Restful API input validation data empty

I have a controller and model to perform basic message request validation, but I can’t get the data into the model. The validation returns ‘xxx cannot be blank’. I’m testing with Postman.
I’ve tried Yii::$app->request, and post() and bodyParams and tried overriding fields() but I just don’t get any data into my model. I can’t think of anything else to try. Any thoughts or help would be much appreciated.

My controller code is:

    public function actionValidate()
        ** 1. Validate Request.
        ** 2. If valid, start Controller for requested service.
        ** 3. Respond.

        $model = new lcms();

        $lcmsRequest = Yii::$app->request;
        $lcmsParams = $lcmsRequest->bodyParams;
        //$model->attributes = \Yii::$app->request->post();

        // This will load data to the safe attributes as defined in the model rules.
        //$model->load($lcmsParams, '');
        $model->type = $lcmsRequest->post('type');
        //Yii::debug(var_export($lcmsParams, true));

        if ($model->validate()) {
            // save API call.
        } else {
            return $model->getErrors();

        ** Build response TBD...
        return $model->getErrors();

A snippet from my model is:

class Lcms extends Model
    //API message structure - Header and Data...
    public $serviceRequestId;
    public $requestorRef;
    public $credential;
    public $type;
    public $service;
    public $version;
    public $timestamp;
    public $data;

    private $requestorCredential;
    private $requestorId;
    private $apiVersion;

    // explicitly list every field, best used when you want to make sure the changes
    // in your model attributes do not cause your field changes (to keep API backward compatibility).
    public function fields()
        return [
            // field names are the same as the attribute names

    public function rules()
        return [
            [['serviceRequestId'], 'integer'],
            [['serviceRequestId', 'requestorRef', 'credential', 'type', 'service', 'version', 'timestamp','data'], 'required'],
            [['requestorRef'], 'string', 'max' => 50],
            [['credential'], 'string', 'max' => 255],
            [['type'], 'string', 'max' => 10],
            [['service'], 'string', 'max' => 255],
            [['version'], 'string', 'max' => 5],
            [['timestamp'], 'integer'],
            [['data'], 'string'],       // validated by the requested service.

            // Additional specific vaidation...
            ['type','validateType', 'skipOnEmpty' => false, 'skipOnError' => false],
            ['version','validateVersion', 'skipOnEmpty' => false, 'skipOnError' => false],
            ['requestorRef','validateRequestorRef', 'skipOnEmpty' => false],
            ['credential','validateCredential','skipOnEmpty' => false],
            ['service','validateService','skipOnEmpty' => false, 'skipOnError' => false],
            ['service','validateRequestorService', 'skipOnEmpty' => false, 'skipOnError' => false],


Any help would be much appreciated.

My problem was the Postman data wasn’t as expected by the yii->request. I had the JSON within brackets[ ]. Once I removed these, then the code fell in place.