Greetings developers,
as a newbie to the wonderful world of Cocoon sitemaps I was struggling
with the problem of using a selector to determine if an external HTTP
URL was available.
* Problem description:
A pipeline matcher with the following steps is triggered:
1. XSP generation
2. cinclude transformation
3. XSLT transformation
4. HTML serialization
The cinclude in step 2 triggers another cocoon pipeline. XSP snippet:
http://apache.org/cocoon/include/1.0"/>
Pipeline #2:
1. (what I wanted) map:select and generation based on status of external
HTTP URL
2. XSLT transformation
3. XML serialization
* My soloution:
I was first trying the map:select with the
org.apache.cocoon.selection.ResourceExistsSelector until I found out
that this was only for content within the current servlet context.
I then wrote the attached (trivial) UrlExistsSelector and used this one
for step 1 in pipeline #2.
This works, but might have som implications in security/performance (no
timeout handling) etc. etc. that I just don't see because I'm new to Cocoon.
Any comments? Other soloutions?
TIA,
Martin
--
Martin Kalén
Curalia AB Web: http://www.curalia.se
Orrspelsvägen 2BMail: [EMAIL PROTECTED]
SE-182 79 StocksundTel: +46-8-410 064 40
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.thread.ThreadSafe;
import org.apache.cocoon.selection.Selector;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;
/**
* Selects the first of a set of URLs that can be connected to.
*
* Like [EMAIL PROTECTED] org.apache.cocoon.selection.ResourceExistsSelector},
* but works with java.net.URL instead of using the servlet
* containter's context resolving.
*
* @author Martin Kalén
* @version CVS $Id: UrlExistsSelector.java,v 1.1 2003/10/10 09:08:47 martin Exp $
*/
public class UrlExistsSelector extends AbstractLogEnabled
implements ThreadSafe, Selector {
public boolean select(String _expression_,
Map objectModel,
Parameters parameters) {
try {
URL url = "" URL(_expression_);
URLConnection connection = url.openConnection();
connection.connect();
return true;
} catch (MalformedURLException e) {
StringBuffer message = new StringBuffer();
message.append("Selector _expression_ '");
message.append(_expression_);
message.append("' is not a valid URL");
getLogger().warn(message.toString());
return false;
} catch (Exception e) {
return false;
}
}
}
