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IPH / AnyEvent-RipeRedis-0.44 / README.md

NAME

AnyEvent::RipeRedis - Flexible non-blocking Redis client

SYNOPSIS

use AnyEvent;
use AnyEvent::RipeRedis;

my $redis = AnyEvent::RipeRedis->new(
  host     => 'localhost',
  port     => 6379,
  password => 'yourpass',
);

my $cv = AE::cv;

$redis->set( 'foo', 'bar',
  sub {
    my $err = $_[1];

    if ( defined $err ) {
      warn $err->message . "\n";
      $cv->send;

      return;
    }

    $redis->get( 'foo',
      sub {
        my $reply = shift;
        my $err   = shift;

        if ( defined $err ) {
          warn $err->message . "\n";
          $cv->send;

          return;
        }

        print "$reply\n";
        $cv->send;
      }
    );
  }
);

$cv->recv;

DESCRIPTION

AnyEvent::RipeRedis is flexible non-blocking Redis client. Supports subscriptions, transactions and can automaticaly restore connection after failure.

Requires Redis 1.2 or higher, and any supported event loop.

CONSTRUCTOR

new( %params )

my $redis = AnyEvent::RipeRedis->new(
  host               => 'localhost',
  port               => 6379,
  password           => 'yourpass',
  database           => 7,
  connection_timeout => 5,
  read_timeout       => 5,
  lazy               => 1,
  reconnect_interval => 5,

  on_connect => sub {
    # handling...
  },

  on_disconnect => sub {
    # handling...
  },

  on_error => sub {
    my $err = shift;

    # error handling...
  },
);

COMMAND EXECUTION

<command>( [ @args ] [, $cb->( $reply, $err ) ] )

To execute the command you must call specific method with corresponding name. The reply to the command is passed to the callback in first argument. If any error occurred during the command execution, the error object is passed to the callback in second argument. Error object is the instance of the class AnyEvent::RipeRedis::Error.

The command callback is optional. If it is not specified and any error occurred, the on_error callback of the client is called.

The full list of the Redis commands can be found here: http://redis.io/commands.

$redis->get( 'foo',
  sub {
    my $reply = shift;
    my $err   = shift;

    if ( defined $err ) {
      my $err_msg  = $err->message;
      my $err_code = $err->code;

      # error handling...

      return;
    }

    print "$reply\n";
  }
);

$redis->lrange( 'list', 0, -1,
  sub {
    my $reply = shift;
    my $err   = shift;

    if ( defined $err ) {
      my $err_msg  = $err->message;
      my $err_code = $err->code;

      # error handling...

      return;
    }

    foreach my $value ( @{$reply}  ) {
      print "$value\n";
    }
  }
);

$redis->incr( 'counter' );

You can execute multi-word commands like this:

$redis->client_getname(
  sub {
    my $reply = shift;
    my $err   = shift;

    if ( defined $err ) {
      my $err_msg  = $err->message;
      my $err_code = $err->code;

      # error handling...

      return;
    }

    print "$reply\n";
  }
);

execute( $command, [ @args ] [, $cb->( $reply, $err ) ] )

An alternative method to execute commands. In some cases it can be more convenient.

$redis->execute( 'get', 'foo',
  sub {
    my $reply = shift;
    my $err   = shift;

    if ( defined $err ) {
      my $err_msg  = $err->message;
      my $err_code = $err->code;

      return;
    }

    print "$reply\n";
  }
);

TRANSACTIONS

The detailed information about the Redis transactions can be found here: http://redis.io/topics/transactions.

multi( [ $cb->( $reply, $err ) ] )

Marks the start of a transaction block. Subsequent commands will be queued for atomic execution using EXEC.

exec( [ $cb->( $reply, $err ) ] )

Executes all previously queued commands in a transaction and restores the connection state to normal. When using WATCH, EXEC will execute commands only if the watched keys were not modified.

If during a transaction at least one command fails, to the callback will be passed error object, and the reply will be contain nested error objects for every failed command.

$redis->multi();
$redis->set( 'foo', 'string' );
$redis->incr('foo');    # causes an error
$redis->exec(
  sub {
    my $reply = shift;
    my $err   = shift;

    if ( defined $err ) {
      my $err_msg  = $err->message();
      my $err_code = $err->code();

      if ( defined $reply ) {
        foreach my $nested_reply ( @{$reply} ) {
          if ( ref($nested_reply) eq 'AnyEvent::RipeRedis::Error' ) {
            my $nested_err_msg  = $nested_reply->message();
            my $nested_err_code = $nested_reply->code();

            # error handling...
          }
        }

        return;
      }

      # error handling...

      return;
    }

    # reply handling...
  },
);

discard( [ $cb->( $reply, $err ) ] )

Flushes all previously queued commands in a transaction and restores the connection state to normal.

If WATCH was used, DISCARD unwatches all keys.

watch( @keys [, $cb->( $reply, $err ) ] )

Marks the given keys to be watched for conditional execution of a transaction.

unwatch( [ $cb->( $reply, $err ) ] )

Forget about all watched keys.

SUBSCRIPTIONS

Once the client enters the subscribed state it is not supposed to issue any other commands, except for additional SUBSCRIBE, PSUBSCRIBE, UNSUBSCRIBE, PUNSUBSCRIBE and QUIT commands.

The detailed information about Redis Pub/Sub can be found here: http://redis.io/topics/pubsub

subscribe( @channels, ( $cb->( $msg, $channel ) | \%cbs ) )

Subscribes the client to the specified channels.

Method can accept two callbacks: on_reply and on_message. The on_reply callback is called when subscription to all specified channels will be activated. In first argument to the callback is passed the number of channels we are currently subscribed. If subscription to specified channels was lost, the on_reply callback is called with the error object in the second argument.

The on_message callback is called on every published message. If the subscribe method is called with one callback, this callback will be act as on_message callback.

$redis->subscribe( qw( foo bar ),
  { on_reply => sub {
      my $channels_num = shift;
      my $err          = shift;

      if ( defined $err ) {
        # error handling...

        return;
      }

      # reply handling...
    },

    on_message => sub {
      my $msg     = shift;
      my $channel = shift;

      # message handling...
    },
  }
);

$redis->subscribe( qw( foo bar ),
  sub {
    my $msg     = shift;
    my $channel = shift;

    # message handling...
  }
);

psubscribe( @patterns, ( $cb->( $msg, $pattern, $channel ) | \%cbs ) )

Subscribes the client to the given patterns. See subscribe() method for details.

$redis->psubscribe( qw( foo_* bar_* ),
  { on_reply => sub {
      my $channels_num = shift;
      my $err          = shift;

      if ( defined $err ) {
        # error handling...

        return;
      }

      # reply handling...
    },

    on_message => sub {
      my $msg     = shift;
      my $pattern = shift;
      my $channel = shift;

      # message handling...
    },
  }
);

$redis->psubscribe( qw( foo_* bar_* ),
  sub {
    my $msg     = shift;
    my $pattern = shift;
    my $channel = shift;

    # message handling...
  }
);

publish( $channel, $message [, $cb->( $reply, $err ) ] )

Posts a message to the given channel.

unsubscribe( [ @channels ] [, $cb->( $reply, $err ) ] )

Unsubscribes the client from the given channels, or from all of them if none is given. In first argument to the callback is passed the number of channels we are currently subscribed or zero if we were unsubscribed from all channels.

$redis->unsubscribe( qw( foo bar ),
  sub {
    my $channels_num = shift;
    my $err          = shift;

    if ( defined $err ) {
      # error handling...

      return;
    }

    # reply handling...
  }
);

punsubscribe( [ @patterns ] [, $cb->( $reply, $err ) ] )

Unsubscribes the client from the given patterns, or from all of them if none is given. See unsubscribe() method for details.

$redis->punsubscribe( qw( foo_* bar_* ),
  sub {
    my $channels_num = shift;
    my $err          = shift;

    if ( defined $err ) {
      # error handling...

      return;
    }

    # reply handling...
  }
);

CONNECTION VIA UNIX-SOCKET

Redis 2.2 and higher support connection via UNIX domain socket. To connect via a UNIX-socket in the parameter host you have to specify unix/, and in the parameter port you have to specify the path to the socket.

my $redis = AnyEvent::RipeRedis->new(
  host => 'unix/',
  port => '/tmp/redis.sock',
);

LUA SCRIPTS EXECUTION

Redis 2.6 and higher support execution of Lua scripts on the server side. To execute a Lua script you can send one of the commands EVAL or EVALSHA, or use the special method eval_cached().

eval_cached( $script, $keys_num [, @keys ] [, @args ] [, $cb->( $reply, $err ) ] ] );

When you call the eval_cached() method, the client first generate a SHA1 hash for a Lua script and cache it in memory. Then the client optimistically send the EVALSHA command under the hood. If the E_NO_SCRIPT error will be returned, the client send the EVAL command.

If you call the eval_cached() method with the same Lua script, client don not generate a SHA1 hash for this script repeatedly, it gets a hash from the cache instead.

$redis->eval_cached( 'return { KEYS[1], KEYS[2], ARGV[1], ARGV[2] }',
    2, 'key1', 'key2', 'first', 'second',
  sub {
    my $reply = shift;
    my $err   = shift;

    if ( defined $err ) {
      # error handling...

      return;
    }

    foreach my $value ( @{$reply}  ) {
      print "$value\n";
    }
  }
);

Be care, passing a different Lua scripts to eval_cached() method every time cause memory leaks.

If Lua script returns multi-bulk reply with at least one error reply, to the callback will be passed error object, and the reply will be contain nested error objects.

$redis->eval_cached( "return { 'foo', redis.error_reply( 'Error.' ) }", 0,
  sub {
    my $reply = shift;
    my $err   = shift;

    if ( defined $err ) {
      my $err_msg  = $err->message;
      my $err_code = $err->code;

      if ( defined $reply ) {
        foreach my $nested_reply ( @{$reply} ) {
          if ( ref($nested_reply) eq 'AnyEvent::RipeRedis::Error' ) {
            my $nested_err_msg  = $nested_reply->message();
            my $nested_err_code = $nested_reply->code();

            # error handling...
          }
        }
      }

      # error handling...

      return;
    }

    # reply handling...
  }
);

ERROR CODES

Every error object, passed to callback, contain error code, which can be used for programmatic handling of errors. AnyEvent::RipeRedis provides constants for error codes. They can be imported and used in expressions.

use AnyEvent::RipeRedis qw( :err_codes );

Error codes available since Redis 2.6.

Error codes available since Redis 2.8.

Error codes available since Redis 3.0.

DISCONNECTION

When the connection to the server is no longer needed you can close it in three ways: call the method disconnect(), send the QUIT command or you can just "forget" any references to an AnyEvent::RipeRedis object, but in this case the client object is destroyed without calling any callbacks, including the on_disconnect callback, to avoid an unexpected behavior.

disconnect()

The method for synchronous disconnection. All uncompleted operations will be aborted.

quit( [ $cb->( $reply, $err ) ] )

The method for asynchronous disconnection.

OTHER METHODS

info( [ $section ] [, $cb->( $reply, $err ) ] )

Gets and parses information and statistics about the server. The result is passed to callback as a hash reference.

More information about INFO command can be found here: http://redis.io/commands/info

host()

Gets current host of the client.

port()

Gets current port of the client.

select( $index, [, $cb->( $reply, $err ) ] )

Selects the database by numeric index.

database()

Gets selected database index.

utf8( [ $boolean ] )

Enables or disables UTF-8 mode.

connection_timeout( [ $fractional_seconds ] )

Gets or sets the connection_timeout of the client. The undef value resets the connection_timeout to default value.

read_timeout( [ $fractional_seconds ] )

Gets or sets the read_timeout of the client.

reconnect( [ $boolean ] )

Enables or disables reconnection mode of the client.

reconnect_interval( [ $fractional_seconds ] )

Gets or sets reconnect_interval of the client.

on_connect( [ $callback ] )

Gets or sets the on_connect callback.

on_disconnect( [ $callback ] )

Gets or sets the on_disconnect callback.

on_error( [ $callback ] )

Gets or sets the on_error callback.

SEE ALSO

AnyEvent::RipeRedis::Cluster, AnyEvent, Redis::hiredis, Redis, RedisDB

AUTHOR

Eugene Ponizovsky, ponizovsky@gmail.com

Sponsored by SMS Online, dev.opensource@sms-online.com

Special thanks

COPYRIGHT AND LICENSE

Copyright (c) 2012-2017, Eugene Ponizovsky, SMS Online. All rights reserved.

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