请问Node.js后端签名直传，上传回调到服务器之后怎么验证oss签名

上传文件成功，nodejs验证回调签名不成功，请问大佬们怎么处理？

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function test( oss_callback) {
  const signature = Buffer. from(oss_callback.authorization, ' base64 '). toString();//callback签名
   const x_oss_pub_key_url = oss_callback[ ' x-oss-pub-key-url '];
   const pub_key_url = Buffer. from(x_oss_pub_key_url, ' base64 '). toString();
  
   if (pub_key_url. match( / http [ s ] ? \:\/\/gosspublic\.alicdn\.com\/ /)) {
     request(pub_key_url, function ( error, response, public_key) {
      
       console. log(public_key); //公钥
      
       const sign_str = md5( decodeURI(path) + ' \n ' + querystring. stringify(reqbody)); //签名字符串

       var verifier = crypto. createVerify( ' md5WithRSAEncryption ');
      verifier. update( Buffer. from(sign_str));
       console. log(verifier. verify(public_key, signature, ' base64 '));
    });
  } else {
     throw new Error( ' public key url illegal ')
  }

}