discourse-webhook.php

<?php

// settings
$slackHook = 'YOUR_SLACK-ISSUED_WEBHOOK_URL_HERE';
$discourseHost = 'YOUR_DISCOURSE_HOSTNAME';


// decode webhook payload
list($post, $topic, $user) = json_decode(file_get_contents('php://input'), true);


// compose message for Slack
$messageText = "New topic on $discourseHost";

#// This doesn't work because the category is a number... we'll need to map them on our own to category names or slack rooms
#if (!empty($topic['category'])) {
#    $messageText .= " in $topic[category]";
#}

$messageText .= ": <http://$discourseHost/t/$post[topic_id]|$topic[title]>";
$messageText .= "\n\n> " . str_replace("\n", "\n> ", $post['raw']) . "\n\n\n" . json_encode(['post' => $post, 'topic' => $topic, 'user' => $user], JSON_PRETTY_PRINT);;


// confugre cURL
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $slackHook);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, [
    'payload' => json_encode([
        'username' => $user['username'] . '@discourse',
        'icon_url' => str_replace('{size}', 100, "http://$discourseHost/$user[avatar_template]"),
        'text' => $messageText
    ])
]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);


// execute request
$response = curl_exec($ch);
curl_close($ch);


// write slack response to output
die($response);