D++ (DPP)  10.0.30
C++ Discord API Bot Library
Attaching a File to a Message

To attach a local file to an message, you can use dpp::utility::read_file. It's a helper function from D++ that allows you to read the file's content and sent it to discord.

An example of this:

#include <dpp/dpp.h>
int main() {
dpp::cluster bot("token");
/* The event is fired when someone issues your commands */
bot.on_slashcommand([&bot](const dpp::slashcommand_t& event) {
/* Check which command they ran */
if (event.command.get_command_name() == "file") {
dpp::message msg(event.command.channel_id, "Hey there, I've got a new file!");
/* attach the file to the message */
msg.add_file("foobar.txt", dpp::utility::read_file("path_to_your_file.txt"));
/* Reply to the user with the message, with our file attached. */
event.reply(msg);
}
});
bot.on_ready([&bot](const dpp::ready_t& event) {
if (dpp::run_once<struct register_bot_commands>()) {
/* Create and register a command when the bot is ready */
bot.global_command_create(dpp::slashcommand("file", "Send a message with a file attached!", bot.me.id));
}
});
bot.start(dpp::st_wait);
return 0;
}

Attachments via URL aren't possible. But there's a workaround for this! You can download the file and then attach it to the message.

Amazingly, D++ also has a function for this! You can use dpp::cluster::request to make HTTP requests, allowing you to go ahead and pull the content from a URL.

The following example program shows how to request a file and attach it to a message:

#include <dpp/dpp.h>
int main() {
dpp::cluster bot("token");
/* The event is fired when someone issues your commands */
bot.on_slashcommand([&bot](const dpp::slashcommand_t& event) {
/* Check which command they ran */
if (event.command.get_command_name() == "file") {
/* Request the image from the URL specified and capture the event in a lambda. */
bot.request("https://dpp.dev/DPP-Logo.png", dpp::m_get, [event](const dpp::http_request_completion_t & httpRequestCompletion) {
/* Create a message */
dpp::message msg(event.command.channel_id, "This is my new attachment:");
/* Attach the image to the message, only on success (Code 200). */
if (httpRequestCompletion.status == 200) {
msg.add_file("logo.png", httpRequestCompletion.body);
}
/* Send the message, with our attachment. */
event.reply(msg);
});
}
});
bot.on_ready([&bot](const dpp::ready_t& event) {
if (dpp::run_once<struct register_bot_commands>()) {
/* Create and register a command when the bot is ready */
bot.global_command_create(dpp::slashcommand("file", "Send a message with an image attached from the internet!", bot.me.id));
}
});
bot.start(dpp::st_wait);
return 0;
}

Here's another example of how to add a local image to an embed.

Upload the image in the same message as the embed and then reference it in the embed.

#include <dpp/dpp.h>
int main() {
dpp::cluster bot("token");
/* The event is fired when someone issues your commands */
bot.on_slashcommand([&bot](const dpp::slashcommand_t& event) {
/* Check which command they ran */
if (event.command.get_command_name() == "file") {
/* Create a message. */
dpp::message msg(event.command.channel_id, "");
/* Attach the image to the message we just created. */
msg.add_file("image.jpg", dpp::utility::read_file("path_to_your_image.jpg"));
/* Create an embed. */
dpp::embed embed;
embed.set_image("attachment://image.jpg"); /* Set the image of the embed to the attached image. */
/* Add the embed to the message. */
msg.add_embed(embed);
event.reply(msg);
}
});
bot.on_ready([&bot](const dpp::ready_t& event) {
if (dpp::run_once<struct register_bot_commands>()) {
/* Create and register a command when the bot is ready */
bot.global_command_create(dpp::slashcommand("file", "Send a local image along with an embed with the image!", bot.me.id));
}
});
bot.start(dpp::st_wait);
return 0;
}
dpp::slashcommand_t
User has issued a slash command.
Definition: dispatcher.h:715
dpp.h
dpp::st_wait
@ st_wait
Wait forever on a condition variable.
Definition: cluster.h:101
main
int main()
Definition: soak.cpp:28
dpp::interaction_create_t::command
interaction command
command interaction
Definition: dispatcher.h:698
dpp::utility::cout_logger
std::function< void(const dpp::log_t &)> DPP_EXPORT cout_logger()
Get a default logger that outputs to std::cout.
Definition: dispatcher.h:228
dpp::slashcommand
Represents an application command, created by your bot either globally, or on a guild.
Definition: appcommand.h:1358
dpp::interaction::get_command_name
std::string get_command_name() const
Get the command name for a command interaction.
Definition: slashcommand.cpp:487
dpp::cluster
The cluster class represents a group of shards and a command queue for sending and receiving commands...
Definition: cluster.h:99
dpp::ready_t
Session ready.
Definition: dispatcher.h:981