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A Redis client for node.js

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README.md

redis-node - Complete Redis Client for Node.js


Blog post coming.

Features include:

  • FAST!!!! (See benchmarks)
  • A comprehensive test suite.
  • Fully asynchronous.
  • Support for all Redis commands.
  • PUBLISH and SUBSCRIBE support.
  • Full transactional support (including nested transactions) (i.e., MULTI/EXEC/DISCARD) (to my knowledge, not present in redis-node-client).
  • Idiomatic command syntax.
  • Automatic re-establishment of connections to the Redis server.

Installation

npm install redis-node

A Quick Tour

// See ./examples/tour.js
var sys = require("sys");
var redis = require("redis-node");
var client = redis.createClient();    // Create the client
client.select(2);                     // Select database 2

// Assign the string "world" to the "hello" key.
// You can provide a callback to handle the response from Redis
// that gets asynchronously run upon seeing the response.
client.set("hello", "world", function (err, status) {
  if (err) throw err;
  console.log(status); // true
});

// ... but you don't have to provide a callback.
client.set("hello", "world");

// We may or may not be connected yet, but that's ok, since
// the client queues up any commands.

// The commands are also idiomatic
client.hmset("hash", { t: "rex", steg: "asaurus" }, function (err, status) {
  if (err) throw err;
  sys.log(status); // true
});

// Support for transactions
console.log("Transfer from checking to savings.");
client.transaction( function () {
  client.decrby("checking", 100, function (err, balance) {
    if (err) throw err;
    console.log("Checking Balance: " + balance);
  });
  client.incrby("savings", 100, function (err, balance) {
    if (err) throw err;
    console.log("Savings Balance: " + balance);
  });
});

// With automatic transaction discard if there are any syntactic errors
client.transaction( function () {
  client.set("I'm missing a 2nd argument"); // Our client with automatically discard the transaction
});

// Close the connection
setTimeout( function () {
    client.close();
}, 1000);

See test/ for examples of each command.

API Reference

redis.createClient(port, host, options)

Creates a new Client instance connected to the Redis server running on host:port. host defaults to 127.0.0.1 port defaults to 6379 You can pass in an options hash, too. They default to:

  • maxReconnectionAttempts (10) The number of times to try reconnecting to the Redis server before giving up.
  • reconnectionDelay (500) How many milliseconds to wait before the 1st reconnection attempt. Using the strategy of exponential backoff, the delay doubles with every re-connection attempt.

Events

The redis-node client emits important events related to the connection with the Redis server. You can bind an event handler to any of the following events:

  • connected

    Emitted when the client successfully makes a connection FOR THE FIRST TIME. You usually will not need to bind an event handler to connected because the client takes care of queueing up any commands you send it and flushes them to the Redis server once it is connected.

  • disconnected

    Emitted when we drop a connection with the Redis server. This can happen if the connection times out due to no recent activity from the client.

  • reconnecting

    Emitted just before the client attempts to reconnect to the Redis server.

  • reconnected

    Emitted when the client successfully makes a successful reconnection.

  • noconnection

    Emitted when the client gives up its connection attempts.

  • connection error

    Emitted when the there is an error that is a result of the connection with the Redis server. The error object is passed to callback. If you do not register a listener with this event, then the error is thrown and the program exits.

Commands operating on all value types

client.exists(key, callback)

Test if a key exists. Passes true to callback if it exists. Passes false to callback if it does not. client.exists("some-key", function (err, doesExist) { console.log(doesExist); });

client.del(key1, key2, ..., keyn, callback)

Delete a key. Passes the number of keys that were deleted to callback. client.del("key1", "key2", function (err, numRemoved) { console.log(numRemoved); // 2 });

client.type(key, callback)

Passes the type of value stored at key to callback. One of:

  • none if the key does not exist
  • string if the key contains a String value
  • list if the key contains a List value
  • set if the key contains a Set value
  • zset if the key contains a Sorted Set value
  • hash if the key contains a Hash value client.type("key-with-string", function (err, type) { console.log(type); // Either: 'none', 'string', 'list', 'set', 'zset', or 'hash' });

client.keys(pattern, callback)

Passes all the keys matching a given pattern to callback. // The * pattern returns an array of all keys client.keys("*", function (err, arrayOfKeys) { arrayOfKeys.forEach( function (key) { console.log(key); }); });

// .* patterns
client.keys("key*", function (err, arrayOfKeys) {
    arrayOfKeys.forEach( function (key) {
        console.log(key);
    });
});

// ? patterns
client.keys("?ar", function (err, arrayOfKeys) {
    arrayOfKeys.forEach( function (key) {
        console.log(key); // e.g., 'car', 'bar', 'far'
    });
});

client.randomkey(callback)

Passes a random key from the key space to callback. client.randomkey( function (err, key) { console.log(key); });

client.rename(oldName, newName, callback)

Renames the old key name oldName to the new key name newName Passes true to callback. client.rename("old", "new", function (err, didSucceed) { console.log(didSucceed); // true });

client.renamenx(oldName, newName, callback)

Renames the old key name oldName to the new key name newName, if the newName key does not already exist. Passes 1 if newName key did not already exist, to callback. Passes 0 if newName key did already exist, to callback. client.renamenx("old", "new", function (err, didSucceed) { console.log(!!didSucceed); // true });

client.dbsize(callback)

Passes the number of keys in the current db. client.dbsize( function (err, numKeys) { console.log(numKeys); });

client.expire(key, ttl, callback)

Tells Redis to delete the key after ttl seconds. If we are using Redis < 2.1.3 and if a ttl was already set with another prior client.expire invocation, then the new ttl does NOT override the old ttl. If we are using Redis >= 2.1.3 and if a ttl was already set with another prior client.expire invocation, then the new ttl DOES override the old ttl. The expiry can be removed from the key if the key is set to a new value using the client.set(key, value) command or when a key is destroyed via the client.del(key) command. Passes 1 to callback if key has no current ttl expiry. Passes 0 to callback if key does not exist or if we are using Redis < 2.1.3, and key already has a current ttl expiry. client.expire("key", 2, function (err, didSetExpiry) { console.log(!!didSetExpiry); });

client.expireat(key, unixtime, callback)

Tells Redis to delete the key at the unixtime datetime in the future. Works similarly to client.expire(key, ttl, callback) client.expireat("key", parseInt((+new Date) / 1000, 10) + 2, function (err, didSetExpiry) { console.log(didSetExpiry); });

client.ttl(key, callback)

Gets the time to live (i.e., how many seconds before key expires) in seconds of key. Passes the number of seconds before key expires to callback. Passes -1 to callback if key has no ttl expiry. client.ttl("key", function (err, ttl) { console.log(ttl); });

client.select(dbIndex, callback)

Selects the DB with the specified dbIndex. Passes true to callback. client.select(2, function (err, didSucceed) { console.log(didSucceed); // true });

client.move(key, dbIndex, callback)

Moves key from the currently selected DB to the dbIndex DB. You can use client.move as a locking primitive. Passes 1 to callback if key was moved successfully. Passes 0 if the target key was already there or if the source key was not found at all. client.move("key", 3, function (err, didSucceed) { console.log(!!didSucceed); });

client.flushdb(callback)

Deletes all the keys of the currently selected DB. The command never fails. Passes true to callback. client.flushdb( function (err, didSucceed) { console.log(didSucceed); // true });

client.flushall(callback)

Deletes all the keys of all the existing databases, not just the currently selected one. This command never fails. Passes true to callback. client.flushall( function (didSucceed) { console.log(didSucceed); // true });

Commands operating on all value types

client.set(key, value, callback)

Sets key to value. value can be a String, Number, or Buffer. Passes true to callback. client.set("key", "value", function (err, didSet) { console.log(didSet); // true });

client.get(key, callback)

Passes the Buffer value at key to callback if the key exists. Passes null to callback if key does not exist.

MULTI/EXEC (aka transactions)

client.transaction(transactionBlock)

Sends commands inside the function transactionBlock as a transaction. Behind the scenes, we precede the commands inside transactionBlock with a MULTI command and commit the commands with an EXEC command. If there is a syntax error with any of the commands sent in the transaction, EXEC will never be called; instead a DISCARD command will be sent to the Redis server to roll back the transaction. client.transaction( function () { client.rpush("txn", 1); client.rpush("txn", 2); client.rpush("txn", 3, function (err, count) { console.log(count); // 3 }); });

Test Coverage

See ./test/ for the list of tests. Currently, the tests are implemented via the Vows. However, the tests will only work with my fork of vows, so install my branch to see the tests pass: git clone git://github.com/bnoguchi/vows.git git checkout teardownFix npm install Then, to run the tests from the command line. make test You can also run the tests directly with the vows binary from the command line. vows test/*.vows.js

Coming Sooner or Later

  • A distributed API for interacting with a Redis cluster.
  • UDP Support

Contributors

Other Redis Clients for Node.js

3rd Party Libraries

License

MIT License


Author

Brian Noguchi

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