Supported Commands

miniRedis supports 22 Redis-compatible commands across strings, lists, key management, and administration.

String Commands

SET

SET <key> <value>

Sets <key> to hold the string <value>. Overwrites existing values.

Response: +OK\r\n

Memory: Tracks byte size; triggers eviction if over maxmemory. On OOM failure, rolls back the insert.

SETEX

SETEX <key> <seconds> <value>

Sets <key> with a TTL in seconds. Atomically sets value and expiry.

Response: +OK\r\n

Internals: Creates Entry with expires_at = Instant::now() + Duration::from_secs(seconds), pushes to TTL min-heap.

PSETEX

PSETEX <key> <milliseconds> <value>

Sets <key> with a TTL in milliseconds.

Response: +OK\r\n

Internals: Same as SETEX but uses Duration::from_millis().

GET

GET <key>

Returns the value of <key>. Performs lazy expiration on access.

Response: $<len>\r\n<value>\r\n (or $-1\r\n if missing/expired)

List Commands

LPUSH

LPUSH <key> <value> [value ...]

Pushes one or more values to the head (left) of the list. Creates a new list if the key doesn’t exist.

Response: :<length>\r\n (list length after push)

Error: -WRONGTYPE\r\n if key holds a non-list value.

Memory: Tracks byte delta; rolls back on OOM.

RPUSH

RPUSH <key> <value> [value ...]

Pushes one or more values to the tail (right) of the list.

Response: :<length>\r\n

Error: -WRONGTYPE\r\n if key holds a non-list value.

LPOP

LPOP <key>

Removes and returns the first element from the list.

Response: $<len>\r\n<value>\r\n (or $-1\r\n if list is empty or key missing)

Internals: Removes the key entirely when the list becomes empty. Adjusts memory tracking.

RPOP

RPOP <key>

Removes and returns the last element from the list.

Response: $<len>\r\n<value>\r\n (or $-1\r\n if list is empty or key missing)

Key Management

DEL

DEL <key> [key ...]

Removes the specified keys. A key is ignored if it does not exist.

Response: :<count>\r\n (number of keys actually removed)

Memory: Calculates freed bytes and adjusts the LRU tracker.

EXISTS

EXISTS <key> [key ...]

Returns the number of keys that exist (non-expired).

Response: :<count>\r\n

Internals: Performs lazy expiration — expired keys are re-pushed to the heap for background cleanup.

EXPIRE

EXPIRE <key> <seconds>

Sets a TTL on <key> in seconds. Overwrites any existing TTL.

Response: :1\r\n (TTL set) or :0\r\n (key doesn’t exist)

PERSIST

PERSIST <key>

Removes the TTL from <key>, making it persistent.

Response: :1\r\n (TTL removed) or :0\r\n (key doesn’t exist or had no TTL)

Internals: Performs lazy expiration check before removing TTL.

TTL

TTL <key>

Returns the remaining time to live in seconds.

Response:

• :<seconds>\r\n — remaining TTL
• :-1\r\n — key exists but has no TTL
• :-2\r\n — key doesn’t exist or is expired

PTTL

PTTL <key>

Returns the remaining time to live in milliseconds.

Response: Same format as TTL but in milliseconds.

TYPE

TYPE <key>

Returns the type of value stored at <key>.

Response:

• +string\r\n — value is a string
• +list\r\n — value is a list
• +none\r\n — key doesn’t exist

Protocol & Administration

PING

PING

Tests if the connection is alive.

Response: +PONG\r\n

QUIT

QUIT

Closes the client connection.

Response: +OK\r\n (then server closes the socket)

HELLO

HELLO [protover]

Protocol handshake. Accepts version 2 or 3.

Response: RESP2-style map with server metadata:

*1\r\n
*6\r\n
$4\r\n
name\r\n
$9\r\n
miniRedis\r\n
...

COMMAND

COMMAND

Returns metadata for all 22 supported commands.

Response: Array of CommandInfo entries, each containing:

• Command name
• Arity (negative = variable args)
• Flags (readonly, write, fast, admin)
• First key position
• Last key position
• Key step

INFO

INFO [section]

Returns server statistics. Supported sections: server, clients, memory, stats.

Response: Bulk string in Redis INFO format:

# Server
redis_version:0.1.0
...

# Clients
connected_clients:3
...

CONFIG GET

CONFIG GET <pattern>

Returns configuration values matching <pattern>. Supports * wildcard.

Response: Array of [key, value, key, value, ...] pairs.

Retrievable keys: maxmemory, maxmemory-policy

CONFIG SET

CONFIG SET <key> <value>

Sets a configuration parameter at runtime.

Response: +OK\r\n

Settable keys:

• maxmemory — byte limit (0 = disabled)
• maxmemory-policy — noeviction, allkeys-lru, or volatile-ttl

CLIENT SETINFO

CLIENT SETINFO <attr> <value>

Accepted but not stored (compatibility shim for Redis clients that send this on connect).

Response: +OK\r\n

All other CLIENT subcommands are rejected.

Command Summary Table

Arity note: Negative values indicate variable-length argument lists. For example, -3 means “at least 3 arguments.”