func (t *SimpleChaincode) get_username(stub *shim.ChaincodeStub) (string, error) {
bytes, err := stub.GetCallerCertificate()
if err != nil {
return "", errors.New("Couldn't retrieve caller certificate")
}
x509Cert, err := x509.ParseCertificate(bytes) // Extract Certificate from result of GetCallerCertificate
if err != nil {
return "", errors.New("Couldn't parse certificate")
}
return x509Cert.Subject.CommonName, nil
}