/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cocoon.generation;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.environment.http.HttpEnvironment;
import org.apache.cocoon.util.RequestForwardingHttpMethod;
import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpConnection;
import org.apache.commons.httpclient.HttpState;
import org.apache.commons.httpclient.HttpURL;
import org.apache.commons.httpclient.UsernamePasswordCredentials;
import org.apache.excalibur.xml.sax.SAXParser;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
/**
* This is a generic HTTP proxy, designed to handle any possible HTTP method,
* but with a particular bias towards WebDAV. As of now it's pretty unstable, but
* still it might be a good proof of concept towards a pure HTTP(++) proxy.
*
* TODO: doesn't handle authentication properly
* TODO: doesn't handle (and doubt it'll ever will) HTTP/1.1 keep-alive
*
* @author <a href="mailto:gianugo@apache.org">Gianugo Rabellino</a>
* @version $Id: GenericProxyGenerator.java,v 1.5 2004/03/05 13:02:20 bdelacretaz Exp $
*/
public class GenericProxyGenerator extends ServiceableGenerator {
/** The real URL to forward requests to */
HttpURL destination;
/** The current request */
HttpServletRequest request;
/** The current response */
HttpServletResponse response;
/** The current request */
String path;
SAXParser parser;
/**
* Compose and get a SAX parser for further use.
*
* @see org.apache.avalon.framework.service.Serviceable#service(org.apache.avalon.framework.service.ServiceManager)
*/
public void service(ServiceManager manager) throws ServiceException {
super.service(manager);
this.parser = (SAXParser)manager.lookup(SAXParser.ROLE);
}
/**
* Dispose
*/
public void dispose() {
if ( this.manager != null ) {
this.manager.release( this.parser );
this.parser = null;
}
super.dispose();
}
/**
* Setup this component by getting the (required) "url" parameter and the
* (optional) "path" parameter. If path is not specified, the request URI will
* be used and forwarded.
*
* TODO: handle query string
*
* @see org.apache.cocoon.sitemap.SitemapModelComponent#setup(org.apache.cocoon.environment.SourceResolver, java.util.Map, java.lang.String, org.apache.avalon.framework.parameters.Parameters)
*/
public void setup(
SourceResolver resolver,
Map objectModel,
String src,
Parameters par)
throws ProcessingException, SAXException, IOException {
String url = par.getParameter("url", null);
request = (HttpServletRequest)objectModel.get(HttpEnvironment.HTTP_REQUEST_OBJECT);
response = (HttpServletResponse)objectModel.get(HttpEnvironment.HTTP_RESPONSE_OBJECT);
if (url == null) {
throw new ProcessingException("Missing the \"url\" parameter");
}
path = par.getParameter("path", null);
if (path == null)
path = request.getRequestURI();
destination = new HttpURL(url);
}
/**
* Get the request data, pass them on to the forwarder and return the result.
*
* TODO: much better header handling
* TODO: handle non XML and bodyless responses (probably needs a smarter Serializer,
* since some XML has to go through the pipeline anyway.
*
* @see org.apache.cocoon.generation.Generator#generate()
*/
public void generate()
throws IOException, SAXException, ProcessingException {
RequestForwardingHttpMethod method =
new RequestForwardingHttpMethod(request, destination);
// Build the forwarded connection
HttpConnection conn = new HttpConnection(destination.getHost(), destination.getPort());
HttpState state = new HttpState();
state.setCredentials(null, destination.getHost(),
new UsernamePasswordCredentials(destination.getUser(), destination.getPassword()));
method.setPath(path);
// Execute the method
method.execute(state, conn);
// Send the output to the client: set the status code...
response.setStatus(method.getStatusCode());
// ... retrieve the headers from the origin server and pass them on
Header[] methodHeaders = method.getResponseHeaders();
for (int i = 0; i < methodHeaders.length; i++) {
// there is more than one DAV header
if (methodHeaders[i].getName().equals("DAV")) {
response.addHeader(methodHeaders[i].getName(), methodHeaders[i].getValue());
} else if (methodHeaders[i].getName().equals("Content-Length")) {
// drop the original Content-Length header. Don't ask me why but there
// it's always one byte off
} else {
response.setHeader(methodHeaders[i].getName(), methodHeaders[i].getValue());
}
}
// no HTTP keepalives here...
response.setHeader("Connection", "close");
// Parse the XML, if any
if (method.getResponseHeader("Content-Type").getValue().startsWith("text/xml")) {
InputStream stream = method.getResponseBodyAsStream();
parser.parse(new InputSource(stream), this.contentHandler, this.lexicalHandler);
} else {
// Just send a dummy XML
this.contentHandler.startDocument();
this.contentHandler.startElement("", "no-xml-content", "no-xml-content", new AttributesImpl());
this.contentHandler.endElement("", "no-xml-content", "no-xml-content");
this.contentHandler.endDocument();
}
// again, no keepalive here.
conn.close();
}
}