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ProxySG Content Policy Language Guide
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• The optional admin_properties is a list of properties set if any of the rules in the layer match.
These act as defaults, and can be overridden by property settings in specific rules in the layer. For
more information on using properties, see Chapter 4: "Property Reference". See also the following
Layer Guards section.
<Cache> Layers
<Cache> layers hold policy that is executed by both cache and proxy transactions. Since cache
transactions have no concept of a client, all
<Cache> layer policy is clientless, so you cannot test client
identity using
client.address=, user=, group=, and the like.
Certain types of policy must be applied consistently to both proxy and cache transactions to preserve
cache consistency. Such policy must not be conditional on client identity or time of day, and belongs in
a
<Cache> layer. Examples include the following:
• Response virus scanning.
• Cache control policy (other than
bypass_cache).
• Modifications to request headers, if the modification affects the content returned by the web
server, and the content is cached.
• Rewrites of the request URL that modify the server URL but not the cache URL. (Place rewrites of
the request URL that change the cache and server URL to the same value in a
<Proxy> layer.)
Only the following properties are safe to make conditional on time or client identity in a
<Cache>
layer:
• Pipelining
• Tracing, logging
• Freshness checks
• Redirection
• Content transforms
The syntax is:
<Cache [label]> [cache_condition][cache_properties] ...
cache_content
where:
• The
<Cache> layer defines the transactions evaluated against this policy, and restricts the triggers
and properties allowed in the rules used in the layer.
• The optional
label, separated from the layer type by space, is a CPL User-defined Identifier.
• The optional
cache_condition is a list of triggers, all of which must evaluate to true before the
layer content is evaluated. For more information on using conditions, see Chapter 3: "Condition
Reference". See also the following Layer Guards section.
• The optional
cache_properties is a list of properties set if any of the rules in the layer match.
These act as defaults, and can be overridden by property settings in specific rules in the layer. For
more information on using properties, see Chapter 4: "Property Reference". See also the following
Layer Guards section.