001 /*
002 * Copyright 2003-2008 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * You are receiving this code free of charge, which represents many hours of
017 * effort from other individuals and corporations. As a responsible member
018 * of the community, you are asked (but not required) to donate any
019 * enhancements or improvements back to the community under a similar open
020 * source license. Thank you. -TMN
021 */
022 package groovyx.net.http;
023
024 import java.io.IOException;
025
026 import org.apache.http.Header;
027 import org.apache.http.HeaderElement;
028 import org.apache.http.HttpEntity;
029 import org.apache.http.HttpException;
030 import org.apache.http.HttpRequest;
031 import org.apache.http.HttpRequestInterceptor;
032 import org.apache.http.HttpResponse;
033 import org.apache.http.HttpResponseInterceptor;
034 import org.apache.http.protocol.HttpContext;
035
036 /**
037 * Base class for handing content-encoding.
038 * @author <a href='mailto:tnichols@enernoc.com'>Tom Nichols</a>
039 */
040 public abstract class ContentEncoding {
041
042 public static final String ACCEPT_ENC_HDR = "Accept-Encoding";
043 public static final String CONTENT_ENC_HDR = "Content-Encoding";
044
045 protected abstract String getContentEncoding();
046 protected abstract HttpEntity wrapResponseEntity( HttpEntity raw );
047
048 public HttpRequestInterceptor getRequestInterceptor() {
049 return new RequestInterceptor();
050 }
051
052 public HttpResponseInterceptor getResponseInterceptor() {
053 return new ResponseInterceptor();
054 }
055
056 /**
057 * Enumeration of common content-encodings.
058 */
059 public static enum Type {
060 GZIP,
061 COMPRESS,
062 DEFLATE;
063
064 /** Prints the value as it should appear in an HTTP header */
065 @Override public String toString() {
066 return this.name().toLowerCase();
067 }
068 }
069
070 /**
071 * Request interceptor that adds the correct <code>Accept</code> header
072 * to the outgoing request.
073 * @author <a href='mailto:tnichols@enernoc.com'>Tom Nichols</a>
074 */
075 protected class RequestInterceptor implements HttpRequestInterceptor {
076 public void process( final HttpRequest req,
077 final HttpContext context ) throws HttpException, IOException {
078
079 // set the Accept-Encoding header:
080 String encoding = getContentEncoding();
081 if ( !req.containsHeader( ACCEPT_ENC_HDR ) )
082 req.addHeader( ACCEPT_ENC_HDR, encoding );
083
084 else {
085 StringBuilder values = new StringBuilder();
086 for ( Header h : req.getHeaders( ACCEPT_ENC_HDR ) )
087 values.append( h.getValue() ).append( "," );
088
089 String encList = (!values.toString().contains( encoding )) ? values
090 .append( encoding ).toString()
091 : values.toString().substring( 0, values.lastIndexOf( "," ) );
092
093 req.setHeader( ACCEPT_ENC_HDR, encList );
094 }
095
096 //TODO compress request and add content-encoding header.
097 }
098 }
099
100 /**
101 * Response interceptor that filters the response stream to decode the
102 * compressed content before it is passed on to the parser.
103 * @author <a href='mailto:tnichols@enernoc.com'>Tom Nichols</a>
104 */
105 protected class ResponseInterceptor implements HttpResponseInterceptor {
106 public void process( final HttpResponse response, final HttpContext context )
107 throws HttpException, IOException {
108
109 if ( hasEncoding( response, getContentEncoding() ) )
110 response.setEntity( wrapResponseEntity( response.getEntity() ) );
111 }
112
113 protected boolean hasEncoding( final HttpResponse response, final String encoding ) {
114 HttpEntity entity = response.getEntity();
115 if ( entity == null ) return false;
116 Header ceHeader = entity.getContentEncoding();
117 if ( ceHeader == null ) return false;
118
119 HeaderElement[] codecs = ceHeader.getElements();
120 for ( int i = 0; i < codecs.length; i++ )
121 if ( encoding.equalsIgnoreCase( codecs[i].getName() ) )
122 return true;
123
124 return false;
125 }
126 }
127 }