create.lua

local namespace = KEYS[1]

local model = {
  id      = namespace .. ":id",
  all     = namespace .. ":all",
  uniques = namespace .. ":uniques",
  indices = namespace .. ":indices",
  key     = namespace .. ":%s"
}

local meta = {
  uniques = redis.call("SMEMBERS", model.uniques),
  indices = redis.call("SMEMBERS", model.indices)
}

local attributes = ARGV

local function dict(list)
  local ret = {}

  for i = 1, #list, 2 do
    ret[list[i]] = list[i + 1]
  end

  return ret
end

local function non_unique(table)
  for _, att in ipairs(meta.uniques) do
    local key = model.key:format("uniques:" .. att)
    local existing = redis.call("HGET", key, table[att])

    if existing then return att end
  end
end

local function save_uniques(table, id)
  for _, att in ipairs(meta.uniques) do
    local key = model.key:format("uniques:" .. att)

    redis.call("HSET", key, table[att], id)
  end
end

local function delete_indices()
end

local this = dict(attributes)

local not_unique = non_unique(this)

if not_unique then
  return { 500, { not_unique, "not_unique" }}
end

local id = redis.call("INCR", model.id)

save_uniques(this, id)

save.lua

KEYS = { "User:1" }
ARGV = { "fname", "John", "lname", "Doe" }

local _unflatten_attributes = function(list)
  local ret = {}

  for i = 1, #list, 2 do
    ret[list[i]] = list[i + 1]
  end

  return ret
end

local _flatten_attributes = function(table)
  local atts = {}

  for k, v in pairs(table) do
    atts[#atts + 1] = k
    atts[#atts + 1] = v
  end

  return atts
end

local save = function (table)
  redis.call("DEL", key)
  redis.call("HMSET", key, _flatten_attributes(table))
end

local pp = function(table)
  for i, v in ipairs(table) do
    print(string.format("%d. %s", i, v))
  end
end

local pph = function(table)
  for k, v in pairs(table) do
    print(string.format("%s => %s", k, v))
  end
end

local key = KEYS[1]
local id  = string.match(key, "(%w+)$")
local this = _unflatten_attributes(ARGV)

pp(_flatten_attributes({ fname="John", lname="Doe" }))
pph(this)

print(key)
print(id)

print(this.fname)
print(this.lname)

this.fname = "Quentin"
this.lname = "Tarantino"

print(this.fname)
print(this.lname)

-- 1   2      3      4    5      6    7
-- 2 email username  3  fname  lname bday
--
--
-- 0   0   fname John lname Doe

shootout.rb

# encoding: UTF-8

require File.expand_path("./helper", File.dirname(__FILE__))

$VERBOSE = false

def redis
  Ohm.redis
end

setup do
  redis.sadd("User:uniques", "email")
  redis.hset("User:uniques:email", "foo@bar.com", 1)    

  Ohm::Lua.new("./test/lua", redis)
end

test "returns the unique constraint error" do |lua|
  res = lua.run("create-uniques-indices", 
    keys: ["User"], 
    argv: ["email", "foo@bar.com"])

  assert_equal [500, ["email", "not_unique"]], res
end

test "returns the unique constraint error" do |lua|
  res = lua.run("create-uniques-indices", 
    keys: ["User"], 
    argv: ["email", "bar@baz.com"])
  
  assert_equal "1", redis.hget("User:uniques:email", "bar@baz.com")
end


__END__
require "sequel"

DB = Sequel.connect("postgres://cyx@localhost/postgres")
DB[:users].truncate
t = Benchmark.measure do
  1000.times do |i|
    DB[:users].insert(email: "foo#{i}@bar.com", fname: "John#{i}", lname: "Doe#{i}")
  end
end

puts t

puts Ohm.redis.keys("User:*").inspect