RedisEx: extension modules to Redis' native data types and commands

Exactly what the doctor ordered.

Included modules:

• rxkeys - extended keys commands (Module Hub page)
• rxstrings - extended Strings commands (Module Hub page)
• rxhashes - extended Hashes commands (Module Hub page)
• rxlists - extended Lists commands (Module Hub page)
• rxsets - extended Sets commands (Module Hub page)
• rxzsets - extended Sorted Sets commands (Module Hub page)
• rxgeo - extended Geo Sets commands (Module Hub page)

Quick start guide

1. Build a Redis server with support for modules (currently available from the unstable branch).
2. Build the redex modules: make
3. To load a module, Start Redis with the --loadmodule /path/to/module.so option, add it as a directive to the configuration file or send a MODULE LOAD command.

rxkeys

This module provides extended Redis keys commands.

PKEYS pattern

Time complexity: O(N) where N is the number of keys in the database.

Returns keys with names matching pattern. pattern should be given as a POSIX Extended Regular Expression.

Return: Array of Strings, the key names matching.

PDEL pattern

Time complexity: O(N)+O(M) where N is the number of keys in the database and M is the number of elements to delete. The deletion's complexity is O(1) for Strings, and O(L) for keys with multiple elements, where L is the number of elements.

Deletes keys with names matching pattern. pattern should be given as a POSIX Extended Regular Expression.

Return: Integer, the number of keys deleted.

rxstrings

This module provides extended Redis Strings commands.

CHECKAND key value [XX] <command> [arg1] [...]

Time complexity: O(1) + O(command)

Checks a String 'key' for 'value' equality and executes a Redis command on it.

The command can be any of the following Redis String commands:

• APPEND
• DECR[BY]
• GETSET
• INCR[BY]
• INCRBYFLOAT
• PSETEX
• SET[EX|NX]

The XX flag means that the key must exist for the equality to be evaluated.

Note: the key shouldn't be repeated for the executed command.

Reply: Null if not equal or for non existing key when the XX flag is used. On success, the reply depends on the actual command executed.

PREPEND key value

Time complexity: O(1). The amortized time complexity is O(1) assuming the prepended value is small and the already present value is of any size, since the dynamic string library used by Redis will double the free space available on every reallocation.

Prepends a value to a String key.

If key does not exist it is created and set as an empty string, so PREPEND will be similar to SET in this special case.

Reply: Integer, the length of the string after the prepend operation.

SETRANGERAND key offset length charset charcase

Time complexity: O(N) where N is the size of the range generated.

Generates a random string, starting at 'offset' and of length 'length'. An optional charset may be provided:

• ALPHA - letters only: a-z
• DIGIT - digits only: 0-9
• ALNUM - letters and digits
• PUNC - all printable characters other than alphanumerics
• HEX - hexadecimal: a-f, 0-9
• CURSE - censored profanity (!@#$%^&?*)
• BINARY - all characters between 0 and 255
• READABLE - letters only, but more pronounceable
• TEXT - this is the default, any printable character (union of ALPHA + DIGIT + PUNC)

Additionally, an optional charcase argument can be provided:

• MIXEDCASE - this is the default, a mix of upper and lower case. Treated as LOWERCASE charcase for HEX and READABLE charsets.
• LOWERCASE - uses only lowercase letters
• UPPERCASE - uses only uppercase letters

Credit: Meni Katz

Reply: Integer, the length of the String after it was modified.

rxhashes

This module provides extended Redis Hashes commands.

HGETSET key field value

Time complexity: O(1)

Sets the field in Hash key to value and returns the previous value, if any.

Reply: String, the previous value or NULL if field didn't exist.

rxlists

This module provides extended Redis Lists commands.

LPUSHCAPPED key cap ele [ele ...]

Time complexity: O(N+M) where N is the number of elements added and M is the number of elements trimmed.

Pushes elements to the head of a list, but trims it from the opposite end to cap afterwards, if reached.

Reply: Integer, the list's new length.

RPUSHCAPPED key cap ele [ele ...]

Time complexity: O(N+M) where N is the number of elements added and M is the number of elements trimmed.

Pushes elements to the tail of a list, but trims it from the opposite end to cap afterwards, if reached.

Reply: Integer, the list's new length.

LPOPRPUSH srclist dstlist

Time complexity: O(1)

Pops an element from the head of srclist and pushes it to the tail of dstlist.

Reply: Bulk string, the element.

LMPOP list count

Time complexity: O(N) where N is the number of elements that were popped.

Pops count elements from the head of list. If less than count elements are available, it pops as many as possible.

Reply: Array of popped elements.

RMPOP list count

Time complexity: O(N) where N is the number of elements that were popped.

Pops count elements from the tail of list. If less than count elements are available, it pops as many as possible.

Note: RMPOP returns the elements in head-to-tail order.

Reply: Array of popped elements.

LSPLICE srclist dstlist count

Time complexity: O(N) where N is the number of elements moved.

Moves 'count' elements from the tail of 'srclist' to the head of 'dstlist'.

If less than count elements are available, it moves as much elements as possible.

Reply: Integer, the new length of srclist.

Copied from: redis/src/modules/helloworld.c

LXSPLICE srclist dstlist count [ATTACH end] [ORDER ASC|DESC|NOEFFORT]

Time complexity: O(N) where N is the number of elements moved.

Moves count from one end of srclist to one of dstlist's ends.

If less than count elements are available, it moves as much elements as possible.

A positive count removes elements from the head of srclist, and negative from its end.

The optional ATTACH subcommand specifies the end of dstlist to which elements are added and end can be either 0 meaning list's head (the default), or -1 for its tail.

To maintain the order of elements from srclist, LSPLICE may perform extra work depending on the count sign and end.

The optional ORDER subscommand specifies how elements will appear in destlist. The default ASC order means that the series of attached elements will be ordered as in the source list from left to right. DESC will cause the elements to be reversed. NOEFFORT avoids the extra work, so the order determined is:

Reply: Integer, the remaining number of elements in 'srclist'.

rxsets

This module provides extended Redis Sets commands.

MSISMEMBER key1 [key2 ...] member

Time complexity: O(N) where N is the number of keys.

Checks for member's membership in multiple sets.

Reply: Integer, the count of sets to which member belongs.

rxzsets

This module provides extended Redis Sorted Sets commands.

ZPOP key [WITHSCORE]

Time complexity: O(LogN) where N is the number of elements in the Sorted Set.

Pops the element with the lowest score from a Sorted Set.

Reply Array reply, the element popped, optionally with the score in case that the 'WITHSCORE' option is given.

ZREVPOP key [WITHSCORE]

Time complexity: O(LogN) where N is the number of elements in the Sorted Set.

Pops the element with the highest score from a Sorted Set.

Reply Array reply, the element popped, optionally with the score in case that the 'WITHSCORE' option is given.

ZADDCAPPED zset cap score member [score member ...]

Time complexity: O(N*LogM) where N is the number of elements added and M is the number of elements in the Sorted Set.

Adds members to a Sorted Set, keeping it at cap cardinality. Removes top scoring members as needed to meet the limit.

Reply: Integer, the number of members added.

ZADDREVCAPPED zset cap score member [score member ...]

Time complexity: O(N*LogM) where N is the number of elements added and M is the number of elements in the Sorted Set.

Adds members to a Sorted Set, keeping it at cap cardinality. Removes bottom scoring members as needed to meet the limit.

Reply: Integer, the number of members added.

MZRANK key ele [ele ...]

Time complexity: O(N*LogM) where N is the number of elements passed as arguments to the command and M is the number of elements in the Sorted Set.

A variadic variant for ZRANK, returns the ranks of multiple members in a Sorted Set.

Reply: Array of Integers.

MZREVRANK key ele [ele ...]

Time complexity: O(N*LogM) where N is the number of elements passed as arguments to the command and M is the number of elements in the Sorted Set.

A variadic variant for ZREVRANK, returns the reverse ranks of multiple members in a Sorted Set.

Reply: Array of Integers.

MZSCORE key ele [ele ...]

Time complexity: O(N*LogM) where N is the number of elements passed as arguments to the command and M is the number of elements in the Sorted Set.

A variadic variant for ZSCORE, returns the scores of multiple members in a Sorted Set.

Reply: Array of Strings.

ZUNIONTOP K numkeys key [key ...] [WEIGHTS weight [weight ...]] [WITHSCORES]

Time complexity: O(numkeys*log(N) + K*log(numkeys)) where N is the number of elements in a Sorted Set.

Union multiple Sorted Sets and return the K elements with lowest scores. Refer to ZUNIONSTORE's documentation for details on using the command.

Reply: Array reply, the top k elements (optionally with the score, in case the 'WITHSCORES' option is given).

ZUNIONREVTOP K numkeys key [key ...] [WEIGHTS weight [weight ...]] [WITHSCORES]

Time complexity: O(numkeys*log(N) + K*log(numkeys)) where N is the number of elements in a Sorted Set.

Union multiple Sorted Sets and return the K elements with highest scores. Refer to ZUNIONSTORE's documentation for details on using the command.

Reply: Array reply, the top k elements (optionally with the score, in case the 'WITHSCORES' option is given).

rxgeo

This module provides extended Redis Geo Sets commands.

GEOCLUSTER geoset radius unit min-points [namespace]

Time complexity: O(N*LogN) where N is the number of points in the Geo Set.

Density based spatial clustering with random sampling. Creates a set of Geo Sets from geoset, each being a cluster. radius is the maximum distance between near neighbours in the cluster, and min-points is a cluster's minimum size. The default cluster namespace is 'DBRS', geo cluster keys are created using the following syntax: namespace:{geoset}:....

Note: the sampling isn't really random, but that shouldn't matter.

More information:

• http://www.ucalgary.ca/wangx/files/wangx/dbrs.pdf
• http://www.ucalgary.ca/wangx/files/wangx/comparison.pdf

Reply: Integer, the number of clusters created

Misc

TODO

Oh so much :)

Contributing

Issue reports, pull and feature requests are welcome.

License

AGPLv3 - see LICENSE