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--Copyright (c) 2006-2008 Neil Richardson (nrich@neiltopia.com)
--
--Permission is hereby granted, free of charge, to any person obtaining a copy
--of this software and associated documentation files (the "Software"), to deal
--in the Software without restriction, including without limitation the rights
--to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
--copies of the Software, and to permit persons to whom the Software is
--furnished to do so, subject to the following conditions:
--
--The above copyright notice and this permission notice shall be included in all
--copies or substantial portions of the Software.
--
--THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
--IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
--FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
--AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
--LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
--OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
--IN THE SOFTWARE.
local _M = {}
local table = require('table')
local socket = require('socket')
local CRC32 = require('CRC32')
local SERVER_RETRIES = 10
local STATS_KEYS = {
malloc = true,
sizes = true,
slabs = true,
items = true,
}
local FLAGS = {
'STORABLE',
'COMPRESSED',
'SERIALISED',
}
local function warn(str)
io.stderr:write(string.format('Warning: %s\n', tostring(str)))
end
local function _select_server(cache, key)
local server_count = #cache.servers
local hashfunc = cache.hash or CRC32.Hash
if server_count == 1 then
return cache.servers[1].socket
else
local serverhash = hashfunc(key)
for i = 0, SERVER_RETRIES do
local index = (serverhash % server_count) + 1
local server = cache.servers[index].socket
if not server then
serverhash = hashfunc(serverhash .. i)
else
return server
end
end
end
error('No servers found')
return nil
end
local function _retrieve(cache, key, str)
local server = _select_server(cache, key)
server:send(str .. '\r\n')
local function toboolean(value)
if type(value) == 'string' then
if value == 'true' then
return true
elseif value == 'false' then
return false
end
end
return nil
end
local function extract_flags(str)
local num = tonumber(str)
local flags = {}
for i = #(FLAGS), 1, -1 do
local bf = 2 ^ (i - 1)
if num >= bf then
flags[FLAGS[i]] = true
num = num - bf
end
end
return flags
end
local returndata = {}
while true do
local line, err = server:receive()
if line == 'END' then
break
elseif string.sub(line, 1, 5) == 'VALUE' then
local key,flagstr,size,cas = string.match(line, 'VALUE (%S+) (%d+) (%d+)')
flags = extract_flags(flagstr)
local data = server:receive(size)
if flags.COMPRESSED and cache.compress_enabled then
data = cache.decompress(data)
end
if flags.SERIALISED then
returndata[key] = cache.decode(data)
else
local ldata = tonumber(data) or toboolean(data)
if ldata == nil then
if data == 'nil' then
returndata[key] = nil
else
returndata[key] = data
end
else
returndata[key] = ldata
end
end
end
end
return returndata
end
local function _send(cache, key, str)
local server = _select_server(cache, key)
server:send(str .. "\r\n")
local line, err = server:receive()
if not err then return line end
end
local function _store(cache, op, key, value, expiry)
local str
local flags = 0
if type(value) == 'table' then
str = cache.encode(value)
-- TODO lookup rather than hard code
flags = flags + 4
else
str = tostring(value)
end
if cache.compress_enabled and string.len(str) > cache.compress_threshold then
local cstr = cache.compress(str)
if string.len(cstr) < (string.len(str) * 0.8) then
str = cstr
-- TODO lookup rather than hard code
flags = flags + 2
end
end
local len = string.len(str)
expiry = expiry or 0
local cmd = op .. ' ' .. key .. ' ' .. flags .. ' ' .. expiry .. ' ' .. len .. '\r\n' .. str
local res = _send(cache, key, cmd)
if res ~= 'STORED' then
return false, res
end
return true
end
local function set(cache, key, value, expiry)
return _store(cache, 'set', key, value, expiry)
end
local function add(cache, key, value, expiry)
return _store(cache, 'add', key, value, expiry)
end
local function replace(cache, key, value, expiry)
return _store(cache, 'replace', key, value, expiry)
end
local function get(cache, key)
local dataset = _retrieve(cache, key, 'get ' .. key)
return dataset[key]
end
local function delete(cache, key)
local res = _send(cache, key, 'delete ' .. key)
if res == 'NOT_FOUND' then
return false
end
if res ~= 'DELETED' then
return false, res
end
return true
end
local function incr(cache, key, val)
val = val or 1
local res = _send(cache, key, 'incr ' .. key .. ' ' .. val)
if res == 'ERROR' or res == 'CLIENT_ERROR' then
return false, res
end
return res
end
local function decr(cache, key, val)
val = val or 1
local res = _send(cache, key, 'decr ' .. key .. ' ' .. val)
if res == 'ERROR' or res == 'CLIENT_ERROR' then
return false, res
end
return res
end
local function stats(cache, key)
local servers = {}
key = key or ''
if string.len(key) > 0 and not STATS_KEYS[key] then
error(string.format("Unknown stats key '%s'", key))
end
for i,server in pairs(cache.servers) do
server.socket:send('stats ' .. key .. '\r\n')
local stats = {}
while true do
local line, err = server.socket:receive()
if line == 'END' or line == 'ERROR' then
break
end
local k,v = string.match(line, 'STAT (%S+) (%S+)')
if k then
stats[k] = v
end
end
servers[server.name] = stats
end
return servers
end
local function get_multi(cache, ...)
local dataset = nil
local arg = {...}
if #(cache.servers) > 1 then
dataset = {}
for i,k in ipairs(arg or table.pack(...)) do
local data = _retrieve(cache, k, 'get ' .. k)
dataset[k] = data[k]
end
else
local keys = table.concat(arg, ' ')
dataset = _retrieve(cache, keys, 'get ' .. keys)
end
return dataset
end
local function flush_all(cache)
local success = true
for i,server in ipairs(cache.servers) do
server.socket:send('flush_all\r\n')
local res = assert(server.socket:receive())
if res ~= 'OK' then
success = false
end
end
return success
end
local function disconnect_all(cache)
while true do
local server = table.remove(cache.servers)
if not server then
break
end
server.socket:close()
end
end
local function set_hash(cache, hashfunc)
cache.hash = hashfunc
end
local function set_encode(cache, func)
cache.encode = func
end
local function set_decode(cache, func)
cache.decode = func
end
local function set_compress(cache, func)
cache.compress = func
end
local function set_decompress(cache, func)
cache.decompress = func
end
function _M.Connect(hostlist, port)
local servers = {}
if type(hostlist) == 'table' then
for i,host in pairs(hostlist) do
local h, p
if type(host) == 'table' then
h = host[1]
p = host[2]
elseif type(host) == 'string' then
h = host
elseif type(host) == 'number' then
p = host
h = nil
end
if not h then
h = '127.0.0.1'
end
if not p then
p = 11211
end
local server = socket.connect(h, p)
if not server then
warn('Could not connect to ' .. h .. ':' .. p)
else
table.insert(servers, {socket = server, name = string.format('%s:%d', h, p)})
end
end
else
local address = hostlist
if type(address) == 'number' then
port = address
address = nil
end
if address == nil then
address = '127.0.0.1'
end
if port == nil then
port = 11211
end
local server = socket.connect(address, port)
if not server then
warn('Could not connect to ' .. address .. ':' .. port)
else
servers = {{socket = server, name = string.format('%s:%d', address, port)}}
end
end
if #(servers) < 1 then
error('No servers available')
end
local cache = {
servers = servers,
set_hash = set_hash,
set_encode = set_encode,
set_decode = set_decode,
set_decompress = set_decompress,
set_compress = set_compress,
compress_enabled = false,
enable_compression = function(self, on)
self.compress_enabled = on
end,
hash = nil,
encode = function()
error('No encode function set')
end,
decode = function()
error('No decode function set')
end,
compress = function()
error('No compress function set')
end,
decompress = function()
error('No decompress function set')
end,
-- 10K default
compress_threshold = 10240,
set_compress_threshold = function(self, threshold)
if threshold == nil then
self:enable_compression(false)
else
self.compress_threshold = threshold
end
end,
set = set,
add = add,
replace = replace,
get = get,
delete = delete,
incr = incr,
decr = decr,
get_multi = get_multi,
stats = stats,
flush_all = flush_all,
disconnect_all = disconnect_all,
}
return cache
end
function _M.New(hostlist, port)
return _M.Connect(hostlist, port)
end
return _M
--
-- Memcached.lua
--
-- A pure Lua implementation of a simple memcached client. 1 or more memcached server(s) are currently supported. Requires the luasocket library.
-- See http://www.danga.com/memcached/ for more information about memcached.
--
--
--
-- Synopsis
--
-- require('Memcached')
--
-- memcache = Memcached.Connect('some.host.com', 11000)
-- OR
-- memcache = Memcached.New('some.host.com', 11000)
--
-- memcache:set('some_key', 1234)
-- memcache:add('new_key', 'add new value')
-- memcache:replace('existing_key', 'replace old value')
--
-- cached_data = memcache:get('some_key')
--
-- memcache:delete('old_key')
--
--
--
-- Methods:
--
-- memcache = Memcached.Connect()
-- Connect to memcached server at localhost on port number 11211.
--
-- memcache = Memcached.Connect(host[, port])
-- Connect to memcached server at 'host' on port number 'port'. If port is not provided, port 11211 is used.
--
---memcache = Memcached.Connect(port)
-- Connect to memcached server at localhost on port number 'port'.
--
-- memcache = Memcached.Connect({{'host', port}, 'host', port})
-- Connect to multiple memcached servers.
--
-- memcache:set(key, value[, expiry])
-- Unconditionally sets a key to a given value in the memcache. The value for 'expiry' is the expiration
-- time (default is 0, never expire).
--
-- memcache:add(key, value[, expiry])
-- Like set, but only stores in memcache if the key doesn't already exist.
--
-- memcache:replace(key, value[, expiry])
-- Like set, but only stores in memcache if the key already exists. The opposite of add.
--
-- value = memcache:get(key)
-- Retrieves a key from the memcache. Returns the value or nil
--
-- values = memcache:get_multi(...)
-- Retrieves multiple keys from the memcache doing just one query. Returns a table of key/value pairs that were available.
--
-- memcache:delete(key)
-- Deletes a key. Returns true on deletion, false if the key was not found.
--
-- value = memcache:incr(key[, value])
-- Sends a command to the server to atomically increment the value for key by value, or by 1 if value is nil.
-- Returns nil if key doesn't exist on server, otherwise it returns the new value after incrementing. Value should be zero or greater.
--
-- value = memcache:decr(key[, value])
-- Like incr, but decrements. Unlike incr, underflow is checked and new values are capped at 0. If server value is 1, a decrement of 2 returns 0, not -1.
--
-- servers = memcache:stats([key])
-- Returns a table of statistical data regarding the memcache server(s). Allowed keys are:
-- '', 'malloc', 'sizes', 'slabs', 'items'
--
-- success = memcache:flush_all()
-- Runs the memcached "flush_all" command on all configured hosts, emptying all their caches.
--
-- memcache:disconnect_all()
-- Closes all cached sockets to all memcached servers.
--
-- memcache:set_hash(hashfunc)
-- Sets a custom hash function for key values. The default is a CRC32 hashing function.
-- 'hashfunc' should be defined receiving a single string parameter and returing a single integer value.
--
-- memcache:set_encode(func)
-- Sets a custom encode function for serialising table values. 'func' should be defined receiving a single
-- table value and returning a single string value.
--
-- memcache:set_decode(func)
-- Sets a custom decode function for deserialising table values. 'func' should be defined receiving a
-- single single and returning a single table value
--
-- memcache:enable_compression(onflag)
-- Turns data compression support on or off.
--
-- memcache:set_compress_threshold(size)
-- Set the compression threshold. If the value to be stored is larger than `size' bytes (and compression
-- is enabled), compress before storing.
--
-- memcache:set_compress(func)
-- Sets a custom data compression function. 'func' should be defined receiving a single string value and
-- returning a single string value.
--
-- memcache:set_decompress(func)
-- Sets a custom data decompression function. 'func' should be defined receiving a single string value and
-- returning a single string value.