//   on the bucket, Amazon S3 will return an
			//   HTTP status code 404 ("no such key")
			//   error.
			// * if you don’t have the s3:ListBucket
			//   permission, Amazon S3 will return an HTTP
			//   status code 403 ("access denied") error.`
			if globalPolicySys.IsAllowed(policy.BucketPolicyArgs{
				Action:          policy.ListBucketAction,
				BucketName:      bucket,

				result.MaxValiditySeconds, minValidityDurationSeconds, maxValidityDurationSeconds)
		}

		return AuthNResponse{
			Success: &result,
		}, nil

	case 403:
		var result AuthNErrorResponse
		if err = json.NewDecoder(resp.Body).Decode(&result); err != nil {
			return AuthNResponse{}, err
		}
		return AuthNResponse{
			Failure: &result,
		}, nil

	default:

		// mean that authentication succeeded, but another
		// side-channel check has failed, we shall take
		// the client offline in such situations.
		// generally all implementations should simply return
		// 403, but in situations where there is a dependency
		// with the caller to take the client offline purpose
		// fully it should make sure to respond with '412'
		// instead, see cmd/storage-rest-server.go for ideas.

// The operation returns a 200 OK if the bucket exists and you
// have permission to access it. Otherwise, the operation might
// return responses such as 404 Not Found and 403 Forbidden.
func (api objectAPIHandlers) HeadBucketHandler(w http.ResponseWriter, r *http.Request) {
	ctx := newContext(r, w, "HeadBucket")

	defer logger.AuditLog(ctx, w, r, mustGetClaimsFromToken(r))

			//   on the bucket, Amazon S3 will return an
			//   HTTP status code 404 ("no such key")
			//   error.
			// * if you don’t have the s3:ListBucket
			//   permission, Amazon S3 will return an HTTP
			//   status code 403 ("access denied") error.`
			if globalPolicySys.IsAllowed(policy.BucketPolicyArgs{
				Action:          policy.ListBucketAction,
				BucketName:      bucket,

			expectedRespStatus: http.StatusNoContent,
		},
		// Test case - 3.
		// Setting Invalid AccessKey to force signature check inside the handler to fail.
		// Should return HTTP response status 403 forbidden.
		{
			bucketName: bucketName,
			objectName: objectName,
			accessKey:  "Invalid-AccessKey",
			secretKey:  credentials.SecretKey,

			expectedRespStatus: http.StatusForbidden,
		},