84 lines
2.6 KiB
Lua
84 lines
2.6 KiB
Lua
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------------------------------------------------------------------------------
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-- Redis client module
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--
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-- LICENCE: http://opensource.org/licenses/MIT
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-- Vladimir Dronnikov <dronnikov@gmail.com>
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--
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-- Example:
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-- local redis = dofile("redis.lua").connect(host, port)
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-- redis:publish("chan1", foo")
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-- redis:subscribe("chan1", function(channel, msg) print(channel, msg) end)
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------------------------------------------------------------------------------
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local M
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do
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-- const
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local REDIS_PORT = 6379
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-- cache
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local pairs, tonumber = pairs, tonumber
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--
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local publish = function(self, chn, s)
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self._fd:send(("*3\r\n$7\r\npublish\r\n$%d\r\n%s\r\n$%d\r\n%s\r\n"):format(
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#chn, chn, #s, s
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))
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-- TODO: confirmation? then queue of answers needed
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end
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local subscribe = function(self, chn, handler)
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-- TODO: subscription to all channels, with single handler
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self._fd:send(("*2\r\n$9\r\nsubscribe\r\n$%d\r\n%s\r\n"):format(
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#chn, chn
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))
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self._handlers[chn] = handler
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-- TODO: confirmation? then queue of answers needed
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end
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local unsubscribe = function(self, chn)
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self._handlers[chn] = false
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end
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-- NB: pity we can not just augment what net.createConnection returns
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local close = function(self)
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self._fd:close()
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end
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local connect = function(host, port)
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local _fd = net.createConnection(net.TCP, 0)
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local self = {
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_fd = _fd,
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_handlers = { },
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-- TODO: consider metatables?
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close = close,
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publish = publish,
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subscribe = subscribe,
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unsubscribe = unsubscribe,
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}
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_fd:on("connection", function()
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--print("+FD")
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end)
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_fd:on("disconnection", function()
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-- FIXME: this suddenly occurs. timeout?
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--print("-FD")
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end)
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_fd:on("receive", function(fd, s) --luacheck: no unused
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--print("IN", s)
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-- TODO: subscription to all channels
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-- lookup message pattern to determine channel and payload
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-- NB: pairs() iteration gives no fixed order!
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for chn, handler in pairs(self._handlers) do
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local p = ("*3\r\n$7\r\nmessage\r\n$%d\r\n%s\r\n$"):format(#chn, chn)
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if s:find(p, 1, true) then
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-- extract and check message length
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-- NB: only the first TCP packet considered!
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local _, start, len = s:find("(%d-)\r\n", #p)
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if start and tonumber(len) == #s - start - 2 and handler then
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handler(chn, s:sub(start + 1, -2)) -- ends with \r\n
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end
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end
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end
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end)
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_fd:connect(port or REDIS_PORT, host)
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return self
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end
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-- expose
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M = {
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connect = connect,
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}
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end
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return M
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