PHP script to delete all messages in Slack channel

slack-deleter.php

<?php

class Slack
{

    private $token = '';
    private $channel = '';

    public function __construct()
    {

    }

    public function deleteAllChannelMessages()
    {
        $data = file_get_contents(sprintf('https://slack.com/api/conversations.history?token=%s&channel=%s', $this->token, $this->channel));
        $jsonData = json_decode($data, JSON_PRETTY_PRINT);
        
        foreach ($jsonData['messages'] as $message) {
            $this->deleteMessage($this->token, $this->channel, $message['ts']);
            printf("Deleting message %s\n", $message['ts']);
        }            
    }

    private function deleteMessage($token, $channel, $ts)
    {
        $url = 'https://slack.com/api/chat.delete';
        $fields = [
            'token' => urlencode($token),
            'channel' => urlencode($channel),
            'ts' => urlencode($ts),
        ];

        $fields_string = '';
        foreach ($fields as $key=>$value) {
            $fields_string .= $key.'='.$value.'&';
        }
        rtrim($fields_string, '&');

        $ch = curl_init();

        curl_setopt($ch,CURLOPT_URL, $url);
        curl_setopt($ch,CURLOPT_POST, count($fields));
        curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);

        $result = curl_exec($ch);

        curl_close($ch);            
    }

}

$slack = new Slack();
$slack->deleteAllChannelMessages();