acs::Cache method eval (public)

 <instance of acs::Cache> eval [ -partition_key partition_key ] \
    [ -expires expires ] [ -timeout timeout ] [ -per_request ] key \
    command

Defined in packages/acs-tcl/tcl/acs-cache-procs.tcl

Evaluate the command unless the result was already computed before and cached.

Switches:

-partition_key (optional)

Used for determining the cache name in partitioned caches. The partition key is computed typically automatically depending on the cache type.

-expires (optional)

Lifetime of the cache entry. The entry will be purged automatically when the time is reached. The time is in seconds unless a time unit is specified (e.g., 5m)

-timeout (optional)

Maximum time to wait for the command to complete. The time is in seconds unless a time unit is specified (e.g., 2.5m)

-per_request (optional)

When set, cache the result per request. So far, no attempt is made to flush the result during the lifetime of the request.

Parameters:

key (required)

The cache key

command (required)

The command to be executed when the result is not yet cached.

Testcases:

No testcase defined.

Source code:

if {![info exists partition_key]} {
    set partition_key $key
}
foreach optional_parameter {expires timeout} {
    if {[info exists $optional_parameter]} {
        set ${optional_parameter}_flag [list -$optional_parameter [set $optional_parameter]]
    } else {
        set ${optional_parameter}_flag ""
    }
}
set cache_name [:cache_name $partition_key]
try {
    if {$per_request} {
        acs::per_request_cache eval -key ::acs-${cache_name}($key) {
            :uplevel [list ns_cache_eval  {*}$expires_flag {*}$timeout_flag --  $cache_name $key $command]
        }
    } else {
        :uplevel [list ns_cache_eval {*}$expires_flag {*}$timeout_flag --  $cache_name $key $command]
    }

} on break {r} {
    #
    # When the command ends with "break", it means:
    # "don't cache". We return in this case always a
    # 0.
    #
    #ns_log notice "====================== [self] $key -> break -> <$r>"
    return 0

} on ok {r} {
    return $r
}

XQL Not present:

Generic, PostgreSQL, Oracle