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1   package com.bradmcevoy.http;
2   
3   import com.bradmcevoy.http.http11.DefaultHttp11ResponseHandler;
4   import com.bradmcevoy.http.exceptions.BadRequestException;
5   import java.io.OutputStream;
6   import java.util.Map;
7   import java.util.zip.GZIPOutputStream;
8   
9   import org.slf4j.Logger;
10  import org.slf4j.LoggerFactory;
11  
12  import com.bradmcevoy.http.exceptions.NotAuthorizedException;
13  import com.bradmcevoy.http.http11.CacheControlHelper;
14  import com.bradmcevoy.http.http11.DefaultCacheControlHelper;
15  import com.bradmcevoy.http.webdav.WebDavResponseHandler;
16  import com.bradmcevoy.io.BufferingOutputStream;
17  import com.bradmcevoy.io.FileUtils;
18  import com.bradmcevoy.io.ReadingException;
19  import com.bradmcevoy.io.StreamUtils;
20  import com.bradmcevoy.io.WritingException;
21  import java.io.InputStream;
22  import java.util.Date;
23  import org.apache.commons.io.IOUtils;
24  
25  /**
26   * Response Handler which wraps another, and compresses content if appropriate
27   * 
28   * Usually, this will wrap a DefaultResponseHandler, but custom implementations
29   * can be wrapped as well.
30   *
31   * @author brad
32   */
33  public class CompressingResponseHandler extends AbstractWrappingResponseHandler {
34  
35      private static final Logger log = LoggerFactory.getLogger( CompressingResponseHandler.class );
36      /**
37       * The size to buffer in memory before switching to disk cache.
38       */
39      private int maxMemorySize = 100000;
40      private CacheControlHelper cacheControlHelper = new DefaultCacheControlHelper();
41  
42      public CompressingResponseHandler() {
43      }
44  
45      public CompressingResponseHandler( WebDavResponseHandler wrapped ) {
46          super( wrapped );
47      }
48  
49      /**
50       * Defaults to com.bradmcevoy.http.http11.DefaultCacheControlHelper
51       * @return
52       */
53      public CacheControlHelper getCacheControlHelper() {
54          return cacheControlHelper;
55      }
56  
57      public void setCacheControlHelper( CacheControlHelper cacheControlHelper ) {
58          this.cacheControlHelper = cacheControlHelper;
59      }
60  
61      @Override
62      public void respondContent( Resource resource, Response response, Request request, Map<String, String> params ) throws NotAuthorizedException, BadRequestException {
63          if( resource instanceof GetableResource ) {
64              GetableResource r = (GetableResource) resource;
65  
66              String acceptableContentTypes = request.getAcceptHeader();
67              String contentType = r.getContentType( acceptableContentTypes );
68  
69              if( canCompress( r, contentType, request.getAcceptEncodingHeader() ) ) {
70                  log.trace( "respondContent: compressable" );
71  
72                  // get the zipped content before sending so we can determine its
73                  // compressed size
74                  BufferingOutputStream tempOut = new BufferingOutputStream( maxMemorySize );
75                  try {
76                      OutputStream gzipOut = new GZIPOutputStream( tempOut );
77                      r.sendContent( gzipOut, null, params, contentType );
78                      gzipOut.flush();
79                      gzipOut.close();
80                      tempOut.flush();
81                  } catch( Exception ex ) {
82                      tempOut.deleteTempFileIfExists();
83                      throw new RuntimeException( ex );
84                  } finally {
85                      FileUtils.close( tempOut );
86                  }
87  
88                  log.trace( "respondContent-compressed: " + resource.getClass() );
89                  setRespondContentCommonHeaders( response, resource, Response.Status.SC_OK, request.getAuthorization() );
90                  response.setContentEncodingHeader( Response.ContentEncoding.GZIP );
91                  response.setVaryHeader( "Accept-Encoding" );
92                  Long contentLength = tempOut.getSize();
93                  response.setContentLengthHeader( contentLength );
94                  response.setContentTypeHeader( contentType );
95                  cacheControlHelper.setCacheControl( r, response, request.getAuthorization() );
96                  InputStream in = tempOut.getInputStream();
97                  try {
98                      StreamUtils.readTo( in, response.getOutputStream() );
99                  } catch( ReadingException ex ) {
100                     throw new RuntimeException( ex );
101                 } catch( WritingException ex ) {
102                     log.warn( "exception writing, client probably closed connection", ex );
103                 } finally {
104                     IOUtils.closeQuietly(in);
105                 }
106                 return;
107             } else {
108                 log.trace( "respondContent: not compressable" );
109                 // We really should set this header, but it causes IE to not cache files (eg images)
110                 //response.setVaryHeader( "Accept-Encoding" );
111                 wrapped.respondContent( resource, response, request, params );
112             }
113         } else {
114             throw new RuntimeException( "Cant generate content for non-Getable resource: " + resource.getClass() );
115         }
116     }
117 
118     protected void setRespondContentCommonHeaders( Response response, Resource resource, Response.Status status, Auth auth ) {
119         response.setStatus( status );
120         response.setDateHeader( new Date() );
121         String etag = wrapped.generateEtag( resource );
122         if( etag != null ) {
123             response.setEtag( etag );
124         }
125         DefaultHttp11ResponseHandler.setModifiedDate( response, resource, auth );
126     }
127 
128     private boolean canCompress( GetableResource r, String contentType, String acceptableEncodings ) {
129         log.trace( "canCompress: contentType: " + contentType + " acceptable-encodings: " + acceptableEncodings );
130         if( contentType != null ) {
131             contentType = contentType.toLowerCase();
132             boolean contentIsCompressable = contentType.contains( "text" ) || contentType.contains( "css" ) || contentType.contains( "js" ) || contentType.contains( "javascript" );
133             if( contentIsCompressable ) {
134                 boolean supportsGzip = ( acceptableEncodings != null && acceptableEncodings.toLowerCase().indexOf( "gzip" ) > -1 );
135                 log.trace( "supports gzip: " + supportsGzip );
136                 return supportsGzip;
137             }
138         }
139         return false;
140     }
141 
142     public void setMaxMemorySize( int maxMemorySize ) {
143         this.maxMemorySize = maxMemorySize;
144     }
145 
146     public int getMaxMemorySize() {
147         return maxMemorySize;
148     }
149 }