mime-type-resolvers.md

MIME type resolvers

MIME type resolvers determine the content type of files sent to the Telegram Bot API. The transport uses a resolver to set the correct Content-Type for each file.

Built-in resolvers

• ApacheMimeTypeResolver — resolves MIME type by file extension based on Apache's mime.types file. Used by default.
• CustomMimeTypeResolver — resolves MIME type by file extension using a custom map.
• CompositeMimeTypeResolver — combines multiple resolvers, returning the first non-null result.

Custom MIME type resolvers

You can create a custom resolver by implementing MimeTypeResolverInterface:

use Phptg\BotApi\Transport\MimeTypeResolver\MimeTypeResolverInterface;
use Phptg\BotApi\Type\InputFile;

final class MyMimeTypeResolver implements MimeTypeResolverInterface
{
    public function resolve(InputFile $inputFile): ?string
    {
        // Return MIME type or null if it cannot be determined
        return null;
    }
}

Pass it to the transport constructor:

use Phptg\BotApi\TelegramBotApi;
use Phptg\BotApi\Transport\NativeTransport;

$transport = new NativeTransport(
    mimeTypeResolver: new MyMimeTypeResolver(),
);

$api = new TelegramBotApi($token, transport: $transport);

Combining resolvers

To combine multiple resolvers use CompositeMimeTypeResolver:

use Phptg\BotApi\Transport\MimeTypeResolver\ApacheMimeTypeResolver;
use Phptg\BotApi\Transport\MimeTypeResolver\CompositeMimeTypeResolver;
use Phptg\BotApi\Transport\MimeTypeResolver\CustomMimeTypeResolver;
use Phptg\BotApi\Transport\NativeTransport;

$transport = new NativeTransport(
    mimeTypeResolver: new CompositeMimeTypeResolver(
        new CustomMimeTypeResolver(['webp' => 'image/webp']),
        new ApacheMimeTypeResolver(),
    ),
);