Receiving invites

Use this topic to add game invites to your Xbox services title. To receive multiplayer invites, your game registers for the multiplayer protocol and game invite callbacks. Your game receives invites for the local user, and then joins that user to the multiplayer session.

Prerequisite

To receive game invite notifications on a Windows PC, install the Xbox Game Bar. The Xbox Game Bar app is installed by default on Windows 10, OS version 1903 or later. Select Windows Key+G to launch the Xbox Game Bar app to verify that it's installed correctly.

Registering for multiplayer protocol

Registering for multiplayer protocol tells the system how to launch your game when the user accepts a multiplayer game invite. To register the multiplayer protocol, you need to add a MultiplayerProtocol element to your MicrosoftGame.config file as shown in the following code.

    <MultiplayerProtocol>true</MultiplayerProtocol>

If you have multiple executables in the package, you can specify which executable handles the multiplayer protocol by using the Executable attribute as shown in the following code.

    <MultiplayerProtocol Executable="MyExecutableForMultiplayer.exe">true</MultiplayerProtocol>

Registering for multiplayer game invite callbacks

To receive multiplayer game invite callbacks, you must register for game invite callbacks by using the XGameInviteRegisterForEvent API as shown in the following code.

For more information about the registering and unregistering game invite callback, see XGameInviteRegisterForEvent and XGameInviteUnregisterForEvent.

Flat C

#include <XTaskQueue.h>
#include <XGameInvite.h>  
  
XTaskQueueHandle g_taskQueue;  
XTaskQueueRegistrationToken g_gameInviteEventToken;  
  
void OnGameInvite(void* context, const char* inviteUri)  
{  
    if (inviteUri != nullptr)
    {
        std::string inviteString(inviteUri);
        auto pos = inviteString.find("handle=");
        auto handleId = inviteString.substr(pos + 7, 36);
        // Now call XblMultiplayerManagerJoinLobby
    }
}  
  
void InitializeGame()  
{  
    XGameInviteRegisterForEvent(g_taskQueue, nullptr, OnGameInvite, &g_gameInviteEventToken);  
}  
  
void ShutdownGame()  
{  
    XGameInviteUnregisterForEvent(g_gameInviteEventToken);  
}  

To properly handle the "accepted invite from a suspended state" scenario, the title must store the inviteUri that's passed into the OnGameInvite() handler method in the sample code above from the XGameInviteRegisterForEvent callback. Then the title must wait for the RegisterAppStateChangeNotification which notifies when the game has fully resumed before the title proceeds to operate on the session by using the details that are provided in the inviteUri.

For more information about RegisterAppStateChangeNotification, see Xbox Game Life Cycle (NDA topic)Authorization required.

Parsing inviteUrl from XGameInviteEventCallback

When your game receives the XGameInviteEventCallback event, you can access the inviteUrl string. The inviteUrl is in one of the following formats.

For accepting a game invite

When the user accepts a game invite, the game receives the game invite callback with an inviteUri as shown in the following code.

    "ms-xbl-multiplayer://inviteHandleAccept?handle=%s&invitedXuid=%s&senderXuid=%s&context=%s"
    
    // for example:
    // "ms-xbl-multiplayer://inviteHandleAccept?handle=00000000-0000-1234-5678-1234567890ab&invitedXuid=1234567890123456&senderXuid=6543210987654321&context="

The URI always starts with "ms-xbl-multiplayer//", and then the following handles.

• inviteHandleAccept indicates that the callback was initiated because the user accepted a game invite.
• handle is the invite handle you use to join the multiplayer session.
• invitedXuid is the ID of the Xbox services user who's invited to the multiplayer session.
• senderXuid is the ID of the Xbox services user who sent the game invite.
• context is the additional (optional) context the sender might have included.

For joining a game session in progress

When the user attempts to join a multiplayer session, the game would receive an invite callback with an inviteUri as shown in the following code.

    "ms-xbl-multiplayer://activityHandleJoin?&handle=%s&joinerXuid=%s&joineeXuid=%s"

The URI always starts with "ms-xbl-multiplayer//", and then the following handles.

• activityHandleJoin indicates that the callback was initiated because the user accepted a game invite.
• handle is the activity handle you use to join the multiplayer session.
• joinerXuid is the ID of the Xbox services user who's attempting to join the multiplayer session.
• joineeXuid is the ID of the Xbox services user who's currently in the multiplayer session.

Joining a multiplayer game session with handleId

Using Multiplayer Manager

If you're using Multiplayer Manager, you can join the user to the multiplayer session by using the XblMultiplayerManagerJoinLobby API and passing in the handleId that's extracted from the inviteUrl. You can also use the xblUserHandle for the invitedXuid as shown in the following code.

Flat C

HRESULT hr = XblMultiplayerManagerJoinLobby(handleId, xblUserHandle);

Using Multiplayer API directly

If you're using Multiplayer API, use the following steps to configure multiplayer sessions and invites for your title.

1. Fetch the multiplayer session document by using the XblMultiplayerGetSessionByHandleAsync API and pass it in the handleId.
2. Join the local user to the multiplayer session document by using the XblMultiplayerSessionJoin API.
3. Write the multiplayer session document to the service to commit this change by using the XblMultiplayerWriteSessionByHandleAsync API.

See also

XGameInvite API
Handling protocol activation to start a game, using Multiplayer Manager