reCAPTCHA v3 使い方（サンプル付き）

• reCAPTCHA v3 の使い方（v2 と異なりチェックボックス UI が出ない）
• 前提: キー登録（https://g.co/recaptcha/v3）が必要
• クライアント:

$gRecaptchaResponse = $_POST["g-recaptcha-response"];

$reCaptchaUrl = "https://www.google.com/recaptcha/api/siteverify?secret=Secret key&response=" . $gRecaptchaResponse;

$response = @file_get_contents($reCaptchaUrl);

$response = json_decode($response,true);

if ($response['success'] != true or $response['score'] < 0.5 ){

    //エラー処理

}

{

  "success": true|false,      // whether this request was a valid reCAPTCHA token for your site

  "score": number             // the score for this request (0.0 - 1.0)

  "action": string            // the action name for this request (important to verify)

  "challenge_ts": timestamp,  // timestamp of the challenge load (ISO format yyyy-MM-dd'T'HH:mm:ssZZ)

  "hostname": string,         // the hostname of the site where the reCAPTCHA was solved

  "error-codes": [...]        // optional

}