Links Top Level Elements Executors Connectors Containers Nested Components Cluster Elements Global Settings | The Valve ComponentIntroduction |
A Valve element represents a component that will be
inserted into the request processing pipeline for the associated
Catalina container (Engine,
Host, or Context).
Individual Valves have distinct processing capabilities, and are
described individually below.
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 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.
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Access Log Valve |
Introduction |
The Access Log Valve 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 Valve
are rolled over nightly at midnight. This Valve
may be associated with any Catalina container (Context ,
Host , or Engine ), and
will record ALL requests processed by that container.
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 Context that
would have handled the request, the request/response will be logged in the
AccessLog (s) associated Context , Host
and Engine . Where Tomcat cannot identify the
Context that would have handled the request, e.g. in cases
where the URL is invalid, Tomcat will look first in the Engine ,
then the default Host for the Engine and finally
the ROOT (or default) Context for the default Host
for an AccessLog implementation. Tomcat will use the first
AccessLog implementation found to log those requests that are
rejected before they are passed to a container.
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Attributes |
The Access Log Valve supports the following
configuration attributes:
Attribute | Description |
---|
className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.AccessLogValve to use the
default access log valve.
| directory |
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).
| pattern |
A formatting layout identifying the various information fields
from the request and response to be logged, or the word
common or combined to select a
standard format. See below for more information on configuring
this attribute. Note that the optimized access does only support
common and combined as the value for this
attribute.
| prefix |
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.
| resolveHosts |
Set to true to convert the IP address of the remote
host into the corresponding host name via a DNS lookup. Set to
false to skip this lookup, and report the remote IP
address instead.
| suffix |
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.
| rotatable |
Flag to determine if log rotation should occur.
If set to false, then this file is never rotated and
fileDateFormat is ignored. Use with caution!
Default value: true
| condition |
Turns on conditional logging. If set, requests will be
logged only if ServletRequest.getAttribute() is
null. For example, if this value is set to
junk, then a particular request will only be logged
if ServletRequest.getAttribute("junk") == null.
The use of Filters is an easy way to set/unset the attribute
in the ServletRequest on many different requests.
| fileDateFormat |
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: yyyy-MM-dd.HH
| buffered |
Flag to determine if logging will be buffered.
If set to false, then access logging will be written after each
request. Default value: true
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Values for the pattern 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:
- %a - Remote IP address
- %A - Local IP address
- %b - Bytes sent, excluding HTTP headers, or '-' if zero
- %B - Bytes sent, excluding HTTP headers
- %h - Remote host name (or IP address if
resolveHosts is false)
- %H - Request protocol
- %l - Remote logical username from identd (always returns
'-')
- %m - Request method (GET, POST, etc.)
- %p - Local port on which this request was received
- %q - Query string (prepended with a '?' if it exists)
- %r - First line of the request (method and request URI)
- %s - HTTP status code of the response
- %S - User session ID
- %t - Date and time, in Common Log Format
- %u - Remote user that was authenticated (if any), else '-'
- %U - Requested URL path
- %v - Local server name
- %D - Time taken to process the request, in millis
- %T - Time taken to process the request, in seconds
- %I - current request thread name (can compare later with stacktraces)
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 apache syntax:
%{xxx}i for incoming headers
%{xxx}o for outgoing response headers
%{xxx}c for a specific cookie
%{xxx}r xxx is an attribute in the ServletRequest
%{xxx}s xxx is an attribute in the HttpSession
The shorthand pattern name common (which is also the
default) corresponds to '%h %l %u %t "%r" %s %b'.
The shorthand pattern name combined appends the
values of the Referer and User-Agent headers,
each in double quotes, to the common pattern
described in the previous paragraph.
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Remote Address Filter |
Introduction |
The Remote Address Filter allows you to compare the
IP address of the client that submitted this request against one or more
regular expressions, 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
(Engine, Host, or
Context), and must accept any request
presented to this container for processing before it will be passed on.
The syntax for regular expressions is different than that for
'standard' wildcard matching. Tomcat uses the java.util.regex
package. Please consult the Java documentation for details of the
expressions supported.
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Attributes |
The Remote Address Filter supports the following
configuration attributes:
Attribute | Description |
---|
className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.RemoteAddrValve.
| allow |
A comma-separated list of regular expression 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 deny
pattern.
| deny |
A comma-separated list of regular expression 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 accept attribute.
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Remote Host Filter |
Introduction |
The Remote Host Filter allows you to compare the
hostname of the client that submitted this request against one or more
regular expressions, 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
(Engine, Host, or
Context), and must accept any request
presented to this container for processing before it will be passed on.
The syntax for regular expressions is different than that for
'standard' wildcard matching. Tomcat uses the java.util.regex
package. Please consult the Java documentation for details of the
expressions supported.
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Attributes |
The Remote Host Filter supports the following
configuration attributes:
Attribute | Description |
---|
className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.RemoteHostValve.
| allow |
A comma-separated list of regular expression 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 deny
pattern.
| deny |
A comma-separated list of regular expression 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 accept attribute.
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Single Sign On Valve |
Introduction |
The Single Sign On Vale 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.
See the Single Sign On special
feature on the Host element for more information.
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Attributes |
The Single Sign On Valve supports the following
configuration attributes:
Attribute | Description |
---|
className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.SingleSignOn.
| requireReauthentication |
Default false. Flag to determine whether each request needs to be
reauthenticated to the security Realm. If "true", this
Valve uses cached security credentials (username and password) to
reauthenticate to the Realm 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 Realm.
| cookieDomain |
Sets the host domain to be used for sso cookies.
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Basic Authenticator Valve |
Introduction |
The Basic Authenticator Valve is automatically added to
any Context that is configured to use BASIC
authentication.
If any non-default settings are required, the valve may be configured
within Context element with the required
values.
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Attributes |
The Basic Authenticator Valve supports the following
configuration attributes:
Attribute | Description |
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className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.BasicAuthenticator.
| changeSessionIdOnAuthentication |
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 true will be
used.
| disableProxyCaching |
Controls the caching of pages that are protected by security
constraints. Setting this to false 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.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.
| securePagesWithPragma |
Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache .
If not set, the default value of true will be used.
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Digest Authenticator Valve |
Introduction |
The Digest Authenticator Valve is automatically added to
any Context that is configured to use DIGEST
authentication.
If any non-default settings are required, the valve may be configured
within Context element with the required
values.
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Attributes |
The Digest Authenticator Valve supports the following
configuration attributes:
Attribute | Description |
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className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.DigestAuthenticator.
| changeSessionIdOnAuthentication |
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 true will be
used.
| disableProxyCaching |
Controls the caching of pages that are protected by security
constraints. Setting this to false 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.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.
| securePagesWithPragma |
Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache .
If not set, the default value of true will be used.
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Form Authenticator Valve |
Introduction |
The Form Authenticator Valve is automatically added to
any Context that is configured to use FORM
authentication.
If any non-default settings are required, the valve may be configured
within Context element with the required
values.
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Attributes |
The Form Authenticator Valve supports the following
configuration attributes:
Attribute | Description |
---|
className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.FormAuthenticator.
| changeSessionIdOnAuthentication |
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 true will be
used.
| characterEncoding |
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.
| disableProxyCaching |
Controls the caching of pages that are protected by security
constraints. Setting this to false 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.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.
| landingPage |
Controls the behavior of the FORM authentication process if the
process is misused, for example by directly requesting the login page
or delaying logging in for so long that the session expires. If this
attribute is set, rather than returning an error response code, Tomcat
will redirect the user to the specified landing page if the login form
is submitted with valid credentials. For the login to be processed, the
landing page must be a protected resource (i.e. one that requires
authentication). If the landing page does not require authentication
then the user will not be logged in and will be prompted for their
credentials again when they access a protected page.
| securePagesWithPragma |
Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache .
If not set, the default value of true will be used.
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SSL Authenticator Valve |
Introduction |
The SSL Authenticator Valve is automatically added to
any Context that is configured to use SSL
authentication.
If any non-default settings are required, the valve may be configured
within Context element with the required
values.
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Attributes |
The SSL Authenticator Valve supports the following
configuration attributes:
Attribute | Description |
---|
className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.SSLAuthenticator.
| changeSessionIdOnAuthentication |
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 true will be
used.
| disableProxyCaching |
Controls the caching of pages that are protected by security
constraints. Setting this to false 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.
securePagesWithPragma offers an alternative, secure,
workaround for browser caching issues. If not set, the default value of
true will be used.
| securePagesWithPragma |
Controls the caching of pages that are protected by security
constraints. Setting this to false may help work around
caching issues in some browsers by using
Cache-Control: private rather than the default of
Pragma: No-cache and Cache-control: No-cache .
If not set, the default value of true will be used.
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Remote IP Valve |
Introduction |
Tomcat port of
mod_remoteip,
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").
Another feature of this valve is to replace the apparent scheme
(http/https), server port and request.secure with the scheme presented
by a proxy or a load balancer via a request header
(e.g. "X-Forwarded-Proto").
This Valve may be used at the Engine , Host or
Context level as required. Normally, this Valve would be used
at the Engine level.
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.
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Attributes |
The Remote IP Valve supports the
following configuration attributes:
Attribute | Description |
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className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.valves.RemoteIpValve.
| remoteIpHeader |
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 x-forwarded-for is used.
| internalProxies |
List of internal proxies' IP addresses as comma separated regular
expressions. If they appear in the remoteIpHeader
value, they will be trusted and will not appear in the
proxiesHeader value. If not specified the default value
of 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} will
be used.
| proxiesHeader |
Name of the HTTP header created by this valve to hold the list of
proxies that have been processed in the incoming
remoteIpHeader. If not specified, the default of
x-forwarded-by is used.
| trustedProxies |
List of trusted proxies' IP addresses as comma separated regular
expressions. If they appear in the remoteIpHeader
value, they will be trusted and will appear in the
proxiesHeader value. If not specified, no proxies will
be trusted.
| protocolHeader |
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 null is used.
| protocolHeaderHttpsValue |
Value of the protocolHeader to indicate that it is
an HTTPS request. If not specified, the default of https is
used.
| httpServerPort |
Value returned by ServletRequest.getServerPort()
when the protocolHeader indicates http
protocol. If not specified, the default of 80 is
used.
| httpsServerPort |
Value returned by ServletRequest.getServerPort()
when the protocolHeader indicates https
protocol. If not specified, the default of 443 is
used.
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