FilterChainProxy

Class Overview

Delegates Filter requests to a list of Spring-managed filter beans. As of version 2.0, you shouldn't need to explicitly configure a FilterChainProxy bean in your application context unless you need very fine control over the filter chain contents. Most cases should be adequately covered by the default <security:http /> namespace configuration options.

The FilterChainProxy is linked into the servlet container filter chain by adding a standard Spring DelegatingFilterProxy declaration in the application web.xml file.

Configuration

As of version 3.1, FilterChainProxy is configured using a list of SecurityFilterChain instances, each of which contains a RequestMatcher and a list of filters which should be applied to matching requests. Most applications will only contain a single filter chain, and if you are using the namespace, you don't have to set the chains explicitly. If you require finer-grained control, you can make use of the <filter-chain> namespace element. This defines a URI pattern and the list of filters (as comma-separated bean names) which should be applied to requests which match the pattern. An example configuration might look like this:

 <bean id="myfilterChainProxy" class="org.springframework.security.util.FilterChainProxy">
     <constructor-arg>
         <util:list>
             <security:filter-chain pattern="/do/not/filter*" filters="none"/>
             <security:filter-chain pattern="/**" filters="filter1,filter2,filter3"/>
         </util:list>
     </constructor-arg>
 </bean>
 

The names "filter1", "filter2", "filter3" should be the bean names of Filter instances defined in the application context. The order of the names defines the order in which the filters will be applied. As shown above, use of the value "none" for the "filters" can be used to exclude a request pattern from the security filter chain entirely. Please consult the security namespace schema file for a full list of available configuration options.

Request Handling

Each possible pattern that the FilterChainProxy should service must be entered. The first match for a given request will be used to define all of the Filters that apply to that request. This means you must put most specific matches at the top of the list, and ensure all Filters that should apply for a given matcher are entered against the respective entry. The FilterChainProxy will not iterate through the remainder of the map entries to locate additional Filters.

FilterChainProxy respects normal handling of Filters that elect not to call doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain), in that the remainder of the original or FilterChainProxy-declared filter chain will not be called.

Request Firewalling

An HttpFirewall instance is used to validate incoming requests and create a wrapped request which provides consistent path values for matching against. See DefaultHttpFirewall, for more information on the type of attacks which the default implementation protects against. A custom implementation can be injected to provide stricter control over the request contents or if an application needs to support certain types of request which are rejected by default.

Note that this means that you must use the Spring Security filters in combination with a FilterChainProxy if you want this protection. Don't define them explicitly in your web.xml file.

FilterChainProxy will use the firewall instance to obtain both request and response objects which will be fed down the filter chain, so it is also possible to use this functionality to control the functionality of the response. When the request has passed through the security filter chain, the reset method will be called. With the default implementation this means that the original values of servletPath and pathInfo will be returned thereafter, instead of the modified ones used for security pattern matching.

Since this additional wrapping functionality is performed by the FilterChainProxy, we don't recommend that you use multiple instances in the same filter chain. It shouldn't be considered purely as a utility for wrapping filter beans in a single Filter instance.

Filter Lifecycle

Note the Filter lifecycle mismatch between the servlet container and IoC container. As described in the DelegatingFilterProxy Javadocs, we recommend you allow the IoC container to manage the lifecycle instead of the servlet container. FilterChainProxy does not invoke the standard filter lifecycle methods on any filter beans that you add to the application context.

Summary

Nested Classes
interface	FilterChainProxy.FilterChainValidator

[Expand] Inherited Fields
From class org.springframework.web.filter.GenericFilterBean protected final Log logger

Public Constructors
	FilterChainProxy()
	FilterChainProxy(SecurityFilterChain chain)
	FilterChainProxy(List<SecurityFilterChain> filterChains)

Public Methods
void	afterPropertiesSet()
void	doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
Map<RequestMatcher, List<Filter>>	getFilterChainMap() This method is deprecated. use the list of SecurityFilterChains instead
List<SecurityFilterChain>	getFilterChains()
List<Filter>	getFilters(String url) Convenience method, mainly for testing.
void	setFilterChainMap(Map<RequestMatcher, List<Filter>> filterChainMap) This method is deprecated. Use the constructor which takes a List&lt;SecurityFilterChain&gt; instead.
void	setFilterChainValidator(FilterChainProxy.FilterChainValidator filterChainValidator) Used (internally) to specify a validation strategy for the filters in each configured chain.
void	setFirewall(HttpFirewall firewall) Sets the "firewall" implementation which will be used to validate and wrap (or potentially reject) the incoming requests.
String	toString()

[Expand] Inherited Methods
From class org.springframework.web.filter.GenericFilterBean final void addRequiredProperty(String arg0) void afterPropertiesSet() void destroy() final FilterConfig getFilterConfig() final String getFilterName() final ServletContext getServletContext() final void init(FilterConfig arg0) void initBeanWrapper(BeanWrapper arg0) void initFilterBean() final void setBeanName(String arg0) final void setFilterConfig(FilterConfig arg0) final void setServletContext(ServletContext arg0)
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait() final void wait(long arg0, int arg1) final void wait(long arg0)
From interface javax.servlet.Filter abstract void destroy() abstract void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) abstract void init(FilterConfig arg0)
From interface org.springframework.beans.factory.BeanNameAware abstract void setBeanName(String arg0)
From interface org.springframework.beans.factory.DisposableBean abstract void destroy()
From interface org.springframework.beans.factory.InitializingBean abstract void afterPropertiesSet()
From interface org.springframework.web.context.ServletContextAware abstract void setServletContext(ServletContext arg0)