Redis

@deprecated The preferred way to create a new client object is using `new`.

This method does not actually establish a connection to Redis,
in contrary to what you might expect.

# File lib/redis.rb, line 15
def self.connect(options = {})
  new(options)
end

Append a value to a key.

@param [String] key @param [String] value value to append @return [Fixnum] length of the string after appending

# File lib/redis.rb, line 879
def append(key, value)
  synchronize do |client|
    client.call([:append, key, value])
  end
end

Authenticate to the server.

@param [String] password must match the password specified in the

`requirepass` directive in the configuration file

@return [String] `OK`

# File lib/redis.rb, line 62
def auth(password)
  synchronize do |client|
    client.call([:auth, password])
  end
end

Asynchronously rewrite the append-only file.

@return [String] `OK`

# File lib/redis.rb, line 115
def bgrewriteaof
  synchronize do |client|
    client.call([:bgrewriteaof])
  end
end

Asynchronously save the dataset to disk.

@return [String] `OK`

# File lib/redis.rb, line 124
def bgsave
  synchronize do |client|
    client.call([:bgsave])
  end
end

Count the number of set bits in a range of the string value stored at key.

@param [String] key @param [Fixnum] start start index @param [Fixnum] stop stop index @return [Fixnum] the number of bits set to 1

# File lib/redis.rb, line 891
def bitcount(key, start = 0, stop = -1)
  synchronize do |client|
    client.call([:bitcount, key, start, stop])
  end
end

Perform a bitwise operation between strings and store the resulting string in a key.

@param [String] operation e.g. `and`, `or`, `xor`, `not` @param [String] destkey destination key @param [String, Array<String>] keys one or more source keys to perform `operation` @return [Fixnum] the length of the string stored in `destkey`

# File lib/redis.rb, line 903
def bitop(operation, destkey, *keys)
  synchronize do |client|
    client.call([:bitop, operation, destkey] + keys)
  end
end

Remove and get the first element in a list, or block until one is available.

@example With timeout

list, element = redis.blpop("list", :timeout => 5)
  # => nil on timeout
  # => ["list", "element"] on success

@example Without timeout

list, element = redis.blpop("list")
  # => ["list", "element"]

@example Blocking pop on multiple lists

list, element = redis.blpop(["list", "another_list"])
  # => ["list", "element"]

@param [String, Array<String>] keys one or more keys to perform the

blocking pop on

@param [Hash] options

- `:timeout => Fixnum`: timeout in seconds, defaults to no timeout

@return [nil, [String, String]]

- `nil` when the operation timed out
- tuple of the list that was popped from and element was popped otherwise

# File lib/redis.rb, line 1063
def blpop(*args)
  _bpop(:blpop, args)
end

Remove and get the last element in a list, or block until one is available.

@param [String, Array<String>] keys one or more keys to perform the

blocking pop on

@param [Hash] options

- `:timeout => Fixnum`: timeout in seconds, defaults to no timeout

@return [nil, [String, String]]

- `nil` when the operation timed out
- tuple of the list that was popped from and element was popped otherwise

@see blpop

# File lib/redis.rb, line 1079
def brpop(*args)
  _bpop(:brpop, args)
end

Pop a value from a list, push it to another list and return it; or block until one is available.

@param [String] source source key @param [String] destination destination key @param [Hash] options

- `:timeout => Fixnum`: timeout in seconds, defaults to no timeout

@return [nil, String]

- `nil` when the operation timed out
- the element was popped and pushed otherwise

# File lib/redis.rb, line 1094
def brpoplpush(source, destination, options = {})
  case options
  when Integer
    # Issue deprecation notice in obnoxious mode...
    options = { :timeout => options }
  end

  timeout = options[:timeout] || 0

  synchronize do |client|
    command = [:brpoplpush, source, destination, timeout]
    timeout += client.timeout if timeout > 0
    client.call_with_timeout(command, timeout)
  end
end

Get or set server configuration parameters.

@param [Symbol] action e.g. `:get`, `:set`, `:resetstat` @return [String, Hash] string reply, or hash when retrieving more than one

property with `CONFIG GET`

# File lib/redis.rb, line 135
def config(action, *args)
  synchronize do |client|
    client.call([:config, action] + args) do |reply|
      if reply.kind_of?(Array) && action == :get
        Hash[_pairify(reply)]
      else
        reply
      end
    end
  end
end

Test whether or not the client is connected

# File lib/redis.rb, line 53
def connected?
  @original_client.connected?
end

Return the number of keys in the selected database.

@return [Fixnum]

# File lib/redis.rb, line 150
def dbsize
  synchronize do |client|
    client.call([:dbsize])
  end
end

Decrement the integer value of a key by one.

@example

redis.decr("value")
  # => 4

@param [String] key @return [Fixnum] value after decrementing it

# File lib/redis.rb, line 582
def decr(key)
  synchronize do |client|
    client.call([:decr, key])
  end
end

Decrement the integer value of a key by the given number.

@example

redis.decrby("value", 5)
  # => 0

@param [String] key @param [Fixnum] decrement @return [Fixnum] value after decrementing it

# File lib/redis.rb, line 597
def decrby(key, decrement)
  synchronize do |client|
    client.call([:decrby, key, decrement])
  end
end

Delete one or more keys.

@param [String, Array<String>] keys @return [Fixnum] number of keys that were deleted

# File lib/redis.rb, line 414
def del(*keys)
  synchronize do |client|
    client.call([:del] + keys)
  end
end

Discard all commands issued after MULTI.

Only call this method when `multi` was called *without* a block.

@return `“OK”`

@see multi @see exec

# File lib/redis.rb, line 2126
def discard
  synchronize do |client|
    client.call([:discard])
  end
end

Return a serialized version of the value stored at a key.

@param [String] key @return [String] serialized_value

# File lib/redis.rb, line 372
def dump(key)
  synchronize do |client|
    client.call([:dump, key])
  end
end

Echo the given string.

@param [String] value @return [String]

# File lib/redis.rb, line 92
def echo(value)
  synchronize do |client|
    client.call([:echo, value])
  end
end

Evaluate Lua script.

@example EVAL without KEYS nor ARGV

redis.eval("return 1")
  # => 1

@example EVAL with KEYS and ARGV as array arguments

redis.eval("return { KEYS, ARGV }", ["k1", "k2"], ["a1", "a2"])
  # => [["k1", "k2"], ["a1", "a2"]]

@example EVAL with KEYS and ARGV in a hash argument

redis.eval("return { KEYS, ARGV }", :keys => ["k1", "k2"], :argv => ["a1", "a2"])
  # => [["k1", "k2"], ["a1", "a2"]]

@param [Array<String>] keys optional array with keys to pass to the script @param [Array<String>] argv optional array with arguments to pass to the script @param [Hash] options

- `:keys => Array<String>`: optional array with keys to pass to the script
- `:argv => Array<String>`: optional array with arguments to pass to the script

@return depends on the script

@see script @see evalsha

# File lib/redis.rb, line 2214
def eval(*args)
  _eval(:eval, args)
end

Evaluate Lua script by its SHA.

@example EVALSHA without KEYS nor ARGV

redis.evalsha(sha)
  # => <depends on script>

@example EVALSHA with KEYS and ARGV as array arguments

redis.evalsha(sha, ["k1", "k2"], ["a1", "a2"])
  # => <depends on script>

@example EVALSHA with KEYS and ARGV in a hash argument

redis.evalsha(sha, :keys => ["k1", "k2"], :argv => ["a1", "a2"])
  # => <depends on script>

@param [Array<String>] keys optional array with keys to pass to the script @param [Array<String>] argv optional array with arguments to pass to the script @param [Hash] options

- `:keys => Array<String>`: optional array with keys to pass to the script
- `:argv => Array<String>`: optional array with arguments to pass to the script

@return depends on the script

@see script @see eval

# File lib/redis.rb, line 2239
def evalsha(*args)
  _eval(:evalsha, args)
end

Execute all commands issued after MULTI.

Only call this method when `multi` was called *without* a block.

@return [nil, Array<…>]

- when commands were not executed, `nil`
- when commands were executed, an array with their replies

@see multi @see discard

# File lib/redis.rb, line 2112
def exec
  synchronize do |client|
    client.call([:exec])
  end
end

Determine if a key exists.

@param [String] key @return [Boolean]

# File lib/redis.rb, line 424
def exists(key)
  synchronize do |client|
    client.call([:exists, key], &_boolify)
  end
end

Set a key’s time to live in seconds.

@param [String] key @param [Fixnum] seconds time to live @return [Boolean] whether the timeout was set or not

# File lib/redis.rb, line 307
def expire(key, seconds)
  synchronize do |client|
    client.call([:expire, key, seconds], &_boolify)
  end
end

Set the expiration for a key as a UNIX timestamp.

@param [String] key @param [Fixnum] unix_time expiry time specified as a UNIX timestamp @return [Boolean] whether the timeout was set or not

# File lib/redis.rb, line 318
def expireat(key, unix_time)
  synchronize do |client|
    client.call([:expireat, key, unix_time], &_boolify)
  end
end

Remove all keys from all databases.

@return [String] `OK`

# File lib/redis.rb, line 165
def flushall
  synchronize do |client|
    client.call([:flushall])
  end
end

Remove all keys from the current database.

@return [String] `OK`

# File lib/redis.rb, line 174
def flushdb
  synchronize do |client|
    client.call([:flushdb])
  end
end

Get the value of a key.

@param [String] key @return [String]

# File lib/redis.rb, line 782
def get(key)
  synchronize do |client|
    client.call([:get, key])
  end
end

Returns the bit value at offset in the string value stored at key.

@param [String] key @param [Fixnum] offset bit offset @return [Fixnum] `0` or `1`

# File lib/redis.rb, line 868
def getbit(key, offset)
  synchronize do |client|
    client.call([:getbit, key, offset])
  end
end

Get a substring of the string stored at a key.

@param [String] key @param [Fixnum] start zero-based start offset @param [Fixnum] stop zero-based end offset. Use -1 for representing

the end of the string

@return [Fixnum] `0` or `1`

# File lib/redis.rb, line 845
def getrange(key, start, stop)
  synchronize do |client|
    client.call([:getrange, key, start, stop])
  end
end

Set the string value of a key and return its old value.

@param [String] key @param [String] value value to replace the current value with @return [String] the old value stored in the key, or `nil` if the key

did not exist

# File lib/redis.rb, line 915
def getset(key, value)
  synchronize do |client|
    client.call([:getset, key, value.to_s])
  end
end

Delete one or more hash fields.

@param [String] key @param [String, Array<String>] field @return [Fixnum] the number of fields that were removed from the hash

# File lib/redis.rb, line 1868
def hdel(key, field)
  synchronize do |client|
    client.call([:hdel, key, field])
  end
end

Determine if a hash field exists.

@param [String] key @param [String] field @return [Boolean] whether or not the field exists in the hash

# File lib/redis.rb, line 1879
def hexists(key, field)
  synchronize do |client|
    client.call([:hexists, key, field], &_boolify)
  end
end

Get the value of a hash field.

@param [String] key @param [String] field @return [String]

# File lib/redis.rb, line 1819
def hget(key, field)
  synchronize do |client|
    client.call([:hget, key, field])
  end
end

Get all the fields and values in a hash.

@param [String] key @return [Hash<String, String>]

# File lib/redis.rb, line 1933
def hgetall(key)
  synchronize do |client|
    client.call([:hgetall, key], &_hashify)
  end
end

Increment the integer value of a hash field by the given integer number.

@param [String] key @param [String] field @param [Fixnum] increment @return [Fixnum] value of the field after incrementing it

# File lib/redis.rb, line 1891
def hincrby(key, field, increment)
  synchronize do |client|
    client.call([:hincrby, key, field, increment])
  end
end

Increment the numeric value of a hash field by the given float number.

@param [String] key @param [String] field @param [Float] increment @return [Float] value of the field after incrementing it

# File lib/redis.rb, line 1903
def hincrbyfloat(key, field, increment)
  synchronize do |client|
    client.call([:hincrbyfloat, key, field, increment], &_floatify)
  end
end

Get all the fields in a hash.

@param [String] key @return [Array<String>]

# File lib/redis.rb, line 1913
def hkeys(key)
  synchronize do |client|
    client.call([:hkeys, key])
  end
end

Get the number of fields in a hash.

@param [String] key @return [Fixnum] number of fields in the hash

# File lib/redis.rb, line 1752
def hlen(key)
  synchronize do |client|
    client.call([:hlen, key])
  end
end

Get the values of all the given hash fields.

@example

redis.hmget("hash", "f1", "f2")
  # => ["v1", "v2"]

@param [String] key @param [Array<String>] fields array of fields @return [Array<String>] an array of values for the specified fields

@see mapped_hmget

# File lib/redis.rb, line 1836
def hmget(key, *fields, &blk)
  synchronize do |client|
    client.call([:hmget, key] + fields, &blk)
  end
end

Set one or more hash values.

@example

redis.hmset("hash", "f1", "v1", "f2", "v2")
  # => "OK"

@param [String] key @param [Array<String>] attrs array of fields and values @return `“OK”`

@see mapped_hmset

# File lib/redis.rb, line 1793
def hmset(key, *attrs)
  synchronize do |client|
    client.call([:hmset, key] + attrs)
  end
end

Scan a hash

@example Retrieve the first batch of key/value pairs in a hash

redis.hscan("hash", 0)

@param [String, Integer] cursor: the cursor of the iteration @param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [String, Array<[String, String]>] the next cursor and all found keys

# File lib/redis.rb, line 2316
def hscan(key, cursor, options={})
  _scan(:hscan, cursor, [key], options) do |reply|
    [reply[0], _pairify(reply[1])]
  end
end

Scan a hash

@example Retrieve all of the key/value pairs in a hash

redis.hscan_each("hash").to_a
# => [["key70", "70"], ["key80", "80"]]

@param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [Enumerator] an enumerator for all found keys

# File lib/redis.rb, line 2333
def hscan_each(key, options={}, &block)
  return to_enum(:hscan_each, key, options) unless block_given?
  cursor = 0
  loop do
    cursor, values = hscan(key, cursor, options)
    values.each(&block)
    break if cursor == "0"
  end
end

Set the string value of a hash field.

@param [String] key @param [String] field @param [String] value @return [Boolean] whether or not the field was *added* to the hash

# File lib/redis.rb, line 1764
def hset(key, field, value)
  synchronize do |client|
    client.call([:hset, key, field, value], &_boolify)
  end
end

Set the value of a hash field, only if the field does not exist.

@param [String] key @param [String] field @param [String] value @return [Boolean] whether or not the field was *added* to the hash

# File lib/redis.rb, line 1776
def hsetnx(key, field, value)
  synchronize do |client|
    client.call([:hsetnx, key, field, value], &_boolify)
  end
end

Get all the values in a hash.

@param [String] key @return [Array<String>]

# File lib/redis.rb, line 1923
def hvals(key)
  synchronize do |client|
    client.call([:hvals, key])
  end
end

Increment the integer value of a key by one.

@example

redis.incr("value")
  # => 6

@param [String] key @return [Fixnum] value after incrementing it

# File lib/redis.rb, line 611
def incr(key)
  synchronize do |client|
    client.call([:incr, key])
  end
end

Increment the integer value of a key by the given integer number.

@example

redis.incrby("value", 5)
  # => 10

@param [String] key @param [Fixnum] increment @return [Fixnum] value after incrementing it

# File lib/redis.rb, line 626
def incrby(key, increment)
  synchronize do |client|
    client.call([:incrby, key, increment])
  end
end

Increment the numeric value of a key by the given float number.

@example

redis.incrbyfloat("value", 1.23)
  # => 1.23

@param [String] key @param [Float] increment @return [Float] value after incrementing it

# File lib/redis.rb, line 641
def incrbyfloat(key, increment)
  synchronize do |client|
    client.call([:incrbyfloat, key, increment], &_floatify)
  end
end

Get information and statistics about the server.

@param [String, Symbol] cmd e.g. “commandstats” @return [Hash<String, String>]

# File lib/redis.rb, line 184
def info(cmd = nil)
  synchronize do |client|
    client.call([:info, cmd].compact) do |reply|
      if reply.kind_of?(String)
        reply = Hash[reply.split("\r\n").map do |line|
          line.split(":", 2) unless line =~ /^(#|$)/
        end.compact]

        if cmd && cmd.to_s == "commandstats"
          # Extract nested hashes for INFO COMMANDSTATS
          reply = Hash[reply.map do |k, v|
            v = v.split(",").map { |e| e.split("=") }
            [k[/^cmdstat_(.*)$/, 1], Hash[v]]
          end]
        end
      end

      reply
    end
  end
end

Find all keys matching the given pattern.

@param [String] pattern @return [Array<String>]

# File lib/redis.rb, line 434
def keys(pattern = "*")
  synchronize do |client|
    client.call([:keys, pattern]) do |reply|
      if reply.kind_of?(String)
        reply.split(" ")
      else
        reply
      end
    end
  end
end

Get the UNIX time stamp of the last successful save to disk.

@return [Fixnum]

# File lib/redis.rb, line 209
def lastsave
  synchronize do |client|
    client.call([:lastsave])
  end
end

Get an element from a list by its index.

@param [String] key @param [Fixnum] index @return [String]

# File lib/redis.rb, line 1115
def lindex(key, index)
  synchronize do |client|
    client.call([:lindex, key, index])
  end
end

Insert an element before or after another element in a list.

@param [String] key @param [String, Symbol] where `BEFORE` or `AFTER` @param [String] pivot reference element @param [String] value @return [Fixnum] length of the list after the insert operation, or `-1`

when the element `pivot` was not found

# File lib/redis.rb, line 1129
def linsert(key, where, pivot, value)
  synchronize do |client|
    client.call([:linsert, key, where, pivot, value])
  end
end

Get the length of a list.

@param [String] key @return [Fixnum]

# File lib/redis.rb, line 936
def llen(key)
  synchronize do |client|
    client.call([:llen, key])
  end
end

Remove and get the first element in a list.

@param [String] key @return [String]

# File lib/redis.rb, line 990
def lpop(key)
  synchronize do |client|
    client.call([:lpop, key])
  end
end

Prepend one or more values to a list, creating the list if it doesn’t exist

@param [String] key @param [String, Array] string value, or array of string values to push @return [Fixnum] the length of the list after the push operation

# File lib/redis.rb, line 947
def lpush(key, value)
  synchronize do |client|
    client.call([:lpush, key, value])
  end
end

Prepend a value to a list, only if the list exists.

@param [String] key @param [String] value @return [Fixnum] the length of the list after the push operation

# File lib/redis.rb, line 958
def lpushx(key, value)
  synchronize do |client|
    client.call([:lpushx, key, value])
  end
end

Get a range of elements from a list.

@param [String] key @param [Fixnum] start start index @param [Fixnum] stop stop index @return [Array<String>]

# File lib/redis.rb, line 1141
def lrange(key, start, stop)
  synchronize do |client|
    client.call([:lrange, key, start, stop])
  end
end

Remove elements from a list.

@param [String] key @param [Fixnum] count number of elements to remove. Use a positive

value to remove the first `count` occurrences of `value`. A negative
value to remove the last `count` occurrences of `value`. Or zero, to
remove all occurrences of `value` from the list.

@param [String] value @return [Fixnum] the number of removed elements

# File lib/redis.rb, line 1156
def lrem(key, count, value)
  synchronize do |client|
    client.call([:lrem, key, count, value])
  end
end

Set the value of an element in a list by its index.

@param [String] key @param [Fixnum] index @param [String] value @return [String] `OK`

# File lib/redis.rb, line 1168
def lset(key, index, value)
  synchronize do |client|
    client.call([:lset, key, index, value])
  end
end

Trim a list to the specified range.

@param [String] key @param [Fixnum] start start index @param [Fixnum] stop stop index @return [String] `OK`

# File lib/redis.rb, line 1180
def ltrim(key, start, stop)
  synchronize do |client|
    client.call([:ltrim, key, start, stop])
  end
end

Get the values of all the given hash fields.

@example

redis.hmget("hash", "f1", "f2")
  # => { "f1" => "v1", "f2" => "v2" }

@param [String] key @param [Array<String>] fields array of fields @return [Hash] a hash mapping the specified fields to their values

@see hmget

# File lib/redis.rb, line 1853
def mapped_hmget(key, *fields)
  hmget(key, *fields) do |reply|
    if reply.kind_of?(Array)
      Hash[fields.zip(reply)]
    else
      reply
    end
  end
end

Set one or more hash values.

@example

redis.mapped_hmset("hash", { "f1" => "v1", "f2" => "v2" })
  # => "OK"

@param [String] key @param [Hash] hash fields mapping to values @return `“OK”`

@see hmset

# File lib/redis.rb, line 1810
def mapped_hmset(key, hash)
  hmset(key, hash.to_a.flatten)
end

Get the values of all the given keys.

@example

redis.mapped_mget("key1", "key1")
  # => { "key1" => "v1", "key2" => "v2" }

@param [Array<String>] keys array of keys @return [Hash] a hash mapping the specified keys to their values

@see mget

# File lib/redis.rb, line 816
def mapped_mget(*keys)
  mget(*keys) do |reply|
    if reply.kind_of?(Array)
      Hash[keys.zip(reply)]
    else
      reply
    end
  end
end

Set one or more values.

@example

redis.mapped_mset({ "f1" => "v1", "f2" => "v2" })
  # => "OK"

@param [Hash] hash keys mapping to values @return `“OK”`

@see mset

# File lib/redis.rb, line 744
def mapped_mset(hash)
  mset(hash.to_a.flatten)
end

Set one or more values, only if none of the keys exist.

@example

redis.msetnx({ "key1" => "v1", "key2" => "v2" })
  # => true

@param [Hash] hash keys mapping to values @return [Boolean] whether or not all values were set

@see msetnx

# File lib/redis.rb, line 774
def mapped_msetnx(hash)
  msetnx(hash.to_a.flatten)
end

Get the values of all the given keys.

@example

redis.mget("key1", "key1")
  # => ["v1", "v2"]

@param [Array<String>] keys @return [Array<String>] an array of values for the specified keys

@see mapped_mget

# File lib/redis.rb, line 800
def mget(*keys, &blk)
  synchronize do |client|
    client.call([:mget] + keys, &blk)
  end
end

Transfer a key from the connected instance to another instance.

@param [String] key @param [Hash] options

- `:host => String`: host of instance to migrate to
- `:port => Integer`: port of instance to migrate to
- `:db => Integer`: database to migrate to (default: same as source)
- `:timeout => Integer`: timeout (default: same as connection timeout)

@return [String] `“OK”`

# File lib/redis.rb, line 399
def migrate(key, options)
  host = options[:host] || raise(RuntimeError, ":host not specified")
  port = options[:port] || raise(RuntimeError, ":port not specified")
  db = (options[:db] || client.db).to_i
  timeout = (options[:timeout] || client.timeout).to_i

  synchronize do |client|
    client.call([:migrate, host, port, key, db, timeout])
  end
end

Listen for all requests received by the server in real time.

There is no way to interrupt this command.

@yield a block to be called for every line of output @yieldparam [String] line timestamp and command that was executed

# File lib/redis.rb, line 221
def monitor(&block)
  synchronize do |client|
    client.call_loop([:monitor], &block)
  end
end

Move a key to another database.

@example Move a key to another database

redis.set "foo", "bar"
  # => "OK"
redis.move "foo", 2
  # => true
redis.exists "foo"
  # => false
redis.select 2
  # => "OK"
redis.exists "foo"
  # => true
redis.get "foo"
  # => "bar"

@param [String] key @param [Fixnum] db @return [Boolean] whether the key was moved or not

# File lib/redis.rb, line 465
def move(key, db)
  synchronize do |client|
    client.call([:move, key, db], &_boolify)
  end
end

Set one or more values.

@example

redis.mset("key1", "v1", "key2", "v2")
  # => "OK"

@param [Array<String>] args array of keys and values @return `“OK”`

@see mapped_mset

# File lib/redis.rb, line 728
def mset(*args)
  synchronize do |client|
    client.call([:mset] + args)
  end
end

Set one or more values, only if none of the keys exist.

@example

redis.msetnx("key1", "v1", "key2", "v2")
  # => true

@param [Array<String>] args array of keys and values @return [Boolean] whether or not all values were set

@see mapped_msetnx

# File lib/redis.rb, line 758
def msetnx(*args)
  synchronize do |client|
    client.call([:msetnx] + args, &_boolify)
  end
end

Mark the start of a transaction block.

Passing a block is optional.

@example With a block

redis.multi do |multi|
  multi.set("key", "value")
  multi.incr("counter")
end # => ["OK", 6]

@example Without a block

redis.multi
  # => "OK"
redis.set("key", "value")
  # => "QUEUED"
redis.incr("counter")
  # => "QUEUED"
redis.exec
  # => ["OK", 6]

@yield [multi] the commands that are called inside this block are cached

and written to the server upon returning from it

@yieldparam [Redis] multi `self`

@return [String, Array<…>]

- when a block is not given, `OK`
- when a block is given, an array with replies

@see watch @see unwatch

# File lib/redis.rb, line 2085
def multi
  synchronize do |client|
    if !block_given?
      client.call([:multi])
    else
      begin
        pipeline = Pipeline::Multi.new
        original, @client = @client, pipeline
        yield(self)
        original.call_pipeline(pipeline)
      ensure
        @client = original
      end
    end
  end
end

Remove the expiration from a key.

@param [String] key @return [Boolean] whether the timeout was removed or not

# File lib/redis.rb, line 296
def persist(key)
  synchronize do |client|
    client.call([:persist, key], &_boolify)
  end
end

Set a key’s time to live in milliseconds.

@param [String] key @param [Fixnum] milliseconds time to live @return [Boolean] whether the timeout was set or not

# File lib/redis.rb, line 340
def pexpire(key, milliseconds)
  synchronize do |client|
    client.call([:pexpire, key, milliseconds], &_boolify)
  end
end

Set the expiration for a key as number of milliseconds from UNIX Epoch.

@param [String] key @param [Fixnum] ms_unix_time expiry time specified as number of milliseconds from UNIX Epoch. @return [Boolean] whether the timeout was set or not

# File lib/redis.rb, line 351
def pexpireat(key, ms_unix_time)
  synchronize do |client|
    client.call([:pexpireat, key, ms_unix_time], &_boolify)
  end
end

Ping the server.

@return [String] `PONG`

# File lib/redis.rb, line 82
def ping
  synchronize do |client|
    client.call([:ping])
  end
end

Set the time to live in milliseconds of a key.

@param [String] key @param [Fixnum] ttl @param [String] value @return `“OK”`

# File lib/redis.rb, line 701
def psetex(key, ttl, value)
  synchronize do |client|
    client.call([:psetex, key, ttl, value.to_s])
  end
end

Listen for messages published to channels matching the given patterns.

# File lib/redis.rb, line 1968
def psubscribe(*channels, &block)
  synchronize do |client|
    _subscription(:psubscribe, channels, block)
  end
end

Get the time to live (in milliseconds) for a key.

@param [String] key @return [Fixnum] remaining time to live in milliseconds, or -1 if the

key does not exist or does not have a timeout

# File lib/redis.rb, line 362
def pttl(key)
  synchronize do |client|
    client.call([:pttl, key])
  end
end

Post a message to a channel.

# File lib/redis.rb, line 1940
def publish(channel, message)
  synchronize do |client|
    client.call([:publish, channel, message])
  end
end

Stop listening for messages posted to channels matching the given patterns.

# File lib/redis.rb, line 1975
def punsubscribe(*channels)
  synchronize do |client|
    raise RuntimeError, "Can't unsubscribe if not subscribed." unless subscribed?
    client.punsubscribe(*channels)
  end
end

Close the connection.

@return [String] `OK`

# File lib/redis.rb, line 101
def quit
  synchronize do |client|
    begin
      client.call([:quit])
    rescue ConnectionError
    ensure
      client.disconnect
    end
  end
end

Return a random key from the keyspace.

@return [String]

# File lib/redis.rb, line 480
def randomkey
  synchronize do |client|
    client.call([:randomkey])
  end
end

Rename a key. If the new key already exists it is overwritten.

@param [String] old_name @param [String] new_name @return [String] `OK`

# File lib/redis.rb, line 491
def rename(old_name, new_name)
  synchronize do |client|
    client.call([:rename, old_name, new_name])
  end
end

Rename a key, only if the new key does not exist.

@param [String] old_name @param [String] new_name @return [Boolean] whether the key was renamed or not

# File lib/redis.rb, line 502
def renamenx(old_name, new_name)
  synchronize do |client|
    client.call([:renamenx, old_name, new_name], &_boolify)
  end
end

Create a key using the serialized value, previously obtained using DUMP.

@param [String] key @param [String] ttl @param [String] serialized_value @return `“OK”`

# File lib/redis.rb, line 384
def restore(key, ttl, serialized_value)
  synchronize do |client|
    client.call([:restore, key, ttl, serialized_value])
  end
end

Remove and get the last element in a list.

@param [String] key @return [String]

# File lib/redis.rb, line 1000
def rpop(key)
  synchronize do |client|
    client.call([:rpop, key])
  end
end

Remove the last element in a list, append it to another list and return it.

@param [String] source source key @param [String] destination destination key @return [nil, String] the element, or nil when the source key does not exist

# File lib/redis.rb, line 1011
def rpoplpush(source, destination)
  synchronize do |client|
    client.call([:rpoplpush, source, destination])
  end
end

Append one or more values to a list, creating the list if it doesn’t exist

@param [String] key @param [String] value @return [Fixnum] the length of the list after the push operation

# File lib/redis.rb, line 969
def rpush(key, value)
  synchronize do |client|
    client.call([:rpush, key, value])
  end
end

Append a value to a list, only if the list exists.

@param [String] key @param [String] value @return [Fixnum] the length of the list after the push operation

# File lib/redis.rb, line 980
def rpushx(key, value)
  synchronize do |client|
    client.call([:rpushx, key, value])
  end
end

Add one or more members to a set.

@param [String] key @param [String, Array<String>] member one member, or array of members @return [Boolean, Fixnum] `Boolean` when a single member is specified,

holding whether or not adding the member succeeded, or `Fixnum` when an
array of members is specified, holding the number of members that were
successfully added

# File lib/redis.rb, line 1204
def sadd(key, member)
  synchronize do |client|
    client.call([:sadd, key, member]) do |reply|
      if member.is_a? Array
        # Variadic: return integer
        reply
      else
        # Single argument: return boolean
        _boolify.call(reply)
      end
    end
  end
end

Synchronously save the dataset to disk.

@return [String]

# File lib/redis.rb, line 230
def save
  synchronize do |client|
    client.call([:save])
  end
end

Scan the keyspace

@example Retrieve the first batch of keys

redis.scan(0)
  # => ["4", ["key:21", "key:47", "key:42"]]

@example Retrieve a batch of keys matching a pattern

redis.scan(4, :match => "key:1?")
  # => ["92", ["key:13", "key:18"]]

@param [String, Integer] cursor: the cursor of the iteration @param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [String, Array<String>] the next cursor and all found keys

# File lib/redis.rb, line 2276
def scan(cursor, options={})
  _scan(:scan, cursor, [], options)
end

Scan the keyspace

@example Retrieve all of the keys (with possible duplicates)

redis.scan_each.to_a
  # => ["key:21", "key:47", "key:42"]

@example Execute block for each key matching a pattern

redis.scan_each(:match => "key:1?") {|key| puts key}
  # => key:13
  # => key:18

@param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [Enumerator] an enumerator for all found keys

# File lib/redis.rb, line 2295
def scan_each(options={}, &block)
  return to_enum(:scan_each, options) unless block_given?
  cursor = 0
  loop do
    cursor, keys = scan(cursor, options)
    keys.each(&block)
    break if cursor == "0"
  end
end

Get the number of members in a set.

@param [String] key @return [Fixnum]

# File lib/redis.rb, line 1190
def scard(key)
  synchronize do |client|
    client.call([:scard, key])
  end
end

Control remote script registry.

@example Load a script

sha = redis.script(:load, "return 1")
  # => <sha of this script>

@example Check if a script exists

redis.script(:exists, sha)
  # => true

@example Check if multiple scripts exist

redis.script(:exists, [sha, other_sha])
  # => [true, false]

@example Flush the script registry

redis.script(:flush)
  # => "OK"

@example Kill a running script

redis.script(:kill)
  # => "OK"

@param [String] subcommand e.g. `exists`, `flush`, `load`, `kill` @param [Array<String>] args depends on subcommand @return [String, Boolean, Array<Boolean>, …] depends on subcommand

@see eval @see evalsha

# File lib/redis.rb, line 2156
def script(subcommand, *args)
  subcommand = subcommand.to_s.downcase

  if subcommand == "exists"
    synchronize do |client|
      arg = args.first

      client.call([:script, :exists, arg]) do |reply|
        reply = reply.map { |r| _boolify.call(r) }

        if arg.is_a?(Array)
          reply
        else
          reply.first
        end
      end
    end
  else
    synchronize do |client|
      client.call([:script, subcommand] + args)
    end
  end
end

Subtract multiple sets.

@param [String, Array<String>] keys keys pointing to sets to subtract @return [Array<String>] members in the difference

# File lib/redis.rb, line 1302
def sdiff(*keys)
  synchronize do |client|
    client.call([:sdiff] + keys)
  end
end

Subtract multiple sets and store the resulting set in a key.

@param [String] destination destination key @param [String, Array<String>] keys keys pointing to sets to subtract @return [Fixnum] number of elements in the resulting set

# File lib/redis.rb, line 1313
def sdiffstore(destination, *keys)
  synchronize do |client|
    client.call([:sdiffstore, destination] + keys)
  end
end

Change the selected database for the current connection.

@param [Fixnum] db zero-based index of the DB to use (0 to 15) @return [String] `OK`

# File lib/redis.rb, line 72
def select(db)
  synchronize do |client|
    client.db = db
    client.call([:select, db])
  end
end

Set the string value of a key.

@param [String] key @param [String] value @param [Hash] options

- `:ex => Fixnum`: Set the specified expire time, in seconds.
- `:px => Fixnum`: Set the specified expire time, in milliseconds.
- `:nx => true`: Only set the key if it does not already exist.
- `:xx => true`: Only set the key if it already exist.

@return [String, Boolean] `“OK”` or true, false if `:nx => true` or `:xx => true`

# File lib/redis.rb, line 657
def set(key, value, options = {})
  args = []

  ex = options[:ex]
  args.concat(["EX", ex]) if ex

  px = options[:px]
  args.concat(["PX", px]) if px

  nx = options[:nx]
  args.concat(["NX"]) if nx

  xx = options[:xx]
  args.concat(["XX"]) if xx

  synchronize do |client|
    if nx || xx
      client.call([:set, key, value.to_s] + args, &_boolify_set)
    else
      client.call([:set, key, value.to_s] + args)
    end
  end
end

Sets or clears the bit at offset in the string value stored at key.

@param [String] key @param [Fixnum] offset bit offset @param [Fixnum] value bit value `0` or `1` @return [Fixnum] the original bit value stored at `offset`

# File lib/redis.rb, line 857
def setbit(key, offset, value)
  synchronize do |client|
    client.call([:setbit, key, offset, value])
  end
end

Set the time to live in seconds of a key.

@param [String] key @param [Fixnum] ttl @param [String] value @return `“OK”`

# File lib/redis.rb, line 689
def setex(key, ttl, value)
  synchronize do |client|
    client.call([:setex, key, ttl, value.to_s])
  end
end

Set the value of a key, only if the key does not exist.

@param [String] key @param [String] value @return [Boolean] whether the key was set or not

# File lib/redis.rb, line 712
def setnx(key, value)
  synchronize do |client|
    client.call([:setnx, key, value.to_s], &_boolify)
  end
end

Overwrite part of a string at key starting at the specified offset.

@param [String] key @param [Fixnum] offset byte offset @param [String] value @return [Fixnum] length of the string after it was modified

# File lib/redis.rb, line 832
def setrange(key, offset, value)
  synchronize do |client|
    client.call([:setrange, key, offset, value.to_s])
  end
end

Synchronously save the dataset to disk and then shut down the server.

# File lib/redis.rb, line 237
def shutdown
  synchronize do |client|
    client.with_reconnect(false) do
      begin
        client.call([:shutdown])
      rescue ConnectionError
        # This means Redis has probably exited.
        nil
      end
    end
  end
end

Intersect multiple sets.

@param [String, Array<String>] keys keys pointing to sets to intersect @return [Array<String>] members in the intersection

# File lib/redis.rb, line 1323
def sinter(*keys)
  synchronize do |client|
    client.call([:sinter] + keys)
  end
end

Intersect multiple sets and store the resulting set in a key.

@param [String] destination destination key @param [String, Array<String>] keys keys pointing to sets to intersect @return [Fixnum] number of elements in the resulting set

# File lib/redis.rb, line 1334
def sinterstore(destination, *keys)
  synchronize do |client|
    client.call([:sinterstore, destination] + keys)
  end
end

Determine if a given value is a member of a set.

@param [String] key @param [String] member @return [Boolean]

# File lib/redis.rb, line 1282
def sismember(key, member)
  synchronize do |client|
    client.call([:sismember, key, member], &_boolify)
  end
end

Make the server a slave of another instance, or promote it as master.

# File lib/redis.rb, line 251
def slaveof(host, port)
  synchronize do |client|
    client.call([:slaveof, host, port])
  end
end

Interact with the slowlog (get, len, reset)

@param [String] subcommand e.g. `get`, `len`, `reset` @param [Fixnum] length maximum number of entries to return @return [Array<String>, Fixnum, String] depends on subcommand

# File lib/redis.rb, line 262
def slowlog(subcommand, length=nil)
  synchronize do |client|
    args = [:slowlog, subcommand]
    args << length if length
    client.call args
  end
end

Get all the members in a set.

@param [String] key @return [Array<String>]

# File lib/redis.rb, line 1292
def smembers(key)
  synchronize do |client|
    client.call([:smembers, key])
  end
end

Move a member from one set to another.

@param [String] source source key @param [String] destination destination key @param [String] member member to move from `source` to `destination` @return [Boolean]

# File lib/redis.rb, line 1271
def smove(source, destination, member)
  synchronize do |client|
    client.call([:smove, source, destination, member], &_boolify)
  end
end

Sort the elements in a list, set or sorted set.

@example Retrieve the first 2 elements from an alphabetically sorted “list”

redis.sort("list", :order => "alpha", :limit => [0, 2])
  # => ["a", "b"]

@example Store an alphabetically descending list in “target”

redis.sort("list", :order => "desc alpha", :store => "target")
  # => 26

@param [String] key @param [Hash] options

- `:by => String`: use external key to sort elements by
- `:limit => [offset, count]`: skip `offset` elements, return a maximum
of `count` elements
- `:get => [String, Array<String>]`: single key or array of keys to
retrieve per element in the result
- `:order => String`: combination of `ASC`, `DESC` and optionally `ALPHA`
- `:store => String`: key to store the result at

@return [Array<String>, Array<Array<String>>, Fixnum]

- when `:get` is not specified, or holds a single element, an array of elements
- when `:get` is specified, and holds more than one element, an array of
elements where every element is an array with the result for every
element specified in `:get`
- when `:store` is specified, the number of elements in the stored result

# File lib/redis.rb, line 533
def sort(key, options = {})
  args = []

  by = options[:by]
  args.concat(["BY", by]) if by

  limit = options[:limit]
  args.concat(["LIMIT"] + limit) if limit

  get = Array(options[:get])
  args.concat(["GET"].product(get).flatten) unless get.empty?

  order = options[:order]
  args.concat(order.split(" ")) if order

  store = options[:store]
  args.concat(["STORE", store]) if store

  synchronize do |client|
    client.call([:sort, key] + args) do |reply|
      if get.size > 1 && !store
        if reply
          reply.each_slice(get.size).to_a
        end
      else
        reply
      end
    end
  end
end

Remove and return a random member from a set.

@param [String] key @return [String]

# File lib/redis.rb, line 1244
def spop(key)
  synchronize do |client|
    client.call([:spop, key])
  end
end

Get one or more random members from a set.

@param [String] key @param [Fixnum] count @return [String]

# File lib/redis.rb, line 1255
def srandmember(key, count = nil)
  synchronize do |client|
    if count.nil?
      client.call([:srandmember, key])
    else
      client.call([:srandmember, key, count])
    end
  end
end

Remove one or more members from a set.

@param [String] key @param [String, Array<String>] member one member, or array of members @return [Boolean, Fixnum] `Boolean` when a single member is specified,

holding whether or not removing the member succeeded, or `Fixnum` when an
array of members is specified, holding the number of members that were
successfully removed

# File lib/redis.rb, line 1226
def srem(key, member)
  synchronize do |client|
    client.call([:srem, key, member]) do |reply|
      if member.is_a? Array
        # Variadic: return integer
        reply
      else
        # Single argument: return boolean
        _boolify.call(reply)
      end
    end
  end
end

Scan a set

@example Retrieve the first batch of keys in a set

redis.sscan("set", 0)

@param [String, Integer] cursor: the cursor of the iteration @param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [String, Array<String>] the next cursor and all found members

# File lib/redis.rb, line 2393
def sscan(key, cursor, options={})
  _scan(:sscan, cursor, [key], options)
end

Scan a set

@example Retrieve all of the keys in a set

redis.sscan("set").to_a
# => ["key1", "key2", "key3"]

@param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [Enumerator] an enumerator for all keys in the set

# File lib/redis.rb, line 2408
def sscan_each(key, options={}, &block)
  return to_enum(:sscan_each, key, options) unless block_given?
  cursor = 0
  loop do
    cursor, keys = sscan(key, cursor, options)
    keys.each(&block)
    break if cursor == "0"
  end
end

Get the length of the value stored in a key.

@param [String] key @return [Fixnum] the length of the value stored in the key, or 0

if the key does not exist

# File lib/redis.rb, line 926
def strlen(key)
  synchronize do |client|
    client.call([:strlen, key])
  end
end

Listen for messages published to the given channels.

# File lib/redis.rb, line 1953
def subscribe(*channels, &block)
  synchronize do |client|
    _subscription(:subscribe, channels, block)
  end
end

Add multiple sets.

@param [String, Array<String>] keys keys pointing to sets to unify @return [Array<String>] members in the union

# File lib/redis.rb, line 1344
def sunion(*keys)
  synchronize do |client|
    client.call([:sunion] + keys)
  end
end

Add multiple sets and store the resulting set in a key.

@param [String] destination destination key @param [String, Array<String>] keys keys pointing to sets to unify @return [Fixnum] number of elements in the resulting set

# File lib/redis.rb, line 1355
def sunionstore(destination, *keys)
  synchronize do |client|
    client.call([:sunionstore, destination] + keys)
  end
end

Internal command used for replication.

# File lib/redis.rb, line 271
def sync
  synchronize do |client|
    client.call([:sync])
  end
end

Return the server time.

@example

r.time # => [ 1333093196, 606806 ]

@return [Array<Fixnum>] tuple of seconds since UNIX epoch and

microseconds in the current second

# File lib/redis.rb, line 284
def time
  synchronize do |client|
    client.call([:time]) do |reply|
      reply.map(&:to_i) if reply
    end
  end
end

Get the time to live (in seconds) for a key.

@param [String] key @return [Fixnum] remaining time to live in seconds, or -1 if the

key does not exist or does not have a timeout

# File lib/redis.rb, line 329
def ttl(key)
  synchronize do |client|
    client.call([:ttl, key])
  end
end

Determine the type stored at key.

@param [String] key @return [String] `string`, `list`, `set`, `zset`, `hash` or `none`

# File lib/redis.rb, line 568
def type(key)
  synchronize do |client|
    client.call([:type, key])
  end
end

Stop listening for messages posted to the given channels.

# File lib/redis.rb, line 1960
def unsubscribe(*channels)
  synchronize do |client|
    raise RuntimeError, "Can't unsubscribe if not subscribed." unless subscribed?
    client.unsubscribe(*channels)
  end
end

Forget about all watched keys.

@return [String] `OK`

@see watch @see multi

# File lib/redis.rb, line 2037
def unwatch
  synchronize do |client|
    client.call([:unwatch])
  end
end

Watch the given keys to determine execution of the MULTI/EXEC block.

Using a block is optional, but is necessary for thread-safety.

An `unwatch` is automatically issued if an exception is raised within the block that is a subclass of StandardError and is not a ConnectionError.

@example With a block

redis.watch("key") do
  if redis.get("key") == "some value"
    redis.multi do |multi|
      multi.set("key", "other value")
      multi.incr("counter")
    end
  else
    redis.unwatch
  end
end
  # => ["OK", 6]

@example Without a block

redis.watch("key")
  # => "OK"

@param [String, Array<String>] keys one or more keys to watch @return [Object] if using a block, returns the return value of the block @return [String] if not using a block, returns `OK`

@see unwatch @see multi

# File lib/redis.rb, line 2012
def watch(*keys)
  synchronize do |client|
    res = client.call([:watch] + keys)

    if block_given?
      begin
        yield(self)
      rescue ConnectionError
        raise
      rescue StandardError
        unwatch
        raise
      end
    else
      res
    end
  end
end

Run code with the client reconnecting

# File lib/redis.rb, line 41
def with_reconnect(val=true, &blk)
  synchronize do |client|
    client.with_reconnect(val, &blk)
  end
end

Run code without the client reconnecting

# File lib/redis.rb, line 48
def without_reconnect(&blk)
  with_reconnect(false, &blk)
end

Add one or more members to a sorted set, or update the score for members that already exist.

@example Add a single `[score, member]` pair to a sorted set

redis.zadd("zset", 32.0, "member")

@example Add an array of `[score, member]` pairs to a sorted set

redis.zadd("zset", [[32.0, "a"], [64.0, "b"]])

@param [String] key @param [[Float, String], Array<[Float, String]>] args

- a single `[score, member]` pair
- an array of `[score, member]` pairs

@return [Boolean, Fixnum]

- `Boolean` when a single pair is specified, holding whether or not it was
**added** to the sorted set
- `Fixnum` when an array of pairs is specified, holding the number of
pairs that were **added** to the sorted set

# File lib/redis.rb, line 1393
def zadd(key, *args)
  synchronize do |client|
    if args.size == 1 && args[0].is_a?(Array)
      # Variadic: return integer
      client.call([:zadd, key] + args[0])
    elsif args.size == 2
      # Single pair: return boolean
      client.call([:zadd, key, args[0], args[1]], &_boolify)
    else
      raise ArgumentError, "wrong number of arguments"
    end
  end
end

Get the number of members in a sorted set.

@example

redis.zcard("zset")
  # => 4

@param [String] key @return [Fixnum]

# File lib/redis.rb, line 1369
def zcard(key)
  synchronize do |client|
    client.call([:zcard, key])
  end
end

Count the members in a sorted set with scores within the given values.

@example Count members with score `>= 5` and `< 100`

redis.zcount("zset", "5", "(100")
  # => 2

@example Count members with scores `> 5`

redis.zcount("zset", "(5", "+inf")
  # => 2

@param [String] key @param [String] min

- inclusive minimum score is specified verbatim
- exclusive minimum score is specified by prefixing `(`

@param [String] max

- inclusive maximum score is specified verbatim
- exclusive maximum score is specified by prefixing `(`

@return [Fixnum] number of members in within the specified range

# File lib/redis.rb, line 1687
def zcount(key, min, max)
  synchronize do |client|
    client.call([:zcount, key, min, max])
  end
end

Increment the score of a member in a sorted set.

@example

redis.zincrby("zset", 32.0, "a")
  # => 64.0

@param [String] key @param [Float] increment @param [String] member @return [Float] score of the member after incrementing it

# File lib/redis.rb, line 1417
def zincrby(key, increment, member)
  synchronize do |client|
    client.call([:zincrby, key, increment, member], &_floatify)
  end
end

Intersect multiple sorted sets and store the resulting sorted set in a new key.

@example Compute the intersection of `2*zsetA` with `1*zsetB`, summing their scores

redis.zinterstore("zsetC", ["zsetA", "zsetB"], :weights => [2.0, 1.0], :aggregate => "sum")
  # => 4

@param [String] destination destination key @param [Array<String>] keys source keys @param [Hash] options

- `:weights => [Float, Float, ...]`: weights to associate with source
sorted sets
- `:aggregate => String`: aggregate function to use (sum, min, max, ...)

@return [Fixnum] number of elements in the resulting sorted set

# File lib/redis.rb, line 1707
def zinterstore(destination, keys, options = {})
  args = []

  weights = options[:weights]
  args.concat(["WEIGHTS"] + weights) if weights

  aggregate = options[:aggregate]
  args.concat(["AGGREGATE", aggregate]) if aggregate

  synchronize do |client|
    client.call([:zinterstore, destination, keys.size] + keys + args)
  end
end

Return a range of members in a sorted set, by index.

@example Retrieve all members from a sorted set

redis.zrange("zset", 0, -1)
  # => ["a", "b"]

@example Retrieve all members and their scores from a sorted set

redis.zrange("zset", 0, -1, :with_scores => true)
  # => [["a", 32.0], ["b", 64.0]]

@param [String] key @param [Fixnum] start start index @param [Fixnum] stop stop index @param [Hash] options

- `:with_scores => true`: include scores in output

@return [Array<String>, Array<[String, Float]>]

- when `:with_scores` is not specified, an array of members
- when `:with_scores` is specified, an array with `[member, score]` pairs

# File lib/redis.rb, line 1487
def zrange(key, start, stop, options = {})
  args = []

  with_scores = options[:with_scores] || options[:withscores]

  if with_scores
    args << "WITHSCORES"
    block = _floatify_pairs
  end

  synchronize do |client|
    client.call([:zrange, key, start, stop] + args, &block)
  end
end

Return a range of members in a sorted set, by score.

@example Retrieve members with score `>= 5` and `< 100`

redis.zrangebyscore("zset", "5", "(100")
  # => ["a", "b"]

@example Retrieve the first 2 members with score `>= 0`

redis.zrangebyscore("zset", "0", "+inf", :limit => [0, 2])
  # => ["a", "b"]

@example Retrieve members and their scores with scores `> 5`

redis.zrangebyscore("zset", "(5", "+inf", :with_scores => true)
  # => [["a", 32.0], ["b", 64.0]]

@param [String] key @param [String] min

- inclusive minimum score is specified verbatim
- exclusive minimum score is specified by prefixing `(`

@param [String] max

- inclusive maximum score is specified verbatim
- exclusive maximum score is specified by prefixing `(`

@param [Hash] options

- `:with_scores => true`: include scores in output
- `:limit => [offset, count]`: skip `offset` members, return a maximum of
`count` members

@return [Array<String>, Array<[String, Float]>]

- when `:with_scores` is not specified, an array of members
- when `:with_scores` is specified, an array with `[member, score]` pairs

# File lib/redis.rb, line 1597
def zrangebyscore(key, min, max, options = {})
  args = []

  with_scores = options[:with_scores] || options[:withscores]

  if with_scores
    args << "WITHSCORES"
    block = _floatify_pairs
  end

  limit = options[:limit]
  args.concat(["LIMIT"] + limit) if limit

  synchronize do |client|
    client.call([:zrangebyscore, key, min, max] + args, &block)
  end
end

Determine the index of a member in a sorted set.

@param [String] key @param [String] member @return [Fixnum]

# File lib/redis.rb, line 1533
def zrank(key, member)
  synchronize do |client|
    client.call([:zrank, key, member])
  end
end

Remove one or more members from a sorted set.

@example Remove a single member from a sorted set

redis.zrem("zset", "a")

@example Remove an array of members from a sorted set

redis.zrem("zset", ["a", "b"])

@param [String] key @param [String, Array<String>] member

- a single member
- an array of members

@return [Boolean, Fixnum]

- `Boolean` when a single member is specified, holding whether or not it
was removed from the sorted set
- `Fixnum` when an array of pairs is specified, holding the number of
members that were removed to the sorted set

# File lib/redis.rb, line 1440
def zrem(key, member)
  synchronize do |client|
    client.call([:zrem, key, member]) do |reply|
      if member.is_a? Array
        # Variadic: return integer
        reply
      else
        # Single argument: return boolean
        _boolify.call(reply)
      end
    end
  end
end

Remove all members in a sorted set within the given indexes.

@example Remove first 5 members

redis.zremrangebyrank("zset", 0, 4)
  # => 5

@example Remove last 5 members

redis.zremrangebyrank("zset", -5, -1)
  # => 5

@param [String] key @param [Fixnum] start start index @param [Fixnum] stop stop index @return [Fixnum] number of members that were removed

# File lib/redis.rb, line 1564
def zremrangebyrank(key, start, stop)
  synchronize do |client|
    client.call([:zremrangebyrank, key, start, stop])
  end
end

Remove all members in a sorted set within the given scores.

@example Remove members with score `>= 5` and `< 100`

redis.zremrangebyscore("zset", "5", "(100")
  # => 2

@example Remove members with scores `> 5`

redis.zremrangebyscore("zset", "(5", "+inf")
  # => 2

@param [String] key @param [String] min

- inclusive minimum score is specified verbatim
- exclusive minimum score is specified by prefixing `(`

@param [String] max

- inclusive maximum score is specified verbatim
- exclusive maximum score is specified by prefixing `(`

@return [Fixnum] number of members that were removed

# File lib/redis.rb, line 1664
def zremrangebyscore(key, min, max)
  synchronize do |client|
    client.call([:zremrangebyscore, key, min, max])
  end
end

Return a range of members in a sorted set, by index, with scores ordered from high to low.

@example Retrieve all members from a sorted set

redis.zrevrange("zset", 0, -1)
  # => ["b", "a"]

@example Retrieve all members and their scores from a sorted set

redis.zrevrange("zset", 0, -1, :with_scores => true)
  # => [["b", 64.0], ["a", 32.0]]

@see zrange

# File lib/redis.rb, line 1513
def zrevrange(key, start, stop, options = {})
  args = []

  with_scores = options[:with_scores] || options[:withscores]

  if with_scores
    args << "WITHSCORES"
    block = _floatify_pairs
  end

  synchronize do |client|
    client.call([:zrevrange, key, start, stop] + args, &block)
  end
end

Return a range of members in a sorted set, by score, with scores ordered from high to low.

@example Retrieve members with score `< 100` and `>= 5`

redis.zrevrangebyscore("zset", "(100", "5")
  # => ["b", "a"]

@example Retrieve the first 2 members with score `<= 0`

redis.zrevrangebyscore("zset", "0", "-inf", :limit => [0, 2])
  # => ["b", "a"]

@example Retrieve members and their scores with scores `> 5`

redis.zrevrangebyscore("zset", "+inf", "(5", :with_scores => true)
  # => [["b", 64.0], ["a", 32.0]]

@see zrangebyscore

# File lib/redis.rb, line 1629
def zrevrangebyscore(key, max, min, options = {})
  args = []

  with_scores = options[:with_scores] || options[:withscores]

  if with_scores
    args << ["WITHSCORES"]
    block = _floatify_pairs
  end

  limit = options[:limit]
  args.concat(["LIMIT"] + limit) if limit

  synchronize do |client|
    client.call([:zrevrangebyscore, key, max, min] + args, &block)
  end
end

Determine the index of a member in a sorted set, with scores ordered from high to low.

@param [String] key @param [String] member @return [Fixnum]

# File lib/redis.rb, line 1545
def zrevrank(key, member)
  synchronize do |client|
    client.call([:zrevrank, key, member])
  end
end

Scan a sorted set

@example Retrieve the first batch of key/value pairs in a hash

redis.zscan("zset", 0)

@param [String, Integer] cursor: the cursor of the iteration @param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [String, Array<[String, Float]>] the next cursor and all found

members and scores

# File lib/redis.rb, line 2355
def zscan(key, cursor, options={})
  _scan(:zscan, cursor, [key], options) do |reply|
    [reply[0], _floatify_pairs.call(reply[1])]
  end
end

Scan a sorted set

@example Retrieve all of the members/scores in a sorted set

redis.zscan_each("zset").to_a
# => [["key70", "70"], ["key80", "80"]]

@param [Hash] options

- `:match => String`: only return keys matching the pattern
- `:count => Integer`: return count keys at most per iteration

@return [Enumerator] an enumerator for all found scores and members

# File lib/redis.rb, line 2372
def zscan_each(key, options={}, &block)
  return to_enum(:zscan_each, key, options) unless block_given?
  cursor = 0
  loop do
    cursor, values = zscan(key, cursor, options)
    values.each(&block)
    break if cursor == "0"
  end
end

Get the score associated with the given member in a sorted set.

@example Get the score for member “a”

redis.zscore("zset", "a")
  # => 32.0

@param [String] key @param [String] member @return [Float] score of the member

# File lib/redis.rb, line 1463
def zscore(key, member)
  synchronize do |client|
    client.call([:zscore, key, member], &_floatify)
  end
end

Add multiple sorted sets and store the resulting sorted set in a new key.

@example Compute the union of `2*zsetA` with `1*zsetB`, summing their scores

redis.zunionstore("zsetC", ["zsetA", "zsetB"], :weights => [2.0, 1.0], :aggregate => "sum")
  # => 8

@param [String] destination destination key @param [Array<String>] keys source keys @param [Hash] options

- `:weights => [Float, Float, ...]`: weights to associate with source
sorted sets
- `:aggregate => String`: aggregate function to use (sum, min, max, ...)

@return [Fixnum] number of elements in the resulting sorted set

# File lib/redis.rb, line 1734
def zunionstore(destination, keys, options = {})
  args = []

  weights = options[:weights]
  args.concat(["WEIGHTS"] + weights) if weights

  aggregate = options[:aggregate]
  args.concat(["AGGREGATE", aggregate]) if aggregate

  synchronize do |client|
    client.call([:zunionstore, destination, keys.size] + keys + args)
  end
end