hedis-0.6.2: Client library for the Redis datastore: supports full command set, pipelining.

Safe HaskellNone

Database.Redis

Contents

Synopsis

How To Use This Module

Connect to a Redis server:

 -- connects to localhost:6379
 conn <- connect defaultConnectInfo

Send commands to the server:

 {-# LANGUAGE OverloadedStrings #-}
 ...
 runRedis conn $ do
      set "hello" "hello"
      set "world" "world"
      hello <- get "hello"
      world <- get "world"
      liftIO $ print (hello,world)

Command Type Signatures

Redis commands behave differently when issued in- or outside of a transaction. To make them work in both contexts, most command functions have a type signature similar to the following:

  echo :: (RedisCtx m f) => ByteString -> m (f ByteString)

Here is how to interpret this type signature:

  • The argument types are independent of the execution context. echo always takes a ByteString parameter, whether in- or outside of a transaction. This is true for all command functions.
  • All Redis commands return their result wrapped in some "container". The type f of this container depends on the commands execution context m. The ByteString return type in the example is specific to the echo command. For other commands, it will often be another type.
  • In the "normal" context Redis, outside of any transactions, results are wrapped in an Either Reply.
  • Inside a transaction, in the RedisTx context, results are wrapped in a Queued.

In short, you can view any command with a RedisCtx constraint in the type signature, to "have two types". For example echo "has both types":

  echo :: ByteString -> Redis (Either Reply ByteString)
  echo :: ByteString -> RedisTx (Queued ByteString)
Exercise
What are the types of expire inside a transaction and lindex outside of a transaction? The solutions are at the very bottom of this page.

Lua Scripting

Lua values returned from the eval and evalsha functions will be converted to Haskell values by the decode function from the RedisResult type class.

  Lua Type      | Haskell Type       | Conversion Example
  --------------|--------------------|-----------------------------
  Number        | Integer            | 1.23   => 1
  String        | ByteString, Double | "1.23" => "1.23" or 1.23
  Boolean       | Bool               | false  => False
  Table         | List               | {1,2}  => [1,2]

Additionally, any of the Haskell types from the table above can be wrapped in a Maybe:

  42  => Just 42 :: Maybe Integer
  nil => Nothing :: Maybe Integer

Note that Redis imposes some limitations on the possible conversions:

  • Lua numbers can only be converted to Integers. Only Lua strings can be interpreted as Doubles.
  • Associative Lua tables can not be converted at all. Returned tables must be "arrays", i.e. indexed only by integers.

The Redis Scripting website (http://redis.io/commands/eval) documents the exact semantics of the scripting commands and value conversion.

Automatic Pipelining

Commands are automatically pipelined as much as possible. For example, in the above "hello world" example, all four commands are pipelined. Automatic pipelining makes use of Haskell's laziness. As long as a previous reply is not evaluated, subsequent commands can be pipelined.

Automatic pipelining also works across several calls to runRedis, as long as replies are only evaluated outside the runRedis block.

To keep memory usage low, the number of requests "in the pipeline" is limited (per connection) to 1000. After that number, the next command is sent only when at least one reply has been received. That means, command functions may block until there are less than 1000 outstanding replies.

Error Behavior

Operations against keys holding the wrong kind of value:
Outside of a transaction, if the Redis server returns an Error, command functions will return Left the Reply. The library user can inspect the error message to gain information on what kind of error occured.
Connection to the server lost:
In case of a lost connection, command functions throw a ConnectionLostException. It can only be caught outside of runRedis.
Exceptions:
Any exceptions can only be caught outside of runRedis. This way the connection pool can properly close the connection, making sure it is not left in an unusable state, e.g. closed or inside a transaction.

The Redis Monad

data Redis a Source

Context for normal command execution, outside of transactions. Use runRedis to run actions of this type.

In this context, each result is wrapped in an Either to account for the possibility of Redis returning an Error reply.

runRedis :: Connection -> Redis a -> IO aSource

Interact with a Redis datastore specified by the given Connection.

Each call of runRedis takes a network connection from the Connection pool and runs the given Redis action. Calls to runRedis may thus block while all connections from the pool are in use.

class MonadRedis m => RedisCtx m f | m -> fSource

This class captures the following behaviour: In a context m, a command will return it's result wrapped in a "container" of type f.

Please refer to the Command Type Signatures section of this page for more information.

Connection

data Connection Source

A threadsafe pool of network connections to a Redis server. Use the connect function to create one.

connect :: ConnectInfo -> IO ConnectionSource

Opens a Connection to a Redis server designated by the given ConnectInfo.

data ConnectInfo Source

Information for connnecting to a Redis server.

It is recommended to not use the ConnInfo data constructor directly. Instead use defaultConnectInfo and update it with record syntax. For example to connect to a password protected Redis server running on localhost and listening to the default port:

 myConnectInfo :: ConnectInfo
 myConnectInfo = defaultConnectInfo {connectAuth = Just "secret"}

Constructors

ConnInfo 

Fields

connectHost :: HostName
 
connectPort :: PortID
 
connectAuth :: Maybe ByteString

When the server is protected by a password, set connectAuth to Just the password. Each connection will then authenticate by the auth command.

connectMaxConnections :: Int

Maximum number of connections to keep open. The smallest acceptable value is 1.

connectMaxIdleTime :: NominalDiffTime

Amount of time for which an unused connection is kept open. The smallest acceptable value is 0.5 seconds. If the timeout value in your redis.conf file is non-zero, it should be larger than connectMaxIdleTime.

defaultConnectInfo :: ConnectInfoSource

Default information for connecting:

  connectHost           = "localhost"
  connectPort           = PortNumber 6379 -- Redis default port
  connectAuth           = Nothing         -- No password
  connectMaxConnections = 50              -- Up to 50 connections
  connectMaxIdleTime    = 30              -- Keep open for 30 seconds

type HostName = String

Either a host name e.g., "haskell.org" or a numeric host address string consisting of a dotted decimal IPv4 address or an IPv6 address e.g., "192.168.0.1".

Commands

Connection

authSource

Arguments

:: ByteString

password

-> Redis (Either Reply Status) 

Authenticate to the server (http://redis.io/commands/auth).

echoSource

Arguments

:: RedisCtx m f 
=> ByteString

message

-> m (f ByteString) 

Echo the given string (http://redis.io/commands/echo).

ping :: RedisCtx m f => m (f Status)Source

Ping the server (http://redis.io/commands/ping).

quit :: RedisCtx m f => m (f Status)Source

Close the connection (http://redis.io/commands/quit).

selectSource

Arguments

:: RedisCtx m f 
=> Integer

index

-> m (f Status) 

Change the selected database for the current connection (http://redis.io/commands/select).

Keys

delSource

Arguments

:: RedisCtx m f 
=> [ByteString]

key

-> m (f Integer) 

dumpSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f ByteString) 

Return a serialized version of the value stored at the specified key. (http://redis.io/commands/dump).

existsSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Bool) 

Determine if a key exists (http://redis.io/commands/exists).

expireSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

seconds

-> m (f Bool) 

Set a key's time to live in seconds (http://redis.io/commands/expire).

expireatSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

timestamp

-> m (f Bool) 

Set the expiration for a key as a UNIX timestamp (http://redis.io/commands/expireat).

keysSource

Arguments

:: RedisCtx m f 
=> ByteString

pattern

-> m (f [ByteString]) 

Find all keys matching the given pattern (http://redis.io/commands/keys).

migrateSource

Arguments

:: RedisCtx m f 
=> ByteString

host

-> ByteString

port

-> ByteString

key

-> Integer

destinationDb

-> Integer

timeout

-> m (f Status) 

Atomically transfer a key from a Redis instance to another one. (http://redis.io/commands/migrate).

moveSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

db

-> m (f Bool) 

Move a key to another database (http://redis.io/commands/move).

objectRefcountSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Inspect the internals of Redis objects (http://redis.io/commands/object). The Redis command OBJECT is split up into objectRefcount, objectEncoding, objectIdletime.

objectEncodingSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f ByteString) 

Inspect the internals of Redis objects (http://redis.io/commands/object). The Redis command OBJECT is split up into objectRefcount, objectEncoding, objectIdletime.

objectIdletimeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Inspect the internals of Redis objects (http://redis.io/commands/object). The Redis command OBJECT is split up into objectRefcount, objectEncoding, objectIdletime.

persistSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Bool) 

Remove the expiration from a key (http://redis.io/commands/persist).

pexpireSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

milliseconds

-> m (f Bool) 

Set a key's time to live in milliseconds (http://redis.io/commands/pexpire).

pexpireatSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

millisecondsTimestamp

-> m (f Bool) 

Set the expiration for a key as a UNIX timestamp specified in milliseconds (http://redis.io/commands/pexpireat).

pttlSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Get the time to live for a key in milliseconds (http://redis.io/commands/pttl).

Return a random key from the keyspace (http://redis.io/commands/randomkey).

renameSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

newkey

-> m (f Status) 

renamenxSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

newkey

-> m (f Bool) 

Rename a key, only if the new key does not exist (http://redis.io/commands/renamenx).

restoreSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

timeToLive

-> ByteString

serializedValue

-> m (f Status) 

Create a key using the provided serialized value, previously obtained using DUMP. (http://redis.io/commands/restore).

data SortOpts Source

Options for the sort command.

Instances

defaultSortOpts :: SortOptsSource

Redis default SortOpts. Equivalent to omitting all optional parameters.

 SortOpts
     { sortBy    = Nothing -- omit the BY option
     , sortLimit = (0,-1)  -- return entire collection
     , sortGet   = []      -- omit the GET option
     , sortOrder = Asc     -- sort in ascending order
     , sortAlpha = False   -- sort numerically, not lexicographically
     }

data SortOrder Source

Constructors

Asc 
Desc 

sortSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> SortOpts 
-> m (f [ByteString]) 

Sort the elements in a list, set or sorted set (http://redis.io/commands/sort). The Redis command SORT is split up into sort, sortStore.

sortStoreSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

destination

-> SortOpts 
-> m (f Integer) 

Sort the elements in a list, set or sorted set (http://redis.io/commands/sort). The Redis command SORT is split up into sort, sortStore.

ttlSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Get the time to live for a key (http://redis.io/commands/ttl).

getTypeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f RedisType) 

Determine the type stored at key (http://redis.io/commands/type).

Hashes

hdelSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [ByteString]

field

-> m (f Integer) 

Delete one or more hash fields (http://redis.io/commands/hdel).

hexistsSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

field

-> m (f Bool) 

Determine if a hash field exists (http://redis.io/commands/hexists).

hgetSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

field

-> m (f (Maybe ByteString)) 

Get the value of a hash field (http://redis.io/commands/hget).

hgetallSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f [(ByteString, ByteString)]) 

Get all the fields and values in a hash (http://redis.io/commands/hgetall).

hincrbySource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

field

-> Integer

increment

-> m (f Integer) 

Increment the integer value of a hash field by the given number (http://redis.io/commands/hincrby).

hincrbyfloatSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

field

-> Double

increment

-> m (f Double) 

Increment the float value of a hash field by the given amount (http://redis.io/commands/hincrbyfloat).

hkeysSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f [ByteString]) 

Get all the fields in a hash (http://redis.io/commands/hkeys).

hlenSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Get the number of fields in a hash (http://redis.io/commands/hlen).

hmgetSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [ByteString]

field

-> m (f [Maybe ByteString]) 

Get the values of all the given hash fields (http://redis.io/commands/hmget).

hmsetSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [(ByteString, ByteString)]

fieldValue

-> m (f Status) 

Set multiple hash fields to multiple values (http://redis.io/commands/hmset).

hsetSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

field

-> ByteString

value

-> m (f Bool) 

Set the string value of a hash field (http://redis.io/commands/hset).

hsetnxSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

field

-> ByteString

value

-> m (f Bool) 

Set the value of a hash field, only if the field does not exist (http://redis.io/commands/hsetnx).

hvalsSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f [ByteString]) 

Get all the values in a hash (http://redis.io/commands/hvals).

Lists

blpopSource

Arguments

:: RedisCtx m f 
=> [ByteString]

key

-> Integer

timeout

-> m (f (Maybe (ByteString, ByteString))) 

Remove and get the first element in a list, or block until one is available (http://redis.io/commands/blpop).

brpopSource

Arguments

:: RedisCtx m f 
=> [ByteString]

key

-> Integer

timeout

-> m (f (Maybe (ByteString, ByteString))) 

Remove and get the last element in a list, or block until one is available (http://redis.io/commands/brpop).

brpoplpushSource

Arguments

:: RedisCtx m f 
=> ByteString

source

-> ByteString

destination

-> Integer

timeout

-> m (f (Maybe ByteString)) 

Pop a value from a list, push it to another list and return it; or block until one is available (http://redis.io/commands/brpoplpush).

lindexSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

index

-> m (f (Maybe ByteString)) 

Get an element from a list by its index (http://redis.io/commands/lindex).

linsertBeforeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

pivot

-> ByteString

value

-> m (f Integer) 

Insert an element before or after another element in a list (http://redis.io/commands/linsert). The Redis command LINSERT is split up into linsertBefore, linsertAfter.

linsertAfterSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

pivot

-> ByteString

value

-> m (f Integer) 

Insert an element before or after another element in a list (http://redis.io/commands/linsert). The Redis command LINSERT is split up into linsertBefore, linsertAfter.

llenSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Get the length of a list (http://redis.io/commands/llen).

lpopSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f (Maybe ByteString)) 

Remove and get the first element in a list (http://redis.io/commands/lpop).

lpushSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [ByteString]

value

-> m (f Integer) 

Prepend one or multiple values to a list (http://redis.io/commands/lpush).

lpushxSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

value

-> m (f Integer) 

Prepend a value to a list, only if the list exists (http://redis.io/commands/lpushx).

lrangeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

stop

-> m (f [ByteString]) 

Get a range of elements from a list (http://redis.io/commands/lrange).

lremSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

count

-> ByteString

value

-> m (f Integer) 

Remove elements from a list (http://redis.io/commands/lrem).

lsetSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

index

-> ByteString

value

-> m (f Status) 

Set the value of an element in a list by its index (http://redis.io/commands/lset).

ltrimSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

stop

-> m (f Status) 

Trim a list to the specified range (http://redis.io/commands/ltrim).

rpopSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f (Maybe ByteString)) 

Remove and get the last element in a list (http://redis.io/commands/rpop).

rpoplpushSource

Arguments

:: RedisCtx m f 
=> ByteString

source

-> ByteString

destination

-> m (f (Maybe ByteString)) 

Remove the last element in a list, append it to another list and return it (http://redis.io/commands/rpoplpush).

rpushSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [ByteString]

value

-> m (f Integer) 

Append one or multiple values to a list (http://redis.io/commands/rpush).

rpushxSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

value

-> m (f Integer) 

Append a value to a list, only if the list exists (http://redis.io/commands/rpushx).

Scripting

evalSource

Arguments

:: (RedisCtx m f, RedisResult a) 
=> ByteString

script

-> [ByteString]

keys

-> [ByteString]

args

-> m (f a) 

Execute a Lua script server side (http://redis.io/commands/eval).

evalshaSource

Arguments

:: (RedisCtx m f, RedisResult a) 
=> ByteString

script

-> [ByteString]

keys

-> [ByteString]

args

-> m (f a) 

Execute a Lua script server side (http://redis.io/commands/evalsha).

scriptExistsSource

Arguments

:: RedisCtx m f 
=> [ByteString]

script

-> m (f [Bool]) 

Check existence of scripts in the script cache. (http://redis.io/commands/script-exists).

Remove all the scripts from the script cache. (http://redis.io/commands/script-flush).

Kill the script currently in execution. (http://redis.io/commands/script-kill).

scriptLoadSource

Arguments

:: RedisCtx m f 
=> ByteString

script

-> m (f ByteString) 

Load the specified Lua script into the script cache. (http://redis.io/commands/script-load).

Server

Asynchronously rewrite the append-only file (http://redis.io/commands/bgrewriteaof).

bgsave :: RedisCtx m f => m (f Status)Source

Asynchronously save the dataset to disk (http://redis.io/commands/bgsave).

configGetSource

Arguments

:: RedisCtx m f 
=> ByteString

parameter

-> m (f [(ByteString, ByteString)]) 

Get the value of a configuration parameter (http://redis.io/commands/config-get).

Reset the stats returned by INFO (http://redis.io/commands/config-resetstat).

configSetSource

Arguments

:: RedisCtx m f 
=> ByteString

parameter

-> ByteString

value

-> m (f Status) 

Set a configuration parameter to the given value (http://redis.io/commands/config-set).

dbsize :: RedisCtx m f => m (f Integer)Source

Return the number of keys in the selected database (http://redis.io/commands/dbsize).

debugObjectSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f ByteString) 

Get debugging information about a key (http://redis.io/commands/debug-object).

Remove all keys from all databases (http://redis.io/commands/flushall).

flushdb :: RedisCtx m f => m (f Status)Source

Remove all keys from the current database (http://redis.io/commands/flushdb).

Get information and statistics about the server (http://redis.io/commands/info).

Get the UNIX time stamp of the last successful save to disk (http://redis.io/commands/lastsave).

save :: RedisCtx m f => m (f Status)Source

Synchronously save the dataset to disk (http://redis.io/commands/save).

slaveofSource

Arguments

:: RedisCtx m f 
=> ByteString

host

-> ByteString

port

-> m (f Status) 

Make the server a slave of another instance, or promote it as master (http://redis.io/commands/slaveof).

data Slowlog Source

A single entry from the slowlog.

Constructors

Slowlog 

Fields

slowlogId :: Integer

A unique progressive identifier for every slow log entry.

slowlogTimestamp :: Integer

The unix timestamp at which the logged command was processed.

slowlogMicros :: Integer

The amount of time needed for its execution, in microseconds.

slowlogCmd :: [ByteString]

The command and it's arguments.

slowlogGetSource

Arguments

:: RedisCtx m f 
=> Integer

cnt

-> m (f [Slowlog]) 

Manages the Redis slow queries log (http://redis.io/commands/slowlog). The Redis command SLOWLOG is split up into slowlogGet, slowlogLen, slowlogReset.

Manages the Redis slow queries log (http://redis.io/commands/slowlog). The Redis command SLOWLOG is split up into slowlogGet, slowlogLen, slowlogReset.

Manages the Redis slow queries log (http://redis.io/commands/slowlog). The Redis command SLOWLOG is split up into slowlogGet, slowlogLen, slowlogReset.

time :: RedisCtx m f => m (f (Integer, Integer))Source

Return the current server time (http://redis.io/commands/time).

Sets

saddSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [ByteString]

member

-> m (f Integer) 

Add one or more members to a set (http://redis.io/commands/sadd).

scardSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Get the number of members in a set (http://redis.io/commands/scard).

sdiffSource

Arguments

:: RedisCtx m f 
=> [ByteString]

key

-> m (f [ByteString]) 

Subtract multiple sets (http://redis.io/commands/sdiff).

sdiffstoreSource

Arguments

:: RedisCtx m f 
=> ByteString

destination

-> [ByteString]

key

-> m (f Integer) 

Subtract multiple sets and store the resulting set in a key (http://redis.io/commands/sdiffstore).

sinterSource

Arguments

:: RedisCtx m f 
=> [ByteString]

key

-> m (f [ByteString]) 

Intersect multiple sets (http://redis.io/commands/sinter).

sinterstoreSource

Arguments

:: RedisCtx m f 
=> ByteString

destination

-> [ByteString]

key

-> m (f Integer) 

Intersect multiple sets and store the resulting set in a key (http://redis.io/commands/sinterstore).

sismemberSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

member

-> m (f Bool) 

Determine if a given value is a member of a set (http://redis.io/commands/sismember).

smembersSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f [ByteString]) 

Get all the members in a set (http://redis.io/commands/smembers).

smoveSource

Arguments

:: RedisCtx m f 
=> ByteString

source

-> ByteString

destination

-> ByteString

member

-> m (f Bool) 

Move a member from one set to another (http://redis.io/commands/smove).

spopSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f (Maybe ByteString)) 

Remove and return a random member from a set (http://redis.io/commands/spop).

srandmemberSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f (Maybe ByteString)) 

Get a random member from a set (http://redis.io/commands/srandmember).

sremSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [ByteString]

member

-> m (f Integer) 

Remove one or more members from a set (http://redis.io/commands/srem).

sunionSource

Arguments

:: RedisCtx m f 
=> [ByteString]

key

-> m (f [ByteString]) 

Add multiple sets (http://redis.io/commands/sunion).

sunionstoreSource

Arguments

:: RedisCtx m f 
=> ByteString

destination

-> [ByteString]

key

-> m (f Integer) 

Add multiple sets and store the resulting set in a key (http://redis.io/commands/sunionstore).

Sorted Sets

zaddSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [(Double, ByteString)]

scoreMember

-> m (f Integer) 

Add one or more members to a sorted set, or update its score if it already exists (http://redis.io/commands/zadd).

zcardSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Get the number of members in a sorted set (http://redis.io/commands/zcard).

zcountSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

min

-> Double

max

-> m (f Integer) 

Count the members in a sorted set with scores within the given values (http://redis.io/commands/zcount).

zincrbySource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

increment

-> ByteString

member

-> m (f Double) 

Increment the score of a member in a sorted set (http://redis.io/commands/zincrby).

data Aggregate Source

Constructors

Sum 
Min 
Max 

zinterstoreSource

Arguments

:: RedisCtx m f 
=> ByteString

destination

-> [ByteString]

keys

-> Aggregate 
-> m (f Integer) 

Intersect multiple sorted sets and store the resulting sorted set in a new key (http://redis.io/commands/zinterstore). The Redis command ZINTERSTORE is split up into zinterstore, zinterstoreWeights.

zinterstoreWeightsSource

Arguments

:: RedisCtx m f 
=> ByteString

destination

-> [(ByteString, Double)]

weighted keys

-> Aggregate 
-> m (f Integer) 

Intersect multiple sorted sets and store the resulting sorted set in a new key (http://redis.io/commands/zinterstore). The Redis command ZINTERSTORE is split up into zinterstore, zinterstoreWeights.

zrangeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

stop

-> m (f [ByteString]) 

Return a range of members in a sorted set, by index (http://redis.io/commands/zrange). The Redis command ZRANGE is split up into zrange, zrangeWithscores.

zrangeWithscoresSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

stop

-> m (f [(ByteString, Double)]) 

Return a range of members in a sorted set, by index (http://redis.io/commands/zrange). The Redis command ZRANGE is split up into zrange, zrangeWithscores.

zrangebyscoreSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

min

-> Double

max

-> m (f [ByteString]) 

Return a range of members in a sorted set, by score (http://redis.io/commands/zrangebyscore). The Redis command ZRANGEBYSCORE is split up into zrangebyscore, zrangebyscoreWithscores, zrangebyscoreLimit, zrangebyscoreWithscoresLimit.

zrangebyscoreWithscoresSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

min

-> Double

max

-> m (f [(ByteString, Double)]) 

Return a range of members in a sorted set, by score (http://redis.io/commands/zrangebyscore). The Redis command ZRANGEBYSCORE is split up into zrangebyscore, zrangebyscoreWithscores, zrangebyscoreLimit, zrangebyscoreWithscoresLimit.

zrangebyscoreLimitSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

min

-> Double

max

-> Integer

offset

-> Integer

count

-> m (f [ByteString]) 

Return a range of members in a sorted set, by score (http://redis.io/commands/zrangebyscore). The Redis command ZRANGEBYSCORE is split up into zrangebyscore, zrangebyscoreWithscores, zrangebyscoreLimit, zrangebyscoreWithscoresLimit.

zrangebyscoreWithscoresLimitSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

min

-> Double

max

-> Integer

offset

-> Integer

count

-> m (f [(ByteString, Double)]) 

Return a range of members in a sorted set, by score (http://redis.io/commands/zrangebyscore). The Redis command ZRANGEBYSCORE is split up into zrangebyscore, zrangebyscoreWithscores, zrangebyscoreLimit, zrangebyscoreWithscoresLimit.

zrankSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

member

-> m (f (Maybe Integer)) 

Determine the index of a member in a sorted set (http://redis.io/commands/zrank).

zremSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> [ByteString]

member

-> m (f Integer) 

Remove one or more members from a sorted set (http://redis.io/commands/zrem).

zremrangebyrankSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

stop

-> m (f Integer) 

Remove all members in a sorted set within the given indexes (http://redis.io/commands/zremrangebyrank).

zremrangebyscoreSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

min

-> Double

max

-> m (f Integer) 

Remove all members in a sorted set within the given scores (http://redis.io/commands/zremrangebyscore).

zrevrangeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

stop

-> m (f [ByteString]) 

Return a range of members in a sorted set, by index, with scores ordered from high to low (http://redis.io/commands/zrevrange). The Redis command ZREVRANGE is split up into zrevrange, zrevrangeWithscores.

zrevrangeWithscoresSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

stop

-> m (f [(ByteString, Double)]) 

Return a range of members in a sorted set, by index, with scores ordered from high to low (http://redis.io/commands/zrevrange). The Redis command ZREVRANGE is split up into zrevrange, zrevrangeWithscores.

zrevrangebyscoreSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

max

-> Double

min

-> m (f [ByteString]) 

Return a range of members in a sorted set, by score, with scores ordered from high to low (http://redis.io/commands/zrevrangebyscore). The Redis command ZREVRANGEBYSCORE is split up into zrevrangebyscore, zrevrangebyscoreWithscores, zrevrangebyscoreLimit, zrevrangebyscoreWithscoresLimit.

zrevrangebyscoreWithscoresSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

max

-> Double

min

-> m (f [(ByteString, Double)]) 

Return a range of members in a sorted set, by score, with scores ordered from high to low (http://redis.io/commands/zrevrangebyscore). The Redis command ZREVRANGEBYSCORE is split up into zrevrangebyscore, zrevrangebyscoreWithscores, zrevrangebyscoreLimit, zrevrangebyscoreWithscoresLimit.

zrevrangebyscoreLimitSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

max

-> Double

min

-> Integer

offset

-> Integer

count

-> m (f [ByteString]) 

Return a range of members in a sorted set, by score, with scores ordered from high to low (http://redis.io/commands/zrevrangebyscore). The Redis command ZREVRANGEBYSCORE is split up into zrevrangebyscore, zrevrangebyscoreWithscores, zrevrangebyscoreLimit, zrevrangebyscoreWithscoresLimit.

zrevrangebyscoreWithscoresLimitSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

max

-> Double

min

-> Integer

offset

-> Integer

count

-> m (f [(ByteString, Double)]) 

Return a range of members in a sorted set, by score, with scores ordered from high to low (http://redis.io/commands/zrevrangebyscore). The Redis command ZREVRANGEBYSCORE is split up into zrevrangebyscore, zrevrangebyscoreWithscores, zrevrangebyscoreLimit, zrevrangebyscoreWithscoresLimit.

zrevrankSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

member

-> m (f (Maybe Integer)) 

Determine the index of a member in a sorted set, with scores ordered from high to low (http://redis.io/commands/zrevrank).

zscoreSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

member

-> m (f (Maybe Double)) 

Get the score associated with the given member in a sorted set (http://redis.io/commands/zscore).

zunionstoreSource

Arguments

:: RedisCtx m f 
=> ByteString

destination

-> [ByteString]

keys

-> Aggregate 
-> m (f Integer) 

Add multiple sorted sets and store the resulting sorted set in a new key (http://redis.io/commands/zunionstore). The Redis command ZUNIONSTORE is split up into zunionstore, zunionstoreWeights.

zunionstoreWeightsSource

Arguments

:: RedisCtx m f 
=> ByteString

destination

-> [(ByteString, Double)]

weighted keys

-> Aggregate 
-> m (f Integer) 

Add multiple sorted sets and store the resulting sorted set in a new key (http://redis.io/commands/zunionstore). The Redis command ZUNIONSTORE is split up into zunionstore, zunionstoreWeights.

Strings

appendSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

value

-> m (f Integer) 

Append a value to a key (http://redis.io/commands/append).

bitcountSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Count set bits in a string (http://redis.io/commands/bitcount). The Redis command BITCOUNT is split up into bitcount, bitcountRange.

bitcountRangeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

end

-> m (f Integer) 

Count set bits in a string (http://redis.io/commands/bitcount). The Redis command BITCOUNT is split up into bitcount, bitcountRange.

bitopAndSource

Arguments

:: RedisCtx m f 
=> ByteString

destkey

-> [ByteString]

srckeys

-> m (f Integer) 

Perform bitwise operations between strings (http://redis.io/commands/bitop). The Redis command BITOP is split up into bitopAnd, bitopOr, bitopXor, bitopNot.

bitopOrSource

Arguments

:: RedisCtx m f 
=> ByteString

destkey

-> [ByteString]

srckeys

-> m (f Integer) 

Perform bitwise operations between strings (http://redis.io/commands/bitop). The Redis command BITOP is split up into bitopAnd, bitopOr, bitopXor, bitopNot.

bitopXorSource

Arguments

:: RedisCtx m f 
=> ByteString

destkey

-> [ByteString]

srckeys

-> m (f Integer) 

Perform bitwise operations between strings (http://redis.io/commands/bitop). The Redis command BITOP is split up into bitopAnd, bitopOr, bitopXor, bitopNot.

bitopNotSource

Arguments

:: RedisCtx m f 
=> ByteString

destkey

-> ByteString

srckey

-> m (f Integer) 

Perform bitwise operations between strings (http://redis.io/commands/bitop). The Redis command BITOP is split up into bitopAnd, bitopOr, bitopXor, bitopNot.

decrSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Decrement the integer value of a key by one (http://redis.io/commands/decr).

decrbySource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

decrement

-> m (f Integer) 

Decrement the integer value of a key by the given number (http://redis.io/commands/decrby).

getSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f (Maybe ByteString)) 

Get the value of a key (http://redis.io/commands/get).

getbitSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

offset

-> m (f Integer) 

Returns the bit value at offset in the string value stored at key (http://redis.io/commands/getbit).

getrangeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

start

-> Integer

end

-> m (f ByteString) 

Get a substring of the string stored at a key (http://redis.io/commands/getrange).

getsetSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

value

-> m (f (Maybe ByteString)) 

Set the string value of a key and return its old value (http://redis.io/commands/getset).

incrSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Increment the integer value of a key by one (http://redis.io/commands/incr).

incrbySource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

increment

-> m (f Integer) 

Increment the integer value of a key by the given amount (http://redis.io/commands/incrby).

incrbyfloatSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Double

increment

-> m (f Double) 

Increment the float value of a key by the given amount (http://redis.io/commands/incrbyfloat).

mgetSource

Arguments

:: RedisCtx m f 
=> [ByteString]

key

-> m (f [Maybe ByteString]) 

Get the values of all the given keys (http://redis.io/commands/mget).

msetSource

Arguments

:: RedisCtx m f 
=> [(ByteString, ByteString)]

keyValue

-> m (f Status) 

Set multiple keys to multiple values (http://redis.io/commands/mset).

msetnxSource

Arguments

:: RedisCtx m f 
=> [(ByteString, ByteString)]

keyValue

-> m (f Bool) 

Set multiple keys to multiple values, only if none of the keys exist (http://redis.io/commands/msetnx).

psetexSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

milliseconds

-> ByteString

value

-> m (f Status) 

Set the value and expiration in milliseconds of a key (http://redis.io/commands/psetex).

setSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

value

-> m (f Status) 

Set the string value of a key (http://redis.io/commands/set).

setbitSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

offset

-> ByteString

value

-> m (f Integer) 

Sets or clears the bit at offset in the string value stored at key (http://redis.io/commands/setbit).

setexSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

seconds

-> ByteString

value

-> m (f Status) 

Set the value and expiration of a key (http://redis.io/commands/setex).

setnxSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> ByteString

value

-> m (f Bool) 

Set the value of a key, only if the key does not exist (http://redis.io/commands/setnx).

setrangeSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> Integer

offset

-> ByteString

value

-> m (f Integer) 

Overwrite part of a string at key starting at the specified offset (http://redis.io/commands/setrange).

strlenSource

Arguments

:: RedisCtx m f 
=> ByteString

key

-> m (f Integer) 

Get the length of the value stored in a key (http://redis.io/commands/strlen).

Unimplemented Commands

These commands are not implemented, as of now. Library users can implement these or other commands from experimental Redis versions by using the sendRequest function.

Transactions

watchSource

Arguments

:: [ByteString]

key

-> Redis (Either Reply Status) 

Watch the given keys to determine execution of the MULTI/EXEC block (http://redis.io/commands/watch).

multiExec :: RedisTx (Queued a) -> Redis (TxResult a)Source

Run commands inside a transaction. For documentation on the semantics of Redis transaction see http://redis.io/topics/transactions.

Inside the transaction block, command functions return their result wrapped in a Queued. The Queued result is a proxy object for the actual command's result, which will only be available after EXECing the transaction.

Example usage (note how Queued 's Applicative instance is used to combine the two individual results):

  runRedis conn $ do
      set "hello" "hello"
      set "world" "world"
      helloworld <- multiExec $ do
          hello <- get "hello"
          world <- get "world"
          return $ (,) <$> hello <*> world
      liftIO (print helloworld)

data Queued a Source

A Queued value represents the result of a command inside a transaction. It is a proxy object for the actual result, which will only be available after returning from a multiExec transaction.

Queued values are composable by utilizing the Functor, Applicative or Monad interfaces.

data TxResult a Source

Result of a multiExec transaction.

Constructors

TxSuccess a

Transaction completed successfully. The wrapped value corresponds to the Queued value returned from the multiExec argument action.

TxAborted

Transaction aborted due to an earlier watch command.

TxError String

At least one of the commands returned an Error reply.

Instances

Eq a => Eq (TxResult a) 
Show a => Show (TxResult a) 

data RedisTx a Source

Command-context inside of MULTI/EXEC transactions. Use multiExec to run actions of this type.

In the RedisTx context, all commands return a Queued value. It is a proxy object for the actual result, which will only be available after finishing the transaction.

Pub/Sub

publishSource

Arguments

:: RedisCtx m f 
=> ByteString

channel

-> ByteString

message

-> m (f Integer) 

Post a message to a channel (http://redis.io/commands/publish).

pubSubSource

Arguments

:: PubSub

Initial subscriptions.

-> (Message -> IO PubSub)

Callback function.

-> Redis () 

Listens to published messages on subscribed channels and channels matching the subscribed patterns. For documentation on the semantics of Redis Pub/Sub see http://redis.io/topics/pubsub.

The given callback function is called for each received message. Subscription changes are triggered by the returned PubSub. To keep subscriptions unchanged, the callback can return mempty.

Example: Subscribe to the "news" channel indefinitely.

  pubSub (subscribe ["news"]) $ \msg -> do
      putStrLn $ "Message from " ++ show (msgChannel msg)
      return mempty

Example: Receive a single message from the "chat" channel.

  pubSub (subscribe ["chat"]) $ \msg -> do
      putStrLn $ "Message from " ++ show (msgChannel msg)
      return $ unsubscribe ["chat"]

data PubSub Source

Encapsulates subscription changes. Use subscribe, unsubscribe, psubscribe, punsubscribe or mempty to construct a value. Combine values by using the Monoid interface, i.e. mappend and mconcat.

Instances

subscribeSource

Arguments

:: [ByteString]

channel

-> PubSub 

Listen for messages published to the given channels (http://redis.io/commands/subscribe).

unsubscribeSource

Arguments

:: [ByteString]

channel

-> PubSub 

Stop listening for messages posted to the given channels (http://redis.io/commands/unsubscribe).

psubscribeSource

Arguments

:: [ByteString]

pattern

-> PubSub 

Listen for messages published to channels matching the given patterns (http://redis.io/commands/psubscribe).

punsubscribeSource

Arguments

:: [ByteString]

pattern

-> PubSub 

Stop listening for messages posted to channels matching the given patterns (http://redis.io/commands/punsubscribe).

Low-Level Command API

sendRequest :: (RedisCtx m f, RedisResult a) => [ByteString] -> m (f a)Source

sendRequest can be used to implement commands from experimental versions of Redis. An example of how to implement a command is given below.

 -- |Redis DEBUG OBJECT command
 debugObject :: ByteString -> Redis (Either Reply ByteString)
 debugObject key = sendRequest ["DEBUG", "OBJECT", key]

data Reply Source

Low-level representation of replies from the Redis server.

Solution to Exercise

Type of expire inside a transaction:

 expire :: ByteString -> Integer -> RedisTx (Queued Bool)

Type of lindex outside of a transaction:

 lindex :: ByteString -> Integer -> Redis (Either Reply ByteString)