[1.7.10] Interceptor framework for incoming vanilla packets

[OreCruncher]

Before I resort to rocket science I figured I would ask the question in hopes that I have overlooked something.  What I am wanting to do is intercept incoming packets from clients before they get handed off to FML/Vanilla packet processing.  Is there a framework in place that allows me to register an interceptor so that my mod can get a crack at the packet before/after processing?

 

The specific thing I am wanting to do is intercept incoming sign text update packets so that I can do some pre/post processing of the event.  What I am hoping for is clean server side entry point to do this without resorting to custom signs/tile entities, ASM, or some other fancy hackery.  The mod I am working on should not be required on a client.

 

(I did look for a Forge event for sign update, but I did not see any.)

[EverythingGames]

There are events such as ClientCustomPacketEvent, ServerCustomPacketEvent, and CustomPacketRegistrationEvent, but I'm not sure how useful these would be to you for intercepting packets.

[OreCruncher]

Yeah.  My understanding, though, that those are for custom packs that my mod generates and send.  Of course, there may be some trick to these guys where I can get vanilla packets.

[diesieben07]

You can get vanilla packets with the following hack:

- Use

ClientConnectedToServerEvent

or

ServerConnectionFromClientEvent

depending on which side you care about.

 

- From that event you have access to the

NetworkManager

, then through the

channel()

method the netty-channel and then finally the

ChannelPipeline

using the

pipeline()

method.

 

- You can now insert your own

ChannelHandler

into the pipeline. To see how the vanilla pipeline is structured, look at e.g.

NetworkManager.provideLanClient

,

NetworkManager#provideLocalClient

,

NetworkSystem#addLanEndpoint

and

NetworkSystem#addLocalEndpoint

.

[Ernio]

^ This could be potentially really damn useful.

 

Other question

Goal: Change packet's data before it's being sent from server to client.

Extend NetHandlerPlayerServer and override sendPacket, and then simply check instance of packet and change data.

For every EntityPlayerMP - LoggedIn or JoinedWorld event? - replace handler field with extension.

Happily manipulate packets with e.g world data (e.g: have 2 players in same world but one will receive totally different world data).

 

Can something go wrong?

[diesieben07]

Ernio, the same procedure applies to your goal (change packet data).

[OreCruncher]

Excellent! On the surface this is exactly what I am looking for.  Now I have my project for the day.