Custom rest api endpoint response json problem

Question

I am using WP 4.6 which the rest api have not yet included in the core. But I still can use rest_api_init to create an api endpoint. The problem is how can I change the endpoint response into proper json format?

This is what I did.

add_action( 'rest_api_init', function () {
  register_rest_route( 'news/v1', '/latest', array(
    'methods' => "GET",
    'callback' =>'get_latest_posts_api',
  ) );
} );

function get_latest_posts_api($data ){
    $data = array(
                   'title' => 'test title',
                   'content' => 'blah blah blah......'
    );
   return  rest_ensure_response($data);
}

When I call the endpoint in another wp site, I got nothing.

$recent_posts = wp_remote_get("http://xxxx.com/wp-json/news/v1/latest/");
$i = 1;

print_r(json_decode($recent_posts['body'], true));//this give me nothing
 echo $recent_posts['body']; //this give me the raw data though. 

When I open directly on firefox, it shows me SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

What is the problem?

UPDATE

I added data array to be returned, but still got the error.

UPDATE

Debug using json_last_error() on decoding the response and it gave me JSON_ERROR_SYNTAX error. But I don't get it, I thought the register_rest_route already handle converting to json?

I also tried with json encoding in the callback function, still got me this error.

I am lost.

Answer 1

Turn out it is caused by a BOM character from one of my included file. If you are having same problem, you can save your file to Encode in UTF8 without BOM.