return
	}

	formValues.Set("Bucket", bucket)
	if fileName != "" && strings.Contains(formValues.Get("Key"), "${filename}") {
		// S3 feature to replace ${filename} found in Key form field
		// by the filename attribute passed in multipart
		formValues.Set("Key", strings.ReplaceAll(formValues.Get("Key"), "${filename}", fileName))
	}
	object := trimLeadingSlash(formValues.Get("Key"))

func checkPostPolicy(formValues http.Header, postPolicyForm PostPolicyForm) error {
	// Check if policy document expiry date is still not reached
	if !postPolicyForm.Expiration.After(UTCNow()) {
		return fmt.Errorf("Invalid according to Policy: Policy expired")
	}
	// check all formValues appear in postPolicyForm or return error. #https://github.com/minio/minio/issues/17391