodeRepresentation#getSupportedEncodings()} static method.
*
* @return The list of supported encodings.
*/
public List<Encoding> getSupportedEncodings() {
return EncodeRepresentation.getSupportedEncodings();
}
/**
* Indicates if the request entity should be encoded.
*
* @return True if the request entity should be encoded.
*/
public boolean isEncodingRequest() {
return this.encodingRequest;
}
/**
* Indicates if the response entity should be encoded.
*
* @return True if the response entity should be encoded.
*/
public boolean isEncodingResponse() {
return this.encodingResponse;
}
}