<?php
date_default_timezone_set('Europe/Madrid');

$bot_id = "";
$chat_id_backup = ""; //chat_id al que mandar datos
$ruta = "/var/www/..."; //ruta del backup
$dbhost   = "127.0.0.1"; $dbuser = ""; $dbpwd = ""; $dbname = "";
$dumpfile = $dbname . "_" . date("Y-m-d_H-i-s") . ".sql";

passthru("/usr/bin/mysqldump --opt --host=$dbhost --user=$dbuser --password=$dbpwd $dbname > $ruta$dumpfile"); //Genera el backup
passthru("rm -f $(ls -1t $ruta*.sql | tail -n +50)"); //Borrar todas las copias menos las últimas 50

//Enviamos backup generado a chat_id
$ch = curl_init('https://api.telegram.org/bot' . $bot_id . '/sendDocument?chat_id='.$chat_id_backup);
$data = array('document' => curl_file_create($ruta.$dumpfile));
curl_setopt($ch, CURLOPT_POST,1);
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type:multipart/form-data']);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_exec($ch);
?>