400 error when POSTing data after enabling CSRF

I've been having this kind of error recently, and I've been looking for the cause. I came across an article that solved it, and I'd like to share it with you.

The first solution is to turn off CSRF

public function init(){
 $this->enableCsrfValidation = false;
}

The second solution is to add hidden fields to the form

The third solution is to add the _csrf field in AJAX

var csrfToken = $('meta[name="csrf-token"]').attr("content");
$.ajax({
 type: 'POST',
 url: url,
 data: {_csrf:csrfToken},
 success: success,
 dataType: dataType
});

Yii matching process and Yii::$app->request->csrfToken value storage location description:

Storage location

 protected function createCsrfCookie($token)
 {
 $options = $this->csrfCookie;
 $options['name'] = $this->csrfParam;
 $options['value'] = $token;
 return new Cookie($options);
 }

Verification method

 public function validateCsrfToken($token = null)
 {
 $method = $this->getMethod();
 // only validate CSRF token on non-"safe" methods http://www.w3 .org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.1
 if (!$this->enableCsrfValidation || in_array($method, ['GET', 'HEAD', 'OPTIONS'], true)) {
 return true;
 }

 $trueToken = $this->loadCsrfToken();

 if ($token !== null) {
 return $this->validateCsrfTokenInternal($token, $trueToken);
 } else {
 return $this->validateCsrfTokenInternal($this->getBodyParam($this->csrfParam), $trueToken)
 || $this->validateCsrfTokenInternal($this->getCsrfTokenFromHeader(), $ trueToken);
 }
 }

The above is the entire content of this article, I hope you all like it.

Csrf, POST