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AnyEvent-Memcached-0.08
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/ AnyEvent::Memcached

NAME

AnyEvent::Memcached - AnyEvent memcached client

SYNOPSIS

use AnyEvent::Memcached;

my $memd = AnyEvent::Memcached->new(
    servers => [ "10.0.0.15:11211", "10.0.0.15:11212" ], # same as in Cache::Memcached
    debug   => 1,
    compress_threshold => 10000,
    namespace => 'my-namespace:',

    # May use another hashing algo:
    hasher  => 'AnyEvent::Memcached::Hash::WithNext',

    cv      => $cv, # AnyEvent->condvar: group callback
);

$memd->set_servers([ "10.0.0.15:11211", "10.0.0.15:11212" ]);

# Basic methods are like in Cache::Memcached, but with additional cb => sub { ... };
# first argument to cb is return value, second is the error(s)

$memd->set( key => $value, cb => sub {
    shift or warn "Set failed: @_"
} );

# Single get
$memd->get( 'key', cb => sub {
    my ($value,$err) = shift;
    $err and return warn "Get failed: @_";
    warn "Value for key is $value";
} );

# Multi-get
$memd->get( [ 'key1', 'key2' ], cb => sub {
    my ($values,$err) = shift;
    $err and return warn "Get failed: @_";
    warn "Value for key1 is $values->{key1} and value for key2 is $values->{key2}"
} );

# Additionally there is rget (see memcachedb-1.2.1-beta)

$memd->rget( 'fromkey', 'tokey', cb => sub {
    my ($values,$err) = shift;
    $err and warn "Get failed: @_";
    while (my ($key,$value) = each %$values) {
        # ...
    }
} );

# Rget with sorted responce values
$memd->rget( 'fromkey', 'tokey', rv => 'array' cb => sub {
    my ($values,$err) = shift;
    $err and warn "Get failed: @_";
    for (0 .. $#values/2) {
        my ($key,$value) = @$values[$_*2,$_*2+1];
    }
} );

DESCRIPTION

Asyncronous memcached/memcachedb client for AnyEvent framework

NOTICE

There is a notices in Cache::Memcached::AnyEvent related to this module. They all has been fixed

Prerequisites

We no longer need Object::Event and Devel::Leak::Cb. At all, the dependency list is like in Cache::Memcached + AnyEvent

Binary protocol

It seems to me, that usage of binary protocol from pure perl gives very little advantage. So for now I don't implement it

Unimplemented Methods

There is a note, that get_multi is not implementeted. In fact, it was implemented by method "get", but the documentation was wrong.

In general, this module follows the spirit of AnyEvent rather than correspondence to Cache::Memcached interface.

METHODS

new %args

Currently supported options:

servers =item namespace =item debug =item cv =item compress_threshold =item compress_enable =item timeout =item hasher

If set, will use instance of this class for hashing instead of default. For implementing your own hashing, see sources of AnyEvent::Memcached::Hash and AnyEvent::Memcached::Hash::With::Next

noreply

If true, additional connection will established for noreply commands.

cas

If true, will enable cas/gets commands (since they are not suppotred in memcachedb)

set_servers

Setup server list

connect

Establish connection to all servers and invoke event C<connected>, when ready

set( $key, $value, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Unconditionally sets a key to a given value in the memcache.

$rc is

'1'

Successfully stored

'0'

Item was not stored

undef

Error happens, see $err

cas( $key, $cas, $value, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

$memd->gets($key, cb => sub {
    my $value = shift;
    unless (@_) { # No errors
        my ($cas,$val) = @$value;
        # Change your value in $val
        $memd->cas( $key, $cas, $value, cb => sub {
            my $rc = shift;
            if ($rc) {
                # stored
            } else {
                # ...
            }
        });
    }
})

$rc is the same, as for "set"

Store the $value on the server under the $key, but only if CAS value associated with this key is equal to $cas. See also "gets"

add( $key, $value, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Like set, but only stores in memcache if the key doesn't already exist.

replace( $key, $value, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Like set, but only stores in memcache if the key already exists. The opposite of add.

append( $key, $value, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Append the $value to the current value on the server under the $key.

append command first appeared in memcached 1.2.4.

prepend( $key, $value, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Prepend the $value to the current value on the server under the $key.

prepend command first appeared in memcached 1.2.4.

get( $key, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Retrieve the value for a $key. $key should be a scalar

get( $keys : ARRAYREF, [cv => $cv], [ expire => $expire ], cb => $cb->( $values_hash, $err ) )

Retrieve the values for a $keys. Return a hash with keys/values

gets( $key, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Retrieve the value and its CAS for a $key. $key should be a scalar.

$rc is a reference to an array [$cas, $value], or nothing for non-existent key

gets( $keys : ARRAYREF, [cv => $cv], [ expire => $expire ], cb => $cb->( $rc, $err ) )

Retrieve the values and their CAS for a $keys.

$rc is a hash reference with $rc->{$key} is a reference to an array [$cas, $value]

delete( $key, [cv => $cv], [ noreply => 1 ], cb => $cb->( $rc, $err ) )

Delete $key and its value from the cache.

If noreply is true, cb doesn't required

del

Alias for "delete"

remove

Alias for "delete"

incr( $key, $increment, [cv => $cv], [ noreply => 1 ], cb => $cb->( $rc, $err ) )

Increment the value for the $key by $delta. Starting with memcached 1.3.3 $key should be set to a number or the command will fail. Note that the server doesn't check for overflow.

If noreply is true, cb doesn't required, and if passed, simply called with rc = 1

Similar to DBI, zero is returned as "0E0", and evaluates to true in a boolean context.

decr( $key, $decrement, [cv => $cv], [ noreply => 1 ], cb => $cb->( $rc, $err ) )

Opposite to incr

rget( $from, $till, [ max => 100 ], [ '+left' => 1 ], [ '+right' => 1 ], [cv => $cv], [ rv => 'array' ], cb => $cb->( $rc, $err ) )

Memcachedb 1.2.1-beta implements rget method, that allows to look through the whole storage

$from

the starting key

$till

finishing key

+left

If true, then starting key will be included in results. true by default

+right

If true, then finishing key will be included in results. true by default

max

Maximum number of results to fetch. 100 is the maximum and is the default

rv

If passed rv => 'array', then the return value will be arrayref with values in order, returned by memcachedb.

incadd ( $key, $increment, [cv => $cv], [ noreply => 1 ], cb => $cb->( $rc, $err ) )

Increment key, and if it not exists, add it with initial value. If add fails, try again to incr or fail

destroy

Shutdown object as much, as possible, incl cleaning of incapsulated objects

BUGS

Feature requests are welcome

Bug reports are welcome

AUTHOR

Mons Anderson, <mons at cpan.org>

COPYRIGHT & LICENSE

Copyright 2009 Mons Anderson, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.