Listening to messages

Sometimes, you may want to listen out for a message, rather than a command. This could be used for many cases like a spam filter, a bot that would respond to movie quotes with gifs, or a chat bot! However, in this page, we'll be using this to create a moderation filter (detect bad words).

Warning

As of August 30th, 2022, Discord made Message Content a privileged intent. Whilst this means you can still use prefixed messages as commands, Discord does not encourage this and heavily suggests you use slash commands. If you wish to create commands, use slash commands, not messages.

#include <dpp/dpp.h>
 
int main() {
    /* Create the bot, but with our intents so we can use messages. */
    dpp::cluster bot("token", dpp::i_default_intents | dpp::i_message_content);
 
    bot.on_log(dpp::utility::cout_logger());
 
    /* The event is fired when the bot detects a message in any server and any channel it has access to. */
    bot.on_message_create([&bot](const dpp::message_create_t& event) {
        /* See if the message contains the phrase we want to check for.
         * If there's at least a single match, we reply and say it's not allowed.
         */
        if (event.msg.content.find("bad word") != std::string::npos) {
            event.reply("That is not allowed here. Please, mind your language!", true);
        }
    });
 
    bot.start(dpp::st_wait);
 
    return 0;
}

If all went well, you should have something like this!