HTML5 Multiplayer

its good to see html5 packaging from the editor on the master (4.8) branch.
however, multiplayer doesn’t seem to be working.


the error is from the client trying to connect over the internet.
console command from blueprints,
open mapname?listen
open [server ip]

is it implemented yet or do i need to mes with steam sockets or something?


heres the link

Hi tegleg,

The HTML5 networking path is still in the early stages and still being worked on atm so I’d expect it to be a little flaky. AFAIK it’s built on websockets which is wrapped in BSD socket api (but don’t quote me on that) so if you want to mess with it please do.

Unreal Networking for HTML5 doesn’t yet exist in main line although if you are interested in testing out a alpha version and providing a test case, please let me know.

hello sorry for the delay. yes i would be interested in that. where do i get it? thanks was just committed. This is still experimental.

thanks :slight_smile:

opening on local machine.

btw, still cant package without a c++ project.

This is what I did to test in Firefox, Chrome hasn’t been tested yet.

  • Make relevant .ini changes ( look up for the plugin )
  • Build editor - test Networked PIE. From the output logs in the IDE, confirm that plugin was used.
  • Start the a server ( dedicated or the editor build)
  • connect a native Win64 client and confirm its working
  • edit the generated html5 file and fix up the command line arguments needed for the client ( i.e ip of the server etc…)
  • open the page in firefox.

( Currently the plugin is not enabled by default, make sure its enabled to actually use it)

when you say “edit the generated html5 file” refering to the host ip, what line is that exactly?

is there currently a way to change the host ip dynamically?
and does it have to be a dedicated server?


i still get the script error above as well as:
Assertion failed: HasFoundDataDirectory [File:G:\UnrealEngine-5a54a880bac95a7e0120bdda90c1caea5005e215\Engine\Source\Runtime\Core\Private\Internationalization\ICUInternationalization.cpp] [Line: 117]
ICU data directory was not discovered:

In google it’s the first result. Can we have any news for this question?

Any updates on this? I have a blueprint based project that would greatly benefit from out-of-the-box multiplayer entry/login through a HTML5 client… And I would also be willing to test any recent alpha/beta packages/plugins.

The dedicated development/shipping server crashes when client tries to connect to port 8889.
Firefox (47.0 64-bit) error:
“The connection to ws://149.56..:8889/ was interrupted while the page was loading.”
NOTE: The normal Win64 client network cannot/wont even initiate Websocket communications!

Normal building of server/client with Visual Studio 2015 works from github source when using default networking.

Instructions used:

Detailed Development Server Error:

[2016.06.20-07.32.45:601][208]LogNet: NotifyAcceptingConnection: Server TheMeetingRoom accept
[2016.06.20-07.32.45:797][208]PacketHandlerLog: Loaded PacketHandler component: Engine.EngineHandlerComponentFactory (StatelessConnectHandlerComponent)
[2016.06.20-07.32.46:011][208]LogNet: NotifyAcceptedConnection: Name: TheMeetingRoom, TimeStamp: 06/20/16 10:32:46, [UNetConnection] RemoteAddr: dsl-hkibra****, Name: WebSocketConnection_0, Driver: GameNetDriver WebSocketNetDriver_0, IsServer: YES, PC: NULL, Owner: NULL
[2016.06.20-07.32.46:011][208]LogNet: AddClientConnection: Added client connection: [UNetConnection] RemoteAddr: dsl-hkibra
****, Name: WebSocketConnection_0, Driver: GameNetDriver WebSocketNetDriver_0, IsServer: YES, PC: NULL, Owner: NULL
[2016.06.20-07.32.46:020][208]LogNetSerialization:Error: FBitReader::SetOverflowed() called
[2016.06.20-07.32.46:042][208]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2016.06.20-07.32.47:226][208]LogWindows:Error: === Critical error: ===
LowLevelFatalError [File:C:\UnrealEngine-release\Engine\Source\Runtime\Engine\Classes\Engine/NetConnection.h] [Line: 561]
Pure virtual not implemented (UNetConnection::RemoteAddressToString)

[2016.06.20-07.32.47:237][208]LogExit: Executing StaticShutdownAfterError
[2016.06.20-07.32.47:261][208]LogWindows: FPlatformMisc::RequestExit(1)
[2016.06.20-07.32.47:262][208]Log file closed, 06/20/16 10:32:47


any news on this? I found a 2 year old github for UE4.8 that was supposed to address networking with HTML5 but it crashes UE4.12 when I try to build.

more info over here: