Custom REST endpoint doesn’t receive POST data

I’m in the process of building a little WordPress plugin.

I registered a REST route this way:

add_action('rest_api_init', function () {
        register_rest_route( 'mypluginame/v1', '/reminder', array(
          'methods' => WP_REST_Server::CREATABLE,
          'callback' => 'reminderManager',
          'permission_callback' => function () {
             return current_user_can( 'manage_options' );
           }
        ));
      });

This is the related reminderManager function:

function reminderManager(WP_REST_Request $data){
    
        $p = file_put_contents2("saved.json", $data->get_json_params());
    
        if($p===false){
            return array("fileWritten"=>"KO", error_get_last());
        }else{
            return array("fileWritten"=>json_encode($data));
        }
    
      }

In the footer of the plugin admin page I have a button.

This button simply calls the REST route endpoint, sending a JSON string in an AJAX POST request, through this basic JS:

function sendData(jsonData) {
        var xhr = new XMLHttpRequest();
        var r = "https://www.mydomain.com/wp-json/myplugin/v1/reminder";
        xhr.open('POST', r);
        // myScriptVars is defined in wp_localize_script and it is readable here
        xhr.setRequestHeader('X-WP-Nonce', myScriptVars.nonce);
        xhr.setRequestHeader('Content-Type', 'application/json');
        xhr.onload = function() {
            if (xhr.status === 200) {
                alert('Data saved');
            } else {
                console.log('Failed with status: ' + xhr.status);
            }
        };
        xhr.send(jsonData);
    }

What happens: when xhr.status===200 I regularly see the alert and, at the same time, the callback reminderManager fires. BUT it doesn’t work as intended, since it doesn’t receive the POST data. Can you help me understand why?

• This topic was modified 3 years, 9 months ago by islp.
• This topic was modified 3 years, 9 months ago by Jan Dembowski. Reason: Formatting. Badly