--- name: "AnyEvent::Memcached" section: "3pm" platform: "linux" package: "libanyevent-memcached-perl" version: "0.08-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/AnyEvent::Memcached" --- # AnyEvent::Memcached(3pm) AnyEvent memcached client ## 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 response 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 Asynchronous `"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, 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 one 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, `""` ## 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.