Slack direct message delete

slack-delete.php

<?php

require_once './vendor/autoload.php';

use GuzzleHttp\Pool;
use GuzzleHttp\Client;
use GuzzleHttp\Psr7\Request;

$apiUrl = 'https://slack.com/api/'; // API URL.
$apiToken = 'xoxp-xxxx-xxxx-xxxx-xxxx'; // Slack Legacy API Token.
$channel = 'D8783SG54'; // Channel ID.
$conversationLimit = 1000; // Amount of conversation in history to delete.
$users = [
    'U8YGMLGJ4' // Only delete messages belonging to user ID's contained in this array.
];

// Get conversation history for timestamps.
$httpClient = new Client();
$response = $httpClient->request('GET', $apiUrl . 'conversations.history', [
    'query' => [
        'token' => $apiToken,
        'channel' => $channel,
        'limit' => $conversationLimit
    ]
]);

$conversationHistory = json_decode($response->getBody(), true);

$requests = function ($messages) use ($apiUrl, $apiToken, $channel, $users) {
    $uri = $apiUrl . 'chat.delete';

    foreach ($messages as $message) {
        if (in_array($message['user'], $users)) {
            yield new Request(
                'POST',
                $uri, [
                    'Content-Type' => 'application/x-www-form-urlencoded'
                ],
                http_build_query([
                    'token' => $apiToken,
                    'channel' => $channel,
                    'ts' => $message['ts']
                ], null, '&')
            );
            sleep(1);
        }
    }
};

if ($conversationHistory['ok']) { // $response->getStatusCode();
    $pool = new Pool($httpClient, $requests($conversationHistory['messages']), [
        'concurrency' => 5,
        'fulfilled' => function ($response, $index) {
        },
        'rejected' => function ($reason, $index) {
            var_dump($reason);
        },
    ]);

    // Initiate the transfers and create a promise.
    $promise = $pool->promise();

    // Force the pool of requests to complete.
    $promise->wait();
}