GH-1524 Regenerate Minecraft client token when the auth token is invalid

This makes the case where users copy MultiMC to other machines
easier to handle. It doesn't require manual intervention and the tokens
do not go in a desync loop.

3 files changed, 9 insertions, 2 deletions

diff --git a/api/logic/minecraft/auth/MojangAccount.cpp b/api/logic/minecraft/auth/MojangAccount.cpp
index 2b073aac..e6247608 100644
--- a/api/logic/minecraft/auth/MojangAccount.cpp
+++ b/api/logic/minecraft/auth/MojangAccount.cpp
@@ -298,3 +298,9 @@ void MojangAccount::incrementUses()
 		qWarning() << "Account" << m_username << "is now in use.";
 	}
 }
+
+void MojangAccount::invalidateClientToken()
+{
+	m_clientToken = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
+	emit changed();
+}
diff --git a/api/logic/minecraft/auth/MojangAccount.h b/api/logic/minecraft/auth/MojangAccount.h
index 4902ec11..86d81c63 100644
--- a/api/logic/minecraft/auth/MojangAccount.h
+++ b/api/logic/minecraft/auth/MojangAccount.h
@@ -95,8 +95,8 @@ public: /* manipulation */
 	 * Attempt to login. Empty password means we use the token.
 	 * If the attempt fails because we already are performing some task, it returns false.
 	 */
-	std::shared_ptr<YggdrasilTask> login(AuthSessionPtr session,
-										 QString password = QString());
+	std::shared_ptr<YggdrasilTask> login(AuthSessionPtr session, QString password = QString());
+	void invalidateClientToken();
 
 public: /* queries */
 	const QString &username() const
diff --git a/application/LaunchController.cpp b/application/LaunchController.cpp
index 62e582d8..e8f369be 100644
--- a/application/LaunchController.cpp
+++ b/application/LaunchController.cpp
@@ -108,6 +108,7 @@ void LaunchController::login()
 				auto failReasonNew = task->failReason();
 				if(failReasonNew == "Invalid token.")
 				{
+					account->invalidateClientToken();
 					failReason = needLoginAgain;
 				}
 				else failReason = failReasonNew;