expire

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Module

The expire accessor is exported by the urn:org:ten60:netkernel:ext:sys module. Import this module to gain access to the accessor.

Syntax

URI

active:expire

Argument	Rules	Description
operand	Mandatory	resource URI
operator	Optional	expiry period

Example Usage

DPML

<instr>
  <type>expire</type>
  <operand>something.xml</operand>
  <operator>
    <expire>
      <value>1</value>
      <unit>hour</unit>
    </expire>
  </operator>
  <target>this:response</target>
</instr>

NetKernel Foundation API

The expire accessor is provided for use with the DMPL language. It is more efficient to use the following NKF methods with scripting languages:

INKFResponse.setExpired() force a response to be always expired

INKFResponse.setNeverExpire() force a response to never expire

INKFResponse.setExpiryPeriod() force a response to expire after a fixed period

Purpose

Use the expire accessor to set the expiry of a resource. Change the expiry, or the time at which the response is no longer to be considered valid, to inform NetKernel when to discard cached values. For example, if the referenced resource computes a value, set the expiry to zero (0) if you require the resource to be computed for each use.

The operand specifies the target resource.

The operator specifies the new expiry information. If the operator is absent, the resource is set to expire immediately. The operator is specified using an XML fragment <expire>

<expire>
  <value> N </value>
  <unit> time-unit </unit>
</expire>

The <value> element contain an integer, and the <unit> element must be contain one of the following: second, minute, hour, or day. It defines an offset from the current time that the resource should expire. This will allow the resource to be cached for a that period of time and inform external clients that the resources current value is valid for that period of time.