Telegram Bot sending a message without needing a ,message to trigger it - php

Question

I am trying to let a Telegram bot send a message to a group without the need of a message by a user to trigger it. To be more specific i am trying to set up a birthday reminder where the bot querys a database, compares entries to the current date and broadcaststs a "Happy birthday" message in the group. As said i would like to do it via a cronjob that opens up the PHP script everyday and lets the bot broadcast it.
My problem is I checked all of Telegrams documentations and demo codes (https://core.telegram.org/bots/samples) but all of it are based on a User triggering the bot by sending a message.
My question is, if anyone was already able to implement a similar functionality and could aid me in extending my code? What might be worth mentioning is that the Bot is already integrated into the Group Chat and i have the chat id that would be needed for the bot to target the chat.
My code is as follows (i have to admit i copied it over from the demo examples):
<?php
define('BOT_TOKEN', 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX');
define('API_URL', 'https://api.telegram.org/bot'.BOT_TOKEN.'/');
function apiRequestWebhook($method, $parameters) {
if (!is_string($method)) {
error_log("Method name must be a string\n");
return false;
}
if (!$parameters) {
$parameters = array();
} else if (!is_array($parameters)) {
error_log("Parameters must be an array\n");
return false;
}
$parameters["method"] = $method;
header("Content-Type: application/json");
echo json_encode($parameters);
return true;
}
function exec_curl_request($handle) {
$response = curl_exec($handle);
if ($response === false) {
$errno = curl_errno($handle);
$error = curl_error($handle);
error_log("Curl returned error $errno: $error\n");
curl_close($handle);
return false;
}
$http_code = intval(curl_getinfo($handle, CURLINFO_HTTP_CODE));
curl_close($handle);
if ($http_code >= 500) {
// do not wat to DDOS server if something goes wrong
sleep(10);
return false;
} else if ($http_code != 200) {
$response = json_decode($response, true);
error_log("Request has failed with error {$response['error_code']}: {$response['description']}\n");
if ($http_code == 401) {
throw new Exception('Invalid access token provided');
}
return false;
} else {
$response = json_decode($response, true);
if (isset($response['description'])) {
error_log("Request was successfull: {$response['description']}\n");
}
$response = $response['result'];
}
return $response;
}
function apiRequest($method, $parameters) {
if (!is_string($method)) {
error_log("Method name must be a string\n");
return false;
}
if (!$parameters) {
$parameters = array();
} else if (!is_array($parameters)) {
error_log("Parameters must be an array\n");
return false;
}
foreach ($parameters as $key => &$val) {
// encoding to JSON array parameters, for example reply_markup
if (!is_numeric($val) && !is_string($val)) {
$val = json_encode($val);
}
}
$url = API_URL.$method.'?'.http_build_query($parameters);
$handle = curl_init($url);
curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
curl_setopt($handle, CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($handle, CURLOPT_TIMEOUT, 60);
return exec_curl_request($handle);
}
function apiRequestJson($method, $parameters) {
if (!is_string($method)) {
error_log("Method name must be a string\n");
return false;
}
if (!$parameters) {
$parameters = array();
} else if (!is_array($parameters)) {
error_log("Parameters must be an array\n");
return false;
}
$parameters["method"] = $method;
$handle = curl_init(API_URL);
curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
curl_setopt($handle, CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($handle, CURLOPT_TIMEOUT, 60);
curl_setopt($handle, CURLOPT_POSTFIELDS, json_encode($parameters));
curl_setopt($handle, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));
return exec_curl_request($handle);
}
function processMessage($message) {
// process incoming message
$message_id = $message['message_id'];
$chat_id = $message['chat']['id'];
if (isset($message['text'])) {
apiRequest("sendChatAction", array('chat_id' => $chat_id, "action" => "typing"));
// incoming text message
$text = $message['text'];
//Command for intializing the backend code for the birthday check (just to check its functionality but would prefer the code to run without a command)
if (strpos($text, "/geburtstagscheck") === 0) {
include 'skripte/start.php';
}
}}
define('WEBHOOK_URL', 'XXXXXXXXXXXXXX');
if (php_sapi_name() == 'cli') {
// if run from console, set or delete webhook
apiRequest('setWebhook', array('url' => isset($argv[1]) && $argv[1] == 'delete' ? '' : WEBHOOK_URL));
exit;
}
$content = file_get_contents("php://input");
$update = json_decode($content, true);
if (!$update) {
// receive wrong update, must not happen
exit;
}
if (isset($update["message"])) {
processMessage($update["message"]);
} ?>