#-
# Copyright (c) 2017 Varnish Software AS
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# Author: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>
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$Module purge 3 "Varnish Purge Module"
$ABI strict

DESCRIPTION
===========

`vmod_purge` contains functions that offer a finer-grained control than the
``purge`` transition in ``vcl_recv``. The functions can only be called from
``vcl_hit`` or ``vcl_miss`` and they should in general be used in both to
ensure that all variants of a same object are taken care of.

EXAMPLE
=======

::

    sub vcl_recv {
	if (req.method == "PURGE") {
	    if (client.ip !~ purge_acl) {
		return (synth(405));
	    }
	    return (hash);
	}
    }

    sub my_purge {
	set req.http.purged = purge.hard();
	if (req.http.purged == "0") {
	    return (synth(404));
	}
	else {
	    return (synth(200));
	}
    }

    sub vcl_hit {
	if (req.method == "PURGE") {
	    call my_purge;
	}
    }

    sub vcl_miss {
	if (req.method == "PURGE") {
	    call my_purge;
	}
    }

    sub vcl_synth {
	if (req.method == "PURGE") {
	    if (req.http.purged) {
		set resp.http.purged = req.http.purged;
	    }
	    return (deliver);
	}
    }

$Function INT hard()

Description
	This is equivalent to ``return(purge)`` but explicitly called from
	``vcl_hit`` and ``vcl_miss``. It returns the number of purged objects.
Example
	set req.http.purged = purge.hard();

$Function INT soft(DURATION ttl = 0, DURATION grace = -1, DURATION keep = -1)

Description
	Sets the TTL, grace and keep. By default, TTL is set to 0 with grace
	and keep periods left untouched. Setting a negative value for grace or
	keep periods leaves them untouched. Setting all three parameters to
	0 is equivalent to a hard purge. It can only be called from ``vcl_hit``
	or ``vcl_miss``. It returns the number of soft-purged objects.

SEE ALSO
========

* :ref:`vcl(7)`
