A Valve component represents an instance of a specified Java class that will be involved in the processing of each request and response handled by the Container within which it is nested, as follows:
Valves are typically used to implement optional features for the associated Container. See the "Special Features" section of the documentation on Engine, host, and Context Containers for more information about the Valves designed to be associated with each Container type. This page summarizes the configuration information for all standard Valve implementations that are provided with Catalina.
All implementations of the Valve component support the following attributes:
| Attribute | Description |
|---|---|
className |
Java class name of the implementation to use. This class must
implement the org.apache.catalina.Valve interface.
Because there is no single standard implementation, this attribute
is required. See
Standard Implementation Attributes for the names of the
supported classes.
|
Unlike most other Catalina components, there is not a single standard
implementation of the Valve component available. Instead,
a variety of standard implementations, with different functional purposes,
are available for your use. To select one, use the specified value for the
className attribute, and configure the remaining attributes
as described below.
org.apache.catalina.valve.AccessLogValve)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 access log Valve shares many configuration characteristics with the File Logger components used to record internal event, exception, and debugging output from Catalina components, including the automatic rollover of log files at midnight each night. An Access Log Valve can be associated with an Engine, Host, or Context Container, and will log requests processed by the associated Container and any nested Containers.
The Access Log Valve supports the following additional attributes:
| Attribute | Description |
|---|---|
directory |
Relative or absolute pathname of the directory into which log files will be created. If a relative path is specified, it is interpreted as relative to $CATALINA_HOME. If no directory is specified, the default value is "logs" (relative to the Catalina home directory). |
pattern |
A formatting layout identifying the various information fields
from the request and response to be logged, or the word
common to select the standard Common Log Format.
See below for more information on pattern variables. If no
value is specified, the common format is utilized.
|
prefix |
The prefix added to the front of each log file name. If not specified, the default value is "access_log.". To specify no prefix, use a zero-length string. |
resolveHosts |
Should the IP address of the remote client for each request be
resolved to the corresponding host name (via a DNS lookup)? You
might wish to turn off host resolution to improve performance
in high activity web applications. If not specified, the default
value is false, indicating that remote host resolution
will not take place.
|
suffix |
The suffix added to the end of each log file name. If not specified, the default value is "". To specify no suffix, use a zero-length string. |
timestamp |
Should log messages be date/time stamped? Set this value to
true or false. If not specified,
log messages will not be date/time stamped.
|
Values for the pattern attribute are made up of literal text
strings, and pattern identifiers prefixed by the % character,
which cause replacement by the corresponding variable value from the current
request and response. The following pattern codes are supported:
If you specify a pattern of common, or do not specify a pattern
at all, the common pattern %h %l %u %t "%r" %s %b is used, which
corresponds to the default logging format for many web servers.
org.apache.catalina.valve.RemoteAddrValve)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 a request from this client based on the outcome of the comparison. A Remote Address Filter can be associated with an Engine, Host, or Context Container, and will filter requests processed by the associated Container and any nested Containers.
The Remote Address Filter supports the following additional attributes:
| Attribute | Description |
|---|---|
| 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 at least
one of the patterns to be allowed. If this attribute is not
specified, all requests are allowed 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 any of
the specified patterns to be allowed. If this attribute is not
specified, any request where the remote address matches one of the
accept patterns is allowed.
|
org.apache.catalina.valve.RemoteHostValve)The Remote Host Filter allows you to compare the remote host 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 a request from this client based on the outcome of the comparison. A Remote Host Filter can be associated with an Engine, Host, or Context Container, and will filter requests processed by the associated Container and any nested Containers.
The Remote Address Host supports the following additional attributes:
| Attribute | Description |
|---|---|
| allow | A comma-separated list of regular expression patterns that
the remote client's host address is compared to. If this attribute is
specified, the remote address must match at least
one of the patterns to be allowed. If this attribute is not
specified, all requests are allowed unless the remote address
matches a deny pattern.
|
| deny | A comma-separated list of regular expression patterns that
the remote client's host address is compared to. If this attribute is
specified, the remote address must not match any of
the specified patterns to be allowed. If this attribute is not
specified, any request where the remote address matches one of the
accept patterns is allowed.
|
org.apache.catalina.valve.RequestDumperValve)The Request Dumper Valve is a debugging tool that lets you insert a component that dumps the HTTP headers associated with the specified request (before processing) and response (after processing) to the Logger that is associated with our corresponding Container. It is especially useful when trying to debug problems related to headers or cookies sent by an HTTP client. A Request Dumper Filter can be associated with an Engine, Host, or Context Container, and will log requests processed by the associated Container and any nested Containers.
The Request Dumper Filter supports no additional attributes.