org.apache.catalina.filters

Class RequestFilter

java.lang.Object

org.apache.catalina.filters.FilterBase

org.apache.catalina.filters.RequestFilter

All Implemented Interfaces:

javax.servlet.Filter, HttpEventFilter

Direct Known Subclasses:

RemoteAddrFilter, RemoteHostFilter

public abstract class RequestFilter
extends FilterBase
implements HttpEventFilter

Implementation of a Filter that performs filtering based on comparing the appropriate request property (selected based on which subclass you choose to configure into your Container's pipeline) against a set of regular expressions configured for this Filter.

This filter is configured by setting the allow and/or deny properties to a comma-delimited list of regular expressions (in the syntax supported by the jakarta-regexp library) to which the appropriate request property will be compared. Evaluation proceeds as follows:

• The subclass extracts the request property to be filtered, and calls the common process() method.
• If there are any deny expressions configured, the property will be compared to each such expression. If a match is found, this request will be rejected with a "Forbidden" HTTP response.
• If there are any allow expressions configured, the property will be compared to each such expression. If a match is found, this request will be allowed to pass through to the next filter in the current pipeline.
• If one or more deny expressions was specified but no allow expressions, allow this request to pass through (because none of the deny expressions matched it).
• The request will be rejected with a "Forbidden" HTTP response.

This Filter may be attached to any Container, depending on the granularity of the filtering you wish to perform.

Author:

Craig R. McClanahan

Field Summary

Fields

Modifier and Type	Field and Description
protected String	allow The comma-delimited set of allow expressions.
protected Pattern[]	allows The set of allow regular expressions we will evaluate.
protected Pattern[]	denies The set of deny regular expressions we will evaluate.
protected String	deny The comma-delimited set of deny expressions.

Constructor Summary

Constructors

Constructor and Description
RequestFilter()

Method Summary

Modifier and Type	Method and Description
abstract void	doFilter(javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.FilterChain chain) Extract the desired request property, and pass it (along with the specified request and response objects) to the protected process() method to perform the actual filtering.
String	getAllow() Return a comma-delimited set of the allow expressions configured for this Filter, if any; otherwise, return null.
String	getDeny() Return a comma-delimited set of the deny expressions configured for this Filter, if any; otherwise, return null.
protected Pattern[]	precalculate(String list) Return an array of regular expression objects initialized from the specified argument, which must be null or a comma-delimited list of regular expression patterns.
protected void	process(String property, javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.FilterChain chain) Perform the filtering that has been configured for this Filter, matching against the specified request property.
protected void	processCometEvent(String property, HttpEvent event, HttpEventFilterChain chain) Perform the filtering that has been configured for this Filter, matching against the specified request property.
void	setAllow(String allow) Set the comma-delimited set of the allow expressions configured for this Filter, if any.
void	setDeny(String deny) Set the comma-delimited set of the deny expressions configured for this Filter, if any.

Methods inherited from class org.apache.catalina.filters.FilterBase

destroy, init

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jboss.servlet.http.HttpEventFilter

doFilterEvent

Methods inherited from interface javax.servlet.Filter

destroy, init

Field Detail

allow

protected String allow

The comma-delimited set of allow expressions.

allows

protected Pattern[] allows

The set of allow regular expressions we will evaluate.

denies

protected Pattern[] denies

The set of deny regular expressions we will evaluate.

deny

protected String deny

The comma-delimited set of deny expressions.

Constructor Detail

RequestFilter

public RequestFilter()

Method Detail

getAllow

public String getAllow()

Return a comma-delimited set of the allow expressions configured for this Filter, if any; otherwise, return null.

setAllow

public void setAllow(String allow)

Set the comma-delimited set of the allow expressions configured for this Filter, if any.

Parameters:

allow - The new set of allow expressions

getDeny

public String getDeny()

Return a comma-delimited set of the deny expressions configured for this Filter, if any; otherwise, return null.

setDeny

public void setDeny(String deny)

Set the comma-delimited set of the deny expressions configured for this Filter, if any.

Parameters:

deny - The new set of deny expressions

doFilter

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

Extract the desired request property, and pass it (along with the specified request and response objects) to the protected process() method to perform the actual filtering. This method must be implemented by a concrete subclass.

Specified by:

doFilter in interface javax.servlet.Filter

Parameters:

request - The servlet request to be processed

response - The servlet response to be created

chain - The filter chain

Throws:

IOException - if an input/output error occurs

javax.servlet.ServletException - if a servlet error occurs

precalculate

protected Pattern[] precalculate(String list)

Return an array of regular expression objects initialized from the specified argument, which must be null or a comma-delimited list of regular expression patterns.

Parameters:

list - The comma-separated list of patterns

Throws:

IllegalArgumentException - if one of the patterns has invalid syntax

process

protected void process(String property,
                       javax.servlet.ServletRequest request,
                       javax.servlet.ServletResponse response,
                       javax.servlet.FilterChain chain)
                throws IOException,
                       javax.servlet.ServletException

Perform the filtering that has been configured for this Filter, matching against the specified request property.

Parameters:

property - The request property on which to filter

request - The servlet request to be processed

response - The servlet response to be processed

Throws:

IOException - if an input/output error occurs

javax.servlet.ServletException - if a servlet error occurs

processCometEvent

protected void processCometEvent(String property,
                                 HttpEvent event,
                                 HttpEventFilterChain chain)
                          throws IOException,
                                 javax.servlet.ServletException

Perform the filtering that has been configured for this Filter, matching against the specified request property.

Parameters:

property - The property to check against the allow/deny rules

event - The comet event to be filtered

chain - The comet filter chain

Throws:

IOException - if an input/output error occurs

javax.servlet.ServletException - if a servlet error occurs