Authentication

1. Add the Dependency

Add minified-auth to your build.gradle file:

repositories {
    mavenCentral()
    maven { url 'https://jitpack.io' }
}

dependencies {
    implementation 'com.github.dervarex.minified:minified-auth:3.0.0'
}

---

2. Initialize the Auth Manager

Before using authentication, initialize the AuthManager with a directory where sessions can be stored.

Java

Path authDirectory = Path.of("<auth-directory>");

AuthManager.init(authDirectory);

Kotlin

val authDirectory = Path.of("<auth-directory>")

AuthManager.init(authDirectory)

---

3. Check for a Saved Session

Before starting a new login, check whether a saved session already exists.

Java

User user = null;

if (AuthManager.hasSessionSaved()) {
    user = AuthManager.loginWithSavedSession();
}

Kotlin

var user: User? = null

if (AuthManager.hasSessionSaved()) {
    user = AuthManager.loginWithSavedSession()
}

If the saved session is valid, loginWithSavedSession() returns the authenticated user.

---

4. Start Device Code Login

If no saved session exists, start the Microsoft device code login:

Java

AuthManager.startDeviceCodeLoginAsync();

Kotlin

AuthManager.startDeviceCodeLoginAsync()

Blocking alternative

AuthManager.login() runs the same device-code flow synchronously and returns the User directly instead of updating LoginState in the background - but it also throws LoginFailedException on failure rather than reporting it through LoginState.status. Only use it from a dedicated background thread; calling it from a UI thread blocks until the user finishes authorizing in the browser. startDeviceCodeLoginAsync() (shown above) is the recommended entry point for most launchers.

The login runs asynchronously. You can access its current state using:

Java

LoginState state = AuthManager.getLoginState();

Kotlin

val state = AuthManager.getLoginState()

Wait until the user code becomes available:

Java

while (true) {
    LoginState state = AuthManager.getLoginState();

    if (state.userCode != null && state.verificationUri != null) {
        System.out.println(
                "Go to " + state.verificationUri
                + " and enter code " + state.userCode
        );
        break;
    }

    Thread.sleep(500);
}

Kotlin

while (true) {
    val state = AuthManager.getLoginState()

    if (state.userCode != null && state.verificationUri != null) {
        println(
            "Go to ${state.verificationUri} and enter code ${state.userCode}"
        )
        break
    }

    Thread.sleep(500)
}

The user can then open the verification URL and enter the displayed code.

---

5. Wait for Authentication

After displaying the login instructions, wait until authentication succeeds or fails:

Java

while (true) {
    LoginState state = AuthManager.getLoginState();

    if (state.status == AuthManager.LoginStatus.SUCCESS) {
        break;
    }

    if (state.status == AuthManager.LoginStatus.ERROR) {
        throw new IllegalStateException(state.message);
    }

    Thread.sleep(500);
}

Kotlin

while (true) {
    val state = AuthManager.getLoginState()

    if (state.status == AuthManager.LoginStatus.SUCCESS) {
        break
    }

    if (state.status == AuthManager.LoginStatus.ERROR) {
        throw IllegalStateException(state.message)
    }

    Thread.sleep(500)
}

After a successful login, get the authenticated user:

Java

User user = AuthManager.getUser();

System.out.println(
        "Logged in as "
        + user.username()
        + " ("
        + user.uuid()
        + ")"
);

Kotlin

val user = AuthManager.getUser()

println(
    "Logged in as ${user.username} (${user.uuid})"
)

---

6. Listening for State Changes

Polling getLoginState() in a loop works, but AuthManager also supports pushing state changes directly to a listener - useful if your UI framework already has a callback/observer pattern instead of a poll loop:

Java

LoginStateChangeListener listener = newState -> {
    System.out.println("New login state: " + newState.status);
};

AuthManager.addStateChangeListener(listener);

Kotlin

val listener = LoginStateChangeListener { newState ->
    println("New login state: ${newState.status}")
}

AuthManager.addStateChangeListener(listener)

The listener is invoked with the same LoginState snapshot every time AuthManager updates it - during login(), startDeviceCodeLoginAsync(), and resetLoginState(). Remove it once you no longer need updates (e.g. when the login UI closes), the same way you would unsubscribe from any other event in Minified:

Java

AuthManager.removeStateChangeListener(listener);

Kotlin

AuthManager.removeStateChangeListener(listener)

---

Complete Example

Java

Path authDirectory = Path.of("<auth-directory>");

AuthManager.init(authDirectory);

User user = null;

if (AuthManager.hasSessionSaved()) {
    user = AuthManager.loginWithSavedSession();
}

if (user == null) {
    AuthManager.startDeviceCodeLoginAsync();

    boolean loginInstructionsShown = false;

    while (true) {
        LoginState state = AuthManager.getLoginState();

        if (!loginInstructionsShown
                && state.userCode != null
                && state.verificationUri != null) {

            System.out.println(
                    "Go to " + state.verificationUri
                    + " and enter code " + state.userCode
            );

            loginInstructionsShown = true;
        }

        if (state.status == AuthManager.LoginStatus.SUCCESS) {
            user = AuthManager.getUser();
            break;
        }

        if (state.status == AuthManager.LoginStatus.ERROR) {
            throw new IllegalStateException(state.message);
        }

        Thread.sleep(500);
    }
}

System.out.println(
        "Logged in as "
        + user.username()
        + " ("
        + user.uuid()
        + ")"
);

Kotlin

val authDirectory = Path.of("<auth-directory>")

AuthManager.init(authDirectory)

var user: User? = null

if (AuthManager.hasSessionSaved()) {
    user = AuthManager.loginWithSavedSession()
}

if (user == null) {
    AuthManager.startDeviceCodeLoginAsync()

    var loginInstructionsShown = false

    while (true) {
        val state = AuthManager.getLoginState()

        if (!loginInstructionsShown
            && state.userCode != null
            && state.verificationUri != null
        ) {
            println(
                "Go to ${state.verificationUri} and enter code ${state.userCode}"
            )

            loginInstructionsShown = true
        }

        if (state.status == AuthManager.LoginStatus.SUCCESS) {
            user = AuthManager.getUser()
            break
        }

        if (state.status == AuthManager.LoginStatus.ERROR) {
            throw IllegalStateException(state.message)
        }

        Thread.sleep(500)
    }
}

println(
    "Logged in as ${user!!.username} (${user.uuid})"
)

The returned User can now be passed directly to Minified Launch:

Java

Launcher.launchMinecraft(
        user,
        config
);

Kotlin

Launcher.launchMinecraft(
    user,
    config
)

---

Encryption Events

Sessions are stored encrypted on disk using a master key. AuthManager.init() accepts an EventBus that these events are dispatched on, see CreateMasterKeyEvent, SaveEncryptedSessionEvent and LoadEncryptedSessionEvent in the Events section for details on exactly when each one fires.