Manual:Supported Protocols

Supported Protocols

Mudlet negotiates and supports the following telnet based protocols:

• CHARSET Telnet Option
• GMCP - Generic Mud Communication Protocol
• MNES - Mud New-Environ Standard
• MSDP - Mud Server Data Protocol
• MSP - Mud Sound Protocol
• MSSP - Mud Server Status Protocol
• MTTS - Mud Terminal-Type Standard
• MXP - Mud eXtension Protocol
• NEW-ENVIRON Telnet Option
• TLS Transport Layer Security

Default Protocol Settings

CHARSET, GMCP, MSP, MSSP, MTTS, MXP, and NEW-ENVIRON are enabled by default. MSDP and MNES may be enabled in the Settings menu. TLS is enabled from the Connections dialog for supported games.

CHARSET (Encoding)

More and more game servers are looking beyond ASCII encoding to support extended character sets, like UTF-8 encoding, to meet demand for localization of language and the use of emoji characters.

Encoding in Mudlet

Reference our manual page on Unicode for more information on Unicode updating, scripting and trigger support in Mudlet.

Manual Encoding Updates

Mudlet supports manual selection of a server data encoding. Mudlet users may update the server data encoding for a profile by choosing Settings, General and selecting a server data encoding from the corresponding drop-down menu. The server data encoding defaults to ASCII. When the setting is changed, the selected encoding saves with the user's profile information.

Automated Encoding Updates

Negotiating the CHARSET telnet option provides game servers the capability to automatically request a preferred character set with Mudlet per RFC 2066. Game servers may send a telopt WILL CHARSET (42), Mudlet responds with a DO CHARSET (42), then the game server may send SB CHARSET (42) REQUEST (1) <separator_character> <charset>. Mudlet will respond with SB CHARSET (42) ACCEPTED (2) <charset> if it supports that character set. Mudlet will respond with SB CHARSET (42) REJECTED (3) if it refuses the requested character set(s). When Mudlet accepts a requested character set, it automatically updates the server data encoding viewable in the Settings menu. It is possible to send a list of requested character sets to Mudlet by appending additional "<separator_character> <charset>" byte groups to a SB CHARSET (42) REQUEST (1).

Success example:

Server	Mudlet
IAC WILL CHARSET (42)	IAC DO CHARSET (42)
IAC SB CHARSET (42) REQUEST (1) <space> UTF-8 IAC SE	IAC SB CHARSET (42) ACCEPTED (2) UTF-8 IAC SE

The following is an example of an attempted negotiation where the encoding was not available with Mudlet:

Server	Mudlet
IAC WILL CHARSET (42)	IAC DO CHARSET (42)
IAC SB CHARSET (42) REQUEST (1) <space> DEEP-6 IAC SE	IAC SB CHARSET (42) REJECTED (3) IAC SE

If a Mudlet user does not want to negotiate character set, they may choose the Settings, Special Options menu item in Mudlet and enable "Force CHARSET negotiation off". The following is an example of an attempted negotiation where "Force CHARSET negotiation off" is enabled.

Server	Mudlet
IAC WILL CHARSET (42)	IAC DONT CHARSET (42)

CHARSET negotiation is available in Mudlet 4.10+.

GMCP

Generic Mud Communication Protocol, or GMCP, is a protocol for game servers to communicate information with game clients in a separate channel from the one which carries all of the text that makes up the game itself. Enabling the Debug window will show you GMCP events as they are coming in, and to get an idea of what information is currently stored, hit the Statistics button.

When working with GMCP on IRE games, this GMCP reference is a useful tool.

Using GMCP

Receiving GMCP data

To "trigger" on GMCP messages, you'll need to create an event handler - Mudlet will call it for you whenever relevant GMCP data is received.

As an example, create a new script and give it a name of the function you'd like to be called when the relevant GMCP message is received. Then, add the GMCP event you'd like the function to fire on under the registered event handlers left. Lastly, define the function - either in this or any other script - and you'll be done. The GMCP data received will be stored in the corresponding field of the gmcp table, which your function will read from.

Example:

The test_gmcp() function will be called whenever Char.Vitals is received from the game, and it'll echo the latest data on the screen.

Sending GMCP data

Certain modules will only send data when a request is made by your client. In Mudlet, you can make such a request using the command sendGMCP("command"). Read your game's relevant documentation, such as the IRE document on GMCP, for information about specific modules.

See Also: sendGMCP

Managing GMCP modules

While some GMCP modules are enabled by Mudlet by default when you connect with a GMCP enabled game, others may not be 'standard' modules and are instead specific to the game itself. In order to provide a way to manage GMCP modules without scripts causing modules in use by other scripts to be disabled.

Registering user

While this step is no longer strictly required, you can register your 'user' with gmod using

gmod.registerUser("MyUser")

Where MyUser is your plugin/addon/whatever name. However, your user will be automatically registered if you enable or disable any modules using it. Which leads us to...

Enabling modules

Enabling a GMCP module is as easy as:

gmod.enableModule("MyUser", "Module.Name")

If MyUser has not been registered previously, then they will be automatically registered when you call this function. An example of a module which would need to be enabled this way is the IRE.Rift module provided by IRE MUDs.

-- add this to a login trigger, or anything that will get done just once per login
gmod.enableModule("<character name>", "IRE.Rift")

Another example would be the Combat module in Lithmeria, which isn't enabled by default:

-- add this to a login trigger, or anything that will get done just once per login
gmod.enableModule("<character name>", "Combat")

Disabling modules

Disabling a GMCP module is just as easy as enabling it:

gmod.disableModule("MyUser", "Module.Name")

The main difference being that the module will be turned on as soon as you enable it if it is not already enabled. If you disable it, it will not be disabled with the server until every user of that module has disabled it. This prevents script A from disabling modules that script B may still be using.

Thorough GMCP tutorial

A good GMCP tutorial that walks you through receiving and sending GMCP data is available here - take a read!

MSDP

MSDP (Mud Server Data Protocol) is a protocol for game servers to communicate information with game clients in a separate channel from the one which carries all of the text that makes up the game itself. Mudlet can be configured to use MSDP by clicking on the Settings button (or Options->Preferences in the menu, or <alt>p). The option is on the General tab.

Once MSDP is enabled, you will need to reconnect to the game so that Mudlet can inform the server it is ready to receive MSDP information. Please note that some servers don't both send MSDP and GMCP at the same time, so even if you enable both in Mudlet, the server will choose to send only one of them.

Enabling the Debug window will show you MSDP events as they are coming in, and to get an idea of what information is currently stored, hit the Statistics button. Also see MSDP reference for some of the commands and values your server might support.

Using MSDP

Receiving MSDP data

To "trigger" on MSDP messages, you'll need to create an event handler - Mudlet will call it for you whenever relevant MSDP data is received.

As an example, lets create a script that'll track whenever we move - that is, the room number changes. To begin with, we need to ask the game to be sending us updates whenever we move - so do:

lua sendMSDP("REPORT", "ROOM_VNUM")

in the command-line first to enable reporting of the room number and name. Then, create a new script and give it a name of the function you'd like to be called when the relevant MSDP message is received. Add the MSDP event you'd like the function to fire on under the registered event handlers - in our case, msdp.ROOM_VNUM. Lastly, define the function - either in this or any other script - and you'll be done. The MSDP data received will be stored in the corresponding field of the msdp table, which your function will read from.

Example:

The test_msdp() function will be called whenever ROOM_VNUM is received from the game, and it'll echo the latest data on the screen.

Sending MSDP data

You can use sendMSDP to send information via MSDP back to the game. The first parameter to the function is the MSDP variable, and all the subsequent ones are values. See the MSDP documentation for some examples of data that you can send:

-- ask the server to report your health changes to you. Result will be stored in msdp.HEALTH in Mudlet
sendMSDP("REPORT", "HEALTH")

-- client - IAC SB MSDP MSDP_VAR "SEND" MSDP_VAL "AREA NAME" MSDP_VAL "ROOM NAME" IAC SE in the documentation translates to the following in Mudlet:
sendMSDP("SEND", "AREA NAME", "ROOM NAME")

See Also: sendMSDP

MSP

Want to add accessibility and excitement into your game? How about implementing sound and music triggers?

Mud Sound Protocol, or MSP, provides a way for games to send sound and music triggers to clients. Clients have the option to implement a framework where the corresponding triggers play. MSP triggers are sent in one direction to game clients and not to game servers. Sounds may be downloaded manually or automatically if conditions are met.

Games could use telnet option negotiation to signal clients support for MSP (WILL, WONT), and toggling MSP processing on and off (DO, DONT). This is communicated using TELOPT 90, which is reserved (unofficially) for the MSP protocol by our community. Games that do not support telnet option negotiation for MSP should provide a means for their players to toggle this feature on and off.

The latest specification for MSP is located here and available in PDF here.

MSP in Mudlet

Mudlet processes MSP sound and music triggers in three ways:

1. MSP over OOB - Mudlet is capable of receiving hidden, out-of-band telnet sound and music triggers from game servers via messaging with TELOPT 90.
2. MSP for Lua - Mudlet triggers may capture and invoke the receiveMSP function available through the Lua interpreter of Mudlet to process MSP.
3. MSP over GMCP - Mudlet may receive GMCP events from game servers sent with the Client.Media package.

Sound or music triggers that contain a media file name will be searched for in the media folder of the corresponding Mudlet profile that matches the host for the game. If the media folder and the file are found by Mudlet, it will be played, given the host's operating system supports playing that type of media file. If the file is not found, Mudlet could initiate a download of the media file when provided a URL to find the file. Alternatively, game administrators may instruct players on other ways to transfer media files by 1) creating a media folder in their game's Mudlet profile and 2) copying files or extracting them from an archive (zip).

MSP is available in Mudlet 4.4+

Receiving MSP Data

Processing of MSP is enabled by default on new game profiles. Control whether the processing is on or off through the Settings menu in Mudlet.

MSP over OOB

Game administrators may send sound and music triggers over the out-of-bounds (hidden) telnet channel encoded with TELOPT 90 after performing telnet negotiation with Mudlet. The advantage to this is that all of the communication is behind the scenes with no additional trigger requirements for the player (see MSP over Lua). Games will send the bytes of out-of-band messages to Mudlet in a format like this:

IAC SB TELOPT_MSP !!SOUND(cow.wav L=2 V=100) IAC SE

Note: Game admins: This option does require a TELOPT 90 WILL message.

MSP for Lua

Check for MSP support with your game and enable any options that allow sound and music triggers to be sent to your screen.

You can download the package from Media:MSP.zip or follow the instructions below.

Create a sound trigger to invoke the Lua interpreter:

Name	Text	Type	Script
Sound Trigger	^!!SOUND\((\S+?)(?: (.+))?\)$	perl regex	deleteLine() receiveMSP(matches[1])

Create a music trigger to invoke the Lua interpreter:

Name	Text	Type	Script
Music Trigger	^!!MUSIC\((\S+?)(?: (.+))?\)$	perl regex	deleteLine() receiveMSP(matches[1])

Note: Game admins: Best practice is to implement a TELOPT 90 WILL message as a signal to the client that MSP is supported. This is not required.

If your game does not negotiate MSP, you can download Media:MSP-Alternate.zip or you can use this script in your trigger instead of receiveMSP for MSP Sound:

deleteLine()
local mspFile = nil
local mspVolume = 100
local mspLength = 1
local mspPriority = 50
local mspType = nil
local mspURL = nil
-- Strip !!SOUND() from the line
local line = matches[1]:sub(9, -2)
-- Break up the line into tokens
local tokens = line:split(" ")
-- Iterate through the tokens to discover MSP values
for index, value in ipairs(tokens) do
  if index == 1 then
    mspFile = value
  elseif value:find("V=", 1, true) == 1 or value:find("v=", 1, true) == 1 then
    mspVolume = tonumber(value:sub(3))
  elseif value:find("L=", 1, true) == 1 or value:find("l=", 1, true) == 1 then
    mspLength = tonumber(value:sub(3))
  elseif value:find("P=", 1, true) == 1 or value:find("p=", 1, true) == 1 then
    mspPriority = tonumber(value:sub(3))
  elseif value:find("T=", 1, true) == 1 or value:find("t=", 1, true) == 1 then
    mspType = value:sub(3)
  elseif value:find("U=", 1, true) == 1 or value:find("u=", 1, true) == 1 then
    mspURL = value:sub(3)
  end
end
if mspFile == "Off" and mspURL == nil then
  stopSounds()
else
  playSoundFile(
    {
      name = mspFile,
      volume = mspVolume,
      loops = mspLength,
      priority = mspPriority,
      tag = mspType,
      url = mspURL,
    }
  )
end

If your game does not negotiate MSP, you can use this script in your trigger instead of receiveMSP for MSP Music:

deleteLine()
local mspFile = nil
local mspVolume = 100
local mspLength = 1
local mspContinue = true
local mspType = nil
local mspURL = nil
-- Strip !!MUSIC() from the line
local line = matches[1]:sub(9, -2)
-- Break up the line into tokens
local tokens = line:split(" ")
-- Iterate through the tokens to discover MSP values
for index, value in ipairs(tokens) do
  if index == 1 then
    mspFile = value
  elseif value:find("V=", 1, true) == 1 or value:find("v=", 1, true) == 1 then
    mspVolume = tonumber(value:sub(3))
  elseif value:find("L=", 1, true) == 1 or value:find("l=", 1, true) == 1 then
    mspLength = tonumber(value:sub(3))
  elseif value:find("C=", 1, true) == 1 or value:find("c=", 1, true) == 1 then
    if tonumber(value:sub(3)) == 0 then
      mspContinue = false
    else
      mspContinue = true
    end
  elseif value:find("T=", 1, true) == 1 or value:find("t=", 1, true) == 1 then
    mspType = value:sub(3)
  elseif value:find("U=", 1, true) == 1 or value:find("u=", 1, true) == 1 then
    mspURL = value:sub(3)
  end
end
if mspFile == "Off" and mspURL == nil then
  stopMusic()
else
  playMusicFile(
    {
      name = mspFile,
      volume = mspVolume,
      loops = mspLength,
      continue = mspContinue,
      tag = mspType,
      url = mspURL,
    }
  )
end

MSP over GMCP

Reference Mudlet's documentation on the MUD Client Media Protocol specification for more information.

Note: Game admins: Do not implement a TELOPT 90 WILL message exchange when exclusively using this option.

MSP Troubleshooting

• Wildcards ? or * within the file name do not trigger automatic sound or music downloads. Ensure the sound was downloaded previously prior to using a wildcard.
• Mudlet < 4.11 would not play the MSP sound if it had unknown elements, Mudlet 4.12+ will ignore the unknown elements and do the best it can to play the sound.

MSP Specification

For more insight into the syntax of sound and music triggers, please reference the specification.

Sound packs

As most games have been around for a long time, they often use Mud Sound Protocol (MSP) to play sounds. We often find that the game administrators have documented a downloadable soundpack on their website, or that a 3rd party has made one. In Mudlet, a profile is created for each game, and you can manually create a media folder inside of it and drop in the media files (sound, music). For games using MSP, you can create simple triggers to play them which are documented above.

MSSP

Mud Server Status Protocol, or MSSP, provides a way for game crawlers (i.e. MSSP Mud Crawler) and game listing sites (search for Listings here) to gather detailed information about a game, including dynamic information like boot time and the current amount of online players. It also makes submitting a new game entry very simple on game listing sites. A player or administrator is only required to fill in the hostname and port and other information is gathered from behind the scenes.

MSSP in Mudlet

The MSSP data presented in Mudlet will enable MSSP standard data fields to be made accessible for scripting. Some useful fields include the game name, number of players, uptime, game hostname, game port, codebase, admin contact, Discord invite URL, year created, link to an icon, ip address, primary language, game location, website and several others may be available. It is up to the game in question to populate the data, so don't expect all fields to be filled in.

MSSP is available in Mudlet 4.1+.

Receiving MSSP Data

To receive MSSP data in Mudlet, these conditions must be met:

1. The Enable MSSP box in the Settings window of Mudlet must be checked (default on).
2. The game must negotiate MSSP with clients like Mudlet at its login screen. Details here.

To see whether your game supports MSSP, after connecting, type lua mssp. If the game does not support MSSP, you will see an empty table mssp = {}. If it does you will see information similar to the example below. The data may be accessed in a similar way to the instructions for GMCP listed above. Typically, MSSP data is only sent once per connection.

mssp = {
  HOSTNAME = "stickmud.com",
  VT100 = "1",
  UPTIME = "1565657220",
  MSDP = "0",
  MCP = "0",
  GMCP = "1",
  PORT = "7680",
  ["MINIMUM AGE"] = "13",
  PUEBLO = "0",
  INTERMUD = "-1",
  SKILLS = "100",
  ["HIRING BUILDERS"] = "0",
  PLAYERS = "6",
  CONTACT = "[email protected]",
  CODEBASE = "LDMud 3.5.0 (3.5.1)",
  ["HIRING CODERS"] = "0",
  ["PAY FOR PERKS"] = "0",
  LOCATION = "Canada",
  GAMESYSTEM = "Custom",
  MCCP = "0",
  SUBGENRE = "Medieval Fantasy",
  ROOMS = "10000",
  STATUS = "Live",
  FAMILY = "LPMud",
  LEVELS = "150",
  CREATED = "1991",
  ["PAY TO PLAY"] = "0",
  IP = "24.138.28.11",
  MOBILES = "-1",
  GAMEPLAY = "Hack and Slash",
  CLASSES = "8",
  NAME = "StickMUD",
  SSL = "7670", -- legacy key, use TLS now please!
  TLS = "7670",
  ANSI = "1",
  ICON = "https://www.stickmud.com/favicon.ico",
  RACES = "12",
  UTF-8 = "0",
  AREAS = "-1",
  MXP = "0",
  HELPFILES = "-1",
  ["XTERM 256 COLORS"] = "0",
  MSP = "1",
  OBJECTS = "9780",
  WEBSITE = "https://www.stickmud.com",
  GENRE = "Fantasy",
  DISCORD = "https://discord.gg/erBBxt",
  LANGUAGE = "English"
}

MTTS

MUD servers frequently seek information about the capabilities of a MUD Client. Despite the availability of various methods, achieving consistency and reliability in this endeavor has proven challenging. The Mud Terminal Type Standard (MTTS) aims to alleviate these issues by introducing a transparent and straightforward standard for MUD Clients to communicate their terminal capabilities. This standard builds upon and formalizes RFC 1091, which outlines the Telnet Terminal-Type Option.

MTTS in Mudlet

By incorporating the Mud Terminal-Type Standard (MTTS), Mudlet will communicate with interested servers that it possesses the following capabilities:

• Support for ANSI Color Codes: The client supports all common ANSI color codes.
• UTF-8 Character Encoding: The client utilizes UTF-8 character encoding.
• Support for 256 Color Codes: Mudlet is equipped to handle all 256 color codes.
• OSC Color Palette: Mudlet acknowledges support for the OSC color palette.
• Screen Reader Support: Mudlet offers support for screen readers, with opt-in functionality (not advertised by default).
• Truecolor Codes: Mudlet supports truecolor codes using semicolon notation.
• Mud New Environment Standard (MNES) Support: The client adheres to the Mud New Environment Standard for information exchange.
• TLS Encryption: The client supports Transport Layer Security for data encryption.

Screen Reader Opt-In

Users can find on the Accessibility tab under the Settings menu a checkbox identified as "Advertise screen reader use via protocols supporting this notice" which when checked will notify interested game servers. This information may be used to optimize the gaming experience.

Available MTTS Information

Through a Telnet TERMINAL-TYPE Option negotiation, Mudlet transfers a bitvector to game servers, (i.e., 2349) for processing. A bitvector, also known as a bitmap, is a data structure that represents a fixed-size sequence of binary digits or bits. In a bitvector, each bit corresponds to a specific position or index in the sequence, and its value can be either 0 or 1. The MTTS bitvector represents is a set of flags and boolean values, where each bit can represent the state of a particular boolean condition or flag. For example, if the third bit is set to 1, it indicates that the client is using UTF-8 character encoding. A 0 indicator would indicate that UTF-8 was not supported.

MTTS Bitvector

Bit	Property	Meaning
1	ANSI	Client supports all common ANSI color codes.
2	VT100	Client supports all common VT100 codes.
4	UTF-8	Client is using UTF-8 character encoding.
8	256 COLORS	Client supports all 256 color codes.
16	MOUSE TRACKING	Client supports xterm mouse tracking.
32	OSC COLOR PALETTE	Client supports OSC and the OSC color palette.
64	SCREEN READER	Client is using a screen reader.
128	PROXY	Client is a proxy allowing different users to connect from the same IP address.
256	TRUECOLOR	Client supports truecolor codes using semicolon notation.
512	MNES	Client supports the Mud New Environment Standard for information exchange.
1024	MSLP	Client supports the Mud Server Link Protocol for clickable link handling.
2048	TLS	Client supports Transport Layer Security for data encryption.

Negotiating MTTS

Per the MTTS guidance, game servers should initiate up to 4 TTYPE requests to complete the TTYPE cycling routine within a given connection. If the connection is reset, negotiate TTYPE again. Reference the MTTS website for more information.

Server	Mudlet
IAC DO TTYPE (24) IAC SE	IAC WILL TTYPE (24) IAC SE
IAC SB TTYPE (24) SEND (1) IAC SE	IAC SB TTYPE (24) IS (0) MUDLET IAC SE
IAC SB TTYPE (24) SEND (1) IAC SE	IAC SB TTYPE (24) IS (0) ANSI-TRUECOLOR IAC SE
IAC SB TTYPE (24) SEND (1) IAC SE	IAC SB TTYPE (24) IS (0) MTTS 2349 IAC SE
IAC SB TTYPE (24) SEND (1) IAC SE	IAC SB TTYPE (24) IS (0) MTTS 2349 IAC SE

If a Mudlet user does not want to enable Mud Terminal Type Standard, they may choose the Settings, General menu item in Mudlet and toggle off the "Enable MTTS" checkbox.

MTTS is available in Mudlet 4.18+.

MXP

MXP is based loosely on the HTML and XML standards supported by modern web browsers. It is only "loosely" based upon these standards because games require dynamic, streaming text, rather than the page-oriented view of web browsers. Also, the existing standards are needlessly verbose for use on a game where text efficiency is important.

In addition, there are additional security concerns to worry about with MXP. While support for HTML tags within a line is desired, players on a game can exploit this power and cause problems. Certain HTML functions need to be restricted so that players cannot abuse them. For example, while it might be desirable to allow players to change the font or color of their chat messages, you would not want to allow them to display a large graphics image, or execute script commands on the client of other users. MXP handles this by grouping the various tags and commands into secure and open categories, and preventing the secure tags from being used by players.

Mudlet implements a subset of MXP features - the most popular ones that are actually in use. Mudlet supports MXP links (including send to prompt and open in browser in Mudlet 3.17+), pop-up menus, creation of custom elements, and line modes. As a game admin, you can ask what features are supported with the <SUPPORT> command.

MXP in Mudlet

Just like GMCP, MXP data is available in the mxp. namespace and events are raised. To see all MXP events, turn on Debug mode.

function testmxpsend()
  print("Text for the link is: ".. mxp.send.href)
  print("Commands to do are: ")
  display(mxp.send.actions)
  print("\n")
end

registerAnonymousEventHandler("mxp.send", "testmxpsend")

Note: Available in Mudlet 4.8+

Receiving MXP Data

MXP example in Mudlet

Processing of MXP is enabled by default on new game profiles. Control whether the processing is on or off through the Settings menu in Mudlet.

Simple example of receiving MXP Data (Server owners)

<SEND href=\"&text;\">  go north...  </SEND>"

This creates a clickable link that will enable the player to navigate without typing the directions into Mudlet. MXP sends the data immediately when clicked.

Advanced example of receiving MXP Data (Server owners)

<send href='examine &#34;&name;&#34;|get &#34;&name;&#34;' hint='Right mouse click to act on this item|Get &desc;|Examine &desc;|Look in &desc;' expire=get>\" ATT='name desc'>

This creates a clickable link that will 'examine' an item. It also enables a right-click function wherein the player can select to either examine or get the item (in this case &name; is the item and &desc; is the item's description ).

MXP Specification

MXP was originally developed and supported by the Zuggsoft team. For more insight into the syntax, reference the specification or the PDF here. Mudlet has a partial implementation version 1.0 of the MXP spec - to see what is supported, ask Mudlet with the <SUPPORT> tag.

NEW-ENVIRON

To enhance the player experience through sharing more client-supported details, the Telnet New-Environ Option may be used to transfer client environment variables from Mudlet to game servers. Sharing supporting information on information such as encoding, terminal emulation, and accessibility options aims to improve initial player setup and increase the retention rate for new gaming community members.

NEW-ENVIRON in Mudlet

Mudlet supports two methods of information exchange via NEW-ENVIRON, the first via RFC 1572: Telnet New-Environ Option (on by default), and the second is MNES: Mud New-Environ Standard (off by default), which shares a standardized set of client information across multiple clients.

Client Environment Variable Updates

Mudlet provides a user-friendly interface for managing environmental variables through its Settings menu. For certain environmental variables, manual selections made in the Settings menus can dynamically notify servers that have expressed interest in the client's environmental variables through the negotiation of the NEW-ENVIRON option. For instance, when a Mudlet user updates the data encoding for a server profile by navigating to Settings, General, and choosing a specific data encoding from the drop-down menu, this information becomes available for transmission via both the RFC (default) and MNES (requires user enabling) options.

Screen Reader Opt-In

Users can find on the Accessibility tab under the Settings menu a checkbox identified as "Advertise screen reader use via protocols supporting this notice" which when checked will notify interested game servers. This information may be used to optimize the gaming experience.

Available Client Environment Variables RFC 1572

Two types of variables are used per RFC 152, well-known variables defined with VAR (0) and for less common variables, USERVAR (3). Currently, per the RFC, Mudlet shares its variables via the USERVAR (3) type.

Some client variables updates may be reported ad-hoc with an INFO (2) message. If there is no value for a defined variable, a VAL (1) will be sent without a value following it.

Type	Variable	Example Values	Mudlet Default	OPT-IN	INFO	Purpose	Available
USERVAR	256_COLORS	1, 0	1			Client supports all 256 color codes. 1 = Yes/True/ACK.	4.18
USERVAR	ANSI	1, 0	1			Client supports all common ANSI color codes. 1 = Yes/True/ACK.	4.18
USERVAR	BOLD_IS_BRIGHT	2, 1, 0			Yes	Use bright colors always (2), sometimes (1), or never (0).	future
USERVAR	CHARSET	UTF-8, ASCII			Yes	Encoding set in the client	4.18
USERVAR	CLIENT_NAME	MUDLET	MUDLET			Name of the client.	4.18
USERVAR	CLIENT_VERSION	4/18, 4/17/2-DEV				Version of the client.	4.18
USERVAR	MTTS	2349			Yes	Bitvector defined in the Mud Terminal Type Standard (MTTS).	4.18
USERVAR	OSC_COLOR_PALETTE	1, 0				Client supports OSC and the OSC color palette. 1 = Yes/True/ACK.	4.18
USERVAR	SCREEN_READER	1, 0	0	Yes	Yes	Client is using a screen reader. 1 = Yes/True/ACK.	4.18
USERVAR	TERMINAL_TYPE	ANSI-TRUECOLOR, ANSI-256COLOR, ANSI, XTERM, VT100, DUMB	ANSI-TRUECOLOR			Terminal type of the client	4.18
USERVAR	TLS	1, 0				Client supports Transport Layer Security for data encryption. 1 = Yes/True/ACK.	4.18
USERVAR	TRUECOLOR	1, 0				Client supports truecolor codes using semicolon notation. 1 = Yes/True/ACK.	4.18
USERVAR	UTF-8	1, 0			Yes	Client is using UTF-8 character encoding. 1 = Yes/True/ACK.	4.18
USERVAR	VT100	1, 0	0			Client supports all common VT100 codes. 1 = Yes/True/ACK. This is not applicable for Mudlet and while defined, is not used.	4.18
USERVAR	WORD_WRAP	100			Yes	Client wraps text at this value	4.18

Negotiating NEW-ENVIRON

Negotiating the NEW-ENVIRON Telnet option empowers game servers to request one, multiple, or all client environment variables configured within Mudlet. The process unfolds with the game server sending a Telopt DO NEW-ENVIRON (39), prompting Mudlet to respond with a WILL NEW-ENVIRON (39). Subsequently, the game server can send SB NEW-ENVIRON (39) SEND to receive all available environment variables. Mudlet responds with SB NEW-ENVIRON (39) IS (0) < VAR (0) | USERVAR (3) > "<variable>" [VAL (1)] ["<value>"] [ .. [ VAR (0) | USERVAR (3) ] "<variable>" VAL (1) "<value>"] containing the list of environmental variables.

Once an environmental variable is transmitted to a server within the ongoing connection, Mudlet replies with SB NEW-ENVIRON (39) INFO (2) < VAR (0) | USERVAR (3) > "<variable>" [VAL (1)] ["<value>"] messages for select variables. Importantly, no reply from the server is required in this context. If there is a need to specify a particular list of requested environmental variables to Mudlet, the format SB NEW-ENVIRON (39) SEND < VAR (0) | USERVAR (3) > "<variable>" [ .. < VAR (0) | USERVAR (3) > "<variable>" ] can be employed.

Success example #1 (one environmental variable):

Server	Mudlet
IAC DO NEW-ENVIRON (39) IAC SE	IAC WILL NEW-ENVIRON (39) IAC SE
IAC SB NEW-ENVIRON (39) SEND (1) USERVAR (3) CHARSET IAC SE	IAC SB NEW-ENVIRON (39) IS (0) USERVAR (3) CHARSET VAL (1) UTF-8 IAC SE

Success example #2 (all environmental variables):

Server	Mudlet
IAC DO NEW-ENVIRON (39) IAC SE	IAC WILL NEW-ENVIRON (39) IAC SE
IAC SB NEW-ENVIRON (39) SEND (1) IAC SE	IAC SB NEW-ENVIRON (39) IS (0) USERVAR (3) 256_COLORS VAL (1) 1 USERVAR (3) ANSI VAL (1) 1 USERVAR (3) CHARSET VAL (1) UTF-8 USERVAR (3) CLIENT_NAME VAL (1) MUDLET USERVAR (3) CLIENT_VERSION VAL (1) 4/17/2-DEV USERVAR (3) USERVAR (3) MTTS VAL (1) 2349 USERVAR (3) OSC_COLOR_PALETTE VAL (1) 1 USERVAR (3) SCREEN_READER VAL (1) USERVAR (3) TERMINAL_TYPE VAL (1) ANSI-TRUECOLOR USERVAR (3) TLS VAL (1) 1 USERVAR (3) TRUECOLOR VAL (1) 1 USERVAR (3) UTF-8 VAL (1) 1 USERVAR (3) VT100 VAL (1) 0 USERVAR (3) WORD_WRAP VAL (1) 100 IAC SE
	[ As updates occur in the client the following are possible... ]
	IAC SB NEW-ENVIRON (39) INFO (2) USERVAR (3) CHARSET VAL (1) UTF-8 IAC SE IAC SB NEW-ENVIRON (39) INFO (2) USERVAR (3) MTTS VAL (1) 2349 IAC SE IAC SB NEW-ENVIRON (39) INFO (2) USERVAR (3) SCREEN_READER VAL (1) IAC SE IAC SB NEW-ENVIRON (39) INFO (2) USERVAR (3) UTF-8 VAL (1) 1 IAC SE IAC SB NEW-ENVIRON (39) INFO (2) USERVAR (3) WORD_WRAP VAL (1) 100 IAC SE

If a Mudlet user does not want to negotiate environmental variables, they may choose the Settings, Special Options menu item in Mudlet and enable "Force NEW_ENVIRON negotiation off". The following is an example of an attempted negotiation where "Force NEW-ENVIRON negotiation off" is enabled.

Server	Mudlet
IAC DO NEW-ENVIRON (39) IAC SE	IAC WONT NEW-ENVIRON (39) IAC SE

NEW-ENVIRON negotiation is available in Mudlet 4.18+.

MNES

The Mud New-Environment Standard is an alternative way to share client-supported details between Mudlet to game servers. MNES is a variant of NEW-ENVIRON, not based on the RFC.

Activating MNES

If your game supports MNES, instruct users to toggle on the `Enable MNES` menu option on the General tab in Mudlet.

 

Mud New-Environ Standard Client Environment Variables MNES

MNES leverages VAR (0) to transfer up to five client environment variables. Some client variables updates may be reported ad-hoc with an INFO message. If there is no value for a defined variable, a VAL (1) will be sent without a value following it.

Type	Variable	Example Values	Mudlet Default	INFO	Purpose
VAR	CHARSET	UTF-8, ASCII		Yes	Encoding set in the client
VAR	CLIENT_NAME	MUDLET	MUDLET		Name of the client.
VAR	CLIENT_VERSION	4/18, 4/17/2-DEV			Version of the client.
VAR	MTTS	2349		Yes	Bitvector defined in the Mud Terminal Type Standard (MTTS).
VAR	TERMINAL_TYPE	ANSI-TRUECOLOR, ANSI-256COLOR, ANSI, XTERM, VT100, DUMB	ANSI-TRUECOLOR		Terminal type of the client

Negotiating MNES

The primary differences between MNES and the out-of-the-box RFC 152 NEW-ENVIRON implementation is that MNES sends no more than 5 client environment variables ("IPADDRESS" will not be implemented in Mudlet), it uses a VAR (0) for the SEND (1), IS (0), and INFO (2) messages, and returns a multiple client variable response in multiple IS (0) messages.

Server	Mudlet
IAC DO NEW-ENVIRON (39) IAC SE	IAC WILL NEW-ENVIRON (39) IAC SE
IAC SB NEW-ENVIRON (39) SEND IAC SE	IAC SB NEW-ENVIRON (39) IS (0) VAR (0) CHARSET VAL (1) UTF-8 IAC SE IAC SB NEW-ENVIRON (39) IS (0) VAR (0) CLIENT_NAME VAL (1) MUDLET IAC SE IAC SB NEW-ENVIRON (39) IS (0) VAR (0) CLIENT_VERSION VAL (1) 4/17/2-DEV IAC SE IAC SB NEW-ENVIRON (39) IS (0) VAR (0) MTTS VAL (1) 2349 IAC SE IAC SB NEW-ENVIRON (39) IS (0) VAR (0) TERMINAL_TYPE VAL (1) ANSI-TRUECOLOR IAC SE
	[ As updates occur in the client the following are possible... ]
	IAC SB NEW-ENVIRON (39) INFO (2) VAR (0) CHARSET VAL (1) ASCII IAC SE IAC SB NEW-ENVIRON (39) INFO (2) VAR (0) MTTS VAL (1) 2345 IAC SE

MNES negotiation is available in Mudlet 4.18+.

TLS (Secure Connections)

To connect to a game using Transport Layer Security (TLS) for more security, tick the 'Secure' box in the profile connection settings:

Note that the game must support a secure (TLS) connection in order for this to work, and this feature is available in Mudlet 3.17+.

If you are a games admin/developer, check out this or this example on how to setup a secure connection to your game, as well as MSSP data in order to let Mudlet know that you do have a secure connection available.

Secure connection prompt

Available in Mudlet4.17+

To encourage enhanced data transfer protection and privacy, Mudlet will respond to the detection of the TLS (or SSL legacy) key of MSSP (Mud Server Status Protocol) and prompt a user not on a TLS (Transport Layer Security) connection with a choice to reconnect with the advertised TLS port from MSSP.

If the user selects Yes, Mudlet automatically updates the port with the TLS value gathered from MSSP, check-marks the Secure checkbox on the connection dialog, then reconnects.  If the user selects No, Mudlet automatically updates a profile preference so they are not asked again for the current profile, then reconnects.  This preference may be controlled on the Settings->Connection menu.  This preference is enabled by default.

Supported Protocols for Specific Games

Mudlet includes support for the legacy, game specific ATCP and channel 102 protocols. Please use standards based protocols in the future (i.e., GMCP) vs. requesting to add a new game specific one.

ATCP

Mudlet includes support for ATCP. This is primarily available on IRE-based MUDs, but Mudlet's implementation is generic enough such that any it should work on others.

Note: ATCP has been overtaken by GMCP, prefer to use that instead.

The latest ATCP data is stored in the atcp table. Whenever new data arrives, the previous is overwritten. An event is also raised for each ATCP message that arrives. To find out the available messages available in the atcp table and the event names, you can use display(atcp).

Note that while the typical message comes in the format of Module.Submodule, ie Char.Vitals or Room.Exits, in Mudlet the dot is removed - so it becomes CharVitals and RoomExits.

Example

room_number = tonumber(atcp.RoomNum)
echo(room_number)

Triggering on ATCP events

If you’d like to trigger on ATCP messages, then you need to create scripts to attach handlers to the ATCP messages. The ATCP handler names follow the same format as the atcp table - RoomNum, RoomExits, CharVitals and so on.

While the concept of handlers for events is to be explained elsewhere in the manual, the quick rundown is this - place the event name you’d like your script to listen to into the Add User Defined Event Handler: field and press the + button to register it. Next, because scripts in Mudlet can have multiple functions, you need to tell Mudlet which function should it call for you when your handler receives a message. You do that by setting the Script name: to the function name in the script you’d like to be called.

For example, if you’d like to listen to the RoomExits event and have it call the process_exits() function - register RoomExits as the event handler, make the script name be process_exits, and use this in the script:

function process_exits(event, args)
    echo("Called event: " .. event .. "\nWith args: " .. args)
end

Feel free to experiment with this to achieve the desired results. A ATCP demo package is also available on the forums for using event handlers and parsing its messages into Lua datastructures.

Mudlet-specific ATCP

See ATCP Extensions for ATCP extensions that have been added to Mudlet.

Aardwolf’s 102 subchannel

Similar to ATCP, Aardwolf includes a hidden channel of information that you can access in Mudlet. Mudlet deals with it in the same way as with ATCP, so for full usage instructions see the ATCP section. All data is stored in the channel102 table, such that you can do:

display(channel102)

... to see all the latest information that has been received. The event to create handlers on is titled channel102Message, and you can use the sendTelnetChannel102(msg) function to send text via the 102 channel back to Aardwolf.

-- Function for detecting AFK status on Aardwolf mud.
function amIafk()
   for k,v in pairs(channel102) do
      if k==100 and v==4 then
         return true
      end
   end
   return false
end

Adding support for a telnet protocol

In addition to supporting ATCP, GMCP, Aardwolf's 102 and MXP, Mudlet has open telnet support - meaning that for any telnet protocol it doesn't support, it has the tools you can use to build the support for. This does not mean Mudlet supports other protocols "out of the box" - you will either have to get code that adds the support, or you could create it yourself.

The basic tools that you need are addSupportedTelnetOption(), sendSocket() and the sysTelnetEvent.

Create an event handler that goes off on sysTelnetEvent - which is raised whenever an unsupported telnet option is encountered. Your logic handling will start in this event handler. Once you decide what you'd like to send to the game, use sendSocket() to send raw data as-is. Finally, when your logic is done, use addSupportedTelnetOption() to register your telnet option with Mudlet, so it will respond with telnet DO on a query from the game server. See this MSDP snippet for a barebones example.

API philosophy

Adding a support for a new telnet protocol will involve adding the user-facing API. It best for users if it was in the same style as Mudlets handling of other protocols. To see how it's done exactly, check out GMCP, ATCP or Aardwolf 102 examples - but the gist of it is provided below.

Mudlet has a built-in event system, which is used to broadcast messages in an independent way. With it, people can "trigger" on 102, ATCP or GMCP events with Lua functions that get called whenever an event they're interested in is raised. Use the event system to provide your users with a way to react to new protocol data.

Events have names, and optionally, any amount of data with them. For protocol support, Mudlet prefixes the relevant message received name with the protocol name in lowercase. For example, an ATCP Char.Vitals getting updated would raise an event titled "atcp.Char.Vitals". A GMCP Room.Info message would raise a "gmcp.Room.Info" message.

Additionally, Mudlet also allows catch-all event - in case the user wants to use one event handler for a variety of sub-events (it's not uncommon for games to use Main.Sub.Add, Main.Sub.Remove, Main.Sub.List to keep track of a list, for example, while conserving data). To accomplish this, it raises events for every relevant namespace - that is, a Main.Sub.Add event will raise protocol.Main.Sub and protocol.Main.Sub.Add events. While it is entirely possible for one event handler to react to multiple events, this is provided for convenience.

For storing protocol data, Mudlet uses an aptly named global table - gmcp for GMCP data, atcp for ATCP data. Data is stored in the same way it is received and the event is raised for - so a Char.Vitals message's contents will be stored in gmcp.Char.Vitals, a Room.Info's contents in gmcp.Room.Info. If there were was any nested data within the message, it is stored as a table within the proper namespace - ie, a "details" JSON array of a GMCP Room.Info message would be stored in gmcp.Room.Info.details. Use a global table with the protocol name in lowerspace for storing permanent data that your users will read from.

That's it! If you'll need any Mudlet-related help, feel free to post on our forums. Once you're done, package your work for distribution which you can optionally post in the finished scripts section.