Failed to decode packet cookie_request

[HumanDuck23]

[x] The FAQ doesn't contain a resolution to my issue

Versions

• minecraft-protocol: 1.55.0
• server: vanilla/spigot/paper 1.21.4
• node: 22.14.0

Detailed description of a problem

I'm trying to set up a simple offline-mode server that (currently) only spawns the player in a void world. The following code works for other versions (tested for 1.8 with slight adaptations to the login packet, 1.18, 1.19 and 1.20 with the same code, different data versions). Attempting to run the same code with 1.21 results in the connection being lost and the following error being shown:

Internal Exception: io.netty.handler.codec.DecoderException: Failed to decode packet 'clientbound/minecraft:cookie_request'.

Current code

const mc = require("minecraft-protocol")
const mcData = require("minecraft-data")("1.21")

const server = mc.createServer({
  host: "127.0.0.1",
  port: 25565,
  version: "1.21",
  "online-mode": false,
})

server.on("login", (client) => {
  const p = mcData.loginPacket
  console.log(p)
  client.write("login", {
    ...p,
  })
  client.write("position", {
    x: 0,
    y: 0,
    z: 0,
    yaw: 0,
    pitch: 0,
  })
})

Expected behavior

The client should spawn in an empty world at the coordinates 0/0/0 immediately upon joining the server.

[HumanDuck23]

anything on this? I don't mean to rush anyone or be rude, would just like to know if anyone has any ideas what's causing this / what I could investigate to fix it myself and / or submit a PR for this.

[rom1504]

The error says you're sending packet cookie_request wrong Can you share the part of your code sending this packet?

…

On Mon, Apr 21, 2025, 10:21 HumanDuck23 ***@***.***> wrote: anything on this? I don't mean to rush anyone or be rude, would just like to know if anyone has any ideas what's causing this / what I could investigate to fix it myself and / or submit a PR for this. — Reply to this email directly, view it on GitHub <#1389 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAR437WRNVV6CPIANXRNSF322RBYJAVCNFSM6AAAAAB2MMAYL6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDQMJXGQ2DQOBXG4> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.*** com> *HumanDuck23* left a comment (PrismarineJS/node-minecraft-protocol#1389) <#1389 (comment)> anything on this? I don't mean to rush anyone or be rude, would just like to know if anyone has any ideas what's causing this / what I could investigate to fix it myself and / or submit a PR for this. — Reply to this email directly, view it on GitHub <#1389 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAR437WRNVV6CPIANXRNSF322RBYJAVCNFSM6AAAAAB2MMAYL6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDQMJXGQ2DQOBXG4> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.*** com>

[HumanDuck23]

I'm not sending the packet myself, my entire code is the code I provided in the beginning... Is it send automatically somewhere?

This also seems to happen with prismarine-proxy, with no extra code, there's an issue there too, I'd link it but I'm on my phone right now

[rom1504]

https://github.com/search?q=repo%3APrismarineJS%2Fnode-minecraft-protocol%20cookie_request&type=code it is not sent by node-minecraft-protocol automatically

[rom1504]

You can enable debug mode to understand better what you receive and send

[HumanDuck23]

This is interesting... I enabled debug mode and it never logs anything about a cookie_request packet, yet I'm still getting that error on my client. This is the full code I'm using right now:

const mc = require("minecraft-protocol")
const mcData = require("minecraft-data")("1.21.4")

const server = mc.createServer({
  host: "127.0.0.1",
  port: 25565,
  version: "1.21.4",
  "online-mode": false,
})

server.on("login", (client) => {
  const p = mcData.loginPacket
  client.write("login", {
    ...p,
  })
  client.write("position", {
    x: 0,
    y: 0,
    z: 0,
    yaw: 0,
    pitch: 0,
  })
})

And this is the error I'm seeing client-side:

And this is the entire log: https://pastebin.com/ixmWMsd4

It's never writing that packet, yet the error still shows up on the client, how is that possible?

[HumanDuck23]

it looks like the state isn't correct when I write my packets?

minecraft-protocol writing packet login.login +176ms

minecraft-protocol writing packet login.position +2ms

These are the only packets I myself write in the code and they should be play.login and play.position, why is this happening?

[rom1504]

https://github.com/PrismarineJS/node-minecraft-protocol/blob/master/examples/server_world/mc.js#L25 you need to listen to playerJoin not login event

[HumanDuck23]

Doing that doesn't work either, though now I just get a "Network Protocol Error" message.

This is the log for that: https://pastebin.com/BYEauP0z
It seems that it never even writes the packets I write in the listener.

I adapted the code to work the way I intend for 1.8.9, and this is it:

const mc = require("minecraft-protocol")

const server = mc.createServer({
  host: "127.0.0.1",
  port: 25565,
  version: "1.8.9",
  "online-mode": false,
})

server.on("login", (client) => {
  client.write("login", {
    entityId: 0,
    gameMode: 0,
    dimension: 0,
    difficulty: 2,
    maxPlayers: 20,
    levelType: "default",
    reducedDebugInfo: false
  })
  client.write("position", {
    x: 0,
    y: 0,
    z: 0,
    yaw: 0,
    pitch: 0,
  })
})

I'm just trying to make this work with any version. Why does it work with login here, and why should I use playerJoin instead? Does the API change between MC versions? It also works with playerJoin though. Why is that the case in 1.8 but not other versions?

[rom1504]

Yes the packet changes between versions, a lot.

If you want something easier I'd recommend https://github.com/PrismarineJS/flying-squid which is an higher level wrapper of node-minecraft-protocol server

[rom1504]

Doing that doesn't work either

Doing what exactly?

[HumanDuck23]

Doing what exactly?

Sorry, using the playerJoin event doesn't work as I would like it to.

If I have this code now:

const mc = require("minecraft-protocol")

const server = mc.createServer({
  host: "127.0.0.1",
  port: 25565,
  version: false,
  "online-mode": false,
})

server.on("login", (client) => {
  const mcData = require("minecraft-data")(client.version)
  const p = mcData.loginPacket
  client.write("login", {
    ...p,
  })
  client.write("position", {
    x: 0,
    y: 0,
    z: 0,
    yaw: 0,
    pitch: 0,
  })
})

This should work on many versions (not 1.8 because mcData.loginPacket doesn't exist, but that doesn't matter. This works on multiple versions (1.18, 1.19, 1.20) but fails for 1.21 with the error I initially had when creating this issue. Why does login work there? Using playerJoin instead works as well, for the versions I tested, yet once again, not for 1.21. Shouldn't this also work for 1.21?

login -> cookie_request error
playerJoin -> Network Protocol Error

[rom1504]

login event is too early

For 1.21 you need other packets as well iirc

But generally if you want something that works across version that's what we built at flying-squid. You can read the code there if you want

[rom1504]

https://github.com/PrismarineJS/flying-squid/blob/4241690254b081ace608050da34b11a2a22a50e7/src/lib/plugins/login.js#L20