Gammon Forum

local codes = {
  IAC_DO_ATCP = "\255\253\200", -- enables ATCP communication
  IAC_SB_ATCP = "\255\250\200", -- begins an ATCP packet
  IAC_SE      = "\255\240",     -- ends an ATCP packet
  ATCP        = 200,            -- ATCP protocol number
}

local hello_msg = "hello MUSHclient " .. Version() .. "\n" ..
                  "auth 1\n" ..
                  "char_name 1\n" ..
                  "char_vitals 1\n" ..
                  "room_brief 1\n" ..
                  "room_exits 1\n" ..
                  "map_display 1\n" ..
                  "composer 1\n" ..
                  "keepalive 1\n" ..
                  "topvote 1\n" ..
                  "ping 1\n"

local callbacks = setmetatable({}, {
  __index = function(tbl, key)
    local group = {}
    rawset(tbl, key, group)
    return group
  end,
})


local Register = function(msg, callback)
  if type(msg) ~= "string" then
    error("Message name must be a string")
  elseif type(callback) ~= "function" then
    error("Callback must be a function")
  end
  table.insert(callbacks[msg], callback)
end

local Unregister = function(msg, callback)
  if type(msg) ~= "string" then
    error("Message name must be a string")
  elseif type(callback) ~= "function" then
    error("Callback must be a function")
  end
  
  for k,v in ipairs(callbacks[msg]) do
    if v == callback then
      table.remove(callbacks[msg], k)
      break
    end
  end
end

local Startup = function(type, data)
  if type == codes.ATCP then
    if data == "WILL" then
      return true
    elseif data == "SENT_DO" then
      SendPkt(codes.IAC_DO_ATCP .. codes.IAC_SB_ATCP .. hello_msg .. codes.IAC_SE)
      return true
    end
  end
  
  return false
end

local Handle = function(type, data)
  if type ~= codes.ATCP then
    return
  end

  local message, content
  local separator = data:find("%s")
  if separator then
    message, content = data:sub(1, separator-1), data:sub(separator+1)
  else
    message, content = data, ""
  end
  
  for _,callback in ipairs(callbacks[message]) do
    local ok, err = pcall(callback, message, content)
    if not ok then
      TraceOut("Error while executing ATCP callback " ..
               tostring(callback) .. " for message " .. message ..
              ":\n  " .. (err or ""))
    end
  end
  
  -- send to catch-all handlers as well
  for _,callback in ipairs(callbacks["*"]) do
    local ok, err = pcall(callback, message, content)
    if not ok then
      TraceOut("Error while executing ATCP callback " ..
               tostring(callback) .. " for message " .. message ..
              ":\n  " .. (err or ""))
    end
  end
end

return {
  Register = Register,
  Unregister = Unregister,
  Startup = Startup,
  Handle = Handle,
}

ATCP = require("atcp")

foo = function(message, content)
  -- ...
end,

bar = function(message, content)
  -- ...
end,

catchall = function(message, content)
  -- ...
end

OnPluginInstall = function()
  ATCP.Register("Char.Vitals", foo)
  ATCP.Register("Room.Name", bar)
  ATCP.Register("*", catchall) -- receives all messages
end

-- Set up ATCP handlers
OnPluginTelnetRequest = ATCP.Startup
OnPluginTelnetSubnegotiation = ATCP.Handle


-- Alternatively, if you want to handle these events yourself, too:

OnPluginTelnetRequest = function(type, data)
  ATCP.Startup(type, data)
  -- ...
end

OnPluginTelnetSubnegotiation = function(type, data)
  ATCP.Handle(type, data)
  -- ...
end