site/blog/irc-chghost-2013-10-04.markdown

title	date
IRCv3.2 CHGHOST Extension	2013-10-04

IRCv3.2 CHGHOST Extension

The chghost client capability allows a server to directly inform clients about a host or user change without having to send a fake quit and join. This capability MUST be referred to as chghost at capability negotiation time.

When enabled, clients will get the CHGHOST message to designate the host of a user changing for clients on common channels with them.

The CHGHOST message is one of the following:

:nick!user@host CHGHOST user new.host.goes.here

This message represents that the user identified by nick!user@host has changed host to another value. The first parameter is the user of the client. The second parameter is the new host the client is using.

On irc daemons with support for changing the user portion of a client, the second form may appear:

:nick!user@host CHGHOST newuser host

If specified, a client may also have their user and host changed at the same time:

:nick!user@host CHGHOST newuser new.host.goes.here

This second and third form should only be seen on IRC daemons that support changing the user field of a user.

In order to take full advantage of the CHGHOST message, clients must be modified to support it. The proper way to do so is this:

1. Enable the chghost capability at capability negotiation time during the login handshake.

2. Update the user and host portions of data structures and process channel users as appropriate.

Examples

In this example, tim!~toolshed@backyard gets their username changed to b and their hostname changed to ckyard:

:tim!~toolshed@backyard CHGHOST b ckyard

In this example, tim!b@ckyard gets their username changed to ~toolshed and their hostname changed to backyard:

:tim!b@ckyard CHGHOST ~toolshed backyard

Errata

A previous version of this specification did not include any examples, which made it unclear as to whether the de-facto ~ prefix should be included on CHGHOST messages. The new examples make clear that it should be included.