MUME Help

Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

MPI PROTOCOL

The MUME MPI (an acronym whose meaning has been lost in time like tears in rain) is an older MUME-specific client protocol. Its functionality has been superseded by GMCP.

Command Format

The MPI commands, which can be sent either from or to the client, are all of the format

<start> <command> [<length>]
<newline> <data>

<start> is the MPI start sequence ~$#E. The MPI must follow a newline (a telnet CR LF sequence).

<command> is one of the following letters:

`I`	identify for remote editing and viewing (from client)
`E`	edit (to/from client)
`V`	view (to client)
`P`	prompt settings (from client; deprecated)
`X`	XML settings (from client)

<length> is the length in bytes of <data> as a string of ASCII digits. If absent, taken to be zero.

<newline> is a single newline, ASCII 10.

The reference client implementation can be found in powwow.

The I command

The I command takes no arguments:

  ~$#EI

The E command

The E command involves several different messages. One of these is sent by the server, and the other two are sent by the client.

The E command sent by the server

When requesting that the client begin a new editing session, the server sends the following:

MPI init string.
The character E.
The length of the remainder of the message in bytes.
A newline character.
The character M.
A session identifier, consisting of a string of digits.
A newline character.
The description of the session. (This is free-form text, terminated by exactly one newline).
The initial contents of the editing session (which may or may not end with a newline).

For the purposes of computing the length field, the message starts with the first byte after the newline at the end of the field.

<data> is raw binary data, duplicating any IACs (as per the Telnet protocol), but any CR or LF are sent unmodified (as opposed to how Telnet does it).

The E command sent by the client

The client may end an active editing session in one of two ways: by uploading the text generated by the editor, or by canceling the message.

Here's what the "cancel" message looks like:

MPI init string.
The character E.
The length of the message.
A newline character.
The character C
The session identifier, represented by a string of digits.
A newline character.

The "upload" message looks like this:

MPI init string.
The character E.
The length of the message.
A newline character.
The character E.
The session identifier.
A newline character.
The edited text.

The edited text must end in a newline, ASCII 10.

The V command

The V (or view) command is even simpler. It consists of one message, from server to client:

MPI init string.
The character V.
Length in bytes.
A newline character.
Text to be displayed with the pager.

Again, for the purposes of computing the length field, the message begins with the byte following the newline that terminates the length field.

Remote editing (E & V commands) in the protocol stack

MUME processes Telnet IAC sequences before the received MUME Protocol data and escapes them (as IAC IAC) in the sent data. No other transformation is applied to the binary data transmitted. The data is expected to be encoded as ISO 8859-1 with Unix line endings (LF only) and not contain any NUL characters.

The P command (deprecated)

The deprecated P command was used to set prompt display settings.

The X command

The X command enables or disables XML mode. It is a variable-length command, with a mode for the first character and options as following characters.

Modes:

`0`	disables XML mode
`1`	enables XML mode
`2`	disables XML mode without sending `</xml>`
`3`	enables XML mode without sending `<xml>`

Options:

`G`	Enable gratuitous output until disconnected. In this mode, descriptions are sent without regard for brief/spam mode, but those that would have been hidden by brief/spam are wrapped in an extra `<gratuitous>` tag.

Example 1:

  ~$#EX2
  1G

Example 2:

  ~$#EX1
  3

Credits: The documentation of the E and V commands was contributed by Kron.

What is MUME?

MUME, Multi-Users in Middle-earth, is a multiplayer text-based online game based upon J. R. R. Tolkien’s Middle-earth during the epic wars of the late Third Age between the forces of the Dark Lord and the armies of the Free peoples. MUME is completely at no cost and has been continuously running, expanded, and remastered by a community of volunteers since 1991.

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