Cassandredis, a possibly ill-advised hack

gistfile1.rb

# cassandredis.rb - It makes your Cassandra look like a Redis.

require "cassandra/0.7"

class Cassandredis

  # Connect to a keyspace and column family.
  def initialize(keyspace, cf)
    @client = Cassandra.new(keyspace)
    @cf = cf
  end

  # Add a value to a set.
  def sadd(key, member)
    client.insert(cf, "set:#{key}", {member => ''})
  end

  # Count the values in a set.
  def scard(key)
    # This bonks due to a problem in cassandra/0.7 ?
    client.count_columns(cf, "set:#{key}")
  end

  # Determine if a given value is a member of a set
  def sismember(key, member)
    !client.exists?(cf, "set:#{key}", member).nil?
  end

  # Get all the members in a set
  def smembers(key)
    client.get(cf, "set:#{key}").keys
  end

  # Remove a member from a set
  def srem(key, member)
    client.remove(cf, "set:#{key}", member)
  end

  # Add multiple sets
  def sunion(*keys)
    client.
      multi_get(cf, keys.map { |k| key_for(k) }).
      inject([]) { |result, set|
        result << set.last.keys
    }.
      flatten
  end

  protected

  def client
    @client
  end
  
  def cf
    @cf
  end

  def key_for(k)
    "set:#{k}"
  end
end

gizmo = Cassandredis.new("Cassandredis", :Gizmo)
gizmo.sadd("beatles", "john")
gizmo.sadd("beatles", "paul")
gizmo.sadd("beatles", "george")
gizmo.sadd("beatles", "ringo")

# if gizmo.sismember("beatles", "john")
#   puts "John is a Beatle."
# else
#   puts "John is not a Beatle."
# end

# puts "Current Beatles: #{gizmo.smembers("beatles").inspect}"
# 
# gizmo.srem("beatles", "john")
# 
# puts "Current Beatles: #{gizmo.smembers("beatles").inspect}"

gizmo.sadd("stones", "mick")
gizmo.sadd("stones", "keif")
gizmo.sadd("stones", "ronnie")
gizmo.sadd("stones", "charlie")

p gizmo.sunion("beatles", "stones")

# puts "Beatles and Stones: #{gizmo.sunion("beatles", "stones").inspect}"

# p gizmo.scard("beatles")