/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.rdf.sail.webapp.lbs;
import javax.servlet.http.HttpServletRequest;
import com.bigdata.rdf.sail.webapp.HALoadBalancerServlet;
/**
* Interface for rewriting the Request-URI once the load balancer has determined
* the target host and service to which the request will be proxied.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
public interface IHARequestURIRewriter extends IHAPolicyLifeCycle {
/**
* Rewrite the <code>originalRequestURI</code> into a <a href=
* "http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2"
* >Request-URL</a> for the web application whose servlet context root is
* given by the <code>proxyToRequestURI</code>.
* <p>
* Note: The <code>proxyToRequestURI</code> is include the protocol, host,
* port, and servlet context path for the target service. It DOES NOT
* include any information from the original request. The purpose of this
* method is to modify the <code>originalRequestURI</code> in order to
* obtain a fully qualified RequestURI for the service to which the request
* will be proxied. For example:
*
* <pre>
* full_prefix: /bigdata/LBS/leader
* -or- full_prefix: /bigdata/LBS/read
* originalRequestURI: http://ha1.example.com:8090/bigdata/LBS/read/sparql
* proxyToRequestURI: http://ha3.example.com:8090/bigdata/
* return: http://ha2.example.com:8090/bigdata/LBS/read/sparql
* </pre>
* <p>
* Note: this method is only invoked if we will proxy to another service.
* Therefore, the <code>proxyToRequestURI</code> is never <code>null</code>.
*
* @param isLeaderRequest
* <code>true</code> iff the request is directed to the leader.
* @param full_prefix
* The path prefix in the <code>originalRequestURI</code> that
* which corresponds to the {@link HALoadBalancerServlet} and
* which must be removed if the request is to be forwarded to a
* local service.
* @param originalRequestURI
* The original <a href=
* "http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2"
* >Request-URL</a> from the <a
* href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1"
* >HTTP Request-Line</a>
* @param proxyToRequestURI
* The RequestURI for the root of the web application for the
* target service and never <code>null</code>.
* @param request
* The original request.
*
* @return The fully qualified <a href=
* "http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2"
* >Request-URL</a> that will be used to proxy the http request to
* the service identified by the <code>proxyToRequestURI</code>
*
* @see ServiceScore#getRequestURI()
*/
public StringBuilder rewriteURI(//
boolean isLeaderRequest,
String full_prefix,//
String originalRequestURI, //
String proxyToRequestURI,//
HttpServletRequest request//
);
}