Sending Packets/1.17

Once a packet has been added to the network, it can be called to send a message to the side it refers to. Usually there are four different directions a packet can be sent:

Direction	Description
PLAY_TO_CLIENT	A packet is sent from the server to the client during gameplay.
PLAY_TO_SERVER	A packet is sent from the client to the server during gameplay.
LOGIN_TO_CLIENT	A packet is sent to the client on initial login.
LOGIN_TO_SERVER	A packet is sent to the server on initial login.

The two login packets are handled internally by forge itself. However, the other two need to be sent using SimpleChannel#send for SimpleChannel#sendToServer. Each method takes a new instance of the message to send.

Client Packet Locations

It might not always be necessary to update every single client with a packet if they are not viewing the entity or are not affected by it. To specify which clients to send a packet from the server to, a PacketDistributor$PacketTarget must also be passed in as a parameter. There are many helpful fields that hold simple implementations of where to send which packet within PacketDistributor. However, they must be supplied with the required input either via PacketDistributor#with or PacketDistributor#noArg if it is going to all players.

Here is a list of distributors available: