Package alpine.filters

Class RequestRateThrottleFilter

java.lang.Object

alpine.filters.RequestRateThrottleFilter

All Implemented Interfaces:

javax.servlet.Filter

public final class RequestRateThrottleFilter
extends Object
implements javax.servlet.Filter

The RequestRateThrottleFilter is a Servlet filter that can place a hard limit on the number of requests per second. The filter conforms to RFC-6585 by sending HTTP status code 429 (too many requests) if the limit is exceeded. Sample usage:

 <filter>
   <filter-name>RequestRateThrottleFilter</filter-name>
   <filter-class>alpine.filters.RequestRateThrottleFilter</filter-class>
   <init-param>
     <param-name>maximumRequestsPerPeriod</param-name>
     <param-value>5</param-value>
   </init-param>
   <init-param>
     <param-name>timePeriodSeconds</param-name>
     <param-value>10</param-value>
   </init-param>
 </filter>

 <!--  Place a request limit on all resources -->
 <filter-mapping>
   <filter-name>RequestRateThrottleFilter</filter-name>
   <url-pattern>/*</url-pattern>
 </filter-mapping>
 

Since:

1.0.0

Author:

Steve Springett

Constructor Summary

Constructors

Constructor	Description
RequestRateThrottleFilter()

Method Summary

Modifier and Type	Method	Description
void	destroy()
void	doFilter(javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.FilterChain chain)	Determines if the request rate is below or has exceeded the the maximum requests per second for the given time period.
void	init(javax.servlet.FilterConfig filterConfig)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RequestRateThrottleFilter

public RequestRateThrottleFilter()

Method Detail

init

public void init(javax.servlet.FilterConfig filterConfig)

Specified by:

init in interface javax.servlet.Filter

doFilter

public void doFilter(javax.servlet.ServletRequest request,
                     javax.servlet.ServletResponse response,
                     javax.servlet.FilterChain chain)
              throws IOException,
                     javax.servlet.ServletException

Determines if the request rate is below or has exceeded the the maximum requests per second for the given time period. If exceeded, a HTTP status code of 429 (too many requests) will be send and no further processing of the request will be done. If the request has not exceeded the limit, the request will continue on as normal.

Specified by:

doFilter in interface javax.servlet.Filter

Parameters:

request - a ServletRequest

response - a ServletResponse

chain - a FilterChain

Throws:

IOException - a IOException

javax.servlet.ServletException - a ServletException

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Filter