Add extension hooks to TelegramBotHandler for URL and curl headers

[EgorGruzdev]

Add extension hooks to TelegramBotHandler for API URL and curl headers

Problem

TelegramBotHandler used a private const BOT_API and hardcoded self::BOT_API directly inside sendCurl(), making it impossible to:

• point the handler at a self-hosted Telegram Bot API server
• inject custom HTTP headers (auth tokens, tracing, proxies) into the curl request

Solution

Two protected hook methods added to sendCurl():

Method	Default	Purpose
botApiUrl(): string	'https://api.telegram.org/bot'	Override to change the API base URL
getCurlHeaders(): array	[]	Override to add extra HTTP headers

No changes to the public API. Fully backwards compatible.

---

Usage example (English)

// Subclass pointing to a self-hosted Bot API + custom auth header
class MyTelegramHandler extends TelegramBotHandler
{
    protected function botApiUrl(): string
    {
        return 'https://telegram-api.internal.example.com/bot';
    }

    protected function getCurlHeaders(): array
    {
        return [
            'X-Internal-Token: my-secret-token',
            'X-Request-Source: monolog',
        ];
    }
}

$handler = new MyTelegramHandler(
    apiKey: 'YOUR_BOT_TOKEN',
    channel: '@your_channel',
);
$logger = new \Monolog\Logger('app');
$logger->pushHandler($handler);
$logger->error('Something went wrong');

---

Пример использования (Russian)

// Наследник, использующий собственный сервер Bot API и токен авторизации
class MyTelegramHandler extends TelegramBotHandler
{
    // Меняем базовый URL на свой сервер (self-hosted Telegram Bot API)
    protected function botApiUrl(): string
    {
        return 'https://telegram-api.internal.example.com/bot';
    }

    // Добавляем произвольные HTTP-заголовки к каждому curl-запросу
    protected function getCurlHeaders(): array
    {
        return [
            'X-Internal-Token: my-secret-token',
            'X-Request-Source: monolog',
        ];
    }
}

$handler = new MyTelegramHandler(
    apiKey: 'YOUR_BOT_TOKEN',
    channel: '@your_channel',
);

$logger = new \Monolog\Logger('app');
$logger->pushHandler($handler);
$logger->error('Что-то пошло не так');

---

Changes

• src/Monolog/Handler/TelegramBotHandler.php
  • Added protected function botApiUrl(): string
  • Added protected function getCurlHeaders(): array
  • sendCurl() now calls $this->botApiUrl() instead of self::BOT_API
  • sendCurl() applies CURLOPT_HTTPHEADER when getCurlHeaders() returns a non-empty array

[daniser]

I think this should be changed to:

$url = $this->botApiUrl() . $this->apiKey . '/SendMessage';