minetest_modding_book/chapters/chat.md

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Chat and Commands	default	../

Introduction

In this chapter we will learn how to interact with player chat, including sending messages, intercepting messages and registering chat commands.

• Send a message to all players.
• Send a message to a certain player.
• Chat commands.
• Complex subcommands.
• Intercepting messages.

Send a message to all players

It's as simple as calling the chat_send_all function, as so:

{% highlight lua %} minetest.chat_send_all("This is a chat message to all players") {% endhighlight %}

Here is an example of how it would appear ingame (there are other messages around it).

<player1> Look at this entrance
This is a chat message to all players
<player2> What about it?

Send a message to a certain player

It's as simple as calling the chat_send_player function, as so:

{% highlight lua %} minetest.chat_send_player("player1", "This is a chat message for player1") {% endhighlight %}

Only player1 can see this message, and it's displayed the same as above.

Older mods

Occasionally you'll see mods with code like this:

{% highlight lua %} minetest.chat_send_player("player1", "This is a server message", true) minetest.chat_send_player("player1", "This is a server message", false) {% endhighlight %}

The boolean at is no longer used, and has no affect ^[commit].

Chat commands

In order to register a chat command, such as /foo, use register_chatcommand:

{% highlight lua %} minetest.register_chatcommand("foo", { privs = { interact = true }, func = function(name, param) return true, "You said " .. param .. "!" end }) {% endhighlight %}

Calling /foo bar will result in You said bar! in the chat console.

Let's do a break down:

{% highlight lua %} privs = { interact = true }, {% endhighlight %}

This makes it so that only players with the interact privilege can run the command. Other players will see an error message informing them which privilege they're missing.

{% highlight lua %} return true, "You said " .. param .. "!" {% endhighlight %}

This returns two values, firstly a boolean which says that the command succeeded and secondly the chat message to send to the player.

The reason that a player name rather than a player object is passed is because the player might not actually be online, but may be running commands from IRC. So don't assume that minetest.get_player_by_name will work in a chat command call back, or any other function that requires an ingame player. minetest.show_formspec will also not work for IRC players, so you should provide a text only version. For example, the email mod allows both /inbox to show the formspec, and /inbox text to send to chat.

Complex subcommands

It is often required to make complex chat commands, such as:

• /msg
• /team join
• /team leave
• /team list

Traditionally mods implemented this using Lua patterns. However, a much easier way is to use a mod library that I wrote to do this for you. See Complex Chat Commands.

Intercepting messages

You can use register_on_chat_message, like so:

{% highlight lua %} minetest.register_on_chat_message(function(name, message) print(name .. " said " .. message) return false end) {% endhighlight %}

By returning false, we're allowing the chat message to be sent by the default handler. You can actually miss out the line return false, and it would still work the same.

WARNING: CHAT COMMANDS ARE ALSO INTERCEPTED. If you only want to catch player messages, you need to do this:

{% highlight lua %} minetest.register_on_chat_message(function(name, message) if message:sub(1, 1) == "/" then print(name .. " ran chat command") return false end

print(name .. " said " .. message)
return false

end) {% endhighlight %}