Easier Rejection Errors (trisacrypto#161)

pkg/trisa/envelope/envelope.go

@@ -239,6 +239,24 @@ func Wrap(msg *api.SecureEnvelope, opts ...Option) (env *Envelope, err error) {
 	return env, nil
 }
 
+// Wrap error initializes an Envelope from a TRISA error to prepare and validate a
+// rejection response without going directly to the SecureEnvelope.
+func WrapError(reject *api.Error, opts ...Option) (env *Envelope, err error) {
+	if env, err = New(nil, opts...); err != nil {
+		return nil, err
+	}
+
+	if env, err = env.Reject(reject); err != nil {
+		return nil, err
+	}
+
+	if err = env.ValidateMessage(); err != nil {
+		return nil, err
+	}
+
+	return env, nil
+}
+
 // Validate is a one-liner for Wrap(msg).ValidateMessage() and can be used to ensure
 // that a secure envelope has been correctly initialized and can be processed.
 func Validate(msg *api.SecureEnvelope) (err error) {
@@ -802,7 +820,7 @@ func (e *Envelope) ValidateMessage() error {
 		if e.msg.Error == nil || e.msg.Error.IsZero() {
 			return ErrNoMessageData
 		}
-		return nil
+		return e.ValidateError()
 	}
 
 	// If there is a payload then all payload fields should be set
@@ -853,3 +871,24 @@ func (e *Envelope) ValidatePayload() error {
 
 	return nil
 }
+
+// ValidateError returns an error if the error message is missing details
+func (e *Envelope) ValidateError() error {
+	if e.msg.Error == nil {
+		return ErrNoError
+	}
+
+	if e.msg.Error.Code == api.Unhandled {
+		return ErrMissingErrorCode
+	}
+
+	if _, ok := api.Error_Code_name[int32(e.msg.Error.Code)]; !ok {
+		return ErrInvalidErrorCode
+	}
+
+	if e.msg.Error.Message == "" {
+		return ErrMissingErrorMessage
+	}
+
+	return nil
+}

pkg/trisa/envelope/envelope_test.go

@@ -446,6 +446,61 @@ func TestTimestamp(t *testing.T) {
 	}
 }
 
+func TestWrapError(t *testing.T) {
+	t.Run("Valid", func(t *testing.T) {
+		testCases := []struct {
+			reject *api.Error
+			opts   []envelope.Option
+		}{
+			{
+				&api.Error{Code: api.BeneficiaryNameUnmatched, Message: "unknown beneficiary, please update your KYC records and try again", Retry: true},
+				nil,
+			},
+			{
+				&api.Error{Code: api.HighRisk, Message: "high risk transaction, do not send or apply transaction to chain", Retry: false},
+				[]envelope.Option{envelope.WithEnvelopeID(uuid.NewString())},
+			},
+		}
+
+		for i, tc := range testCases {
+			env, err := envelope.WrapError(tc.reject, tc.opts...)
+			require.NoError(t, err, "could not correctly wrap error %d", i)
+			require.Equal(t, envelope.Error, env.State(), "incorrect state for test case %d", err)
+			require.Equal(t, tc.reject, env.Error(), "test case %d failed error mismatch", i)
+		}
+	})
+
+	t.Run("Invalid", func(t *testing.T) {
+		testCases := []struct {
+			reject   *api.Error
+			opts     []envelope.Option
+			expected error
+		}{
+			{
+				&api.Error{Code: api.BeneficiaryNameUnmatched, Message: "", Retry: true},
+				nil,
+				envelope.ErrMissingErrorMessage,
+			},
+			{
+				&api.Error{Code: api.Unhandled, Message: "high risk transaction, do not send or apply transaction to chain", Retry: false},
+				[]envelope.Option{envelope.WithEnvelopeID(uuid.NewString())},
+				envelope.ErrMissingErrorCode,
+			},
+			{
+				&api.Error{Code: api.Error_Code(21332122), Message: "this is not a good error", Retry: true},
+				nil,
+				envelope.ErrInvalidErrorCode,
+			},
+		}
+
+		for i, tc := range testCases {
+			_, err := envelope.WrapError(tc.reject, tc.opts...)
+			require.ErrorIs(t, err, tc.expected, "expected validation error on test case %d", i)
+		}
+	})
+
+}
+
 const (
 	expectedEnvelopeId = "2b3b4c95-0a78-4f2a-a9fa-041970f97144"
 )

pkg/trisa/envelope/errors.go

@@ -17,6 +17,10 @@ var (
 	ErrNoSentAtPayload          = errors.New("invalid payload: sent at timestamp is missing")
 	ErrInvalidSentAtPayload     = errors.New("invalid payload: could not parse sent at timestamp in RFC3339 format")
 	ErrInvalidReceivedatPayload = errors.New("invalid payload: could not parse received at timestamp in RFC3339 format")
+	ErrNoError                  = errors.New("invalid rejection: missing expected rejection error")
+	ErrMissingErrorCode         = errors.New("invalid rejection: missing error code")
+	ErrMissingErrorMessage      = errors.New("invalid rejection: missing error message")
+	ErrInvalidErrorCode         = errors.New("invalid rejection: unknown trisa error code")
 	ErrCannotEncrypt            = errors.New("cannot encrypt envelope: no cryptographic handler available")
 	ErrCannotSeal               = errors.New("cannot seal envelope: no public key cryptographic handler available")
 	ErrCannotUnseal             = errors.New("cannot unseal envelope: no private key cryptographic handler available")