Caching Messages

By default D++ does not cache messages. The example program below demonstrates how to instantiate a custom cache using dpp::cache which will allow you to cache messages and query the cache for messages by ID.

This can be adjusted to cache any type derived from dpp::managed including types you define yourself.

Note

This example will cache and hold onto messages forever! In a real world situation this would be bad. If you do use this, you should use the dpp::cache::remove() method periodically to remove stale items. This is left out of this example as a learning exercise to the reader. For further reading please see the documentation of dpp::cache

#include <dpp/dpp.h>
#include <sstream>
 
int main() {
    /* Create bot */
    dpp::cluster bot("token");
 
    /* Create a cache to contain types of dpp::message */
    dpp::cache<dpp::message> message_cache;
 
    /* Message handler */
    bot.on_message_create([&](const dpp::message_create_t &event) {
 
        /* Make a permanent pointer using new, for each message to be cached */
        dpp::message* m = new dpp::message();
        /* Store the message into the pointer by copying it */
        *m = event.msg;
        /* Store the new pointer to the cache using the store() method */
        message_cache.store(m);
 
        /* Simple ghetto command handler. In the real world, use slashcommand or commandhandler here. */
        std::stringstream ss(event.msg.content);
        std::string cmd;
        dpp::snowflake msg_id;
        ss >> cmd;
 
        /* Look for our command */
        if (cmd == "!get") {
            ss >> msg_id;
            /* Search our cache for a cached message */
            dpp::message* find_msg = message_cache.find(msg_id);
            if (find_msg != nullptr) {
                /* Found a cached message, echo it out */
                bot.message_create(dpp::message(event.msg.channel_id, "This message had the following content: " + find_msg->content));
            } else {
                /* Nothing like that here. Have you checked under the carpet? */
                bot.message_create(dpp::message(event.msg.channel_id, "There is no message cached with this ID"));
            }
        }
    });
 
    /* Start bot */
    bot.start(false);
 
    return 0;
}