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<!DOCTYPE document [
<!ENTITY project SYSTEM "project.xml">
]>
<document url="valve.html">
&project;
<properties>
<author email="craigmcc@apache.org">Craig R. McClanahan</author>
<title>The Valve Component</title>
</properties>
<body>
<section name="Table of Contents">
<toc/>
</section>
<section name="Introduction">
<p>A <strong>Valve</strong> element represents a component that will be
inserted into the request processing pipeline for the associated
Catalina container (<a href="engine.html">Engine</a>,
<a href="host.html">Host</a>, or <a href="context.html">Context</a>).
Individual Valves have distinct processing capabilities, and are
described individually below.</p>
<blockquote><em>
<p>The description below uses the variable name $CATALINA_BASE to refer the
base directory against which most relative paths are resolved. If you have
not configured Tomcat 6 for multiple instances by setting a CATALINA_BASE
directory, then $CATALINA_BASE will be set to the value of $CATALINA_HOME,
the directory into which you have installed Tomcat 6.</p>
</em></blockquote>
</section>
<section name="Access Log Valve">
<subsection name="Introduction">
<p>The <strong>Access Log Valve</strong> creates log files in the same
format as those created by standard web servers. These logs can later
be analyzed by standard log analysis tools to track page hit counts,
user session activity, and so on. The files produces by this <code>Valve</code>
are rolled over nightly at midnight. This <code>Valve</code>
may be associated with any Catalina container (<code>Context</code>,
<code>Host</code>, or <code>Engine</code>), and
will record ALL requests processed by that container.</p>
<p>Some requests may be handled by Tomcat before they are passed to a
container. These include redirects from /foo to /foo/ and the rejection of
invalid requests. Where Tomcat can identify the <code>Context</code> that
would have handled the request, the request/response will be logged in the
<code>AccessLog</code>(s) associated <code>Context</code>, <code>Host</code>
and <code>Engine</code>. Where Tomcat cannot identify the
<code>Context</code> that would have handled the request, e.g. in cases
where the URL is invalid, Tomcat will look first in the <code>Engine</code>,
then the default <code>Host</code> for the <code>Engine</code> and finally
the ROOT (or default) <code>Context</code> for the default <code>Host</code>
for an <code>AccessLog</code> implementation. Tomcat will use the first
<code>AccessLog</code> implementation found to log those requests that are
rejected before they are passed to a container.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Access Log Valve</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.valves.AccessLogValve</strong> to use the
default access log valve.</p>
</attribute>
<attribute name="directory" required="false">
<p>Absolute or relative pathname of a directory in which log files
created by this valve will be placed. If a relative path is
specified, it is interpreted as relative to $CATALINA_BASE. If
no directory attribute is specified, the default value is "logs"
(relative to $CATALINA_BASE).</p>
</attribute>
<attribute name="encoding" required="false">
<p>Character set used to write the log file. An empty string means
to use the system default character set. Default value: use the
system default character set.
</p>
</attribute>
<attribute name="pattern" required="false">
<p>A formatting layout identifying the various information fields
from the request and response to be logged, or the word
<code>common</code> or <code>combined</code> to select a
standard format. See below for more information on configuring
this attribute. Note that the optimized access does only support
<code>common</code> and <code>combined</code> as the value for this
attribute.</p>
</attribute>
<attribute name="prefix" required="false">
<p>The prefix added to the start of each log file's name. If not
specified, the default value is "access_log.". To specify no prefix,
use a zero-length string.</p>
</attribute>
<attribute name="resolveHosts" required="false">
<p>Set to <code>true</code> to convert the IP address of the remote
host into the corresponding host name via a DNS lookup. Set to
<code>false</code> to skip this lookup, and report the remote IP
address instead.</p>
</attribute>
<attribute name="suffix" required="false">
<p>The suffix added to the end of each log file's name. If not
specified, the default value is "". To specify no suffix,
use a zero-length string.</p>
</attribute>
<attribute name="rotatable" required="false">
<p>Flag to determine if log rotation should occur.
If set to <tt>false</tt>, then this file is never rotated and
<tt>fileDateFormat</tt> is ignored. Use with caution!
Default value: <tt>true</tt>
</p>
</attribute>
<attribute name="condition" required="false">
<p>Turns on conditional logging. If set, requests will be
logged only if <tt>ServletRequest.getAttribute()</tt> is
null. For example, if this value is set to
<tt>junk</tt>, then a particular request will only be logged
if <tt>ServletRequest.getAttribute("junk") == null</tt>.
The use of Filters is an easy way to set/unset the attribute
in the ServletRequest on many different requests.
</p>
</attribute>
<attribute name="fileDateFormat" required="false">
<p>Allows a customized date format in the access log file name.
The date format also decides how often the file is rotated.
If you wish to rotate every hour, then set this value
to: <tt>yyyy-MM-dd.HH</tt>
</p>
</attribute>
<attribute name="buffered" required="false">
<p>Flag to determine if logging will be buffered.
If set to <tt>false</tt>, then access logging will be written after each
request. Default value: <tt>true</tt>
</p>
</attribute>
</attributes>
<p>Values for the <code>pattern</code> attribute are made up of literal
text strings, combined with pattern identifiers prefixed by the "%"
character to cause replacement by the corresponding variable value from
the current request and response. The following pattern codes are
supported:</p>
<ul>
<li><b>%a</b> - Remote IP address</li>
<li><b>%A</b> - Local IP address</li>
<li><b>%b</b> - Bytes sent, excluding HTTP headers, or '-' if zero</li>
<li><b>%B</b> - Bytes sent, excluding HTTP headers</li>
<li><b>%h</b> - Remote host name (or IP address if
<code>resolveHosts</code> is false)</li>
<li><b>%H</b> - Request protocol</li>
<li><b>%l</b> - Remote logical username from identd (always returns
'-')</li>
<li><b>%m</b> - Request method (GET, POST, etc.)</li>
<li><b>%p</b> - Local port on which this request was received</li>
<li><b>%q</b> - Query string (prepended with a '?' if it exists)</li>
<li><b>%r</b> - First line of the request (method and request URI)</li>
<li><b>%s</b> - HTTP status code of the response</li>
<li><b>%S</b> - User session ID</li>
<li><b>%t</b> - Date and time, in Common Log Format</li>
<li><b>%u</b> - Remote user that was authenticated (if any), else '-'</li>
<li><b>%U</b> - Requested URL path</li>
<li><b>%v</b> - Local server name</li>
<li><b>%D</b> - Time taken to process the request, in millis</li>
<li><b>%T</b> - Time taken to process the request, in seconds</li>
<li><b>%I</b> - current request thread name (can compare later with stacktraces)</li>
</ul>
<p>
There is also support to write information from the cookie, incoming
header, the Session or something else in the ServletRequest.
It is modeled after the
<a href="http://httpd.apache.org/">Apache HTTP Server</a> log configuration
syntax:</p>
<ul>
<li><b><code>%{xxx}i</code></b> for incoming headers</li>
<li><b><code>%{xxx}o</code></b> for outgoing response headers</li>
<li><b><code>%{xxx}c</code></b> for a specific cookie</li>
<li><b><code>%{xxx}r</code></b> xxx is an attribute in the ServletRequest</li>
<li><b><code>%{xxx}s</code></b> xxx is an attribute in the HttpSession</li>
</ul>
<p>The shorthand pattern name <code>common</code> (which is also the
default) corresponds to <strong>'%h %l %u %t "%r" %s %b'</strong>.</p>
<p>The shorthand pattern name <code>combined</code> appends the
values of the <code>Referer</code> and <code>User-Agent</code> headers,
each in double quotes, to the <code>common</code> pattern
described in the previous paragraph.</p>
</subsection>
</section>
<section name="Remote Address Filter">
<subsection name="Introduction">
<p>The <strong>Remote Address Filter</strong> allows you to compare the
IP address of the client that submitted this request against one or more
<em>regular expressions</em>, and either allow the request to continue
or refuse to process the request from this client. A Remote Address
Filter can be associated with any Catalina container
(<a href="engine.html">Engine</a>, <a href="host.html">Host</a>, or
<a href="context.html">Context</a>), and must accept any request
presented to this container for processing before it will be passed on.</p>
<p>The syntax for <em>regular expressions</em> is different than that for
'standard' wildcard matching. Tomcat uses the <code>java.util.regex</code>
package. Please consult the Java documentation for details of the
expressions supported.</p>
<p>See also: <a href="#Remote_Host_Filter">Remote Host Filter</a>,
<a href="#Remote_IP_Valve">Remote IP Valve</a>.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Remote Address Filter</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.valves.RemoteAddrValve</strong>.</p>
</attribute>
<attribute name="allow" required="false">
<p>A comma-separated list of <em>regular expression</em> patterns
that the remote client's IP address is compared to. If this attribute
is specified, the remote address MUST match for this request to be
accepted. If this attribute is not specified, all requests will be
accepted UNLESS the remote address matches a <code>deny</code>
pattern.</p>
</attribute>
<attribute name="deny" required="false">
<p>A comma-separated list of <em>regular expression</em> patterns
that the remote client's IP address is compared to. If this attribute
is specified, the remote address MUST NOT match for this request to be
accepted. If this attribute is not specified, request acceptance is
governed solely by the <code>accept</code> attribute.</p>
</attribute>
<attribute name="denyStatus" required="false">
<p>HTTP response status code that is used when rejecting denied
request. The default value is <code>403</code>. For example,
it can be set to the value <code>404</code>.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Remote Host Filter">
<subsection name="Introduction">
<p>The <strong>Remote Host Filter</strong> allows you to compare the
hostname of the client that submitted this request against one or more
<em>regular expressions</em>, and either allow the request to continue
or refuse to process the request from this client. A Remote Host
Filter can be associated with any Catalina container
(<a href="engine.html">Engine</a>, <a href="host.html">Host</a>, or
<a href="context.html">Context</a>), and must accept any request
presented to this container for processing before it will be passed on.</p>
<p>The syntax for <em>regular expressions</em> is different than that for
'standard' wildcard matching. Tomcat uses the <code>java.util.regex</code>
package. Please consult the Java documentation for details of the
expressions supported.</p>
<p><strong>Note:</strong> This filter processes the value returned by
method <code>ServletRequest.getRemoteHost()</code>. To allow the method
to return proper host names, you have to enable "DNS lookups" feature on
a <strong>Connector</strong>.</p>
<p>See also: <a href="#Remote_Address_Filter">Remote Address Filter</a>,
<a href="http.html">HTTP Connector</a> configuration.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Remote Host Filter</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.valves.RemoteHostValve</strong>.</p>
</attribute>
<attribute name="allow" required="false">
<p>A comma-separated list of <em>regular expression</em> patterns
that the remote client's hostname is compared to. If this attribute
is specified, the remote hostname MUST match for this request to be
accepted. If this attribute is not specified, all requests will be
accepted UNLESS the remote hostname matches a <code>deny</code>
pattern.</p>
</attribute>
<attribute name="deny" required="false">
<p>A comma-separated list of <em>regular expression</em> patterns
that the remote client's hostname is compared to. If this attribute
is specified, the remote hostname MUST NOT match for this request to be
accepted. If this attribute is not specified, request acceptance is
governed solely by the <code>accept</code> attribute.</p>
</attribute>
<attribute name="denyStatus" required="false">
<p>HTTP response status code that is used when rejecting denied
request. The default value is <code>403</code>. For example,
it can be set to the value <code>404</code>.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Request Dumper Valve">
<subsection name="Introduction">
<p>The <em>Request Dumper Valve</em> is a useful tool in debugging
interactions with a client application (or browser) that is sending
HTTP requests to your Tomcat-based server. When configured, it causes
details about each request processed by its associated <code>Engine</code>,
<code>Host</code>, or <code>Context</code> to be logged according to
the logging configuration for that container.</p>
<p><strong>WARNING: Using this valve has side-effects.</strong> The
output from this valve includes any parameters included with the request.
The parameters will be decoded using the default platform encoding. Any
subsequent calls to <code>request.setCharacterEncoding()</code> within
the web application will have no effect. NOTE: Since all parameters are
included in the output, the InputStream is consumed for requests made with
the method POST and content-type application/x-www-form-urlencoded.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Request Dumper Valve</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.valves.RequestDumperValve</strong>.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Single Sign On Valve">
<subsection name="Introduction">
<p>The <em>Single Sign On Vale</em> is utilized when you wish to give users
the ability to sign on to any one of the web applications associated with
your virtual host, and then have their identity recognized by all other
web applications on the same virtual host.</p>
<p>See the <a href="host.html#Single Sign On">Single Sign On</a> special
feature on the <strong>Host</strong> element for more information.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Single Sign On</strong> Valve supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.authenticator.SingleSignOn</strong>.</p>
</attribute>
<attribute name="requireReauthentication" required="false">
<p>Default false. Flag to determine whether each request needs to be
reauthenticated to the security <strong>Realm</strong>. If "true", this
Valve uses cached security credentials (username and password) to
reauthenticate to the <strong>Realm</strong> each request associated
with an SSO session. If "false", the Valve can itself authenticate
requests based on the presence of a valid SSO cookie, without
rechecking with the <strong>Realm</strong>.</p>
</attribute>
<attribute name="cookieDomain" required="false">
<p>Sets the host domain to be used for sso cookies.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Basic Authenticator Valve">
<subsection name="Introduction">
<p>The <strong>Basic Authenticator Valve</strong> is automatically added to
any <a href="context.html">Context</a> that is configured to use BASIC
authentication.</p>
<p>If any non-default settings are required, the valve may be configured
within <a href="context.html">Context</a> element with the required
values.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Basic Authenticator Valve</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.authenticator.BasicAuthenticator</strong>.</p>
</attribute>
<attribute name="changeSessionIdOnAuthentication" required="false">
<p>Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of <code>true</code> will be
used.</p>
</attribute>
<attribute name="cnonceCacheSize" required="false">
<p>To protect against replay attacks, the DIGEST authenticator tracks
client nonce and nonce count values. This attribute controls the size
of that cache. If not specified, the default value of 1000 is used.</p>
</attribute>
<attribute name="disableProxyCaching" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
<code>securePagesWithPragma</code> offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
<code>true</code> will be used.</p>
</attribute>
<attribute name="key" required="false">
<p>The secret key used by digest authentication. If not set, a secure
random value is generated. This should normally only be set when it is
necessary to keep key values constant either across server restarts
and/or across a cluster.</p>
</attribute>
<attribute name="nonceValidity" required="false">
<p>The time, in milliseconds, that a server generated nonce will be
considered valid for use in authentication. If not specified, the
default value of 300000 (5 minutes) will be used.</p>
</attribute>
<attribute name="opaque" required="false">
<p>The opaque server string used by digest authentication. If not set, a
random value is generated. This should normally only be set when it is
necessary to keep opaque values constant either across server restarts
and/or across a cluster.</p>
</attribute>
<attribute name="securePagesWithPragma" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers by using
<code>Cache-Control: private</code> rather than the default of
<code>Pragma: No-cache</code> and <code>Cache-control: No-cache</code>.
If not set, the default value of <code>true</code> will be used.</p>
</attribute>
<attribute name="validateUri" required="false">
<p>Should the URI be validated as required by RFC2617? If not specified,
the default value of <code>true</code> will be used. This should
normally only be set when Tomcat is located behind a reverse proxy and
the proxy is modifying the URI passed to Tomcat such that DIGEST
authentication always fails.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Digest Authenticator Valve">
<subsection name="Introduction">
<p>The <strong>Digest Authenticator Valve</strong> is automatically added to
any <a href="context.html">Context</a> that is configured to use DIGEST
authentication.</p>
<p>If any non-default settings are required, the valve may be configured
within <a href="context.html">Context</a> element with the required
values.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Digest Authenticator Valve</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="cache" required="false">
<p>Should we cache authenticated Principals if the request is part of an
HTTP session? If not specified, the default value of <code>false</code>
will be used.</p>
</attribute>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.authenticator.DigestAuthenticator</strong>.</p>
</attribute>
<attribute name="changeSessionIdOnAuthentication" required="false">
<p>Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of <code>true</code> will be
used.</p>
</attribute>
<attribute name="disableProxyCaching" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
<code>securePagesWithPragma</code> offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
<code>true</code> will be used.</p>
</attribute>
<attribute name="key" required="false">
<p>The secret key used by digest authentication. If not set, a secure
random value is generated. This should normally only be set when it is
necessary to keep key values constant either across server restarts
and/or across a cluster.</p>
</attribute>
<attribute name="nonceCacheSize" required="false">
<p>To protect against replay attacks, the DIGEST authenticator tracks
server nonce and nonce count values. This attribute controls the size
of that cache. If not specified, the default value of 1000 is used.</p>
</attribute>
<attribute name="nonceValidity" required="false">
<p>The time, in milliseconds, that a server generated nonce will be
considered valid for use in authentication. If not specified, the
default value of 300000 (5 minutes) will be used.</p>
</attribute>
<attribute name="opaque" required="false">
<p>The opaque server string used by digest authentication. If not set, a
random value is generated. This should normally only be set when it is
necessary to keep opaque values constant either across server restarts
and/or across a cluster.</p>
</attribute>
<attribute name="securePagesWithPragma" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers by using
<code>Cache-Control: private</code> rather than the default of
<code>Pragma: No-cache</code> and <code>Cache-control: No-cache</code>.
If not set, the default value of <code>true</code> will be used.</p>
</attribute>
<attribute name="validateUri" required="false">
<p>Should the URI be validated as required by RFC2617? If not specified,
the default value of <code>true</code> will be used. This should
normally only be set when Tomcat is located behind a reverse proxy and
the proxy is modifying the URI passed to Tomcat such that DIGEST
authentication always fails.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Form Authenticator Valve">
<subsection name="Introduction">
<p>The <strong>Form Authenticator Valve</strong> is automatically added to
any <a href="context.html">Context</a> that is configured to use FORM
authentication.</p>
<p>If any non-default settings are required, the valve may be configured
within <a href="context.html">Context</a> element with the required
values.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Form Authenticator Valve</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.authenticator.FormAuthenticator</strong>.</p>
</attribute>
<attribute name="changeSessionIdOnAuthentication" required="false">
<p>Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of <code>true</code> will be
used.</p>
</attribute>
<attribute name="characterEncoding" required="false">
<p>Character encoding to use to read the username and password parameters
from the request. If not set, the encoding of the request body will be
used.</p>
</attribute>
<attribute name="disableProxyCaching" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
<code>securePagesWithPragma</code> offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
<code>true</code> will be used.</p>
</attribute>
<attribute name="securePagesWithPragma" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers by using
<code>Cache-Control: private</code> rather than the default of
<code>Pragma: No-cache</code> and <code>Cache-control: No-cache</code>.
If not set, the default value of <code>true</code> will be used.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="SSL Authenticator Valve">
<subsection name="Introduction">
<p>The <strong>SSL Authenticator Valve</strong> is automatically added to
any <a href="context.html">Context</a> that is configured to use SSL
authentication.</p>
<p>If any non-default settings are required, the valve may be configured
within <a href="context.html">Context</a> element with the required
values.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>SSL Authenticator Valve</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.authenticator.SSLAuthenticator</strong>.</p>
</attribute>
<attribute name="changeSessionIdOnAuthentication" required="false">
<p>Controls if the session ID is changed if a session exists at the
point where users are authenticated. This is to prevent session fixation
attacks. If not set, the default value of <code>true</code> will be
used.</p>
</attribute>
<attribute name="disableProxyCaching" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers but will also cause secured pages to be
cached by proxies which will almost certainly be a security issue.
<code>securePagesWithPragma</code> offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
<code>true</code> will be used.</p>
</attribute>
<attribute name="securePagesWithPragma" required="false">
<p>Controls the caching of pages that are protected by security
constraints. Setting this to <code>false</code> may help work around
caching issues in some browsers by using
<code>Cache-Control: private</code> rather than the default of
<code>Pragma: No-cache</code> and <code>Cache-control: No-cache</code>.
If not set, the default value of <code>true</code> will be used.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="WebDAV Fix Valve">
<subsection name="Introduction">
<p>Microsoft operating systems have two WebDAV clients. One is used with
port 80, the other is used for all other ports. The implementation used with
port 80 does not adhere to the WebDAV specification and fails when trying to
communicate with the Tomcat WebDAV Servlet. This valve provides a fix for
this by forcing the use of the WebDAV implementation that works, even when
connecting via port 80.</p>
<p>This Valve may be used at the <code>Engine</code>, <code>Host</code> or
<code>Context</code> level as required. Normally, this Valve would be used
at the <code>Context</code> level.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>WebDAV Fix Valve</strong> supports the following
configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.valves.WebdavFixValve</strong>.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Remote IP Valve">
<subsection name="Introduction">
<p>Tomcat port of
<a href="http://httpd.apache.org/docs/trunk/mod/mod_remoteip.html">mod_remoteip</a>,
this valve replaces the apparent client remote IP address and hostname for
the request with the IP address list presented by a proxy or a load balancer
via a request headers (e.g. "X-Forwarded-For").</p>
<p>Another feature of this valve is to replace the apparent scheme
(http/https), server port and <code>request.secure</code> with the scheme presented
by a proxy or a load balancer via a request header
(e.g. "X-Forwarded-Proto").</p>
<p>This Valve may be used at the <code>Engine</code>, <code>Host</code> or
<code>Context</code> level as required. Normally, this Valve would be used
at the <code>Engine</code> level.</p>
<p>If used in conjunction with Remote Address/Host valves then this valve
should be defined first to ensure that the correct client IP address is
presented to the Remote Address/Host valves.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Remote IP Valve</strong> supports the
following configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.valves.RemoteIpValve</strong>.</p>
</attribute>
<attribute name="remoteIpHeader" required="false">
<p>Name of the HTTP Header read by this valve that holds the list of
traversed IP addresses starting from the requesting client. If not
specified, the default of <code>x-forwarded-for</code> is used.</p>
</attribute>
<attribute name="internalProxies" required="false">
<p>List of internal proxies' IP addresses as comma separated regular
expressions. If they appear in the <strong>remoteIpHeader</strong>
value, they will be trusted and will not appear in the
<strong>proxiesHeader</strong> value. If not specified the default value
of <code>10\.\d{1,3}\.\d{1,3}\.\d{1,3}, 192\.168\.\d{1,3}\.\d{1,3},
169\.254\.\d{1,3}\.\d{1,3}, 127\.\d{1,3}\.\d{1,3}\.\d{1,3}</code> will
be used.</p>
</attribute>
<attribute name="proxiesHeader" required="false">
<p>Name of the HTTP header created by this valve to hold the list of
proxies that have been processed in the incoming
<strong>remoteIpHeader</strong>. If not specified, the default of
<code>x-forwarded-by</code> is used.</p>
</attribute>
<attribute name="trustedProxies" required="false">
<p>List of trusted proxies' IP addresses as comma separated regular
expressions. If they appear in the <strong>remoteIpHeader</strong>
value, they will be trusted and will appear in the
<strong>proxiesHeader</strong> value. If not specified, no proxies will
be trusted.</p>
</attribute>
<attribute name="protocolHeader" required="false">
<p>Name of the HTTP Header read by this valve that holds the protocol
used by the client to connect to the proxy. If not specified, the
default of <code>null</code> is used.</p>
</attribute>
<attribute name="protocolHeaderHttpsValue" required="false">
<p>Value of the <strong>protocolHeader</strong> to indicate that it is
an HTTPS request. If not specified, the default of <code>https</code> is
used.</p>
</attribute>
<attribute name="httpServerPort" required="false">
<p>Value returned by <code>ServletRequest.getServerPort()</code>
when the <strong>protocolHeader</strong> indicates <code>http</code>
protocol. If not specified, the default of <code>80</code> is
used.</p>
</attribute>
<attribute name="httpsServerPort" required="false">
<p>Value returned by <code>ServletRequest.getServerPort()</code>
when the <strong>protocolHeader</strong> indicates <code>https</code>
protocol. If not specified, the default of <code>443</code> is
used.</p>
</attribute>
</attributes>
</subsection>
</section>
<section name="Stuck Thread Detection Valve">
<subsection name="Introduction">
<p>This valve allows to detect requests that take a long time to process, which might
indicate that the thread that is processing it is stuck.</p>
<p>When such a request is detected, the current stack trace of its thread is written
to Tomcat log with a WARN level.</p>
<p>The IDs and names of the stuck threads are available through JMX in the
<code>stuckThreadIds</code> and <code>stuckThreadNames</code> attributes.
The IDs can be used with the standard Threading JVM MBean
(<code>java.lang:type=Threading</code>) to retrieve other information
about each stuck thread.</p>
</subsection>
<subsection name="Attributes">
<p>The <strong>Stuck Thread Detection Valve</strong> supports the
following configuration attributes:</p>
<attributes>
<attribute name="className" required="true">
<p>Java class name of the implementation to use. This MUST be set to
<strong>org.apache.catalina.valves.StuckThreadDetectionValve</strong>.
</p>
</attribute>
<attribute name="threshold" required="false">
<p>Minimum duration in seconds after which a thread is considered stuck.
Default is 600 seconds. If set to 0, the detection is disabled.</p>
<p>Note: since the detection is done in the background thread of the Container
(Engine, Host or Context) declaring this Valve, the threshold should be higher
than the <code>backgroundProcessorDelay</code> of this Container.</p>
</attribute>
</attributes>
</subsection>
</section>
</body>
</document>