D++ (DPP)
C++ Discord API Bot Library
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", dpp::i_default_intents | dpp::i_message_content); /* Because we're handling messages, we need to use the "i_message_content" intent! */
/* Create a cache to contain types of dpp::message */
dpp::cache<dpp::message> message_cache;
/* Message handler */
bot.on_message_create([&message_cache](const dpp::message_create_t &event) {
/* Make a permanent pointer using new, for each message to be cached */
/* 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);
});
/* The event is fired when someone issues your commands */
bot.on_slashcommand([&bot, &message_cache](const dpp::slashcommand_t& event) {
/* Check which command they ran */
if (event.command.get_command_name() == "get") {
dpp::message* find_msg = message_cache.find(std::get<std::string>(event.get_parameter("message_id")));
/* If find_msg is null, tell the user and return. */
if (!find_msg) {
event.reply("There is no message cached with this ID");
return;
}
event.reply("This message had the following content: " + find_msg->content);
}
});
bot.on_ready([&bot](const dpp::ready_t& event) {
if (dpp::run_once<struct register_bot_commands>()) {
/* Create a new command. */
dpp::slashcommand newcommand("get", "Get the contents of a message that was cached via an id", bot.me.id);
/* Add a parameter option. */
newcommand.add_option(dpp::command_option(dpp::co_string, "message_id", "The ID of the message you want to find", true));
/* Register the command */
bot.global_command_create(newcommand);
}
});
/* Start bot */
bot.start(dpp::st_wait);
return 0;
}
dpp::i_default_intents
@ i_default_intents
Default D++ intents (all non-privileged intents).
Definition: intents.h:172
dpp::slashcommand_t
User has issued a slash command.
Definition: dispatcher.h:715
dpp::cache
A cache object maintains a cache of dpp::managed objects.
Definition: cache.h:70
dpp::interaction_create_t::get_parameter
virtual command_value get_parameter(const std::string &name) const
Get a slashcommand parameter.
dpp::message::content
std::string content
Contents of the message.
Definition: message.h:1803
dpp::st_wait
@ st_wait
Wait forever on a condition variable. The cluster will spawn threads for each shard and start() will ...
Definition: cluster.h:101
dpp::cache::store
void store(T *object)
Store an object in the cache. Passing a nullptr will have no effect.
Definition: cache.h:121
dpp::message_create_t
Create message.
Definition: dispatcher.h:1655
dpp::message
Represents messages sent and received on Discord.
Definition: message.h:1758
dpp::interaction_create_t::command
interaction command
command interaction
Definition: dispatcher.h:698
dpp::i_message_content
@ i_message_content
Intent for receipt of message content.
Definition: intents.h:152
dpp::slashcommand
Represents an application command, created by your bot either globally, or on a guild.
Definition: appcommand.h:1358
dpp::co_string
@ co_string
A string value.
Definition: appcommand.h:83
dpp::utility::cout_logger
std::function< void(const dpp::log_t &)> DPP_EXPORT cout_logger()
Get a default logger that outputs to std::cout. e.g.
Definition: dispatcher.h:228
dpp::interaction::get_command_name
std::string get_command_name() const
Get the command name for a command interaction.
dpp::cache::find
T * find(snowflake id)
Find an object in the cache by id.
Definition: cache.h:174
dpp::command_option
Each command option is a command line parameter. It can have a type (see dpp::command_option_type),...
Definition: appcommand.h:222
dpp::cluster
The cluster class represents a group of shards and a command queue for sending and receiving commands...
Definition: cluster.h:99
dpp::unicode_emoji::m
constexpr const char m[]
Definition: unicode_emoji.h:5119
dpp::ready_t
Session ready.
Definition: dispatcher.h:981
D++ Library version 9.0.13D++ Library version 9.0.12D++ Library version 9.0.11D++ Library version 9.0.10D++ Library version 9.0.9D++ Library version 9.0.8D++ Library version 9.0.7D++ Library version 9.0.6D++ Library version 9.0.5D++ Library version 9.0.4D++ Library version 9.0.3D++ Library version 9.0.2D++ Library version 9.0.1D++ Library version 9.0.0D++ Library version 1.0.2D++ Library version 1.0.1D++ Library version 1.0.0