Complete rewrite of message handler

Client/CMH.lua

@@ -1,65 +1,34 @@
+local debug = false
+
 local CMH = {}
+local datacache = {}
 
-local links = {}
+local CSMHMsgPrefix = "♠"
+local delim = {"♥", "♚", "♛", "♜"}
+local pck = {REQ = 1, ACK = 2, DAT = 3, NAK = 4}
 
-function CMH.OnReceive(self, event, prefix, _, Type, sender)
+-- HELPERS START
-	if event == "CHAT_MSG_ADDON" and sender == UnitName("player") and Type == "WHISPER" then
+local function debugOut(msg)
-		local source, functionId, link, linkCount, MSG = prefix:match("(%D)(%d%d)(%d%d%d)(%d%d%d)(.+)");
+	if(debug == true) then
-		if not source or not functionId or not link or not linkCount or not MSG then
+		print("CMH Debug: "..msg)
-			return
-		end
-		
-		if(source == "S") then
-			functionId, link, linkCount = tonumber(functionId), tonumber(link), tonumber(linkCount);
-			links[functionId] = links[functionId] or {count = 0};
-			links[functionId][link] = MSG;
-			links[functionId].count = links[functionId].count + 1;
-			if (links[functionId].count ~= linkCount) then
-				return
-			end
-			
-			local fullMessage = table.concat(links[functionId]);
-			links[functionId] = {count = 0};
-			
-			local VarTable = ParseMessage(fullMessage)
-			if not VarTable then
-				return
-			end
-
-			if not(CMH[VarTable[1]]) then
-				return
-			end
-
-			local func = CMH[VarTable[1]][functionId]
-			if func then
-				_G[func](sender, VarTable)
-			end
-			return
-		end
 	end
 end
 
-local CMHFrame = CreateFrame("Frame")
+local function GenerateReqId()
-CMHFrame:RegisterEvent("CHAT_MSG_ADDON")
+	local length = 6
-CMHFrame:SetScript("OnEvent", CMH.OnReceive)
+	local reqId = ""
 
-function RegisterServerResponses(config)
+	for i = 1, length do
-	if(CMH[config.Prefix]) then
+		reqId = reqId .. string.char(math.random(97, 122))
-		return;
 	end
 
-	CMH[config.Prefix] = {}
+	return reqId
-	
-	for functionId, functionName in pairs(config.Functions) do
-		CMH[config.Prefix][functionId] = functionName
-	end
 end
 
-function ParseMessage(str)
+local function ParseMessage(prefix, str)
 	local output = {}
 	local valTemp = {}
 	local typeTemp = {}
-	local delim = {"♠", "♥", "♚", "♛", "♜"}
 	
 	local valMatch = "[^"..table.concat(delim).."]+"
 	local typeMatch = "["..table.concat(delim).."]+"
@@ -81,11 +50,11 @@ function ParseMessage(str)
 	-- Convert value to correct type
 	for k, v in pairs(valTemp) do
 		local varType = typeTemp[k]
-		if(varType == 3) then -- Ints
+		if(varType == 2) then -- Ints
 			v = tonumber(v)
-		elseif(varType == 4) then -- Tables
+		elseif(varType == 3) then -- Tables
 			v = Smallfolk.loads(v, #v)
-		elseif(varType == 5) then -- Booleans
+		elseif(varType == 4) then -- Booleans
 			if(v == "true") then v = true else v = false end
 		end
 		table.insert(output, v)
@@ -97,45 +66,262 @@ function ParseMessage(str)
 	return output
 end
 
-function SendClientRequest(prefix, functionId, ...)
+local function ProcessVariables(reqId, ...)
-	-- ♠ = Prefix prefix
-	-- ♥ = ArgumentPrefix for Strings 
-	-- ♚ = ArgumentPrefix for Ints
-	-- ♛ = ArgumentPrefix for Tables
-	-- ♜ = ArgumentPrefix for Boolean
-	
 	local arg = {...}
-	local splitLength = 230
+	local splitLength = 200
-	local msg = "♠" .. prefix
+	local msg = ""
 	
 	for _, v in pairs(arg) do
 		if(type(v) == "string") then
-			msg = msg .. "♥"
+			msg = msg .. delim[1]
 		elseif(type(v) == "number") then
-			msg = msg .. "♚"
+			msg = msg .. delim[2]
 		elseif(type(v) == "table") then
 			-- use Smallfolk to convert table structure to string
 			v = Smallfolk.dumps(v)
-			msg = msg .. "♛"
+			msg = msg .. delim[3]
 		elseif(type(v) == "boolean") then
 			v = tostring(v)
-			msg = msg .. "♜"
+			msg = msg .. delim[4]
 		end
 		msg = msg .. v
 	end
 	
-	local splits = math.ceil(msg:len() / splitLength)
+	if not datacache[reqId] then
-	local send
+		datacache[reqId] = { count = 1, data = {}}
-	local counter = 1
+	end
-	for i=1, msg:len(), splitLength do
-		send = string.format("%01s%03d%02d%02d", "C", functionId, counter, splits)
-		if ((i + splitLength) > msg:len()) then
-			send = send .. msg:sub(i, msg:len())
-		else
-			send = send .. msg:sub(i, i + splitLength - 1)
-		end
-		counter = counter + 1
 	
-		SendAddonMessage(send, "", "WHISPER", UnitName("player"))
+	for i=1, msg:len(), splitLength do
+		datacache[reqId]["data"][#datacache[reqId]["data"]+1] = msg:sub(i,i+splitLength - 1)
+		datacache[reqId].count = datacache[reqId].count + 1
+	end
+	
+	return datacache[reqId]
+end
+
+-- HELPERS END
+
+-- Rx START
+
+function CMH.OnReceive(self, event, prefix, _, Type, sender)
+	-- Ensure the sender and receiver is the same, the message is an addon message, and the message type is WHISPER
+	if event == "CHAT_MSG_ADDON" and sender == UnitName("player") and Type == "WHISPER" then
+		-- unpack and validate addon message structure
+		local pfx, source, pckId, data = prefix:match("(...)(%u)(%d%d)(.+)")	
+		if not pfx or not source or not pckId or not data then
+			return
+		end
+		
+		-- Make sure we're only processing addon messages using our framework prefix character as welll as server messages
+		if(pfx == CSMHMsgPrefix and source == "S") then
+			debugOut("Received CSMH packet, processing data.")
+			
+			-- convert ID to number so we can compare with our packet list
+			pckId = tonumber(pckId)
+			
+			if(pckId == pck.REQ) then
+				debugOut("REQ received, data: "..data)
+				CMH.OnREQ(sender, data)
+			elseif(pckId == pck.ACK) then
+				debugOut("ACK received, data: "..data)
+				CMH.OnACK(sender, data)
+			elseif(pckId == pck.DAT) then
+				debugOut("DAT received, data: "..data)
+				CMH.OnDAT(sender, data)
+			elseif(pckId == pck.NAK) then
+				debugOut("NAK received, data: "..data)
+				CMH.OnNAK(sender, data)
+			else
+				debugOut("Invalid packet ID, aborting")
+				return
+			end
+		end
 	end
 end
+
+local CMHFrame = CreateFrame("Frame")
+CMHFrame:RegisterEvent("CHAT_MSG_ADDON")
+CMHFrame:SetScript("OnEvent", CMH.OnReceive)
+
+function CMH.OnREQ(sender, data)
+	debugOut("Processing REQ data")
+	-- split header string into proper variables and ensure the string is the expected format
+	local functionId, linkCount, reqId, addon = data:match("(%d%d)(%d%d)(%w%w%w%w%w%w)(.+)");
+	if not functionId or not linkCount or not reqId or not addon then
+		debugOut("Malformed REQ data, aborting.")
+		return
+	end
+	
+	-- make sure the functionId and linkCount is converted to a number
+	functionId, linkCount = tonumber(functionId), tonumber(linkCount);
+	
+	-- if the addon does not exist, abort
+	if not CMH[addon] then
+		CMH.SendNAK(reqId)
+		debugOut("Invalid addon, aborting")
+		return
+	end
+	
+	-- if the functionId does not exist for said addon, abort
+	if not CMH[addon][functionId] then
+		CMH.SendNAK(reqId)
+		debugOut("Invalid addon function, aborting")
+		return
+	end
+	
+	-- the request cache already exists, this should not happen. 
+	-- abort and send error to the client, as well as purge id from cache.
+	if(datacache[reqId]) then
+		CMH.SendNAK(reqId)
+		datacache[reqId] = nil
+		debugOut("Request cache already exists, aborting.")
+		return
+	end
+	
+	-- Insert header info for request id and prepare temporary data storage
+	datacache[reqId] = {addon = addon, funcId = functionId, count = linkCount, data = {}}
+	
+	-- send ACK to client notifying client that data is ready to be received
+	debugOut("REQ OK, sending ACK..")
+	CMH.SendACK(reqId)
+end
+
+function CMH.OnACK(sender, reqId)
+	-- We received ACK but no data is available in cache. This should never happen
+	if not datacache[reqId] then
+		debugOut("ACK received but no data available to transmit. Aborting.")
+		return
+	end
+	
+	-- If data exists, we send it
+	debugOut("ACK validated, data exists. Sending..")
+	CMH.SendDAT(reqId)
+end
+
+function CMH.OnDAT(sender, data)
+	-- Separate REQ ID from payload and verify
+	local reqId, payload = data:match("(%w%w%w%w%w%w)(.*)");
+	if not reqId and not payload then
+		return
+	end
+	
+	-- If no REQ header info has been cached, abort
+	if not datacache[reqId] then
+		debugOut("Data received, but not expected. Aborting.")
+		return
+	end
+	
+	local reqTable = datacache[reqId]
+	local sizeOfDataCache = #reqTable.data
+	
+	-- Some functions are trigger functions and expect no payload
+	-- Skip the rest of the functionality and call the expected function
+	if reqTable.count == 0 then
+		-- Retrieve the function from global namespace and pass variables if it exists 
+		local func = SMH[reqTable.addon][reqTable.funcId]
+		if func then
+			debugOut(func)
+			_G[func](sender, {})
+			datacache[reqId] = nil
+		end
+		return
+	end
+	
+	-- If the size of the cache is larger than expected, abort
+	if sizeOfDataCache+1 > reqTable.count then
+		debugOut("Received more data than expected. Aborting.")
+		return
+	end
+	
+	-- Add payload to cache and update size variable
+	reqTable["data"][sizeOfDataCache+1] = payload
+	sizeOfDataCache = #reqTable.data
+	
+	-- If the last expected message has been received, process it
+	if(sizeOfDataCache == reqTable.count) then
+		-- Concatenate the cache and parse the full payload for function variables to return
+		local fullPayload = table.concat(reqTable.data);
+		local VarTable = ParseMessage(reqTable.addon, fullPayload)
+		
+		-- Retrieve the function from global namespace and pass variables if it exists 
+		local func = CMH[reqTable.addon][reqTable.funcId]
+		if func then
+			debugOut(func)
+			_G[func](sender, VarTable)
+		end
+		
+		-- Delete the request session cache
+		datacache[reqId] = nil
+	end
+end
+
+function CMH.OnNAK(sender, reqId)
+	-- when we receive an error from the server, purge the local cache data
+	debugOut("Purging cache data with REQ ID: "..reqId)
+	datacache[reqId] = nil
+end
+
+-- Rx END
+
+-- Tx START
+
+function CMH.SendREQ(functionId, linkCount, reqId, addon)
+	debugOut("Sending REQ with ID: "..reqId)
+	local send = string.format("%01s%01s%02d%02d%02d%06s%0"..tostring(#addon).."s", CSMHMsgPrefix, "C", pck.REQ, functionId, linkCount, reqId, addon)
+	SendAddonMessage(send, "", "WHISPER", UnitName("player"))
+end
+
+function CMH.SendACK(reqId)
+	local send = string.format("%01s%01s%02d%06s", CSMHMsgPrefix, "C", pck.ACK, reqId)
+	SendAddonMessage(send, "", "WHISPER", UnitName("player"))
+end
+
+function CMH.SendDAT(reqId)
+	-- Build data message header
+	local send = string.format("%01s%01s%02d%06s", CSMHMsgPrefix, "C", pck.DAT, reqId)
+	
+	-- iterate all items in the message data cache and send
+	-- functions can also be trigger functions without any data, only send header and no payload
+	if(#datacache[reqId]["data"] == 0) then
+		SendAddonMessage(send, "", "WHISPER", UnitName("player"))
+	else
+		for _, v in pairs (datacache[reqId]["data"]) do
+			local payload = send..v
+			SendAddonMessage(payload, "", "WHISPER", UnitName("player"))
+		end
+	end
+	
+	-- all items have been sent, cache can be purged
+	debugOut("All data sent, cleaning up cache.")
+	datacache[reqId] = nil
+end
+
+function CMH.SendNAK(reqId)
+	local send = string.format("%01s%01s%02d%06s", CSMHMsgPrefix, "C", pck.NAK, reqId)
+	SendAddonMessage(send, "", "WHISPER", UnitName("player"))
+end
+
+-- Tx END
+
+-- API START
+
+function RegisterServerResponses(config)
+	if(CMH[config.Prefix]) then
+		return;
+	end
+	
+	CMH[config.Prefix] = {}
+	
+	for functionId, functionName in pairs(config.Functions) do
+		CMH[config.Prefix][functionId] = functionName
+	end
+end
+
+function SendClientRequest(prefix, functionId, ...)
+	local reqId = GenerateReqId()
+	local varTable = ProcessVariables(reqId, ...)
+	
+	CMH.SendREQ(functionId, #varTable["data"], reqId, prefix)
+end
+
+--A API END

Client/CMH.toc

@@ -1,7 +1,7 @@
 ## Interface: 30300
 ## Title: CMH
 ## Notes: Client & Server Message Handler framework for communication between server and client.
-## Version: 1.0
+## Version: 2.0
 ## Author: Foereaper, Stoneharry, Terrorblade
 
 smallfolk.lua

Example_StatPointUI/Client/StatPointUI.lua

@@ -138,7 +138,7 @@ function StatPointUI.OnLoad()
 end
 
 function OnCacheReceived(sender, argTable)
-	StatPointUI.cache = argTable[2]
+	StatPointUI.cache = argTable[1]
 	local rowContent = {"Strength", "Agility", "Stamina", "Intellect", "Spirit"}
 	for i = 1, 5 do
 		StatPointUI[rowContent[i]].Val:SetText(StatPointUI.cache[i])

Example_StatPointUI/Client/StatPointUI.toc

@@ -1,7 +1,7 @@
 ## Interface: 30300
 ## Title: StatPointUI
 ## Notes: CMH Stat Point UI example script.
-## Version: 1.0
+## Version: 1.1
 ## Author: Foereaper, Kaev
 ##RequiredDeps: CMH
 

Example_StatPointUI/Server/StatPointUI.lua

@@ -107,8 +107,8 @@ end
 function OnSpendPointRequest(player, argTable)
 	if(StatPointUI.cache[player:GetGUIDLow()][6] > 0) then
 		-- Double check that the stat requested is actually a valid number
-		if(tonumber(argTable[2]) <= 5 and tonumber(argTable[2]) >= 0) then
+		if(tonumber(argTable[1]) <= 5 and tonumber(argTable[1]) >= 0) then
-			StatPointUI.OnPointSpent(player:GetGUIDLow(), argTable[2])
+			StatPointUI.OnPointSpent(player:GetGUIDLow(), argTable[1])
 		end
 	else
 		player:SendBroadcastMessage("You have no points left!")

Server/SMH.lua

@@ -1,70 +1,36 @@
 local smallfolk = smallfolk or require("smallfolk")
+
+local debug = false
+
 local SMH = {}
-local links = {}
+local datacache = {}
 
-function SMH.OnReceive(event, sender, _type, prefix, _, target)
+local CSMHMsgPrefix = "♠"
-	if not sender or not target or not sender.GetName or not target.GetName or type(sender) ~= "userdata" or type(target) ~= "userdata" then
+local delim = {"♥", "♚", "♛", "♜"}
-		return
+local pck = {REQ = 1, ACK = 2, DAT = 3, NAK = 4}
-	end
-	if sender:GetName() == target:GetName() and _type == 7 then
-		local source, functionId, link, linkCount, MSG = prefix:match("(%D)(%d%d%d)(%d%d)(%d%d)(.+)");
-		if not source or not functionId or not link or not linkCount or not MSG then
-			return
-		end
-		if(source == "C") then
-			functionId, link, linkCount = tonumber(functionId), tonumber(link), tonumber(linkCount);
 
-			links[sender:GetGUIDLow()] = links[sender:GetGUIDLow()] or {}
+-- HELPERS START
-			links[sender:GetGUIDLow()][functionId] = links[sender:GetGUIDLow()][functionId] or {count = 0};
+local function debugOut(msg)
-			links[sender:GetGUIDLow()][functionId][link] = MSG;
+	if(debug == true) then
-			links[sender:GetGUIDLow()][functionId].count = links[sender:GetGUIDLow()][functionId].count + 1;
+		print("SMH Debug: "..msg)
-			if (links[sender:GetGUIDLow()][functionId].count ~= linkCount) then
-				return
-			end
-			
-			local fullMessage = table.concat(links[sender:GetGUIDLow()][functionId]);
-			links[sender:GetGUIDLow()][functionId] = {count = 0};
-			
-			local VarTable = ParseMessage(fullMessage)
-			if not VarTable then
-				return
-			end
-			
-			if not(SMH[VarTable[1]]) then
-				return
-			end
-
-			local func = SMH[VarTable[1]][functionId]
-			if func then
-				_G[func](sender, VarTable)
-			end
-			return
-		end
 	end
 end
 
-RegisterServerEvent(30, SMH.OnReceive)
+local function GenerateReqId()
+	local length = 6
+	local reqId = ""
 
-function RegisterClientRequests(config)
+	for i = 1, length do
-	-- If a config table with the Prefix already exists, abort loading it into the register.
+		reqId = reqId .. string.char(math.random(97, 122))
-	if(SMH[config.Prefix]) then
-		return;
 	end
 
-	-- Create subtable for PrefixName
+	return reqId
-	SMH[config.Prefix] = {}
-	
-	-- Insert function ID and function name into the register table.
-	for functionId, functionName in pairs(config.Functions) do
-		SMH[config.Prefix][functionId] = functionName
-	end
 end
 
-function ParseMessage(str)
+local function ParseMessage(prefix, str)
 	local output = {}
 	local valTemp = {}
 	local typeTemp = {}
-	local delim = {"♠", "♥", "♚", "♛", "♜"}
 	
 	local valMatch = "[^"..table.concat(delim).."]+"
 	local typeMatch = "["..table.concat(delim).."]+"
@@ -86,11 +52,11 @@ function ParseMessage(str)
 	-- Convert value to correct type
 	for k, v in pairs(valTemp) do
 		local varType = typeTemp[k]
-		if(varType == 3) then -- Ints
+		if(varType == 2) then -- Ints
 			v = tonumber(v)
-		elseif(varType == 4) then -- Tables
+		elseif(varType == 3) then -- Tables
 			v = smallfolk.loads(v)
-		elseif(varType == 5) then -- Booleans
+		elseif(varType == 4) then -- Booleans
 			if(v == "true") then v = true else v = false end
 		end
 		table.insert(output, v)
@@ -102,44 +68,274 @@ function ParseMessage(str)
 	return output
 end
 
-function Player:SendServerResponse(prefix, functionId, ...)
+local function ProcessVariables(sender, reqId, ...)
-	-- ♠ = Prefix prefix
-	-- ♥ = ArgumentPrefix for Strings 
-	-- ♚ = ArgumentPrefix for Ints
-	-- ♛ = ArgumentPrefix for Tables
-	-- ♜ = ArgumentPrefix for Boolean
-	
 	local arg = {...}
-	local splitLength = 230
+	local splitLength = 200
-	local msg = "♠" .. prefix
+	local msg = ""
 	
 	for _, v in pairs(arg) do
 		if(type(v) == "string") then
-			msg = msg .. "♥"
+			msg = msg .. delim[1]
 		elseif(type(v) == "number") then
-			msg = msg .. "♚"
+			msg = msg .. delim[2]
 		elseif(type(v) == "table") then
 			-- use Smallfolk to convert table structure to string
-			v = smallfolk.dumps(v)
+			v = Smallfolk.dumps(v)
-			msg = msg .. "♛"
+			msg = msg .. delim[3]
 		elseif(type(v) == "boolean") then
 			v = tostring(v)
-			msg = msg .. "♜"
+			msg = msg .. delim[4]
 		end
 		msg = msg .. v
 	end
 	
-	local splits = math.ceil(msg:len() / splitLength)
+	datacache[sender:GetGUIDLow()] = datacache[sender:GetGUIDLow()] or {}
-	local send
+	
-	local counter = 1
+	if not datacache[sender:GetGUIDLow()][reqId] then
+		datacache[sender:GetGUIDLow()][reqId] = { count = 1, data = {}}
+	end
+	
 	for i=1, msg:len(), splitLength do
-		send = string.format("%01s%02d%03d%03d", "S", functionId, counter, splits)
+		datacache[sender:GetGUIDLow()][reqId]["data"][#datacache[sender:GetGUIDLow()][reqId]["data"]+1] = msg:sub(i,i+splitLength - 1)
-		if ((i + splitLength) > msg:len()) then
+		datacache[sender:GetGUIDLow()][reqId].count = datacache[sender:GetGUIDLow()][reqId].count + 1
-			send = send .. msg:sub(i, msg:len())
+	end
-		else
+	
-			send = send .. msg:sub(i, i + splitLength - 1)
+	return datacache[sender:GetGUIDLow()][reqId]
+end
+
+-- HELPERS END
+
+-- Rx START
+
+function SMH.OnReceive(event, sender, _type, prefix, _, target)
+	-- Make sure the sender and receiver of the addon message is set and is the correct type.
+	-- Prevents error spam in the console
+	if not sender or not target or not sender.GetName or not target.GetName or type(sender) ~= "userdata" or type(target) ~= "userdata" then
+		return
+	end
+	
+	-- Ensure the sender and receiver is the same, and the message type is WHISPER
+	if sender:GetName() == target:GetName() and _type == 7 then
+		-- unpack and validate addon message structure
+		local pfx, source, pckId, data = prefix:match("(...)(%u)(%d%d)(.+)")
+		if not pfx or not source or not pckId then
+			return
+		end
+		
+		-- Make sure we're only processing addon messages using our framework prefix character as well as client messages
+		if(pfx == CSMHMsgPrefix and source == "C") then
+			debugOut("Received CSMH packet, processing data.")
+			
+			-- convert ID to number so we can compare with our packet list
+			pckId = tonumber(pckId)
+			
+			if(pckId == pck.REQ) then
+				debugOut("REQ received, data: "..data)
+				SMH.OnREQ(sender, data)
+			elseif(pckId == pck.ACK) then
+				debugOut("ACK received, data: "..data)
+				SMH.OnACK(sender, data)
+			elseif(pckId == pck.DAT) then
+				debugOut("DAT received, data: "..data)
+				SMH.OnDAT(sender, data)
+			elseif(pckId == pck.NAK) then
+				debugOut("NAK received, data: "..data)
+				SMH.OnNAK(sender, data)
+			else
+				debugOut("Invalid packet ID, aborting")
+				return
+			end
 		end
-		counter = counter + 1
-		self:SendAddonMessage(send, "", 7, self)
 	end
 end
+
+RegisterServerEvent(30, SMH.OnReceive)
+
+function SMH.OnREQ(sender, data)
+	debugOut("Processing REQ data")
+	-- split header string into proper variables and ensure the string is the expected format
+	local functionId, linkCount, reqId, addon = data:match("(%d%d)(%d%d)(%w%w%w%w%w%w)(.+)");
+	if not functionId or not linkCount or not reqId or not addon then
+		debugOut("Malformed REQ data, aborting.")
+		return
+	end
+	
+	-- make sure the functionId and linkCount is converted to a number
+	functionId, linkCount = tonumber(functionId), tonumber(linkCount);
+	
+	-- if the addon does not exist, abort
+	if not SMH[addon] then
+		SMH.SendNAK(sender, reqId)
+		debugOut("Invalid addon, aborting")
+		return
+	end
+	
+	-- if the functionId does not exist for said addon, abort
+	if not SMH[addon][functionId] then
+		SMH.SendNAK(sender, reqId)
+		debugOut("Invalid addon function, aborting")
+		return
+	end
+	
+	-- header is OK, create cache
+	datacache[sender:GetGUIDLow()] = datacache[sender:GetGUIDLow()] or {}
+	
+	-- the request cache already exists, this should not happen. 
+	-- abort and send error to the client, as well as purge id from cache.
+	if(datacache[sender:GetGUIDLow()][reqId]) then
+		SMH.SendNAK(sender, reqId)
+		datacache[sender:GetGUIDLow()][reqId] = nil
+		debugOut("Request cache already exists, aborting.")
+		return
+	end
+	
+	-- Insert header info for request id and prepare temporary data storage
+	datacache[sender:GetGUIDLow()][reqId] = {addon = addon, funcId = functionId, count = linkCount, data = {}}
+	
+	-- send ACK to client notifying client that data is ready to be received
+	debugOut("REQ OK, sending ACK..")
+	SMH.SendACK(sender, reqId)
+end
+
+function SMH.OnACK(sender, reqId)
+	-- We received ACK but no data is available in cache. This should never happen
+	if not datacache[sender:GetGUIDLow()][reqId] then
+		debugOut("ACK received but no data available to transmit. Aborting.")
+		return
+	end
+	
+	-- If data exists, we send it
+	debugOut("ACK validated, data exists. Sending..")
+	SMH.SendDAT(sender, reqId)
+end
+
+function SMH.OnDAT(sender, data)
+	-- Separate REQ ID from payload and verify
+	local reqId, payload = data:match("(%w%w%w%w%w%w)(.*)");
+	if not reqId then
+		return
+	end
+	
+	-- If no REQ header info has been cached, abort
+	if not datacache[sender:GetGUIDLow()][reqId] then
+		debugOut("Data received, but not expected. Aborting.")
+		return
+	end
+	
+	local reqTable = datacache[sender:GetGUIDLow()][reqId]
+	local sizeOfDataCache = #reqTable.data
+	
+	-- Some functions are trigger functions and expect no payload
+	-- Skip the rest of the functionality and call the expected function
+	if reqTable.count == 0 then
+		-- Retrieve the function from global namespace and pass variables if it exists 
+		local func = SMH[reqTable.addon][reqTable.funcId]
+		if func then
+			debugOut(func)
+			_G[func](sender, {})
+			datacache[sender:GetGUIDLow()][reqId] = nil
+		end
+		return
+	end
+	
+	-- If the size of the cache is larger than expected, abort
+	if sizeOfDataCache+1 > reqTable.count then
+		debugOut("Received more data than expected. Aborting.")
+		return
+	end
+	
+	-- Add payload to cache and update size variable
+	reqTable["data"][sizeOfDataCache+1] = payload
+	sizeOfDataCache = #reqTable.data
+	
+	-- If the last expected message has been received, process it
+	if(sizeOfDataCache == reqTable.count) then
+		-- Concatenate the cache and parse the full payload for function variables to return
+		local fullPayload = table.concat(reqTable.data);
+		local VarTable = ParseMessage(reqTable.addon, fullPayload)
+		
+		-- Retrieve the function from global namespace and pass variables if it exists 
+		local func = SMH[reqTable.addon][reqTable.funcId]
+		if func then
+			debugOut(func)
+			_G[func](sender, VarTable)
+		end
+		
+		-- Delete the request session cache
+		datacache[sender:GetGUIDLow()][reqId] = nil
+	end
+end
+
+function SMH.OnNAK(sender, reqId)
+	-- when we receive an error from the server, purge the local cache data
+	debugOut("Purging cache data with REQ ID: "..reqId)
+	datacache[sender:GetGUIDLow()][reqId] = nil
+end
+
+-- Rx END
+
+-- Tx START
+
+function SMH.SendREQ(sender, functionId, linkCount, reqId, addon)
+	debugOut("Sending REQ with ID: "..reqId)
+	local send = string.format("%01s%01s%02d%02d%02d%06s%0"..tostring(#addon).."s", CSMHMsgPrefix, "S", pck.REQ, functionId, linkCount, reqId, addon)
+	sender:SendAddonMessage(send, "", 7, sender)
+end
+
+function SMH.SendACK(sender, reqId)
+	local send = string.format("%01s%01s%02d%06s", CSMHMsgPrefix, "S", pck.ACK, reqId)
+	sender:SendAddonMessage(send, "", 7, sender)
+end
+
+function SMH.SendDAT(sender, reqId)
+	-- Build data message header
+	local send = string.format("%01s%01s%02d%06s", CSMHMsgPrefix, "S", pck.DAT, reqId)
+	
+	-- iterate all items in the message data cache and send
+	-- functions can also be trigger functions without any data, only send header and no payload
+	if(#datacache[sender:GetGUIDLow()][reqId]["data"] == 0) then
+		sender:SendAddonMessage(send, "", 7, sender)
+	else
+		for _, v in pairs (datacache[sender:GetGUIDLow()][reqId]["data"]) do
+			local payload = send..v
+			sender:SendAddonMessage(payload, "", 7, sender)
+		end
+	end
+	
+	debugOut("All data sent, cleaning up cache.")
+	-- all items have been sent, cache can be purged
+	datacache[sender:GetGUIDLow()][reqId] = nil
+end
+
+function SMH.SendNAK(sender, reqId)
+	local send = string.format("%01s%01s%02d%06s", CSMHMsgPrefix, "S", pck.NAK, reqId)
+	sender:SendAddonMessage(send, "", 7, sender)
+end
+
+-- Tx END
+
+-- API START
+
+function RegisterClientRequests(config)
+	-- If a config table with the Prefix already exists, abort loading it into the register.
+	if(SMH[config.Prefix]) then
+		return;
+	end
+	
+	-- Create subtable for PrefixName
+	SMH[config.Prefix] = {}
+	
+	-- Insert function ID and function name into the register table.
+	for functionId, functionName in pairs(config.Functions) do
+		SMH[config.Prefix][functionId] = functionName
+	end
+end
+
+function Player:SendServerResponse(prefix, functionId, ...)
+	local reqId = GenerateReqId()
+	local varTable = ProcessVariables(self, reqId, ...)
+	
+	SMH.SendREQ(self, functionId, #varTable["data"], reqId, prefix)
+end
+
+-- API END