Add NewClientFromBackup to messenger

api/messenger/backupRestore.go

+// FIXME: This is placeholder, there's got to be a better place to put
+// backup restoration than inside messenger.
+
+package messenger
+
+import (
+	"github.com/pkg/errors"
+	"gitlab.com/elixxir/client/api"
+	"gitlab.com/elixxir/client/e2e"
+	"gitlab.com/elixxir/client/e2e/rekey"
+	"gitlab.com/elixxir/client/storage"
+	"gitlab.com/elixxir/client/storage/user"
+	"gitlab.com/elixxir/client/ud"
+	cryptoBackup "gitlab.com/elixxir/crypto/backup"
+	"gitlab.com/elixxir/primitives/fact"
+	"gitlab.com/xx_network/primitives/id"
+)
+
+// NewClientFromBackup constructs a new Client from an encrypted
+// backup. The backup is decrypted using the backupPassphrase. On
+// success a successful client creation, the function will return a
+// JSON encoded list of the E2E partners contained in the backup and a
+// json-encoded string containing parameters stored in the backup
+func NewClientFromBackup(ndfJSON, storageDir string, sessionPassword,
+	backupPassphrase []byte, backupFileContents []byte) ([]*id.ID,
+	string, error) {
+
+	backUp := &cryptoBackup.Backup{}
+	err := backUp.Decrypt(string(backupPassphrase), backupFileContents)
+	if err != nil {
+		return nil, "", errors.WithMessage(err,
+			"Failed to unmarshal decrypted client contents.")
+	}
+
+	usr := user.NewUserFromBackup(backUp)
+
+	def, err := api.ParseNDF(ndfJSON)
+	if err != nil {
+		return nil, "", err
+	}
+
+	cmixGrp, e2eGrp := api.DecodeGroups(def)
+
+	// Note we do not need registration here
+	storageSess, err := api.CheckVersionAndSetupStorage(def, storageDir,
+		[]byte(sessionPassword), usr, cmixGrp, e2eGrp,
+		backUp.RegistrationCode)
+	if err != nil {
+		return nil, "", err
+	}
+
+	storageSess.SetReceptionRegistrationValidationSignature(
+		backUp.ReceptionIdentity.RegistrarSignature)
+	storageSess.SetTransmissionRegistrationValidationSignature(
+		backUp.TransmissionIdentity.RegistrarSignature)
+	storageSess.SetRegistrationTimestamp(backUp.RegistrationTimestamp)
+
+	//move the registration state to indicate registered with
+	// registration on proto client
+	err = storageSess.ForwardRegistrationStatus(
+		storage.PermissioningComplete)
+	if err != nil {
+		return nil, "", err
+	}
+
+	privkey := usr.E2eDhPrivateKey
+
+	//initialize the e2e storage
+	err = e2e.Init(storageSess.GetKV(), usr.ReceptionID, privkey, e2eGrp,
+		rekey.GetDefaultParams())
+	if err != nil {
+		return nil, "", err
+	}
+
+	udInfo := backUp.UserDiscoveryRegistration
+	var username, email, phone fact.Fact
+	for _, f := range udInfo.FactList {
+		switch f.T {
+		case fact.Email:
+			email = f
+		case fact.Username:
+			username = f
+		case fact.Phone:
+			phone = f
+		}
+	}
+	ud.InitStoreFromBackup(storageSess.GetKV(), username, email, phone)
+
+	return backUp.Contacts.Identities, backUp.JSONParams, nil
+}