This action allows you to change the name of a channel from the requested name as it is being joined.

Its only parameter is the new channel name.


This action allows you to give the channel an entirely different name from what was requested, though you should only do so in custom clients that expect the behavior.

You can view the original name using the Requested channel name (for channel join request) expression, but note once you use this action, the expression will return the name you changed it to.

Relay notes

Relay Server will let you set a blank channel name, or a name that is too long. Once approved, any clients attempting to join the channel will get a broken channel join message, resulting in Relay Client showing a corrupt list of peers and Blue Client rejecting the join message.


In Relay, there is an additional strange design flaw:

If the original requested channel already exists, and you change their name, the peer is not redirected to the new channel as you might expect.

Instead, this creates the confusing effect: the channel is renamed on server side, but peers already on the channel before the rename will still use the old channel name.

To all intents and purposes the original peers are joined to the original channel; they will get all the messages and so on as if they were, the only difference is their name is different to what the server sees it as.


As a demonstration:

Log of a Client object showing that it joins a channel with a name that is later shown to be different in the channel listing, showing Relay is broken.

This is one of those originally-joined channels. On server side, there is only one channel named Yes, even though to this client, they are on the "originalChannel" channel.

In Blue, this design flaw does not exist; changing the channel name in a join request makes you join or create the channel with a changed channel name.

Blue notes

If a client requests a channel join request with an invalid name and you do not change it, e.g. blank or too long, then before approval it will fail checks and be rejected.

A deny reason will be sent back to the client. This denial does not create a server-side error.


If you change the channel name with Blue Server to an invalid name, you will get an error, and the name change request will be denied. The reasoning is that if the original channel name was approvable, you would not have run the change channel name action in the first place.

The only error that will not cause the request to be denied is if you set the channel name to what it already was.


Note that the Blue Server's Unicode allowlist for channel names also applies to channel names the server has modified. You can set the allowlist using the (Advanced) Set Unicode allowlist action.

If a modified channel name fails the allowlist, you will get a server error similar to:

Cannot change joining channel name: Code point at index 6 does not match allowed list. Code point U+0031, decimal 49; valid = yes, Unicode category = Nd.

For a breakdown on what parts of the error message means, see the Convert string to UTF-8 and check against Unicode allowlist expression.