Custom domain emailing

Earlier this year, I set up my robotics club's website to be able to send and receive emails from its domain. For example, [email protected] or [email protected].

The problem with a shared email account is that most people don't check it very often because of the hassle of logging in. People check chat messages more often, so being updated with email messages in a chat client leads to quicker responses.

So to make team emails more accessible, I made the Spartabots website send a webhook to a private Discord channel when an email is received.

Create a Mailgun route

I used Mailgun's free tier to collect email sent to *@spartabots.org. I made a new Mailgun route that forwards all emails to the /new-incoming-email endpoint on the spartabots.org server.

The server takes the email data, formats it, and sends it to Discord.

PHP code on the server

Then, the webserver needs to handle the incoming POST request. This short function sends a JSON message to a Discord webhook using cURL.

post('/new-incoming-email', function() {
	$webhook_url = 'https://discordapp.com/api/webhooks/.../...';

    $webhook_content = '**From**: ' . $_POST['from'] .
                       "\n**To**: " .$_POST['recipient'] .
	                   "\n**Subject**: " . $_POST['subject'] .
                       "\n**Content**: " . $_POST['stripped-text'];
    $webhook_data = json_encode(array('content' => $webhook_content),
                    JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);

    $ch = curl_init();
    curl_setopt_array($ch, [
        CURLOPT_URL => $webhook_url,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => $webhook_data,
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/json'
        ]
    ]);
    curl_exec($ch);
    curl_close($ch);
});

This code will produce a non-embed webhook that simply lists out the email information.

Fancy embeds

Discord supports sending rich embeds, which are sleek gray boxes with formatted lines and fields. The embed field is an array of Embed objects, as defined by the Discord docs. There are other fields that could be set, but I chose to only include the most relevant information.

post('/new-incoming-email', function() {
	$webhook_url = 'https://discordapp.com/api/webhooks/.../...';

    send_discord_email_webhook($_POST['from'], $_POST['recipient'], $_POST['subject'],
                               $_POST['stripped-text'], $webhook_url);
});

function send_discord_email_webhook($sender_email, $recipient_email, $email_subject,
                                    $email_content, $webhook_url) {
    $webhook_data = json_encode([
        'content' => '',
        "embeds" => [[
			'type' => 'rich',
			'timestamp' => date('c', time()),
			'footer' => [
				'text' => 'Received'
			],
			'fields' => [
				[
					'name' => 'From',
					'value' => $sender_email,
					'inline' => true
				], [
					'name' => 'To',
					'value' => $recipient_email,
					'inline' => true
				], [
					'name' => 'Subject',
					'value' => $email_subject,
					'inline' => true
				], [
					'name' => 'Content',
					'value' => $email_content,
					'inline' => false
				]
			]
		]]
    ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);

    $ch = curl_init();
    curl_setopt_array($ch, [
        CURLOPT_URL => $webhook_url,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => $webhook_data,
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/json'
        ]
    ]);
    curl_exec($ch);
    curl_close($ch);
}