unexpected '{' in header.php on line 1 of WordPress

I am using following code to redirect users based on browser language:

if(!isset($_SESSION['lang'])){
  if(preg_match('/en-US/', $_SERVER['HTTP_USER_AGENT'])){
    $_SESSION['lang'] = 'en';
    hea开发者_如何学编程der("location:index.php");
  }else{
    $_SESSION['lang'] = 'other';
    header("location:http://cn.gearor.com");
  }
}

I put the code in my WordPress theme, at the very beginning before DOCTYPE, and I got an error: unexpected '{' in header.php on line 1. I can't figure out what causes this.

Related: How to redirect users based on browser language

Can you please supply the code of your header.php? Your post does not tell us where to find line 1 of your code.

Wordpress encourages developers to use the function wp_redirect() for redirecting to other resources instead of sending header() like you would do in php.

For usage see: http://codex.wordpress.org/Function_Reference/wp_redirect

Related: http://wordpressapi.com/solved-header-function-issue-wordpress