# Channels In a multiplayer game, players often need other means of in-game communication than moving to the same room and use `say` or `emote`. _Channels_ allows Evennia's to act as a fancy chat program. When a player is connected to a channel, sending a message to it will automatically distribute it to every other subscriber. Channels can be used both for chats between [Accounts](./Accounts.md) and between [Objects](./Objects.md) (usually Characters). Chats could be both OOC (out-of-character) or IC (in-charcter) in nature. Some examples: - A support channel for contacting staff (OOC) - A general chat for discussing anything and foster community (OOC) - Admin channel for private staff discussions (OOC) - Private guild channels for planning and organization (IC/OOC depending on game) - Cyberpunk-style retro chat rooms (IC) - In-game radio channels (IC) - Group telepathy (IC) - Walkie-talkies (IC) ```{versionchanged} 1.0 Channel system changed to use a central 'channel' command and nicks instead of auto-generated channel-commands and -cmdset. ChannelHandler was removed. ``` ## Working with channels ### Viewing and joining channels In the default command set, channels are all handled via the mighty [channel command](evennia.commands.default.comms.CmdChannel), `channel` (or `chan`). By default, this command will assume all entities dealing with channels are `Accounts`. Viewing channels channel - shows your subscriptions channel/all - shows all subs available to you channel/who - shows who subscribes to this channel To join/unsub a channel do channel/sub channelname channel/unsub channelname If you temporarily don't want to hear the channel for a while (without actually unsubscribing), you can mute it: channel/mute channelname channel/unmute channelname ### Talk on channels To speak on a channel, do channel public Hello world! If the channel-name has spaces in it, you need to use a '`=`': channel rest room = Hello world! Now, this is more to type than we'd like, so when you join a channel, the system automatically sets up an personal alias so you can do this instead: public Hello world ```{warning} This shortcut will not work if the channel-name has spaces in it. So channels with long names should make sure to provide a one-word alias as well. ``` Any user can make up their own channel aliases: channel/alias public = foo;bar You can now just do foo Hello world! bar Hello again! And even remove the default one if they don't want to use it channel/unalias public public Hello (gives a command-not-found error now) But you can also use your alias with the `channel` command: channel foo Hello world! > What happens when aliasing is that a [nick](./Nicks.md) is created that maps your > alias + argument onto calling the `channel` command. So when you enter `foo hello`, > what the server sees is actually `channel foo = hello`. The system is also > clever enough to know that whenever you search for channels, your channel-nicks > should also be considered so as to convert your input to an existing channel name. You can check if you missed channel conversations by viewing the channel's scrollback with channel/history public This retrieves the last 20 lines of text (also from a time when you were offline). You can step further back by specifying how many lines back to start: channel/history public = 30 This again retrieve 20 lines, but starting 30 lines back (so you'll get lines 30-50 counting backwards). ### Channel administration Evennia can create certain channels when it starts. Channels can also be created on-the-fly in-game. #### Default channels from settings You can specify 'default' channels you want to auto-create from the Evennia settings. New accounts will automatically be subscribed to such 'default' channels if they have the right permissions. This is a list of one dict per channel (example is the default public channel): ```python # in mygame/server/conf/settings.py DEFAULT_CHANNELS = [ { "key": "Public", "aliases": ("pub",), "desc": "Public discussion", "locks": "control:perm(Admin);listen:all();send:all()", }, ] ``` Each dict is fed as `**channeldict` into the [create_channel](evennia.utils.create.create_channel) function, and thus supports all the same keywords. Evennia also has two system-related channels: - `CHANNEL_MUDINFO` is a dict describing the "MudInfo" channel. This is assumed to exist and is a place for Evennia to echo important server information. The idea is that server admins and staff can subscribe to this channel to stay in the loop. - `CHANNEL_CONECTINFO` is not defined by default. It will receive connect/disconnect-messages and could be visible also for regular players. If not given, connection-info will just be logged quietly. #### Managing channels in-game To create/destroy a new channel on the fly you can do channel/create channelname;alias;alias = description channel/destroy channelname Aliases are optional but can be good for obvious shortcuts everyone may want to use. The description is used in channel-listings. You will automatically join a channel you created and will be controlling it. You can also use `channel/desc` to change the description on a channel you own later. If you control a channel you can also kick people off it: channel/boot mychannel = annoyinguser123 : stop spamming! The last part is an optional reason to send to the user before they are booted. You can give a comma-separated list of channels to kick the same user from all those channels at once. The user will be unsubbed from the channel and all their aliases will be wiped. But they can still rejoin if they like. channel/ban mychannel = annoyinguser123 channel/ban - view bans channel/unban mychannel = annoyinguser123 Banning adds the user to the channels blacklist. This means they will not be able to _rejoin_ if you boot them. You will need to run `channel/boot` to actually kick them out. See the [Channel command](evennia.commands.default.comms.CmdChannel) api docs (and in-game help) for more details. Admin-level users can also modify channel's [locks](./Locks.md): channel/lock buildchannel = listen:all();send:perm(Builders) Channels use three lock-types by default: - `listen` - who may listen to the channel. Users without this access will not even be able to join the channel and it will not appear in listings for them. - `send` - who may send to the channel. - `control` - this is assigned to you automatically when you create the channel. With control over the channel you can edit it, boot users and do other management tasks. #### Restricting channel administration By default everyone can use the channel command ([evennia.commands.default.comms.CmdChannel](evennia.commands.default.comms.CmdChannel)) to create channels and will then control the channels they created (to boot/ban people etc). If you as a developer does not want regular players to do this (perhaps you want only staff to be able to spawn new channels), you can override the `channel` command and change its `locks` property. The default `help` command has the following `locks` property: ```python locks = "cmd:not perm(channel_banned); admin:all(); manage:all(); changelocks: perm(Admin)" ``` This is a regular [lockstring](./Locks.md). - `cmd: pperm(channel_banned)` - The `cmd` locktype is the standard one used for all Commands. an accessing object failing this will not even know that the command exists. The `pperm()` lockfunc checks an on-account [Permission](Building Permissions) 'channel_banned' - and the `not` means that if they _have_ that 'permission' they are cut off from using the `channel` command. You usually don't need to change this lock. - `admin:all()` - this is a lock checked in the `channel` command itself. It controls access to the `/boot`, `/ban` and `/unban` switches (by default letting everyone use them). - `manage:all()` - this controls access to the `/create`, `/destroy`, `/desc` switches. - `changelocks: perm(Admin)` - this controls access to the `/lock` and `/unlock` switches. By default this is something only [Admins](Building Permissions) can change. > Note - while `admin:all()` and `manage:all()` will let everyone use these switches, users > will still only be able to admin or destroy channels they actually control! If you only want (say) Builders and higher to be able to create and admin channels you could override the `help` command and change the lockstring to: ```python # in for example mygame/commands/commands.py from evennia import default_cmds class MyCustomChannelCmd(default_cmds.CmdChannel): locks = "cmd: not pperm(channel_banned);admin:perm(Builder);manage:perm(Builder);changelocks:perm(Admin)" ``` Add this custom command to your default cmdset and regular users will now get an access-denied error when trying to use use these switches. ## Using channels in code For most common changes, the default channel, the recipient hooks and possibly overriding the `channel` command will get you very far. But you can also tweak channels themselves. ### Allowing Characters to use Channels The default `channel` command ([evennia.commands.default.comms.CmdChannel](evennia.commands.default.comms.CmdChannel)) sits in the `Account` [command set](./Command-Sets.md). It is set up such that it will always operate on `Accounts`, even if you were to add it to the `CharacterCmdSet`. It's a one-line change to make this command accept non-account callers. But for convenience we provide a version for Characters/Objects. Just import [evennia.commands.default.comms.CmdObjectChannel](evennia.commands.default.comms.CmdObjectChannel) and inherit from that instead. ### Customizing channel output and behavior When distributing a message, the channel will call a series of hooks on itself and (more importantly) on each recipient. So you can customize things a lot by just modifying hooks on your normal Object/Account typeclasses. Internally, the message is sent with `channel.msg(message, senders=sender, bypass_mute=False, **kwargs)`, where `bypass_mute=True` means the message ignores muting (good for alerts or if you delete the channel etc) and `**kwargs` are any extra info you may want to pass to the hooks. The `senders` (it's always only one in the default implementation but could in principle be multiple) and `bypass_mute` are part of the `kwargs` below: 1. `channel.at_pre_msg(message, **kwargs)` 2. For each recipient: - `message = recipient.at_pre_channel_msg(message, channel, **kwargs)` - allows for the message to be tweaked per-receiver (for example coloring it depending on the users' preferences). If this method returns `False/None`, that recipient is skipped. - `recipient.channel_msg(message, channel, **kwargs)` - actually sends to recipient. - `recipient.at_post_channel_msg(message, channel, **kwargs)` - any post-receive effects. 3. `channel.at_post_channel_msg(message, **kwargs)` Note that `Accounts` and `Objects` both have their have separate sets of hooks. So make sure you modify the set actually used by your subscribers (or both). Default channels all use `Account` subscribers. ### Channel class Channels are [Typeclassed](./Typeclasses.md) entities. This means they are persistent in the database, can have [attributes](./Attributes.md) and [Tags](./Tags.md) and can be easily extended. To change which channel typeclass Evennia uses for default commands, change `settings.BASE_CHANNEL_TYPECLASS`. The base command class is [`evennia.comms.comms.DefaultChannel`](evennia.comms.comms.DefaultChannel). There is an empty child class in `mygame/typeclasses/channels.py`, same as for other typelass-bases. In code you create a new channel with `evennia.create_channel` or `Channel.create`: ```python from evennia import create_channel, search_object from typeclasses.channels import Channel channel = create_channel("my channel", aliases=["mychan"], locks=..., typeclass=...) # alternative channel = Channel.create("my channel", aliases=["mychan"], locks=...) # connect to it me = search_object(key="Foo")[0] channel.connect(me) # send to it (this will trigger the channel_msg hooks described earlier) channel.msg("Hello world!", senders=me) # view subscriptions (the SubscriptionHandler handles all subs under the hood) channel.subscriptions.has(me) # check we subbed channel.subscriptions.all() # get all subs channel.subscriptions.online() # get only subs currently online channel.subscriptions.clear() # unsub all # leave channel channel.disconnect(me) # permanently delete channel (will unsub everyone) channel.delete() ``` The Channel's `.connect` method will accept both `Account` and `Object` subscribers and will handle them transparently. The channel has many more hooks, both hooks shared with all typeclasses as well as special ones related to muting/banning etc. See the channel class for details. ### Channel logging ```{versionchanged} 0.7 Channels changed from using Msg to TmpMsg and optional log files. ``` ```{versionchanged} 1.0 Channels stopped supporting Msg and TmpMsg, using only log files. ``` The channel messages are not stored in the database. A channel is instead always logged to a regular text log-file `mygame/server/logs/channel_.log`. This is where `channels/history channelname` gets its data from. A channel's log will rotate when it grows too big, which thus also automatically limits the max amount of history a user can view with `/history`. The log file name is set on the channel class as the `log_file` property. This is a string that takes the formatting token `{channelname}` to be replaced with the (lower-case) name of the channel. By default the log is written to in the channel's `at_post_channel_msg` method. ### Properties on Channels Channels have all the standard properties of a Typeclassed entity (`key`, `aliases`, `attributes`, `tags`, `locks` etc). This is not an exhaustive list; see the [Channel api docs](evennia.comms.comms.DefaultChannel) for details. - `send_to_online_only` - this class boolean defaults to `True` and is a sensible optimization since people offline people will not see the message anyway. - `log_file` - this is a string that determines the name of the channel log file. Default is `"channel_{channelname}.log"`. The log file will appear in `settings.LOG_DIR` (usually `mygame/server/logs/`). You should usually not change this. - `channel_prefix_string` - this property is a string to easily change how the channel is prefixed. It takes the `channelname` format key. Default is `"[{channelname}] "` and produces output like `[public] ...`. - `subscriptions` - this is the [SubscriptionHandler](evennia.comms.models.SubscriptionHandler), which has methods `has`, `add`, `remove`, `all`, `clear` and also `online` (to get only actually online channel-members). - `wholist`, `mutelist`, `banlist` are properties that return a list of subscribers, as well as who are currently muted or banned. - `channel_msg_nick_pattern` - this is a regex pattern for performing the in-place nick replacement (detect that `channelalias ` to `channel channelname = `. - `remove_user_channel_alias(user, alias, **kwargs)` - remove an alias. Note that this is a class-method that will happily remove found channel-aliases from the user linked to _any_ channel, not only from the channel the method is called on. - `pre_join_channel(subscriber)` - if this returns `False`, connection will be refused. - `post_join_channel(subscriber)` - by default this sets up a users' channel-nicks/aliases. - `pre_leave_channel(subscriber)` - if this returns `False`, the user is not allowed to leave. - `post_leave_channel(subscriber)` - this will clean up any channel aliases/nicks of the user. - `delete` the standard typeclass-delete mechanism will also automatically un-subscribe all subscribers (and thus wipe all their aliases).