Signed messages

Since Minecraft version 1.19, the client now signs any messages it sends so that they are uniquely identifiable and verifiable to be sent by a specific player. With this update, they also introduced the ability delete specific messages previously sent by a player.

How are signed messages represented in code?

Paper uses Adventure’s SignedMessage object to represent a signed message. We differentiate two kinds of signed messages: system messages and non-system messages. System messages (checked with SignedMessage#isSystem()) are messages send by the server, whilst non-system messages are not.

You can also differentiate the signed plain text String content of the message (SignedMessage#message()) from the unsigned, nullable Component content (SignedMessage#unsignedContent()).

Obtaining a signed message

Signed messages can be obtained in two ways.

From an AsyncChatEvent using AbstractChatEvent#signedMessage().
From an ArgumentTypes.signedMessage() Brigadier argument type.

Using signed messages

You can send signed message objects to an Audience using the Audience#sendMessage(SignedMessage, ChatType.Bound) method. You can obtain a ChatType.Bound object from the ChatType interface.

Deleting messages is much simpler. Adventure provides the Audience#deleteMessage(SignedMessage) or Audience#deleteMessage(SignedMessage.Signature) methods for that.

Example: Making user sent messages deletable

For our example, we will create a chat format plugin which allows a user to delete their own messages in case they made a mistake. For this we will use the AsyncChatEvent.

In-game preview

Code


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package io.papermc.docs.signedmessages;
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import io.papermc.paper.event.player.AsyncChatEvent;
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import net.kyori.adventure.text.Component;
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import net.kyori.adventure.text.event.ClickEvent;
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import net.kyori.adventure.text.format.NamedTextColor;
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import net.kyori.adventure.text.format.TextDecoration;
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import org.bukkit.Bukkit;
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import org.bukkit.event.EventHandler;
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import org.bukkit.event.Listener;
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public class SignedChatListener implements Listener {
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    @EventHandler
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    void onPlayerChat(AsyncChatEvent event) {
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        // We modify the chat format, so we use a chat renderer.
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        event.renderer((player, playerName, message, viewer) -> {
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            // This is the base format of our message. It will format chat as "<player> » <message>".
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            final Component base = Component.textOfChildren(
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                playerName.colorIfAbsent(NamedTextColor.GOLD),
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                Component.text(" » ", NamedTextColor.DARK_GRAY),
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                message
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            );
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            // Send the base format to any player who is not the sender.
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            if (viewer != player) {
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                return base;
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            }
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            // Create a base delete suffix. The creation is separated into two
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            // parts purely for readability reasons.
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            final Component deleteCrossBase = Component.textOfChildren(
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                Component.text("[", NamedTextColor.DARK_GRAY),
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                Component.text("X", NamedTextColor.DARK_RED, TextDecoration.BOLD),
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                Component.text("]", NamedTextColor.DARK_GRAY)
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            );
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            // Add a hover and click event to the delete suffix.
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            final Component deleteCross = deleteCrossBase
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                .hoverEvent(Component.text("Click to delete your message!", NamedTextColor.RED))
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                // We retrieve the signed message with event.signedMessage() and request a server-wide deletion if the
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                // deletion cross were to be clicked.
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                .clickEvent(ClickEvent.callback(audience -> Bukkit.getServer().deleteMessage(event.signedMessage())));
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            // Send the base format but with the delete suffix.
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            return base.appendSpace().append(deleteCross);
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        });
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    }
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}