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/*
* ModifiedTemplate.java
*
* Brazil project web application toolkit,
* export version: 2.3
* Copyright (c) 2000-2002 Sun Microsystems, Inc.
*
* Sun Public License Notice
*
* The contents of this file are subject to the Sun Public License Version
* 1.0 (the "License"). You may not use this file except in compliance with
* the License. A copy of the License is included as the file "license.terms",
* and also available at http://www.sun.com/
*
* The Original Code is from:
* Brazil project web application toolkit release 2.3.
* The Initial Developer of the Original Code is: suhler.
* Portions created by suhler are Copyright (C) Sun Microsystems, Inc.
* All Rights Reserved.
*
* Contributor(s): suhler.
*
* Version: 2.1
* Created by suhler on 00/11/19
* Last modified by suhler on 02/10/01 16:36:50
*
* Version Histories:
*
* 2.1 02/10/01-16:36:50 (suhler)
* version change
*
* 1.4 01/05/11-14:50:46 (suhler)
* use template.debug()
*
* 1.3 00/12/11-13:31:16 (suhler)
* add class=props for automatic property extraction
*
* 1.2 00/11/20-13:25:14 (suhler)
* doc fixes
*
* 1.2 00/11/19-10:31:38 (Codemgr)
* SunPro Code Manager data about conflicts, renames, etc...
* Name history : 1 0 handlers/templates/ModifiedTemplate.java
*
* 1.1 00/11/19-10:31:37 (suhler)
* date and time created 00/11/19 10:31:37 by suhler
*
*/
package sunlabs.brazil.template;
import sunlabs.brazil.util.http.HttpUtil;
import sunlabs.brazil.server.Server;
import java.io.Serializable;
/**
* Template class for computing last-modified times
* for content that is processed through templates.
*
* For traditional web content that is stored in a file, it is easy to
* keep track of the last time the content changed, simply by looking at the
* modify-time attribute of the file. Many browsers (and caches) use
* this information,
* obtained from the last-modified http header to determine
* whether to use an existing copy of the document, or a cached copy.
*
* When the content is dynamically transformed, however, the last modified
* time is more complex: a combination of the original file modification
* time combined with the last change made to the transformation
* parameters.
*
* A new HTML tag,
* <modified> is defined, and is intended to be
* used in conjunction with the BSLTemplate. When present in a
* page, the last-modified time of the transformation
* is set to the server's current time. When the content is delivered
* to the client, the last-modified header is set to the
* more recent of the origin last-modified time and the transformation
* modified time.
*
* Properties:
*
* - debug
*
- If this configuration parameter is present,
modified
* tag is replaced by a comment. Otherwise it is removed from the document.
*
*
* @author Stephen Uhler
* @version %V% 07/01/08
*/
public class ModifiedTemplate extends Template implements Serializable {
long modified = 0; // last modified time of session transformation
/**
* Set the content transformation modifiy time to NOW
*/
public void
tag_modified(RewriteContext hr) {
modified = hr.request.startMillis;
hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix +
"setting transform modified time: " + modified);
hr.killToken();
debug(hr);
}
/**
* Compute the http last modified value by comparing the origin
* last-modified value (if any) with the transform value
*/
public boolean
done(RewriteContext hr) {
if (modified == 0) {
modified = hr.request.startMillis;
}
/*
* Find the last-mod time from the origin document. Look
* in the request props first.
*/
long originTime;
String propsTime = hr.request.props.getProperty("lastModified");
if (propsTime == null) {
originTime = HttpUtil.parseTime(hr.request.responseHeaders.get(
"last-modified"));
} else {
originTime = Long.parseLong(propsTime);
}
/*
* Muck with the last-modified header, only if we need to
*/
if (originTime < modified) {
hr.request.responseHeaders.remove("last-modified");
hr.request.addHeader("Last-Modified",HttpUtil.formatTime(modified));
hr.request.log(Server.LOG_DIAGNOSTIC, hr.prefix +
"Adjusting mod time: " + originTime + " -> " + modified);
}
return true;
}
}