[Archive-access-cvs] SF.net SVN: archive-access:[2490] trunk/archive-access/projects/nutchwax/ archive/src/java/org/archive/nutchwax/XSLTFilter.java

[<bi...@us...>]

Revision: 2490
          http://archive-access.svn.sourceforge.net/archive-access/?rev=2490&view=rev
Author:   binzino
Date:     2008-07-24 23:31:54 +0000 (Thu, 24 Jul 2008)

Log Message:
-----------
Initial check of servlet filter which applies an XSLT transform to the
output of the filter chain.

Added Paths:
-----------
    trunk/archive-access/projects/nutchwax/archive/src/java/org/archive/nutchwax/XSLTFilter.java

Added: trunk/archive-access/projects/nutchwax/archive/src/java/org/archive/nutchwax/XSLTFilter.java
===================================================================
--- trunk/archive-access/projects/nutchwax/archive/src/java/org/archive/nutchwax/XSLTFilter.java	                        (rev 0)
+++ trunk/archive-access/projects/nutchwax/archive/src/java/org/archive/nutchwax/XSLTFilter.java	2008-07-24 23:31:54 UTC (rev 2490)
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2008 Internet Archive.
+ * 
+ * This file is part of the archive-access tools project
+ * (http://sourceforge.net/projects/archive-access).
+ * 
+ * The archive-access tools are free software; you can redistribute them and/or
+ * modify them under the terms of the GNU Lesser Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or any
+ * later version.
+ * 
+ * The archive-access tools are distributed in the hope that they will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+ * Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser Public License along with
+ * the archive-access tools; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+package org.archive.nutchwax;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.CharArrayWriter;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.ServletResponseWrapper;
+import javax.servlet.http.*;
+
+import javax.xml.transform.Source;
+import javax.xml.transform.stream.StreamSource;
+import javax.xml.transform.Templates;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+
+
+public class XSLTFilter implements Filter
+{
+  private String xsltUrl;
+  private String contentType;
+
+  public void init( FilterConfig config )
+    throws ServletException
+  {
+    ServletContext app = config.getServletContext( );
+
+    this.xsltUrl = config.getInitParameter( "xsltUrl" );
+
+    if ( this.xsltUrl != null )
+      {
+        this.xsltUrl = this.xsltUrl.trim( );
+        
+        if ( this.xsltUrl.length( ) == 0 )
+          {
+            this.xsltUrl = null;
+          }
+      }
+
+    this.contentType = config.getInitParameter( "contentType" );
+
+    if ( this.contentType != null )
+      {
+        this.contentType = this.contentType.trim( );
+        
+        if ( this.contentType.length( ) == 0 )
+          {
+            this.contentType = null;
+          }
+      }
+
+    if ( this.contentType == null )
+      {
+        this.contentType = "application/xml";
+      }
+  }
+
+  public void doFilter( ServletRequest request, ServletResponse response, FilterChain chain )
+    throws IOException, ServletException 
+  {
+    if ( this.xsltUrl != null )
+      {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream( 8 * 1024 );
+
+        HttpServletResponseInterceptor capturedResponse = new HttpServletResponseInterceptor( (HttpServletResponse) response, baos );
+        
+        chain.doFilter( request, capturedResponse );
+        
+        byte output[] = baos.toByteArray( );
+        
+        try
+          {
+            Source      xsltSource    = new StreamSource( xsltUrl );
+            Templates   xsltTemplates = TransformerFactory.newInstance( ).newTemplates( xsltSource );
+            Transformer transformer   = xsltTemplates.newTransformer( );
+            
+            StreamSource source = new StreamSource( new ByteArrayInputStream( output ) );
+            StreamResult result = new StreamResult( response.getOutputStream( ) );
+            
+            // Enforce XML content-type in the response.
+            response.setContentType( this.contentType );
+            
+            transformer.transform( source, result );
+          }
+        catch ( javax.xml.transform.TransformerConfigurationException tce )
+          {
+          }
+        catch( javax.xml.transform.TransformerException te )
+          {
+          }
+      }
+    else
+      {
+        chain.doFilter( request, response );
+      }
+  }
+
+  public void destroy()
+  {
+
+  }
+
+}
+
+
+class HttpServletResponseInterceptor extends HttpServletResponseWrapper
+{
+  private OutputStream os;
+
+  HttpServletResponseInterceptor( HttpServletResponse response, OutputStream os )
+  {
+    super( response );
+    
+    this.os = os;
+  }
+
+  public ServletOutputStream getOutputStream() 
+  {
+    ServletOutputStream sos = new ServletOutputStream( )
+      {
+        public void write( int b )
+          throws java.io.IOException
+        {
+          HttpServletResponseInterceptor.this.os.write( b );
+        }
+      };
+    
+    return sos;
+  }
+
+  public PrintWriter getWriter( )
+  {
+    PrintWriter pw = new PrintWriter( this.os );
+
+    return pw;
+  }
+
+}
\ No newline at end of file


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