Redis(3pm) User Contributed Perl Documentation Redis(3pm)
NAME
Redis - Perl binding for Redis database
VERSION
version 1.951
SYNOPSIS
## Defaults to $ENV{REDIS_SERVER} or 127.0.0.1:6379
my $redis = Redis->new;
my $redis = Redis->new(server => 'redis.example.com:8080');
## Use UNIX domain socket
my $redis = Redis->new(sock => '/path/to/socket');
## Enable auto-reconnect
## Try to reconnect every 500ms 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);
## Disable the automatic utf8 encoding => much more performance
## !!!! This will be the default after 2.000, see ENCODING below
my $redis = Redis->new(encoding => undef);
## Use all the regular Redis commands, they all accept a list of
## arguments
## See http://redis.io/commands for full list
$redis->get('key');
$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
" if defined $error;
print "$_
" for @$reply;
});
long_computation();
$redis->wait_all_responses;
## 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;
$redis->wait_all_responses;
## Publish/Subscribe
$redis->subscribe(
'topic_1',
'topic_2',
sub {
my ($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');
DESCRIPTION
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".
PIPELINING
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:
o A non-pipelined (synchronous) command has been sent on the same connection
o A pub/sub subscription command (one of "subscribe", "unsubscribe", "psubscribe", or "punsubscribe") is about to be sent on the same
connection.
o The "wait_all_responses" method is called explicitly.
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".
ENCODING
This feature is deprecated and will be removed before 2.000. You should start testing your code with "encoding => undef" because that will
be the new default with 2.000.
Since Redis knows nothing about encoding, we are forcing utf-8 flag on all data received from Redis. This change was introduced in 1.2001
version. Please note that this encoding option severely degrades performance.
You can disable this automatic encoding by passing an option to "new": "encoding => undef".
This allows us to round-trip utf-8 encoded characters correctly, but might be problem if you push binary junk into Redis and expect to get
it back without utf-8 flag turned on.
METHODS
Constructors
new
my $r = Redis->new; # $ENV{REDIS_SERVER} or 127.0.0.1:6379
my $r = Redis->new( server => '192.168.0.1:6379', debug => 0 );
my $r = Redis->new( server => '192.168.0.1:6379', encoding => undef );
my $r = Redis->new( sock => '/path/to/sock' );
my $r = Redis->new( reconnect => 60, every => 5000 );
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
'127.0.0.1:6379'.
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:
o /path/to/sock
o unix:/path/to/sock
o 127.0.0.1:11011
o tcp:127.0.0.1:11011
The "encoding" parameter speficies 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" miliseconds (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.
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
quit
$r->quit;
Closes the connection to the server. The "quit" method does not support pipelined operation.
ping
$r->ping || die "no server?";
The "ping" method does not support pipelined operation.
Pipeline management
wait_all_responses
Waits until all pending pipelined responses have been received, and invokes the pipeline callback for each one. 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 <https://github.com/melo/perl-redis/issues/17>.
multi
$r->multi;
discard
$r->discard;
exec
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
set
$r->set( foo => 'bar' );
$r->setnx( foo => 42 );
get
my $value = $r->get( 'foo' );
mget
my @values = $r->mget( 'foo', 'bar', 'baz' );
incr
$r->incr('counter');
$r->incrby('tripplets', 3);
decr
$r->decr('counter');
$r->decrby('tripplets', 3);
exists
$r->exists( 'key' ) && print "got key!";
del
$r->del( 'key' ) || warn "key doesn't exist";
type
$r->type( 'key' ); # = string
Commands operating on the key space
keys
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.
randomkey
my $key = $r->randomkey;
rename
my $ok = $r->rename( 'old-key', 'new-key', $new );
dbsize
my $nr_keys = $r->dbsize;
Commands operating on lists
See also Redis::List for tie interface.
rpush
$r->rpush( $key, $value );
lpush
$r->lpush( $key, $value );
llen
$r->llen( $key );
lrange
my @list = $r->lrange( $key, $start, $end );
ltrim
my $ok = $r->ltrim( $key, $start, $end );
lindex
$r->lindex( $key, $index );
lset
$r->lset( $key, $index, $value );
lrem
my $modified_count = $r->lrem( $key, $count, $value );
lpop
my $value = $r->lpop( $key );
rpop
my $value = $r->rpop( $key );
Commands operating on sets
sadd
my $ok = $r->sadd( $key, $member );
scard
my $n_elements = $r->scard( $key );
sdiff
my @elements = $r->sdiff( $key1, $key2, ... );
my $elements = $r->sdiff( $key1, $key2, ... ); # ARRAY ref
sdiffstore
my $ok = $r->sdiffstore( $dstkey, $key1, $key2, ... );
sinter
my @elements = $r->sinter( $key1, $key2, ... );
my $elements = $r->sinter( $key1, $key2, ... ); # ARRAY ref
sinterstore
my $ok = $r->sinterstore( $dstkey, $key1, $key2, ... );
sismember
my $bool = $r->sismember( $key, $member );
smembers
my @elements = $r->smembers( $key );
my $elements = $r->smembers( $key ); # ARRAY ref
smove
my $ok = $r->smove( $srckey, $dstkey, $element );
spop
my $element = $r->spop( $key );
spop
my $element = $r->srandmember( $key );
srem
$r->srem( $key, $member );
sunion
my @elements = $r->sunion( $key1, $key2, ... );
my $elements = $r->sunion( $key1, $key2, ... ); # ARRAY ref
sunionstore
my $ok = $r->sunionstore( $dstkey, $key1, $key2, ... );
Sorting
sort
$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:
o The published message.
o The topic over which the message was sent.
o The subscribed topic that matched the topic for the message. With "subscribe" these last two are the same, always. But with
"psubscribe", this parameter tells you the pattern that matched.
See the Pub/Sub notes <http://redis.io/topics/pubsub> for more information about the messages you will receive on your callbacks after each
"subscribe", "unsubscribe", "psubscribe" and "punsubscribe".
publish
$r->publish($topic, $message);
Publishes the $message to the $topic.
subscribe
$r->subscribe(
@topics_to_subscribe_to,
sub {
my ($message, $topic, $subscribed_topic) = @_;
...
},
);
Subscribe one or more topics. Messages published into one of them will be received by Redis, and the specificed callback will be executed.
unsubscribe
$r->unsubscribe(@topic_list, sub { my ($m, $t, $s) = @_; ... });
Stops receiving messages for all the topics in @topic_list.
psubscribe
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.
punsubscribe
my @topic_matches = ('prefix1.*', 'prefix2.*');
$r->punsubscribe(@topic_matches, sub { my ($m, $t, $s) = @_; ... });
Stops receiving messages for all the topics pattern matches in @topic_list.
is_subscriber
if ($r->is_subscriber) { say "We are in Pub/Sub mode!" }
Returns true if we are in Pub/Sub mode.
wait_for_messages
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 ammount of seconds without a single notification.
Please note that the timeout is not a commitement 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
save
$r->save;
bgsave
$r->bgsave;
lastsave
$r->lastsave;
Remote server control commands
info
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.
shutdown
$r->shutdown;
The "shutdown" method does not support pipelined operation.
Multiple databases handling commands
select
$r->select( $dbindex ); # 0 for new clients
move
$r->move( $key, $dbindex );
flushdb
$r->flushdb;
flushall
$r->flushall;
SUPPORT
Perldoc
You can find documentation for this module with the perldoc command.
perldoc Redis
Websites
The following websites have more information about this module, and may be of help to you. As always, in addition to those websites please
use your favorite search engine to discover more resources.
o CPAN Testers
The CPAN Testers is a network of smokers who run automated tests on uploaded CPAN distributions.
<http://www.cpantesters.org/distro/R/Redis>
o CPAN Testers Matrix
The CPAN Testers Matrix is a website that provides a visual overview of the test results for a distribution on various Perls/platforms.
<http://matrix.cpantesters.org/?dist=Redis>
o CPAN Testers Dependencies
The CPAN Testers Dependencies is a website that shows a chart of the test results of all dependencies for a distribution.
<http://deps.cpantesters.org/?module=Redis>
o CPAN Ratings
The CPAN Ratings is a website that allows community ratings and reviews of Perl modules.
<http://cpanratings.perl.org/d/Redis>
Email
You can email the author of this module at "MELO at cpan.org" asking for help with any problems you have.
Bugs / Feature Requests
Please report any bugs or feature requests by email to "bug-redis at rt.cpan.org", or through the web interface at
<http://rt.cpan.org/Public/Dist/Display.html?Name=Redis>. You will be automatically notified of any progress on the request by the system.
Source Code
https://github.com/melo/perl-redis <https://github.com/melo/perl-redis>
git clone https://github.com/melo/perl-redis.git
ACKNOWLEDGEMENTS
The following persons contributed to this project (alphabetical order):
o Aaron Crane (pipelining and AUTOLOAD caching support)
o Dirk Vleugels
o Flavio Poletti
o Jeremy Zawodny
o sunnavy at bestpractical.com
o Thiago Berlitz Rondon
o Ulrich Habel
AUTHOR
Pedro Melo <melo@cpan.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2012 by Pedro Melo.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)
perl v5.14.2 2012-03-13 Redis(3pm)