Lightweight Redis Client
Lightweight Redis Client inspired by redigo, a Redis client library for golang.
# Accepts a Redis URL and defaults to "redis://127.0.0.1:6379". redis = Redic.new # Processes the command and returns the response. redis.call("SET", "foo", "bar") assert_equal "bar", redis.call("GET", "foo") # Pipelining is implemented by buffering commands, # then calling Redic#commit redis.queue("SET", "foo", "bar") redis.queue("GET", "foo") assert_equal ["OK", "bar"], redis.commit
You can provide the password and the database to be selected. The format for Redis URLs is
redis://user:[email protected]:port/db. As Redis only needs a password for authentication, the user can be omitted:
# Connect to localhost:6380 using "bar" as password and use the # database 2. Both AUTH and SELECT commands are issued after # connecting. The user part of the URL is not provided. redis = Redic.new("redis://:[email protected]:6380/2")
It is also possible to configure a timeout for the connection. The default timeout is 10 seconds.
# Timeout expressed in microseconds. redis = Redic.new(REDIS_URL, 2_000_000) redis.timeout == 2_000_000 #=> true
A client can be re-configured, forcing the next connection to be established with the new details:
redis = Redic.new("redis://localhost:6379") redis.configure("redis://localhost:6380")
Here's one final example using both a Redis URL and a timeout:
# It's recommended to store the REDIS_URL as an environment # variable. Use `fetch` to retrieve values that must be present, # as it raises an error if the value is not found. REDIS_URL = ENV.fetch("REDIS_URL") REDIS_TIMEOUT = ENV.fetch("REDIS_TIMEOUT") redis = Redic.new(REDIS_URL, REDIS_TIMEOUT)
Both the initializer and the
configure method accept a
URL and a
In order to close the connection, call
redis = Redic.new("redis://localhost:6379") redis.quit
With that command,
"QUIT" is sent to Redis and the socket is closed.
Differences with redis-rb
Redic uses hiredis for the connection and for parsing the replies. There are no alternative connection drivers. Unlike redis-rb it doesn't define all the Redis commands, and instead it acts as a transport layer. The lock provided is smaller than that of redis-rb, as it only wraps the writing and reading from the connection. So even if both clients are thread-safe by default, the peformance of a smaller lock is marginally better.
When a client enters a subscribed mode, further reads to retrieve the messages are not thread safe. It is very important to take this into account and to create a different client if you need to send different operations while a client is subscribed to a channel.
# Example of pub/sub usage. c1 = Redic.new c2 = Redic.new # After this command, the client is no longer thread safe. c1.call("SUBSCRIBE", "foo") # That's why we need to publish from a different connection. c2.call("PUBLISH", "foo") # Note that this operation is not thread safe. assert_equal ["message", "foo", "value1"], c1.client.read
You can wrap thread unsafe operations in a mutex:
redis = Redic.new mutex = Mutex.new mutex.synchronize do redis.call("MONITOR") # Display every command sent to Redis. loop do puts redis.client.read end end
You can install it using rubygems.
$ gem install redic