Package org.apache.catalina.valves.rewrite

Class RewriteValve

java.lang.Object

org.apache.catalina.util.LifecycleBase

org.apache.catalina.util.LifecycleMBeanBase

org.apache.catalina.valves.ValveBase

org.apache.catalina.valves.rewrite.RewriteValve

All Implemented Interfaces:

MBeanRegistration, Contained, JmxEnabled, Lifecycle, Valve

public class RewriteValve
extends ValveBase

Note: Extra caution should be used when adding a Rewrite Rule. When specifying a regex to match for in a Rewrite Rule, certain regex could allow an attacker to DoS your server, as Java's regex parsing is vulnerable to "catastrophic backtracking" (also known as "Regular expression Denial of Service", or ReDoS). There are some open source tools to help detect vulnerable regex, though in general it is a hard problem. A good defence is to use a regex debugger on your desired regex, and read more on the subject of catastrophic backtracking.

See Also:

• OWASP ReDoS

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle

Lifecycle.SingleUse

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	context	Will be set to true if the valve is associated with a context.
protected boolean	enabled	enabled this component
protected ThreadLocal<Boolean>	invoked	If rewriting occurs, the whole request will be processed again.
protected Map<String,RewriteMap>	maps	Maps to be used by the rules.
protected ArrayList<String>	mapsConfiguration	Maps configuration.
protected String	resourcePath	Relative path to the configuration file.
protected RewriteRule[]	rules	The rewrite rules that the valve will use.

Fields inherited from class org.apache.catalina.valves.ValveBase

asyncSupported, container, containerLog, next, sm

Fields inherited from interface org.apache.catalina.Lifecycle

AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT

Constructor Summary

Constructors

Constructor	Description
RewriteValve()

Method Summary

Modifier and Type	Method	Description
String	getConfiguration()
boolean	getEnabled()
protected void	initInternal()	Sub-classes implement this method to perform any instance initialisation required.
void	invoke(Request request, Response response)	Perform request processing as required by this Valve.
protected void	parse(BufferedReader reader)
static Object	parse(String line)	This factory method will parse a line formed like:
protected static void	parseCondFlag(String line, RewriteCond condition, String flag)	Parser for RewriteCond flags.
protected static void	parseRuleFlag(String line, RewriteRule rule, String flag)	Parser for RewriteRule flags.
void	setConfiguration(String configuration)
void	setEnabled(boolean enabled)
protected void	startInternal()	Start this component and implement the requirements of LifecycleBase.startInternal().
protected void	stopInternal()	Stop this component and implement the requirements of LifecycleBase.stopInternal().

Methods inherited from class org.apache.catalina.valves.ValveBase

backgroundProcess, getContainer, getDomainInternal, getNext, getObjectNameKeyProperties, isAsyncSupported, setAsyncSupported, setContainer, setNext, toString

Methods inherited from class org.apache.catalina.util.LifecycleMBeanBase

destroyInternal, getDomain, getObjectName, postDeregister, postRegister, preDeregister, preRegister, register, setDomain, unregister, unregister

Methods inherited from class org.apache.catalina.util.LifecycleBase

addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, getThrowOnFailure, init, removeLifecycleListener, setState, setState, setThrowOnFailure, start, stop

Methods inherited from class java.lang.Object

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

Field Details

rules

protected RewriteRule[] rules

The rewrite rules that the valve will use.

invoked

protected ThreadLocal<Boolean> invoked

If rewriting occurs, the whole request will be processed again.

resourcePath

protected String resourcePath

Relative path to the configuration file. Note: If the valve's container is a context, this will be relative to /WEB-INF/.

context

protected boolean context

Will be set to true if the valve is associated with a context.

enabled

protected boolean enabled

enabled this component

maps

protected Map<String,RewriteMap> maps

Maps to be used by the rules.

mapsConfiguration

protected ArrayList<String> mapsConfiguration

Maps configuration.

Constructor Details

RewriteValve

public RewriteValve()

Method Details

getEnabled

public boolean getEnabled()

setEnabled

public void setEnabled(boolean enabled)

initInternal

protected void initInternal()
                     throws LifecycleException

Description copied from class: LifecycleBase

Sub-classes implement this method to perform any instance initialisation required.

Overrides:

initInternal in class ValveBase

Throws:

LifecycleException - If the initialisation fails

startInternal

protected void startInternal()
                      throws LifecycleException

Description copied from class: ValveBase

Start this component and implement the requirements of LifecycleBase.startInternal().

Overrides:

startInternal in class ValveBase

Throws:

LifecycleException - if this component detects a fatal error that prevents this component from being used

setConfiguration

public void setConfiguration(String configuration)
                      throws Exception

Throws:

Exception

getConfiguration

public String getConfiguration()

parse

protected void parse(BufferedReader reader)
              throws LifecycleException

Throws:

LifecycleException

stopInternal

protected void stopInternal()
                     throws LifecycleException

Description copied from class: ValveBase

Stop this component and implement the requirements of LifecycleBase.stopInternal().

Overrides:

stopInternal in class ValveBase

Throws:

LifecycleException - if this component detects a fatal error that prevents this component from being used

invoke

public void invoke(Request request,
 Response response)
            throws IOException,
ServletException

Description copied from interface: Valve

Perform request processing as required by this Valve.

An individual Valve MAY perform the following actions, in the specified order:

• Examine and/or modify the properties of the specified Request and Response.
• Examine the properties of the specified Request, completely generate the corresponding Response, and return control to the caller.
• Examine the properties of the specified Request and Response, wrap either or both of these objects to supplement their functionality, and pass them on.
• If the corresponding Response was not generated (and control was not returned, call the next Valve in the pipeline (if there is one) by executing getNext().invoke().
• Examine, but not modify, the properties of the resulting Response (which was created by a subsequently invoked Valve or Container).

A Valve MUST NOT do any of the following things:

• Change request properties that have already been used to direct the flow of processing control for this request (for instance, trying to change the virtual host to which a Request should be sent from a pipeline attached to a Host or Context in the standard implementation).
• Create a completed Response AND pass this Request and Response on to the next Valve in the pipeline.
• Consume bytes from the input stream associated with the Request, unless it is completely generating the response, or wrapping the request before passing it on.
• Modify the HTTP headers included with the Response after the getNext().invoke() method has returned.
• Perform any actions on the output stream associated with the specified Response after the getNext().invoke() method has returned.

Parameters:

request - The servlet request to be processed

response - The servlet response to be created

Throws:

IOException - if an input/output error occurs, or is thrown by a subsequently invoked Valve, Filter, or Servlet

ServletException - if a servlet error occurs, or is thrown by a subsequently invoked Valve, Filter, or Servlet

parse

public static Object parse(String line)

This factory method will parse a line formed like:

Example: RewriteCond %{REMOTE_HOST} ^host1.* [OR]

Parameters:

line - A line from the rewrite configuration

Returns:

The condition, rule or map resulting from parsing the line

parseCondFlag

protected static void parseCondFlag(String line,
 RewriteCond condition,
 String flag)

Parser for RewriteCond flags.

Parameters:

line - The configuration line being parsed

condition - The current condition

flag - The flag

parseRuleFlag

protected static void parseRuleFlag(String line,
 RewriteRule rule,
 String flag)

Parser for RewriteRule flags.

Parameters:

line - The configuration line being parsed

rule - The current rule

flag - The flag