Damien Krotkine > Redis-1.966 > Redis



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Module Version: 1.966   Source   Latest Release: Redis-1.981


Redis - Perl binding for Redis database


version 1.966


    ## Defaults to $ENV{REDIS_SERVER} or
    my $redis = Redis->new;

    my $redis = Redis->new(server => 'redis.example.com:8080');

    ## Set the connection name (requires Redis 2.6.9)
    my $redis = Redis->new(
      server => 'redis.example.com:8080',
      name => 'my_connection_name',
    my $generation = 0;
    my $redis = Redis->new(
      server => 'redis.example.com:8080',
      name => sub { "cache-$$-".++$generation },

    ## Use UNIX domain socket
    my $redis = Redis->new(sock => '/path/to/socket');

    ## Enable auto-reconnect
    ## Try to reconnect every 1s up to 60 seconds until success
    ## Die if you can't after that
    my $redis = Redis->new(reconnect => 60);

    ## Try each 100ms upto 2 seconds (every is in milisecs)
    my $redis = Redis->new(reconnect => 2, every => 100);

    ## Use all the regular Redis commands, they all accept a list of
    ## arguments
    ## See http://redis.io/commands for full list
    $redis->set('key' => 'value');
    $redis->sort('list', 'DESC');
    $redis->sort(qw{list LIMIT 0 5 ALPHA DESC});

    ## Add a coderef argument to run a command in the background
    $redis->sort(qw{list LIMIT 0 5 ALPHA DESC}, sub {
      my ($reply, $error) = @_;
      die "Oops, got an error: $error\n" if defined $error;
      print "$_\n" for @$reply;
    ## or

    ## Or run a large batch of commands in a pipeline
    my %hash = _get_large_batch_of_commands();
    $redis->hset('h', $_, $hash{$_}, sub {}) for keys %hash;

    ## Publish/Subscribe
      sub {
        my ($message, $topic, $subscribed_topic) = @_

          ## $subscribed_topic can be different from topic if
          ## you use psubscribe() with wildcards
    $redis->psubscribe('nasdaq.*', sub {...});

    ## Blocks and waits for messages, calls subscribe() callbacks
    ##  ... forever
    my $timeout = 10;
    $redis->wait_for_messages($timeout) while 1;

    ##  ... until some condition
    my $keep_going = 1; ## other code will set to false to quit
    $redis->wait_for_messages($timeout) while $keep_going;

    $redis->publish('topic_1', 'message');


Pure perl bindings for http://redis.io/

This version supports protocol 2.x (multi-bulk) or later of Redis available at https://github.com/antirez/redis/.

This documentation lists commands which are exercised in test suite, but additional commands will work correctly since protocol specifies enough information to support almost all commands with same piece of code with a little help of AUTOLOAD.


Usually, running a command will wait for a response. However, if you're doing large numbers of requests, it can be more efficient to use what Redis calls pipelining: send multiple commands to Redis without waiting for a response, then wait for the responses that come in.

To use pipelining, add a coderef argument as the last argument to a command method call:

  $r->set('foo', 'bar', sub {});

Pending responses to pipelined commands are processed in a single batch, as soon as at least one of the following conditions holds:

The coderef you supply to a pipelined command method is invoked once the response is available. It takes two arguments, $reply and $error. If $error is defined, it contains the text of an error reply sent by the Redis server. Otherwise, $reply is the non-error reply. For almost all commands, that means it's undef, or a defined but non-reference scalar, or an array ref of any of those; but see "keys", "info", and "exec".

Note the contrast with synchronous commands, which throw an exception on receipt of an error reply, or return a non-error reply directly.

The fact that pipelined commands never throw an exception can be particularly useful for Redis transactions; see "exec".


There is no encoding feature anymore, it has been deprecated and finally removed. This module consider that any data sent to the Redis server is a raw octets string, even if it has utf8 flag set. And it doesn't do anything when getting data from the Redis server.

So, do you pre-encoding or post-decoding operation yourself if needed !




    my $r = Redis->new; # $ENV{REDIS_SERVER} or

    my $r = Redis->new( server => '', debug => 0 );
    my $r = Redis->new( server => '', encoding => undef );
    my $r = Redis->new( sock => '/path/to/sock' );
    my $r = Redis->new( reconnect => 60, every => 5000 );
    my $r = Redis->new( password => 'boo' );
    my $r = Redis->new( on_connect => sub { my ($redis) = @_; ... } );
    my $r = Redis->new( name => 'my_connection_name' );
    my $r = Redis->new( name => sub { "cache-for-$$" });

The server parameter specifies the Redis server we should connect to, via TCP. Use the 'IP:PORT' format. If no server option is present, we will attempt to use the REDIS_SERVER environment variable. If neither of those options are present, it defaults to ''.

Alternatively you can use the sock parameter to specify the path of the UNIX domain socket where the Redis server is listening.

The REDIS_SERVER can be used for UNIX domain sockets too. The following formats are supported:

The encoding parameter specifies the encoding we will use to decode all the data we receive and encode all the data sent to the redis server. Due to backwards-compatibility we default to utf8. To disable all this encoding/decoding, you must use encoding => undef. This is the recommended option.

Warning: this option has several problems and it is deprecated. A future version might add other filtering options though.

The reconnect option enables auto-reconnection mode. If we cannot connect to the Redis server, or if a network write fails, we enter retry mode. We will try a new connection every every milliseconds (1000ms by default), up-to reconnect seconds.

Be aware that read errors will always thrown an exception, and will not trigger a retry until the new command is sent.

If we cannot re-establish a connection after reconnect seconds, an exception will be thrown.

If your Redis server requires authentication, you can use the password attribute. After each established connection (at the start or when reconnecting), the Redis AUTH command will be send to the server. If the password is wrong, an exception will be thrown and reconnect will be disabled.

You can also provide a code reference that will be immediately after each successful connection. The on_connect attribute is used to provide the code reference, and it will be called with the first parameter being the Redis object.

You can also set a name for each connection. This can be very useful for debugging purposes, using the CLIENT LIST command. To set a connection name, use the name parameter. You can use both a scalar value or a CodeRef. If the latter, it will be called after each connection, with the Redis object, and it should return the connection name to use. If it returns a undefined value, Redis will not set the connection name.

Please note that there are restrictions on the name you can set, the most important of which is, no spaces. See the CLIENT SETNAME documentation for all the juicy details. This feature is safe to use with all versions of Redis servers. If CLIENT SETNAME support is not available (Redis servers 2.6.9 and above only), the name parameter is ignored.

The debug parameter enables debug information to STDERR, including all interactions with the server. You can also enable debug with the REDIS_DEBUG environment variable.

Connection Handling



Closes the connection to the server. The quit method does not support pipelined operation.


  $r->ping || die "no server?";

The ping method does not support pipelined operation.


  @clients = $r->client_list;

Returns list of clients connected to the server. See CLIENT LIST documentation for a description of the fields and their meaning.


  my $connection_name = $r->client_getname;

Returns the name associated with this connection. See "client_setname" or the name parameter to "new" for ways to set this name.



Sets this connection name. See the CLIENT SETNAME documentation for restrictions on the connection name string. The most important one: no spaces.

Pipeline management


Waits until all pending pipelined responses have been received, and invokes the pipeline callback for each one. See "PIPELINING".


Waits until the first pending pipelined response has been received, and invokes its callback. See "PIPELINING".

Transaction-handling commands

Warning: the behaviour of these commands when combined with pipelining is still under discussion, and you should NOT use them at the same time just now.

You can follow the discussion to see the open issues with this.






  my @individual_replies = $r->exec;

exec has special behaviour when run in a pipeline: the $reply argument to the pipeline callback is an array ref whose elements are themselves [$reply, $error] pairs. This means that you can accurately detect errors yielded by any command in the transaction, and without any exceptions being thrown.

Commands operating on string values


  $r->set( foo => 'bar' );

  $r->setnx( foo => 42 );


  my $value = $r->get( 'foo' );


  my @values = $r->mget( 'foo', 'bar', 'baz' );



  $r->incrby('tripplets', 3);



  $r->decrby('tripplets', 3);


  $r->exists( 'key' ) && print "got key!";


  $r->del( 'key' ) || warn "key doesn't exist";


  $r->type( 'key' ); # = string

Commands operating on the key space


  my @keys = $r->keys( '*glob_pattern*' );
  my $keys = $r->keys( '*glob_pattern*' ); # count of matching keys

Note that synchronous keys calls in a scalar context return the number of matching keys (not an array ref of matching keys as you might expect). This does not apply in pipelined mode: assuming the server returns a list of keys, as expected, it is always passed to the pipeline callback as an array ref.


  my $key = $r->randomkey;


  my $ok = $r->rename( 'old-key', 'new-key', $new );


  my $nr_keys = $r->dbsize;

Commands operating on lists

See also Redis::List for tie interface.


  $r->rpush( $key, $value );


  $r->lpush( $key, $value );


  $r->llen( $key );


  my @list = $r->lrange( $key, $start, $end );


  my $ok = $r->ltrim( $key, $start, $end );


  $r->lindex( $key, $index );


  $r->lset( $key, $index, $value );


  my $modified_count = $r->lrem( $key, $count, $value );


  my $value = $r->lpop( $key );


  my $value = $r->rpop( $key );

Commands operating on sets


  my $ok = $r->sadd( $key, $member );


  my $n_elements = $r->scard( $key );


  my @elements = $r->sdiff( $key1, $key2, ... );
  my $elements = $r->sdiff( $key1, $key2, ... ); # ARRAY ref


  my $ok = $r->sdiffstore( $dstkey, $key1, $key2, ... );


  my @elements = $r->sinter( $key1, $key2, ... );
  my $elements = $r->sinter( $key1, $key2, ... ); # ARRAY ref


  my $ok = $r->sinterstore( $dstkey, $key1, $key2, ... );


  my $bool = $r->sismember( $key, $member );


  my @elements = $r->smembers( $key );
  my $elements = $r->smembers( $key ); # ARRAY ref


  my $ok = $r->smove( $srckey, $dstkey, $element );


  my $element = $r->spop( $key );


  my $element = $r->srandmember( $key );


  $r->srem( $key, $member );


  my @elements = $r->sunion( $key1, $key2, ... );
  my $elements = $r->sunion( $key1, $key2, ... ); # ARRAY ref


  my $ok = $r->sunionstore( $dstkey, $key1, $key2, ... );

Commands operating on hashes

Hashes in Redis cannot be nested as in perl, if you want to store a nested hash, you need to serialize the hash first. If you want to have a named hash, you can use Redis-hashes. You will find an example in the tests of this module t/01-basic.t


Sets the value to a key in a hash.

  $r->hset('hashname', $key => $value); ## returns true on success


Gets the value to a key in a hash.

  my $value = $r->hget('hashname', $key);


  if($r->hexists('hashname', $key) {
    ## do something, the key exists
  else {
    ## the key does not exist


Deletes a key from a hash

  if($r->hdel('hashname', $key)) {
    ## key is deleted
  else {
    ## oops


Adds an integer to a value. The integer is signed, so a negative integer decrements.

  my $key = 'testkey';
  $r->hset('hashname', $key => 1); ## value -> 1
  my $increment = 1; ## has to be an integer
  $r->hincrby('hashname', $key => $increment); ## value -> 2
  $increment = 5;
  $r->hincrby('hashname', $key => $increment); ## value -> 7
  $increment = -1;
  $r->hincrby('hashname', $key => $increment); ## value -> 6


Adds a key to a hash unless it is not already set.

  my $key = 'testnx';
  $r->hsetnx('hashname', $key => 1); ## returns true
  $r->hsetnx('hashname', $key => 2); ## returns false because key already exists


Adds multiple keys to a hash.

  $r->hmset('hashname', 'key1' => 'value1', 'key2' => 'value2'); ## returns true on success


Returns multiple keys of a hash.

  my @values = $r->hmget('hashname', 'key1', 'key2');


Returns the whole hash.

  my %hash = $r->hgetall('hashname');


Returns the keys of a hash.

  my @keys = $r->hkeys('hashname');


Returns the values of a hash.

  my @values = $r->hvals('hashname');


Returns the count of keys in a hash.

  my $keycount = $r->hlen('hashname');



  $r->sort("key BY pattern LIMIT start end GET pattern ASC|DESC ALPHA');

Publish/Subscribe commands

When one of "subscribe" or "psubscribe" is used, the Redis object will enter PubSub mode. When in PubSub mode only commands in this section, plus "quit", will be accepted.

If you plan on using PubSub and other Redis functions, you should use two Redis objects, one dedicated to PubSub and the other for regular commands.

All Pub/Sub commands receive a callback as the last parameter. This callback receives three arguments:

See the Pub/Sub notes for more information about the messages you will receive on your callbacks after each "subscribe", "unsubscribe", "psubscribe" and "punsubscribe".


  $r->publish($topic, $message);

Publishes the $message to the $topic.


      sub {
        my ($message, $topic, $subscribed_topic) = @_;

Subscribe one or more topics. Messages published into one of them will be received by Redis, and the specified callback will be executed.


  $r->unsubscribe(@topic_list, sub { my ($m, $t, $s) = @_; ... });

Stops receiving messages for all the topics in @topic_list.


  my @topic_matches = ('prefix1.*', 'prefix2.*');
  $r->psubscribe(@topic_matches, sub { my ($m, $t, $s) = @_; ... });

Subscribes a pattern of topics. All messages to topics that match the pattern will be delivered to the callback.


  my @topic_matches = ('prefix1.*', 'prefix2.*');
  $r->punsubscribe(@topic_matches, sub { my ($m, $t, $s) = @_; ... });

Stops receiving messages for all the topics pattern matches in @topic_list.


  if ($r->is_subscriber) { say "We are in Pub/Sub mode!" }

Returns true if we are in Pub/Sub mode.


  my $keep_going = 1; ## Set to false somewhere to leave the loop
  my $timeout = 5;
  $r->wait_for_messages($timeout) while $keep_going;

Blocks, waits for incoming messages and delivers them to the appropriate callbacks.

Requires a single parameter, the number of seconds to wait for messages. Use 0 to wait for ever. If a positive non-zero value is used, it will return after that amount of seconds without a single notification.

Please note that the timeout is not a commitment to return control to the caller at most each timeout seconds, but more a idle timeout, were control will return to the caller if Redis is idle (as in no messages were received during the timeout period) for more than timeout seconds.

The "wait_for_messages" call returns the number of messages processed during the run.

Persistence control commands







Scripting commands


  $r->eval($lua_script, $num_keys, $key1, ..., $arg1, $arg2);

Executes a Lua script server side.

Note that this commands sends the Lua script every time you call it. See "evalsha" and "script_load" for an alternative.


  $r->eval($lua_script_sha1, $num_keys, $key1, ..., $arg1, $arg2);

Executes a Lua script cached on the server side by its SHA1 digest.

See "script_load".


  my ($sha1) = $r->script_load($lua_script);

Cache Lua script, returns SHA1 digest that can be used with "evalsha".


  my ($exists1, $exists2, ...) = $r->script_exists($scrip1_sha, $script2_sha, ...);

Given a list of SHA1 digests, returns a list of booleans, one for each SHA1, that report the existence of each script in the server cache.



Kills the currently running script.



Flush the Lua scripts cache.

Remote server control commands


  my $info_hash = $r->info;

The info method is unique in that it decodes the server's response into a hashref, if possible. This decoding happens in both synchronous and pipelined modes.



The shutdown method does not support pipelined operation.


  my $nr_items = $r->slowlog("len");
  my @last_ten_items = $r->slowlog("get", 10);

The slowlog command gives access to the server's slow log.

Multiple databases handling commands


  $r->select( $dbindex ); # 0 for new clients


  $r->move( $key, $dbindex );






The following persons contributed to this project (alphabetical order):



This software is Copyright (c) 2013 by Pedro Melo, Damien Krotkine.

This is free software, licensed under:

  The Artistic License 2.0 (GPL Compatible)
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