Mailing-List: contact cocoon-cvs-help@xml.apache.org; run by ezmlm
Date: 13 Jan 2001 13:39:19 -0000
Message-ID: <20010113133919.3093.qmail@apache.org>
From: giacomo@apache.org
To: xml-cocoon-cvs@apache.org
Subject: cvs commit: xml-cocoon/src/org/apache/cocoon/reading
 ResourceReader.java

giacomo     01/01/13 05:39:19

  Modified:    src/org/apache/cocoon/reading Tag: xml-cocoon2
                        ResourceReader.java
  Log:
  The ResourceReader conforms now much more to the HTTP protocol concerning the caching headers like if-modified-since. This will increase performance of this Component
  
  Revision  Changes    Path
  No                   revision
  
  
  No                   revision
  
  
  1.1.2.11  +34 -9     xml-cocoon/src/org/apache/cocoon/reading/Attic/ResourceReader.java
  
  Index: ResourceReader.java
  ===================================================================
  RCS file: /home/cvs/xml-cocoon/src/org/apache/cocoon/reading/Attic/ResourceReader.java,v
  retrieving revision 1.1.2.10
  retrieving revision 1.1.2.11
  diff -u -r1.1.2.10 -r1.1.2.11
  --- ResourceReader.java	2001/01/12 09:53:09	1.1.2.10
  +++ ResourceReader.java	2001/01/13 13:39:19	1.1.2.11
  @@ -15,9 +15,11 @@
   import java.net.URL;
   import java.net.MalformedURLException;
   import java.net.URLConnection;
  +import java.util.Enumeration;
   import java.util.Hashtable;
   
   import javax.servlet.http.HttpServletResponse;
  +import javax.servlet.http.HttpServletRequest;
   import javax.servlet.ServletContext;
   
   import org.apache.cocoon.Cocoon;
  @@ -28,17 +30,19 @@
   /**
    *
    * @author <a href="mailto:Giacomo.Pati@pwr.ch">Giacomo Pati</a>
  - * @version CVS $Revision: 1.1.2.10 $ $Date: 2001/01/12 09:53:09 $
  + * @version CVS $Revision: 1.1.2.11 $ $Date: 2001/01/13 13:39:19 $
    *
    * The <code>ResourceReader</code> component is used to serve binary data
  - * in a sitemap pipeline.
  + * in a sitemap pipeline. It makes use of HTTP Headers to determine if
  + * the requested resource should be written to the <code>OutputStream</code>
  + * or if it can signal that it hasn't changed.
    *
    * Parameters:
    *   <dl>
    *     <dt>&lt;expires&gt;</dt>
    *       <dd>This parameter is optional. When specified it determines how long
  - *           in miliseconds the resources can be cached by any proxy between
  - *           Cocoon2 and the requesting browser.
  + *           in miliseconds the resources can be cached by any proxy or browser
  + *           between Cocoon2 and the requesting visitor.
    *       </dd>
    *   </dl>
    */
  @@ -48,32 +52,40 @@
        * Generates the requested resource.
        */
       public void generate() throws IOException, ProcessingException {
  +        HttpServletRequest req = (HttpServletRequest) objectModel.get(Cocoon.REQUEST_OBJECT);
           HttpServletResponse res = (HttpServletResponse) objectModel.get(Cocoon.RESPONSE_OBJECT);
  +
           if (res == null) {
              throw new ProcessingException ("Missing a Response object in the objectModel");
           }
  +        if (req == null) {
  +           throw new ProcessingException ("Missing a Request object in the objectModel");
  +        }
           String src = null;
           File file = null;
           URL url = null;
           URLConnection conn = null;
           InputStream is = null;
           long len = 0;
  -        long lastModified = 0;
           try {
  -            if(this.source.indexOf(":/")!=-1) {
  +            if(this.source.indexOf(":/") != -1) {
                   src = this.source;
                   url = new URL (src);
                   conn = url.openConnection();
  +                if (!modified (conn.getLastModified(), req, res)) {
  +                    return;
  +                }
                   len = conn.getContentLength();
                   is = conn.getInputStream();
  -                lastModified = conn.getLastModified();
               } else {
                   src = this.resolver.resolveEntity (null,this.source).getSystemId();
                   url = new URL (src);
                   file = new File (url.getFile());
  +                if (!modified (file.lastModified(), req, res)) {
  +                    return;
  +                }
                   len = file.length();
                   is = new FileInputStream (file);
  -                lastModified = file.lastModified();
               }
           } catch (SAXException se) {
               log.error("ResourceReader: error resolving source \"" + source + "\"", se);
  @@ -88,7 +100,6 @@
           is.read(buffer);
           is.close();
           res.setContentLength(buffer.length);
  -        res.setDateHeader("Last-Modified", lastModified);
           long expires = parameters.getParameterAsInteger("expires", -1);
           if (expires > 0) {
               res.setDateHeader("Expires", System.currentTimeMillis()+expires);
  @@ -96,6 +107,20 @@
           res.setHeader("Accept-Ranges", "bytes");
           out.write ( buffer );
       }
  +
  +    /**
  +     * Checks if the file has been modified
  +     */
  +    private boolean modified (long lastModified, HttpServletRequest req, HttpServletResponse res) {
  +        res.setDateHeader("Last-Modified", lastModified);
  +        long if_modified_since = req.getDateHeader("if-modified-since");
  +        if (if_modified_since >= lastModified) {
  +            res.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
  +        }
  +        log.debug("ResourceReader: resource has " + ((if_modified_since < lastModified) ? "" : "not ") + "been modified");
  +        return (if_modified_since < lastModified);
  +    }
  +
       /**
        * Returns the mime-type of the resource in process.
        */