Added support for HTTP Last-Modified and If-Modified-Since headers and

304 Not Modified response.

src/helma/framework/RequestBean.java

@@ -4,6 +4,7 @@ import java.io.Serializable;
 import java.util.Map;
 
 import helma.framework.core.Application;
+import java.util.Date;
 
 public class RequestBean implements Serializable {
 
@@ -55,6 +56,18 @@ public class RequestBean implements Serializable {
 	return req.getUsername ();
 	}
 
+	public Date getLastModified () {
+	long since = req.getIfModifiedSince ();
+	if (since < 0)
+	    return null;
+	else
+	    return new Date (since);
+	}
+
+	public void setLastModified () {
+	throw new RuntimeException ("The lastModified property of the Request object is read-only. "+
+		"Set lastModified on the Response object if you want to mark the last modification date of a resource.");
+	}
 }
 
 

src/helma/framework/RequestTrans.java

@@ -24,6 +24,10 @@ public class RequestTrans implements Externalizable {
     // the request method - 0 for GET, 1 for POST
     private byte httpMethod = 0;
 
+    // timestamp of client-cached version, if present in request
+    private long ifModifiedSince = -1;
+    
+
     // this is used to hold the EcmaScript form data object
     public transient Object data;
     // when was execution started on this request?
@@ -32,8 +36,8 @@ public class RequestTrans implements Externalizable {
     // the name of the action being invoked
     public transient String action;
 
-	private transient String httpUsername;
-	private transient String httpPassword;
+    private transient String httpUsername;
+    private transient String httpPassword;
 
     static final long serialVersionUID = 5398880083482000580L;
 
@@ -125,6 +129,7 @@ public class RequestTrans implements Externalizable {
 	session = s.readUTF ();
 	values = (Map) s.readObject ();
 	httpMethod = s.readByte ();
+	ifModifiedSince = s.readLong ();
     }
 
     /**
@@ -135,6 +140,15 @@ public class RequestTrans implements Externalizable {
 	s.writeUTF (session);
 	s.writeObject (values);
 	s.writeByte (httpMethod);
+	s.writeLong (ifModifiedSince);
+    }
+
+    public void setIfModifiedSince (long since) {
+	ifModifiedSince = since;
+    }
+    
+    public long getIfModifiedSince () {
+	return ifModifiedSince;
     }
 
 	public String getUsername()	{

src/helma/framework/ResponseBean.java

@@ -4,6 +4,7 @@ import java.io.Serializable;
 import java.util.Map;
 
 import helma.framework.core.Application;
+import java.util.Date;
 
 public class ResponseBean implements Serializable {
 
@@ -92,6 +93,13 @@ public class ResponseBean implements Serializable {
 	res.contentType = contentType;
     }
 
+    public void setLastModified (Date date) {
+	if (date == null)
+	    res.setLastModified (-1);
+	else
+	    res.setLastModified (date.getTime());
+    }
+
     public Map getdata () {
 	return res.getResponseData ();
     }
@@ -132,6 +140,18 @@ public class ResponseBean implements Serializable {
 	res.status = status;
     }
     
+    public Date getLastModified () {
+	long modified = res.getLastModified ();
+	if (modified > -1)
+	    return new Date (modified);
+	else 
+	    return null;
+    }
+    
+    public void notModified () throws RedirectException {
+	res.setNotModified (true);
+    }
+
 }
 
 

src/helma/framework/ResponseTrans.java

@@ -50,6 +50,12 @@ public final class ResponseTrans implements Externalizable {
     // contains the redirect URL
     private String redir = null;
     
+    // the last-modified date, if it should be set in the response
+    private long lastModified = -1;
+    // flag to signal that resource has not been modified
+    private boolean notModified = false;
+
+
     // cookies
     String cookieKeys[];
     String cookieValues[];
@@ -120,6 +126,7 @@ public final class ResponseTrans implements Externalizable {
 	skin = null;
 	title = head = body = message = error = null;
 	values.clear ();
+	lastModified = -1;
     }
 
 
@@ -327,6 +334,24 @@ public final class ResponseTrans implements Externalizable {
 	return contentType;
     }
 
+    public void setLastModified (long modified) {
+	lastModified = modified;
+    }
+    
+    public long getLastModified () {
+	return lastModified;
+    }
+    
+    public void setNotModified (boolean notmod) throws RedirectException {
+	notModified = notmod;
+	if (notmod)
+	    throw new RedirectException (null);
+    }
+    
+    public boolean getNotModified () {
+	return notModified; 
+    }
+
     public void setSkinpath (Object[] arr) {
 	this.skinpath = arr;
 	skincache = null;
@@ -408,6 +433,8 @@ public final class ResponseTrans implements Externalizable {
 	cache = s.readBoolean ();
 	status = s.readInt ();
 	realm = (String) s.readObject ();
+	lastModified = s.readLong ();
+	notModified = s.readBoolean ();
     }
 
     public void writeExternal (ObjectOutput s) throws IOException {
@@ -421,6 +448,8 @@ public final class ResponseTrans implements Externalizable {
 	s.writeBoolean (cache);
 	s.writeInt (status);
 	s.writeObject (realm);
+	s.writeLong (lastModified);
+	s.writeBoolean (notModified);
     }
 
 }

src/helma/servlet/AbstractServletClient.java

@@ -169,6 +169,12 @@ public abstract class AbstractServletClient extends HttpServlet {
 	    if (referer != null)
 	        reqtrans.set ("http_referer", referer);
 
+	    try {
+	        long ifModifiedSince = request.getDateHeader ("If-Modified-Since");
+	        if (ifModifiedSince > -1)
+	            reqtrans.setIfModifiedSince (ifModifiedSince);
+	    } catch (IllegalArgumentException ignore) {}
+
 	    String remotehost = request.getRemoteAddr ();
 	    if (remotehost != null)
 	        reqtrans.set ("http_remotehost", remotehost);
@@ -226,7 +232,8 @@ public abstract class AbstractServletClient extends HttpServlet {
 	    try {
 	        res.sendRedirect(trans.getRedirect ());
 	    } catch(Exception io_e) {}
-
+	} else if (trans.getNotModified ()) {
+	    res.setStatus (HttpServletResponse.SC_NOT_MODIFIED);
 	} else {
 
 	    if (!trans.cache || ! caching) {
@@ -240,6 +247,10 @@ public abstract class AbstractServletClient extends HttpServlet {
 	        res.setHeader( "WWW-Authenticate", "Basic realm=\"" + trans.realm + "\"" );
 	    if (trans.status > 0)
 	        res.setStatus (trans.status);
+	    // set last-modified header to now
+	    long modified = trans.getLastModified ();
+	    if (modified > -1)
+	        res.setDateHeader ("Last-Modified", System.currentTimeMillis ());
 	    // if we don't know which charset to use for parsing HTTP params,
 	    // take the one from the response. This usually works because
 	    // browsers send parrameters in the same encoding as the page
@@ -254,19 +265,11 @@ public abstract class AbstractServletClient extends HttpServlet {
 	        out.write (trans.getContent ());
 	        out.close ();
 	    } catch(Exception io_e) {
-	        System.err.println ("Exception in writeResponse: "+io_e);
+	        log ("Exception in writeResponse: "+io_e);
 	    }
 	}
     }
 
-    private void redirectResponse (HttpServletRequest request, HttpServletResponse res, ResponseTrans trans, String url) { 		
-	try { 
-	    res.sendRedirect(url); 
-	} catch (Exception e) { 
-	    System.err.println ("Exception at redirect: " + e + e.getMessage());
-	}
-    }
-	
 
     public FileUpload getUpload (HttpServletRequest request) throws Exception {
 	int contentLength = request.getContentLength ();