John Davidson

Message:

I'm a PHP newbie trying to extend the Wordpress API on our BuddyPress website. I've created a database table which I plan on using to store a user's friends (or in our specific case "favourite members"). I would like to write an API endpoint to return a user's friends using the user's id as an input (i.e. "myapi/v1/favouritemembers/[user id]"). This is what I've done so far;

/*** Grab favourite members for a specified user ***/

function favourite_members( $data ) {

  $favourites = get_favourite_members(array(

    'user_id' => $data['user_id'],

  ) );



  if ( empty( $favourites ) ) {

    return null;

  }



  return $favourites;

}



function get_favourite_members( $data ){

  global $wpdb;

  $sql = $wpdb->prepare( "SELECT member_id FROM wp_my_favourite_members WHERE user_id = %d", $data['user_id'] );

  return $wpdb->get_results( $sql );

}



/*** Register register_rest_route ***/

add_action( 'rest_api_init', function () {

  register_rest_route( 'myapi/v1', '/favouritemembers/(?P<id>\d+)', array(

    'methods' => 'GET',

    'callback' => 'favourite_members',

  ) );

} );

I'm having trouble getting this to work correctly, the endpoint just returns an empty response. If I replace the query
"SELECT member_id FROM wp_my_favourite_members WHERE user_id = %d", $data['user_id'] with "SELECT member_id FROM wp_my_favourite_members WHERE user_id = 1" then it works as expected, so I'm suspecting there may be something wrong with the way I am dealing with the input parameters in the get_favourite_members function, but I'm not sure.

---

My Answer:
It looks like the issue might be with how you are passing the user_id parameter to the get_favourite_members function. In your favourite_members function, you are passing the user_id parameter as an array key, but in your get_favourite_members function, you are accessing it as $data['user_id'].

Try updating your favourite_members function to pass the user_id parameter as a direct argument to the get_favourite_members function like this:

php
/*** Grab favourite members for a specified user ***/
function favourite_members( $data ) {
$favourites = get_favourite_members( $data['user_id'] );

if ( empty( $favourites ) ) {
return null;
}

return $favourites;
}

function get_favourite_members( $user_id ){
global $wpdb;
$sql = $wpdb->prepare( "SELECT member_id FROM wp_my_favourite_members WHERE user_id = %d", $user_id );
return $wpdb->get_results( $sql );
}

/*** Register register_rest_route ***/
add_action( 'rest_api_init', function () {
register_rest_route( 'myapi/v1', '/favouritemembers/(?P\d+)', array(
'methods' => 'GET',
'callback' => 'favourite_members',
) );
} );


By making this change, you should be able to correctly pass the user_id parameter to the get_favourite_members function and retrieve the desired data from the database table.