Apache Tomcat Configuration ReferenceThe Valve Component | ![](../../images/void.gif) |
Introduction |
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_HOME
to refer to the directory into which you have installed Tomcat 6,
and is the base directory against which most relative paths are
resolved. However, if you have configured Tomcat 6 for multiple
instances by setting a CATALINA_BASE directory, you should use
$CATALINA_BASE instead of $CATALINA_HOME for each of these
references.
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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.
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Attributes |
The Access Log 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.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_HOME. If
no directory attribute is specified, the default value is "logs"
(relative to $CATALINA_HOME).
| 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 |
Deafult true. 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!
| 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 |
Deafult true. Flag to determine if logging will be buffered.
If set to false, then access logging will be written after each
request.
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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
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}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 |
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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 |
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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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Request Dumper Valve |
Introduction |
The Request Dumper Valve 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 Engine ,
Host , or Context to be logged according to
the logging configuration for that container.
WARNING: Using this valve has side-effects. 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 request.setCharacterEncoding() within
the web application will have no effect.
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Attributes |
The Request Dumper 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.RequestDumperValve.
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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 |
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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.
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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 |
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className |
Java class name of the implementation to use. This MUST be set to
org.apache.catalina.authenticator.FormAuthenticator.
| 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.
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