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Multiplay Hosting

Blueprint integration

Learn how to integrate Multiplay Hosting with Unreal Engine Blueprints.
Read time 6 minutesLast updated 3 days ago
Learn how to use the Blueprint Visual Scripting system in the Unreal Engine to integrate with the Multiplay Game Server SDK. The Multiplay Game Server SDK can interact with the following interfaces:

Install the Multiplay Game Server SDK plug-in

Before proceeding, make sure the Multiplay Game Server SDK plug-in is properly installed.

Multiplay server configuration subsystem

This subsystem has the server configuration for the current session. This subsystem retrieves this information from the 
server.json
file on subsystem initialization. You can retrieve the server configuration by placing a MultiplayServerConfigSubsystem node and accessing the Server Config variable. Server Config has the following values:
  • A server ID
  • An allocation ID
  • A Server Query Protocol Port
  • A connection port for the session
  • A directory in which the game server saves log files
A diagram representing the setup of a multiplayer server's configuration.

A diagram representing the setup of a multiplayer server's configuration.

Multiplay Game Server Subsystem

The Multiplay Game Server Subsystem allows you to subscribe (and respond) to game server events, such as when a game server becomes allocated and when a game server is ready for players. Refer to Game server lifecycle and Server readiness. Use the instance of MultiplayGameServerSubsystem to interact with the Multiplay Game Server Subsystem through the following Blueprints:

SubscribeToServerEvents

After you have an instance of MultiplayGameServerSubsystem, you can use the Subscribe Blueprint to subscribe to Multiplay events, including OnAllocate, ReadyServerForPlayers, UnreadyServer, and OnDeallocate.
A diagram showing the Multiplay game server subsystem node connecting to the Subscribe node to subscribe to Multiplay events.

A diagram showing the Multiplay game server subsystem node connecting to the Subscribe node to subscribe to Multiplay events.

After subscribed to events, the game server must wait for an allocation. Use the OnAllocate Blueprint to enable the game server to know when it has been allocated.

OnAllocate

Use this Blueprint as an opportunity to perform any setup logic necessary before players can join the game server for a game match, such as loading game assets and starting backfill with ReadyServerForPlayers.
A diagram showing the process of subscribing to allocation events and breaking down allocation details into Event ID, Server ID, and Allocation ID. This setup is used for managing server allocation in multiplayer games.

A diagram showing the process of subscribing to allocation events and breaking down allocation details into Event ID, Server ID, and Allocation ID. This setup is used for managing server allocation in multiplayer games.

After performing any setup logic to allow players to join the game server, you can inform Multiplay that the game server is ready to accept players with the ReadyServerForPlayers Blueprint.

ReadyServerForPlayers

Use this Blueprint to let Multiplay know when a game server is ready to accept players for a game match.
A diagram depicting the node connections necessary to manage server readiness and allocation processes to accept players for a match.

A diagram depicting the node connections necessary to manage server readiness and allocation processes to accept players for a match.

If at any point the state of the game match changes so that you no longer want to accept new players, use the UnreadyServer Blueprint to let Multiplay know that the game server is no longer ready to accept players.

UnreadyServer

Use this Blueprint to let Multiplay know that the game server is no longer ready to accept players. Scenarios in which you might want to use the UnreadyServer Blueprint include:
  • A game match is almost complete
  • A game match is complete
  • The game server is full
A diagram demonstrating the node connections to let Multiplay know that the server is not ready to accept players.

A diagram demonstrating the node connections to let Multiplay know that the server is not ready to accept players.

OnDeallocate

Use this Blueprint to know when Multiplay is deallocating the game server. The OnDeallocate Blueprint provides an opportunity to perform any last-minute cleanup or bookkeeping necessary before the game server shuts down.
A node diagram representing the setup for handling server deallocation events in multiplayer games.

A node diagram representing the setup for handling server deallocation events in multiplayer games.

Multiplay Server Query Handler Subsystem

The Multiplay Server Query Handler Subsystem allows you to set game server variables monitored by the game server query protocol. This implementation uses SQP. Refer to Server Query Protocol. You can use the 
UMultiplayServerCheckSubsystem
to:

Setting Blueprints

Use the following setting Blueprints to set the query values for the game server. These setting Blueprints include SetCurrentPlayers, SetMaxPlayers, SetServerName, SetGameType, SetBuildId, SetMap, and SetPort.

SetCurrentPlayers

Use this Blueprint to set the number of players connected to the game server.
A node diagram providing a workflow for initiating player count on a multiplayer server at the beginning of gameplay.

A node diagram providing a workflow for initiating player count on a multiplayer server at the beginning of gameplay.

SetMaxPlayers

Use this Blueprint to set the maximum number of players that can connect to the game server.
A node diagram providing a workflow for initiating the maximum player limit on a multiplayer server at the beginning of gameplay.

A node diagram providing a workflow for initiating the maximum player limit on a multiplayer server at the beginning of gameplay.

SetServerName

Use this Blueprint to set the current name of the game server.
A node diagram representing setting the server name in a multiplayer game.

A node diagram representing setting the server name in a multiplayer game.

SetGameType

Use this Blueprint to set the game type that the game server is running.
A node diagram representing setting the game type of a multiplayer game, for example, Team Deathmatch.

A node diagram representing setting the game type of a multiplayer game, for example, Team Deathmatch.

SetBuildId

Use this Blueprint to set the current build ID of the game server.
A node diagram representing setting the build ID of the game server, for example, v 1.0.0.

A node diagram representing setting the build ID of the game server, for example, v 1.0.0.

SetMap

Use this Blueprint to set the current map of the game server.
A node diagram representing setting a specific map of a multiplayer game when gameplay begins.

A node diagram representing setting a specific map of a multiplayer game when gameplay begins.

SetPort

Use this Blueprint to set the port number of the game server.
A node diagram representing setting the port number from which the game client can connect to the game server.

A node diagram representing setting the port number from which the game client can connect to the game server.

Make sure to continuously update these values as they're bound to change during the game. This ensures Multiplay collects and displays data while the server is running. After setting all the values, you can add the Connect Blueprint.

Connect Blueprint

Use this Blueprint to establish a connection to the game server. You must establish a connection to the game server before using any of the Accessor Blueprints.
A node diagram representing conncting a Blueprint to the game server.

A node diagram representing conncting a Blueprint to the game server.

Accessor Blueprints

Use this Blueprint to access the values you set. These Accessor Blueprints include GetCurrentPlayers, GetMaxPlayers, GetServerName, GetGameType, GetBuildId, GetMap, and GetPort.

GetCurrentPlayers

Use this Blueprint to get the current number of players connected to the game server.
A node diagram representing the connection process to get the current number of players connected to the game server.

A node diagram representing the connection process to get the current number of players connected to the game server.

GetMaxPlayers

Use this Blueprint to get the maximum number of players allowed to connect to the game server.
A node diagram representing the connection process to get the maximum number of allowable players connected to the game server.

A node diagram representing the connection process to get the maximum number of allowable players connected to the game server.

GetServerName

Use this Blueprint to get the current name of the game server.
A node diagram representing the connection process to get the current name of the game server.

A node diagram representing the connection process to get the current name of the game server.

GetGameType

Use this Blueprint to get the game type the game server is running.
A node diagram representing the connection process to get the game type that the server is running.

A node diagram representing the connection process to get the game type that the server is running.

GetBuildId

Use this Blueprint to get the ID of the build the game server is running.
A node diagram representing the connection process to get the build ID that the game server is running.

A node diagram representing the connection process to get the build ID that the game server is running.

GetMap

Use this Blueprint to get the current map of the game server.
A node diagram representing the connection process to get the current map of the game server.

A node diagram representing the connection process to get the current map of the game server.

GetPort

Use this Blueprint to get the current port of the game server.
A node diagram representing the connection process to get the current port that the game client uses to connect to the game server.

A node diagram representing the connection process to get the current port that the game client uses to connect to the game server.

Disconnect Blueprint

Use this Blueprint to disconnect from the game server before shutting it down.
A node diagram illustrating a server disconnection upon the end play event.

A node diagram illustrating a server disconnection upon the end play event.