cache.config

The cache.config file defines how the proxy caches Web objects. You can add caching rules to specify the following configuration:

Not to cache objects from specific IP addresses

How long to pin particular objects in the cache

How long to consider cached objects as fresh

Whether to ignore no-cache directives from the server


	Important After you modify this file, run content_line -x from the Content Gateway bin directory (/opt/WCG/bin) to apply the changes. When you apply the changes to a node in a cluster, Content Gateway applies the changes to all nodes in the cluster.

Format

Each line in the cache.config file contains a caching rule. Content Gateway recognizes three space-delimited tags:

primary_destination=value secondary_specifier=value action=value

The following table lists the possible primary destinations and their allowed values.


Primary Destination	Allowed Value
dest_domain	A requested domain name
dest_host	A requested hostname
dest_ip	A requested IP address
url_regex	A regular expression to be found in a URL. See Specifying URL regular expressions (url_regex) for information on using regular expressions.

Secondary specifiers are optional in the cache.config file. The following table lists the possible secondary specifiers and their allowed values.


	Note You can use more than one secondary specifier in a rule. However, you cannot repeat a secondary specifier.

A request URL protocol; one of the following:

HTTP

FTP

prefix

A prefix in the path part of a URL

suffix

A file suffix in the URL

method

A request URL method; one of the following:

A time range, such as 08:00-14:00

src_ip

A client IP address.

user_agent

A request header User-Agent value.

Takes a regular expression that is applied to the user-agent string. SeeSpecifying URL regular expressions (url_regex) for information on using regular expressions.

The following table lists the possible actions and their allowed values.

Action

Value

action

One of the following values:

never-cache configures the proxy to never cache specified objects.

ignore-no-cache configures the proxy to ignore all Cache-Control: no-cache headers.

ignore-client-no-cache configures the proxy to ignore Cache-Control: no-cache headers from client requests.

ignore-server-no-cache configures the proxy to ignore Cache-Control: no-cache headers from origin server responses.

pin-in-cache

The amount of time you want to keep the object(s) in the cache. The following time formats are allowed:

d for days (for example 2d)

h for hours (for example, 10h)

m for minutes (for example, 5m)

s for seconds (for example, 20s)

mixed units (for example, 1h15m20s)

revalidate

The amount of time you want to consider the object(s) fresh. Use the same time formats as pin-in-cache.

ttl-in-cache

The amount of time you want to keep objects in the cache regardless of Cache-Control response headers. Use the same time formats as pin-in-cache and revalidate.

Examples

The following example configures the proxy to never cache FTP documents requested from the IP address 112.12.12.12:

dest_ip=112.12.12.12 scheme=ftp action=never-cache

The following example configures the proxy to keep documents with URLs that contain the regular expression politics and the path prefix/viewpoint in the cache for 12 hours:

url_regex=politics prefix=/viewpoint pin-in-cache=12h

The following example configures the proxy to revalidate gif and jpeg objects in the domain mydomain.com every 6 hours and all other objects in mydomain.com every hour:

dest_domain=mydomain.com suffix=gif revalidate=6h

dest_domain=mydomain.com suffix=jpeg revalidate=6h

dest_domain=mydomain.com revalidate=1h


	Note The rules are applied in the order listed.