Simplify errors

protocol/messages.go

@@ -23,10 +23,11 @@ type ErrorCode string
 
 // Error is a protocol error.
 type Error struct {
-	ErrorCode
 	error
-	info string
+	ErrorCode
 	*ApiError
+	Info   string
+	Status int
 }
 
 // Statuses
@@ -57,17 +58,23 @@ const (
 	ErrorCrypto = ErrorCode("cryptoResponseError")
 	// Server rejected our response (second IRMA message)
 	ErrorRejected = ErrorCode("rejectedByServer")
+	// (De)serializing of a message failed
+	ErrorSerialization = ErrorCode("serializationError")
 )
 
-// Qr contains the data of an IRMA session QR.
+// Qr contains the data of an IRMA session QR (as generated by irma_js),
+// suitable for NewSession().
 type Qr struct {
-	URL                string `json:"u"`
+	// Server with which to perform the session
+	URL string `json:"u"`
+	// Session type (disclosing, signing, issuing)
+	Type               Action `json:"irmaqr"`
 	ProtocolVersion    string `json:"v"`
 	ProtocolMaxVersion string `json:"vmax"`
-	Type               Action `json:"irmaqr"`
 }
 
-// A SessionInfo is the first message in the IRMA protocol.
+// A SessionInfo is the first message in the IRMA protocol (i.e., GET on the server URL),
+// containing the session request info.
 type SessionInfo struct {
 	Jwt     string                          `json:"jwt"`
 	Nonce   *big.Int                        `json:"nonce"`

protocol/protocol_test.go

@@ -47,5 +47,7 @@ func TestTransport(t *testing.T) {
 	}{}
 
 	err := transport.Get("614/info.0.json", obj)
-	require.NoError(t, err)
+	if err != nil { // require.NoError() does not work because of the type of err
+		t.Fatalf("%+v\n", err)
+	}
 }

protocol/session.go

@@ -106,7 +106,7 @@ func NewSession(qr *Qr, handler Handler) {
 	case ActionUnknown:
 		fallthrough
 	default:
-		handler.Failure(ActionUnknown, &Error{ErrorCode: ErrorUnknownAction, error: nil, info: string(session.Action)})
+		handler.Failure(ActionUnknown, &Error{ErrorCode: ErrorUnknownAction, error: nil, Info: string(session.Action)})
 		return
 	}
 
@@ -126,9 +126,9 @@ func (session *session) start() {
 
 	// Get the first IRMA protocol message and parse it
 	info := &SessionInfo{}
-	err := session.transport.Get("jwt", info)
-	if err != nil {
-		session.Handler.Failure(session.Action, &Error{ErrorCode: ErrorTransport, ApiError: err.(*TransportError).ApiErr})
+	Err := session.transport.Get("jwt", info)
+	if Err != nil {
+		session.Handler.Failure(session.Action, Err)
 		return
 	}
 	jwtparts := strings.Split(info.Jwt, ".")
@@ -231,33 +231,32 @@ func (session *session) do(proceed bool, choice *irmago.DisclosureChoice) {
 		return
 	}
 
+	var Err *Error
 	switch session.Action {
 	case ActionSigning:
 		fallthrough
 	case ActionDisclosing:
 		response := ""
-		err = session.transport.Post("proofs", &response, message)
-		if err != nil {
-			session.Handler.Failure(session.Action,
-				&Error{ErrorCode: ErrorTransport, ApiError: err.(*TransportError).ApiErr, info: err.Error(), error: err})
+		Err = session.transport.Post("proofs", &response, message)
+		if Err != nil {
+			session.Handler.Failure(session.Action, Err)
 			return
 		}
 		if response != "VALID" {
-			session.Handler.Failure(session.Action, &Error{ErrorCode: ErrorRejected, info: response})
+			session.Handler.Failure(session.Action, &Error{ErrorCode: ErrorRejected, Info: response})
 			return
 		}
 	case ActionIssuing:
 		response := []*gabi.IssueSignatureMessage{}
-		err = session.transport.Post("commitments", &response, message)
-		if err != nil {
-			session.Handler.Failure(session.Action,
-				&Error{ErrorCode: ErrorTransport, ApiError: err.(*TransportError).ApiErr, info: err.Error(), error: err})
+		Err = session.transport.Post("commitments", &response, message)
+		if Err != nil {
+			session.Handler.Failure(session.Action, Err)
 			return
 		}
 
 		err = irmago.Manager.ConstructCredentials(response, session.irmaSession.(*irmago.IssuanceRequest))
 		if err != nil {
-			session.Handler.Failure(session.Action, &Error{ErrorCode: ErrorCrypto, error: err})
+			session.Handler.Failure(session.Action, &Error{error: err, ErrorCode: ErrorCrypto})
 			return
 		}
 	}

protocol/session_test.go

@@ -192,7 +192,7 @@ func sessionHelper(t *testing.T, jwtcontents interface{}, url string) {
 	jwt := base64.RawStdEncoding.EncodeToString(headerbytes) + "." + base64.RawStdEncoding.EncodeToString(bodybytes) + "."
 	qr, transportErr := StartSession(jwt, url)
 	if transportErr != nil {
-		fmt.Println(transportErr.(*TransportError).ApiErr)
+		fmt.Printf("+%v\n", transportErr)
 	}
 	require.NoError(t, transportErr)
 	qr.URL = url + "/" + qr.URL

protocol/transport.go

@@ -25,17 +25,6 @@ type ApiError struct {
 	Stacktrace  string `json:"stacktrace"`
 }
 
-// TransportError is an error occuring during HTTP traffic.
-type TransportError struct {
-	Err    string
-	Status int
-	ApiErr *ApiError
-}
-
-func (te TransportError) Error() string {
-	return te.Err
-}
-
 // NewHTTPTransport returns a new HTTPTransport.
 func NewHTTPTransport(serverURL string) *HTTPTransport {
 	url := serverURL
@@ -50,7 +39,7 @@ func NewHTTPTransport(serverURL string) *HTTPTransport {
 	}
 }
 
-func (transport *HTTPTransport) request(url string, method string, result interface{}, object interface{}) error {
+func (transport *HTTPTransport) request(url string, method string, result interface{}, object interface{}) *Error {
 	if method != http.MethodPost && method != http.MethodGet {
 		panic("Unsupported HTTP method " + method)
 	}
@@ -67,7 +56,8 @@ func (transport *HTTPTransport) request(url string, method string, result interf
 		} else {
 			marshaled, err := json.Marshal(object)
 			if err != nil {
-				return &TransportError{Err: err.Error()}
+				return &Error{error: err, ErrorCode: ErrorSerialization}
+				//return &TransportError{Err: err.Error()}
 			}
 			//fmt.Printf("POST: %s\n", string(marshaled))
 			reader = bytes.NewBuffer(marshaled)
@@ -76,7 +66,7 @@ func (transport *HTTPTransport) request(url string, method string, result interf
 
 	req, err := http.NewRequest(method, transport.Server+url, reader)
 	if err != nil {
-		return &TransportError{Err: err.Error()}
+		return &Error{error: err, ErrorCode: ErrorTransport}
 	}
 
 	req.Header.Set("User-Agent", "irmago")
@@ -90,39 +80,39 @@ func (transport *HTTPTransport) request(url string, method string, result interf
 
 	res, err := transport.client.Do(req)
 	if err != nil {
-		return &TransportError{Err: err.Error()}
+		return &Error{error: err, ErrorCode: ErrorTransport}
 	}
 
 	body, err := ioutil.ReadAll(res.Body)
 	if err != nil {
-		return &TransportError{Err: err.Error(), Status: res.StatusCode}
+		return &Error{error: err, Status: res.StatusCode}
 	}
 	if res.StatusCode != 200 {
 		apierr := &ApiError{}
 		json.Unmarshal(body, apierr)
 		if apierr.ErrorName == "" { // Not an ApiErrorMessage
-			return &TransportError{Status: res.StatusCode}
+			return &Error{ErrorCode: ErrorTransport, Status: res.StatusCode}
 		}
 		//fmt.Printf("ERROR: %+v\n", apierr)
-		return &TransportError{Err: apierr.ErrorName, Status: res.StatusCode, ApiErr: apierr}
+		return &Error{ErrorCode: ErrorTransport, Status: res.StatusCode, ApiError: apierr}
 	}
 
 	//fmt.Printf("RESPONSE: %s\n", string(body))
 	err = json.Unmarshal(body, result)
 	if err != nil {
-		return &TransportError{Err: err.Error(), Status: res.StatusCode}
+		return &Error{error: err, Status: res.StatusCode}
 	}
 
 	return nil
 }
 
 // Post sends the object to the server and parses its response into result.
-func (transport *HTTPTransport) Post(url string, result interface{}, object interface{}) error {
+func (transport *HTTPTransport) Post(url string, result interface{}, object interface{}) *Error {
 	return transport.request(url, http.MethodPost, result, object)
 }
 
 // Get performs a GET request and parses the server's response into result.
-func (transport *HTTPTransport) Get(url string, result interface{}) error {
+func (transport *HTTPTransport) Get(url string, result interface{}) *Error {
 	return transport.request(url, http.MethodGet, result, nil)
 }