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redis client for node

Merge pull request #887 from NodeRedis/rename-commands

Add rename_commands option

Closes #499
latest commit 8c0d11361a
@BridgeAR BridgeAR authored

redis - a node.js redis client

Build Status Coverage Status Windows Tests

This is a complete and feature rich Redis client for node.js. It supports all Redis commands and focuses on performance.

Install with:

npm install redis


Simple example, included as examples/simple.js:

var redis = require("redis"),
    client = redis.createClient();

// if you'd like to select database 3, instead of 0 (default), call
//, function() { /* ... */ });

client.on("error", function (err) {
    console.log("Error " + err);

client.set("string key", "string val", redis.print);
client.hset("hash key", "hashtest 1", "some value", redis.print);
client.hset(["hash key", "hashtest 2", "some other value"], redis.print);
client.hkeys("hash key", function (err, replies) {
    console.log(replies.length + " replies:");
    replies.forEach(function (reply, i) {
        console.log("    " + i + ": " + reply);

This will display:

mjr:~/work/node_redis (master)$ node example.js
Reply: OK
Reply: 0
Reply: 0
2 replies:
    0: hashtest 1
    1: hashtest 2
mjr:~/work/node_redis (master)$

Note that the API is entire asynchronous. To get data back from the server, you'll need to use a callback. The return value from most of the API is a backpressure indicator.


You can also use node_redis with promises by promisifying node_redis with bluebird as in:

var redis = require('redis');

It'll add a Async to all node_redis functions (e.g. return client.getAsync().then())

// We expect a value 'foo': 'bar' to be present
// So instead of writing client.get('foo', cb); you have to write:
return client.getAsync('foo').then(function(res) {
    console.log(res); // => 'bar'

// Using multi with promises looks like:

return client.multi().get('foo').execAsync().then(function(res) {
    console.log(res); // => 'bar'

Sending Commands

Each Redis command is exposed as a function on the client object. All functions take either an args Array plus optional callback Function or a variable number of individual arguments followed by an optional callback. Here are examples how to use the api:

client.hmset(["key", "test keys 1", "test val 1", "test keys 2", "test val 2"], function (err, res) {});
// Works the same as
client.hmset("key", ["test keys 1", "test val 1", "test keys 2", "test val 2"], function (err, res) {});
// Or
client.hmset("key", "test keys 1", "test val 1", "test keys 2", "test val 2", function (err, res) {});

Note that in either form the callback is optional:

client.set("some key", "some val");
client.set(["some other key", "some val"]);

If the key is missing, reply will be null. Only if the Redis Command Reference states something else it will not be null.

client.get("missingkey", function(err, reply) {
    // reply is null when the key is missing

For a list of Redis commands, see Redis Command Reference

The commands can be specified in uppercase or lowercase for convenience. client.get() is the same as client.GET().

Minimal parsing is done on the replies. Commands that return a single line reply return JavaScript Strings, integer replies return JavaScript Numbers, "bulk" replies return node Buffers, and "multi bulk" replies return a JavaScript Array of node Buffers. HGETALL returns an Object with Buffers keyed by the hash keys.


Connection Events

client will emit some events about the state of the connection to the Redis server.


client will emit ready once a connection is established. Commands issued before the ready event are queued, then replayed just before this event is emitted.


client will emit connect at the same time as it emits ready unless client.options.no_ready_check is set. If this options is set, connect will be emitted when the stream is connected.


client will emit reconnecting when trying to reconnect to the Redis server after losing the connection. Listeners are passed an object containing delay (in ms) and attempt (the attempt #) attributes.


client will emit error when encountering an error connecting to the Redis server or when any other in node_redis occurs.

So please attach the error listener to node_redis.


client will emit end when an established Redis server connection has closed.


client will emit drain when the TCP connection to the Redis server has been buffering, but is now writable. This event can be used to stream commands in to Redis and adapt to backpressure. Right now, you need to check client.command_queue.length to decide when to reduce your send rate and resume sending commands when you get drain.


client will emit idle when there are no outstanding commands that are awaiting a response.


If you have redis-server running on the same computer as node, then the defaults for port and host are probably fine and you don't need to supply any arguments. createClient() returns a RedisClient object.


  • redis.createClient()
  • redis.createClient(options)
  • redis.createClient(unix_socket, options)
  • redis.createClient('redis://user:pass@host:port', options)
  • redis.createClient(port, host, options)

    options is an object with the following possible properties:

  • host:; The host to connect to

  • port: 6370; The port to connect to
  • parser: hiredis; Which Redis protocol reply parser to use. If hiredis is not installed it will fallback to javascript.
  • return_buffers: false; If set to true, then all replies will be sent to callbacks as Buffers instead of Strings.
  • detect_buffers: false; If set to true, then replies will be sent to callbacks as Buffers if any of the input arguments to the original command were Buffers. This option lets you switch between Buffers and Strings on a per-command basis, whereas return_buffers applies to every command on a client.
  • socket_nodelay: true; Disables the Nagle algorithm. Setting this option to false can result in additional throughput at the cost of more latency. Most applications will want this set to true.
  • socket_keepalive true; Whether the keep-alive functionality is enabled on the underlying socket.
  • no_ready_check: false; When a connection is established to the Redis server, the server might still be loading the database from disk. While loading the server will not respond to any commands. To work around this, node_redis has a "ready check" which sends the INFO command to the server. The response from the INFO command indicates whether the server is ready for more commands. When ready, node_redis emits a ready event. Setting no_ready_check to true will inhibit this check.
  • enable_offline_queue: true; By default, if there is no active connection to the redis server, commands are added to a queue and are executed once the connection has been established. Setting enable_offline_queue to false will disable this feature and the callback will be executed immediately with an error, or an error will be emitted if no callback is specified.
  • retry_max_delay: null; By default every time the client tries to connect and fails the reconnection delay almost doubles. This delay normally grows infinitely, but setting retry_max_delay limits it to the maximum value, provided in milliseconds.
  • connect_timeout: 86400000; Setting connect_timeout limits total time for client to reconnect. The value is provided in milliseconds and is counted once the disconnect occurred. The last retry is going to happen exactly at the timeout time. That way the default is to try reconnecting until 24h passed.
  • max_attempts: 0; By default client will try reconnecting until connected. Setting max_attempts limits total amount of connection tries. Setting this to 1 will prevent any reconnect tries.
  • auth_pass: null; If set, client will run redis auth command on connect.
  • family: IPv4; You can force using IPv6 if you set the family to 'IPv6'. See Node.js net or dns modules how to use the family type.
  • disable_resubscribing: false; If set to true, a client won't resubscribe after disconnecting
  • rename_commands: null; pass a object with renamed commands to use those instead of the original functions. See the redis security topics for more info.
var redis = require("redis"),
    client = redis.createClient({detect_buffers: true});

client.set("foo_rand000000000000", "OK");

// This will return a JavaScript String
client.get("foo_rand000000000000", function (err, reply) {
    console.log(reply.toString()); // Will print `OK`

// This will return a Buffer since original key is specified as a Buffer
client.get(new Buffer("foo_rand000000000000"), function (err, reply) {
    console.log(reply.toString()); // Will print `<Buffer 4f 4b>`

client.auth(password, callback)

When connecting to a Redis server that requires authentication, the AUTH command must be sent as the first command after connecting. This can be tricky to coordinate with reconnections, the ready check, etc. To make this easier, client.auth() stashes password and will send it after each connection, including reconnections. callback is invoked only once, after the response to the very first AUTH command sent. NOTE: Your call to client.auth() should not be inside the ready handler. If you are doing this wrong, client will emit an error that looks something like this Error: Ready check failed: ERR operation not permitted.


Forcibly close the connection to the Redis server. Note that this does not wait until all replies have been parsed. If you want to exit cleanly, call client.quit() to send the QUIT command after you have handled all replies.

If flush is set to true, all commands will be rejected instead of ignored after using .end.

This example closes the connection to the Redis server before the replies have been read. You probably don't want to do this:

var redis = require("redis"),
    client = redis.createClient();

client.set("foo_rand000000000000", "some fantastic value");
client.end(); // No further commands will be processed
client.get("foo_rand000000000000", function (err, reply) {
    // This won't be called anymore, since flush has not been set to true!

client.end() is useful for timeout cases where something is stuck or taking too long and you want to start over.


Call unref() on the underlying socket connection to the Redis server, allowing the program to exit once no more commands are pending.

This is an experimental feature, and only supports a subset of the Redis protocol. Any commands where client state is saved on the Redis server, e.g. *SUBSCRIBE or the blocking BL* commands will NOT work with .unref().

var redis = require("redis")
var client = redis.createClient()

    Calling unref() will allow this program to exit immediately after the get command finishes. Otherwise the client would hang as long as the client-server connection is alive.
client.get("foo", function (err, value){
    if (err) throw(err)

Friendlier hash commands

Most Redis commands take a single String or an Array of Strings as arguments, and replies are sent back as a single String or an Array of Strings. When dealing with hash values, there are a couple of useful exceptions to this.


The reply from an HGETALL command will be converted into a JavaScript Object by node_redis. That way you can interact with the responses using JavaScript syntax.


client.hmset("hosts", "mjr", "1", "another", "23", "home", "1234");
client.hgetall("hosts", function (err, obj) {


{ mjr: '1', another: '23', home: '1234' }

client.hmset(hash, obj, [callback])

Multiple values in a hash can be set by supplying an object:

client.HMSET(key2, {
    "0123456789": "abcdefghij", // NOTE: key and value will be coerced to strings
    "some manner of key": "a type of value"

The properties and values of this Object will be set as keys and values in the Redis hash.

client.hmset(hash, key1, val1, ... keyn, valn, [callback])

Multiple values may also be set by supplying a list:

client.HMSET(key1, "0123456789", "abcdefghij", "some manner of key", "a type of value");

Publish / Subscribe

Here is a simple example of the API for publish / subscribe. This program opens two client connections, subscribes to a channel on one of them, and publishes to that channel on the other:

var redis = require("redis"),
    client1 = redis.createClient(), client2 = redis.createClient(),
    msg_count = 0;

client1.on("subscribe", function (channel, count) {
    client2.publish("a nice channel", "I am sending a message.");
    client2.publish("a nice channel", "I am sending a second message.");
    client2.publish("a nice channel", "I am sending my last message.");

client1.on("message", function (channel, message) {
    console.log("client1 channel " + channel + ": " + message);
    msg_count += 1;
    if (msg_count === 3) {

client1.subscribe("a nice channel");

When a client issues a SUBSCRIBE or PSUBSCRIBE, that connection is put into a "subscriber" mode. At that point, only commands that modify the subscription set are valid. When the subscription set is empty, the connection is put back into regular mode.

If you need to send regular commands to Redis while in subscriber mode, just open another connection.

Subscriber Events

If a client has subscriptions active, it may emit these events:

"message" (channel, message)

Client will emit message for every message received that matches an active subscription. Listeners are passed the channel name as channel and the message Buffer as message.

"pmessage" (pattern, channel, message)

Client will emit pmessage for every message received that matches an active subscription pattern. Listeners are passed the original pattern used with PSUBSCRIBE as pattern, the sending channel name as channel, and the message Buffer as message.

"subscribe" (channel, count)

Client will emit subscribe in response to a SUBSCRIBE command. Listeners are passed the channel name as channel and the new count of subscriptions for this client as count.

"psubscribe" (pattern, count)

Client will emit psubscribe in response to a PSUBSCRIBE command. Listeners are passed the original pattern as pattern, and the new count of subscriptions for this client as count.

"unsubscribe" (channel, count)

Client will emit unsubscribe in response to a UNSUBSCRIBE command. Listeners are passed the channel name as channel and the new count of subscriptions for this client as count. When count is 0, this client has left subscriber mode and no more subscriber events will be emitted.

"punsubscribe" (pattern, count)

Client will emit punsubscribe in response to a PUNSUBSCRIBE command. Listeners are passed the channel name as channel and the new count of subscriptions for this client as count. When count is 0, this client has left subscriber mode and no more subscriber events will be emitted.


MULTI commands are queued up until an EXEC is issued, and then all commands are run atomically by Redis. The interface in node_redis is to return an individual Multi object by calling client.multi().

var redis  = require("./index"),
    client = redis.createClient(), set_size = 20;

client.sadd("bigset", "a member");
client.sadd("bigset", "another member");

while (set_size > 0) {
    client.sadd("bigset", "member " + set_size);
    set_size -= 1;

// multi chain with an individual callback
    .keys("*", function (err, replies) {
        // NOTE: code in this callback is NOT atomic
        // this only happens after the the .exec call finishes.
        client.mget(replies, redis.print);
    .exec(function (err, replies) {
        console.log("MULTI got " + replies.length + " replies");
        replies.forEach(function (reply, index) {
            console.log("Reply " + index + ": " + reply.toString());

Multi.exec( callback )

client.multi() is a constructor that returns a Multi object. Multi objects share all of the same command methods as client objects do. Commands are queued up inside the Multi object until Multi.exec() is invoked.

If your code contains an syntax error an EXECABORT error is going to be thrown and all commands are going to be aborted. That error contains a .errors property that contains the concret errors. If all commands were queued successfully and an error is thrown by redis while processing the commands that error is going to be returned in the result array! No other command is going to be aborted though than the onces failing.

You can either chain together MULTI commands as in the above example, or you can queue individual commands while still sending regular client command as in this example:

var redis  = require("redis"),
    client = redis.createClient(), multi;

// start a separate multi command queue
multi = client.multi();
multi.incr("incr thing", redis.print);
multi.incr("incr other thing", redis.print);

// runs immediately
client.mset("incr thing", 100, "incr other thing", 1, redis.print);

// drains multi queue and runs atomically
multi.exec(function (err, replies) {
    console.log(replies); // 101, 2

// you can re-run the same transaction if you like
multi.exec(function (err, replies) {
    console.log(replies); // 102, 3

In addition to adding commands to the MULTI queue individually, you can also pass an array of commands and arguments to the constructor:

var redis  = require("redis"),
    client = redis.createClient(), multi;

    ["mget", "multifoo", "multibar", redis.print],
    ["incr", "multifoo"],
    ["incr", "multibar"]
]).exec(function (err, replies) {

Monitor mode

Redis supports the MONITOR command, which lets you see all commands received by the Redis server across all client connections, including from other client libraries and other computers.

After you send the MONITOR command, no other commands are valid on that connection. node_redis will emit a monitor event for every new monitor message that comes across. The callback for the monitor event takes a timestamp from the Redis server and an array of command arguments.

Here is a simple example:

var client  = require("redis").createClient(),
    util = require("util");

client.monitor(function (err, res) {
    console.log("Entering monitoring mode.");

client.on("monitor", function (time, args) {
    console.log(time + ": " + util.inspect(args));


Some other things you might like to know about.


After the ready probe completes, the results from the INFO command are saved in the client.server_info object.

The versions key contains an array of the elements of the version string for easy comparison.

> client.server_info.redis_version
> client.server_info.versions
[ 2, 3, 0 ]


A handy callback function for displaying return values when testing. Example:

var redis = require("redis"),
    client = redis.createClient();

client.on("connect", function () {
    client.set("foo_rand000000000000", "some fantastic value", redis.print);
    client.get("foo_rand000000000000", redis.print);

This will print:

Reply: OK
Reply: some fantastic value

Note that this program will not exit cleanly because the client is still connected.

Multi-word commands

To execute redis multi-word commands like SCRIPT LOAD or CLIENT LIST pass the second word as first parameter:

client.script('load', 'return 1');
client.multi().script('load', 'return 1').exec(...);
client.multi([['script', 'load', 'return 1']]).exec(...);

client.send_command(command_name, args, callback)

Used internally to send commands to Redis. Nearly all Redis commands have been added to the client object. However, if new commands are introduced before this library is updated, you can use send_command() to send arbitrary commands to Redis. The command has to be lower case.

All commands are sent as multi-bulk commands. args can either be an Array of arguments, or omitted / set to undefined.


Boolean tracking the state of the connection to the Redis server.


The number of commands that have been sent to the Redis server but not yet replied to. You can use this to enforce some kind of maximum queue depth for commands while connected.

Don't mess with client.command_queue though unless you really know what you are doing.


The number of commands that have been queued up for a future connection. You can use this to enforce some kind of maximum queue depth for pre-connection commands.


Current delay in milliseconds before a connection retry will be attempted. This starts at 200.


Multiplier for future retry timeouts. This should be larger than 1 to add more time between retries. Defaults to 1.7. The default initial connection retry is 200, so the second retry will be 340, followed by 578, etc.

Commands with Optional and Keyword arguments

This applies to anything that uses an optional [WITHSCORES] or [LIMIT offset count] in the documentation.


var args = [ 'myzset', 1, 'one', 2, 'two', 3, 'three', 99, 'ninety-nine' ];
client.zadd(args, function (err, response) {
    if (err) throw err;
    console.log('added '+response+' items.');

    // -Infinity and +Infinity also work
    var args1 = [ 'myzset', '+inf', '-inf' ];
    client.zrevrangebyscore(args1, function (err, response) {
        if (err) throw err;
        console.log('example1', response);
        // write your code here

    var max = 3, min = 1, offset = 1, count = 2;
    var args2 = [ 'myzset', max, min, 'WITHSCORES', 'LIMIT', offset, count ];
    client.zrevrangebyscore(args2, function (err, response) {
        if (err) throw err;
        console.log('example2', response);
        // write your code here


Much effort has been spent to make node_redis as fast as possible for common operations. As pipelining happens naturally from shared connections, overall efficiency goes up.

Here are results of multi_bench.js which is similar to redis-benchmark from the Redis distribution.

hiredis parser (Lenovo T450s i7-5600U):

Client count: 5, node version: 2.5.0, server version: 3.0.3, parser: hiredis
         PING,     1/5 min/max/avg/p95:    0/   3/   0.03/   0.00    540ms total, 37037.04 ops/sec
         PING,    50/5 min/max/avg/p95:    0/   4/   0.65/   1.00    260ms total, 76923.08 ops/sec
   SET 4B str,     1/5 min/max/avg/p95:    0/  20/   0.04/   0.00    816ms total, 24509.80 ops/sec
   SET 4B str,    50/5 min/max/avg/p95:    0/  13/   1.00/   2.00    401ms total, 49875.31 ops/sec
   SET 4B buf,     1/5 min/max/avg/p95:    0/   4/   0.06/   1.00   1293ms total, 15467.90 ops/sec
   SET 4B buf,    50/5 min/max/avg/p95:    0/   5/   2.58/   4.00   1033ms total, 19361.08 ops/sec
   GET 4B str,     1/5 min/max/avg/p95:    0/  14/   0.03/   0.00    717ms total, 27894.00 ops/sec
   GET 4B str,    50/5 min/max/avg/p95:    0/   3/   0.62/   1.00    249ms total, 80321.29 ops/sec
   GET 4B buf,     1/5 min/max/avg/p95:    0/   6/   0.03/   0.00    561ms total, 35650.62 ops/sec
   GET 4B buf,    50/5 min/max/avg/p95:    0/   3/   0.64/   1.00    259ms total, 77220.08 ops/sec
 SET 4KiB str,     1/5 min/max/avg/p95:    0/   4/   0.03/   0.00    678ms total, 29498.53 ops/sec
 SET 4KiB str,    50/5 min/max/avg/p95:    0/   3/   0.91/   2.00    364ms total, 54945.05 ops/sec
 SET 4KiB buf,     1/5 min/max/avg/p95:    0/  20/   0.07/   1.00   1354ms total, 14771.05 ops/sec
 SET 4KiB buf,    50/5 min/max/avg/p95:    0/   5/   1.86/   3.00    744ms total, 26881.72 ops/sec
 GET 4KiB str,     1/5 min/max/avg/p95:    0/   3/   0.03/   0.00    575ms total, 34782.61 ops/sec
 GET 4KiB str,    50/5 min/max/avg/p95:    0/   5/   0.82/   2.00    327ms total, 61162.08 ops/sec
 GET 4KiB buf,     1/5 min/max/avg/p95:    0/  25/   0.04/   0.00    808ms total, 24752.48 ops/sec
 GET 4KiB buf,    50/5 min/max/avg/p95:    0/   4/   0.92/   2.00    371ms total, 53908.36 ops/sec
         INCR,     1/5 min/max/avg/p95:    0/  28/   0.03/   0.00    556ms total, 35971.22 ops/sec
         INCR,    50/5 min/max/avg/p95:    0/   4/   0.67/   1.00    269ms total, 74349.44 ops/sec
        LPUSH,     1/5 min/max/avg/p95:    0/   2/   0.03/   0.00    534ms total, 37453.18 ops/sec
        LPUSH,    50/5 min/max/avg/p95:    0/   2/   0.89/   2.00    357ms total, 56022.41 ops/sec
    LRANGE 10,     1/5 min/max/avg/p95:    0/  12/   0.04/   0.00    829ms total, 24125.45 ops/sec
    LRANGE 10,    50/5 min/max/avg/p95:    0/   3/   1.04/   2.00    415ms total, 48192.77 ops/sec
   LRANGE 100,     1/5 min/max/avg/p95:    0/  16/   0.06/   1.00   1212ms total, 16501.65 ops/sec
   LRANGE 100,    50/5 min/max/avg/p95:    0/   5/   1.76/   3.00    707ms total, 28288.54 ops/sec
 SET 4MiB buf,     1/5 min/max/avg/p95:    1/  22/   2.66/   4.00   1335ms total,   374.53 ops/sec
 SET 4MiB buf,    50/5 min/max/avg/p95:   13/ 122/ 101.33/ 114.00   1062ms total,   470.81 ops/sec
 GET 4MiB str,     1/5 min/max/avg/p95:    3/  14/   6.07/  12.00    607ms total,   164.74 ops/sec
 GET 4MiB str,    50/5 min/max/avg/p95:   17/ 431/ 286.75/ 418.00    686ms total,   145.77 ops/sec
 GET 4MiB buf,     1/5 min/max/avg/p95:    3/  38/   6.83/  12.95    684ms total,   146.20 ops/sec
 GET 4MiB buf,    50/5 min/max/avg/p95:   10/ 273/ 194.07/ 253.90    495ms total,   202.02 ops/sec

The hiredis and js parser should most of the time be on the same level. The js parser lacks speed for large responses though. Therefor the hiredis parser is the default used in node_redis. To use hiredis, do:

npm install hiredis redis


To get debug output run your node_redis application with NODE_DEBUG=redis.

How to Contribute

  • Open a pull request or an issue about what you want to implement / change. We're glad for any help!


Many people have have added features and fixed bugs in node_redis. Thanks to all of them!

LICENSE - "MIT License"

Copyright (c) by NodeRedis

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.


Originally developed by Matthew Ranney,

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