roryqueue / exredis

Redis client for Elixir

exredis

---

Redis client for Elixir.

---

Installation

Add this to the dependencies:

{:exredis, ">= 0.2.4"}

---

Configuration

In your applications config.exs file you need to add new section for customizing redis connection.

config :exredis,
  host: "127.0.0.1",
  port: 6379,
  password: "",
  db: 0,
  reconnect: :no_reconnect,
  max_queue: :infinity

or

config :exredis,
  url: "redis://user:password@host:1234/10",
  reconnect: :no_reconnect,
  max_queue: :infinity

Usage (web docs)

As mixin

Warning: this example should not be used in production. It spawns new connection to redis on each call, and these connections will not be closed.

defmodule Pi do
  import Exredis

  def get, do: start_link |> elem(1) |> query ["GET", "Pi"]
  def set, do: start_link |> elem(1) |> query ["SET", "Pi", "3.14"]
end

Pi.set
# => "OK"

Pi.get
# => "3.14"

defmodule Api do
  import Exredis.Api

  def set(client), do:
    client |> set "key", "value"

  def get(client), do:
    client |> get "key"

end

{:ok, client} = Exredis.start_link

client |> Api.set
# => "OK"

client |> Api.get
# => "value"

Using Exredis.Api with multiple keys

{:ok, client} = Exredis.start_link

client |> Exredis.Api.sadd("set1", "bar")
# => "1"

client |> Exredis.Api.sadd("set2", ["bar", "foo"])
# => "2"

client |> Exredis.Api.sdiff(["set2", "set1"])
# => ["foo"]

client |> Exredis.Api.sdiffstore("dest", ["set2", "set1"])
# => "1"

Connect to the Redis server

{:ok, client} = Exredis.start_link
# or
client = Exredis.start_using_connection_string("redis://127.0.0.1:6379")

Disconnect from the server

client |> Exredis.stop

Set & Get

# set
client |> Exredis.query ["SET", "FOO", "BAR"]

# get
client |> Exredis.query ["GET", "FOO"]
# => "BAR"

Mset & Mget

# mset
client |> Exredis.query ["MSET" | ["key1", "value1", "key2", "value2", "key3", "value3"]]

# mget
client |> Exredis.query ["MGET" | ["key1", "key2", "key3"]]
# => ["value1", "value2", "value3"]

Transactions

# start
client |> Exredis.query ["MULTI"]

# exec
client |> Exredis.query ["SET", "foo", "bar"]
client |> Exredis.query ["SET", "bar", "baz"]

# commit
client |> Exredis.query ["EXEC"]

Pipelining

client |> Exredis.query_pipe [["SET", :a, "1"], ["LPUSH", :b, "3"], ["LPUSH", :b, "2"]]

Pub/sub

{:ok, client_sub} = Exredis.Sub.start_link
{:ok, client} = Exredis.start_link
pid = Kernel.self

client_sub |> Exredis.Sub.subscribe "foo", fn(msg) ->
  send(pid, msg)
end

receive do
  msg ->
    IO.inspect msg
    # => {:subscribed, "foo", #PID<0.85.0>}
end

client |> Exredis.Api.publish "foo", "Hello World!"

receive do
  msg ->
    IO.inspect msg
    # => {:message, "foo", "Hello World!", #PID<0.85.0>}
end

Pub/sub by a pattern

{:ok, client_sub} = Exredis.Sub.start_link
{:ok, client} = Exredis.start_link
pid = Kernel.self

client_sub |> Exredis.Sub.psubscribe "bar_*", fn(msg) ->
  send(pid, msg)
end

receive do
  msg ->
    IO.inspect msg
    # => {:subscribed, "bar_*", #PID<0.104.0>}
end

client |> Exredis.Api.publish "bar_test", "Hello World!"

receive do
  msg ->
    IO.inspect msg
    # => {:pmessage, "bar_*", "bar_test", "Hello World!", #PID<0.104.0>}
end

Scripting

client |> Exredis.Api.script_load "return 1 + 1"
# => "c301e0c5bc3538d2bad3fdbf2e281887e643ada4"
client |> Exredis.Api.evalsha "c301e0c5bc3538d2bad3fdbf2e281887e643ada4", 0, ["key1"], ["argv1"]
# => "2"

defmodule MyScripts do
  import Exredis.Script

  defredis_script :lua_echo, "return ARGV[1]"
  defredis_script :huge_command, file_path: "lua_scripts/huge_command.lua"
end

client |> MyScripts.lua_echo(["mykey"], ["foo"])
# => "foo"

Supervised example

defmodule SomeApp do
  use Application
  def start(_type, _args) do
    import Supervisor.Spec, warn: false

    children = [
      worker(SomeApp.RedisRepo, [:myredis, "redis://localhost:6379/0"]),
    ]

    opts = [strategy: :one_for_one, name: SomeApp.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

defmodule SomeApp.RedisRepo do
  def start_link(name, uri) do
    client = Exredis.start_using_connection_string(uri)
    true = Process.register(client, name)
    {:ok, client}
  end
end

---

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request