com.bigdata.rdf.sail.webapp.lbs

Interface IHARequestURIRewriter

All Superinterfaces:

IHAPolicyLifeCycle

All Known Implementing Classes:

DefaultHARequestURIRewriter

public interface IHARequestURIRewriter
extends IHAPolicyLifeCycle

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:

Bryan Thompson

Method Summary

Methods

Modifier and Type	Method and Description
StringBuilder	rewriteURI(boolean isLeaderRequest, String full_prefix, String originalRequestURI, String proxyToRequestURI, javax.servlet.http.HttpServletRequest request) Rewrite the originalRequestURI into a Request-URL for the web application whose servlet context root is given by the proxyToRequestURI.

Methods inherited from interface com.bigdata.rdf.sail.webapp.lbs.IHAPolicyLifeCycle

destroy, init

Method Detail

rewriteURI

StringBuilder rewriteURI(boolean isLeaderRequest,
                       String full_prefix,
                       String originalRequestURI,
                       String proxyToRequestURI,
                       javax.servlet.http.HttpServletRequest request)

Rewrite the originalRequestURI into a Request-URL for the web application whose servlet context root is given by the proxyToRequestURI.

Note: The proxyToRequestURI 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 originalRequestURI in order to obtain a fully qualified RequestURI for the service to which the request will be proxied. For example:

        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
 

Note: this method is only invoked if we will proxy to another service. Therefore, the proxyToRequestURI is never null.

Parameters:

isLeaderRequest - true iff the request is directed to the leader.

full_prefix - The path prefix in the originalRequestURI that which corresponds to the HALoadBalancerServlet and which must be removed if the request is to be forwarded to a local service.

originalRequestURI - The original Request-URL from the HTTP Request-Line

proxyToRequestURI - The RequestURI for the root of the web application for the target service and never null.

request - The original request.

Returns:

The fully qualified Request-URL that will be used to proxy the http request to the service identified by the proxyToRequestURI

See Also:

ServiceScore.getRequestURI()