Difference between revisions of "Protocol"
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Revision as of 10:20, 5 March 2012
This page presents a dissection of the current stable Minecraft protocol. The current pre-release protocol is documented elsewhere.
Credit goes to the Great Old Ones, and the citizens of #mcdevs who helped by providing packet dumps and insight. If you're having trouble, check out the FAQ. Make sure you check the Data Types and Units of Measurement pages.
Note: While you may use the contents of this page without restriction to create servers, clients, bots, etc… you still need to provide the attribution above if you copy any of the contents of this page for publication elsewhere.
The protocol for Pocket Minecraft is substantially different, and is documented at Pocket Minecraft Protocol.
This is a fairly lengthy page, and to make it more readable certain terminology must be understood. Terms used on this page and their definition are provided below.
Definition | |
---|---|
Player | When used in in the singular, Player always refers to the client connected to the server |
Entity | Entity refers to any item, player, mob, minecart or boat in the world. This definition is subject to change as Notch extends the protocol |
EID | An EID - or Entity ID - is a unique 4-byte integer used to identify a specific entity |
XYZ | In this document, the axis names are the same as those used by Notch. Y points upwards, X points South, and Z points West. |
Contents
- 1 Packets
- 1.1 Keep Alive (0x00)
- 1.2 Login Request (0x01)
- 1.3 Handshake (0x02)
- 1.4 Chat Message (0x03)
- 1.5 Time Update (0x04)
- 1.6 Entity Equipment (0x05)
- 1.7 Spawn Position (0x06)
- 1.8 Use Entity (0x07)
- 1.9 Update Health (0x08)
- 1.10 Respawn (0x09)
- 1.11 Player (0x0A)
- 1.12 Player Position (0x0B)
- 1.13 Player Look (0x0C)
- 1.14 Player Position & Look (0x0D)
- 1.15 Player Digging (0x0E)
- 1.16 Player Block Placement (0x0F)
- 1.17 Holding Change (0x10)
- 1.18 Use Bed (0x11)
- 1.19 Animation (0x12)
- 1.20 Entity Action (0x13)
- 1.21 Spawn Named Entity (0x14)
- 1.22 Spawn Dropped Item (0x15)
- 1.23 Collect Item (0x16)
- 1.24 Spawn Object/Vehicle (0x17)
- 1.25 Spawn Mob (0x18)
- 1.26 Spawn Painting (0x19)
- 1.27 Spawn Experience Orb (0x1A)
- 1.28 Entity Velocity (0x1C)
- 1.29 Destroy Entity (0x1D)
- 1.30 Entity (0x1E)
- 1.31 Entity Relative Move (0x1F)
- 1.32 Entity Look (0x20)
- 1.33 Entity Look and Relative Move (0x21)
- 1.34 Entity Teleport (0x22)
- 1.35 Entity Head Look (0x23)
- 1.36 Entity Status (0x26)
- 1.37 Attach Entity (0x27)
- 1.38 Entity Metadata (0x28)
- 1.39 Entity Effect (0x29)
- 1.40 Remove Entity Effect (0x2A)
- 1.41 Set Experience (0x2B)
- 1.42 Map Column Allocation (0x32)
- 1.43 Map Chunks (0x33)
- 1.44 Multi Block Change (0x34)
- 1.45 Block Change (0x35)
- 1.46 Block Action (0x36)
- 1.47 Explosion (0x3C)
- 1.48 Sound/Particle Effect (0x3D)
- 1.49 Change Game State (0x46)
- 1.50 Thunderbolt (0x47)
- 1.51 Open Window (0x64)
- 1.52 Close Window (0x65)
- 1.53 Click Window (0x66)
- 1.54 Set Slot (0x67)
- 1.55 Set Window Items (0x68)
- 1.56 Update window property (0x69)
- 1.57 Transaction (0x6A)
- 1.58 Creative inventory action (0x6B)
- 1.59 Enchant Item (0x6C)
- 1.60 Update Sign (0x82)
- 1.61 Item Data (0x83)
- 1.62 Update Tile Entity (0x84)
- 1.63 Increment Statistic (0xC8)
- 1.64 Player List Item (0xC9)
- 1.65 Plugin message (0xFA)
- 1.66 Server List Ping (0xFE)
- 1.67 Disconnect/Kick (0xFF)
- 2 See Also
Packets
All packets begin with a single "Packet ID" byte. Listed packet size includes this byte. Packets are either "server to client", "client to server", or both. If not specified, assume that the packet can be sent both ways. There is no "length" field; for variable length packets, you must parse to the end to determine the length.
Keep Alive (0x00)
The server will frequently send out a keep-alive, each containing a random ID. The client must respond with the same packet. The Beta server will disconnect a client if it doesn't receive at least one packet before 1200 in-game ticks, and the Beta client will time out the connection under the same conditions. The client may send packets with Keep-alive ID=0.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x00 | Keep-alive ID | int | 957759560
|
Server-generated random id |
Total Size: | 5 bytes |
Login Request (0x01)
Sent by the client after the handshake to finish logging in. If the version is outdated or any field is invalid, the server will disconnect the client with a kick. If the client is started in offline mode, the player's username will default to Player
, making LAN play with more than one player impossible (without authenticating) as the server will prevent multiple users with the same name.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x01 | Protocol Version | int | 20
|
1.1's protocol version is 23
|
Username | string | TkTech
|
The name of the user attempting to login, max length of 16 | |
Not used | string | (empty string) | ||
Not used | int | 0
|
||
Not used | int | 0
|
||
Not used | byte | 0
|
||
Not used | unsigned byte | 0
|
||
Not used | unsigned byte | 0
|
||
Total Size: | 20 bytes + length of strings |
Sent by the server if it accepts the clients login request. If it didn't, it'll send a kick instead.
Max players is used by the client to draw the player list. Setting this value lower than the actual max players, or indeed the number of players online, will only affect the size and number of users displayed. Values above 127 will cause the player list not to be drawn. Values above 60 will cause usernames to overlap and not fit in their bounding boxes.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x01 | Entity ID | int | 1298
|
The Players Entity ID |
Not used | string | (empty string) | Not used | |
Level Type | string | DEFAULT | DEFAULT or SUPERFLAT; level-type in server.properties | |
Server mode | int | 0
|
0 for survival, 1 for creative | |
Dimension | int | 0
|
-1 : The Nether, 0 : The Overworld, 1 : The End
| |
Difficulty | byte | 1
|
0 thru 3 for Peaceful, Easy, Normal, Hard
| |
World height | unsigned byte | 128
|
Defaults to 128
| |
Max players | unsigned byte | 8
|
Used by the client to draw the player list | |
Total Size: | 20 bytes + length of strings |
Handshake (0x02)
This is the first packet sent by the client and is used for Authentication.
Contains the username of the connecting player, and the server host/port they're connecting to, most likely to allow virtual hosting. (sample implementation)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x02 | Username and Host | string | TkTech;localhost:25565
|
The username of the player attempting to connect, and the host he is connecting to, seperated by a semicolon. |
Total Size: | 3 bytes + length of string |
This is the first packet sent by the server, in response to the client, and is used for Authentication
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x02 | Connection Hash | string | 2e66f1dc032ab5f0
|
A unique, per-connection hash, or '+' |
Total Size: | 3 bytes + length of strings |
If connect hash is '+', the server is in offline mode and no name authentication needs to take place. The client will just send a 0x01 straight back, and the server won't perform the similar authentication step.
Otherwise, it contains a randomly generated long as a series of hex digits. For details on what to do with it, see Authentication
Chat Message (0x03)
A message from the client to the server, or the server to the client. The actual handling of chat messages is variable and depends on the server and client; there are no de facto standards yet.
The Alpha server will check the message to see if it begins with a '/'. If it doesn't, the username of the sender is prepended and sent to all other clients (including the original sender). If it does, the server assumes it to be a command and attempts to process it. A message longer than 100 characters will cause the server to kick the client. This limits the chat message packet length to 103 bytes. Note that this limit does not apply to incoming chat messages as the server may have prepended other information, not limited to, but usually including, a username.
A message longer than 119 characters will cause the Beta (≥1.5) server and client to crash to print the message "Received string length longer than maximum allowed (X > 119)", with no side effects.
For more information, see Chat.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x03 | Message | string | <Bob> Hello World!
|
User input must be sanitized server-side |
Total Size: | 3 bytes + length of strings |
Time Update (0x04)
Time is based on ticks, where 20 ticks happen every second. There are 24000 ticks in a day, making Minecraft days exactly 20 minutes long.
The time of day is based on the timestamp modulo 24000. 0 is sunrise, 6000 is noon, 12000 is sunset, and 18000 is midnight.
The default SMP server increments the time by 20
every second.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x04 | Time | long |
|
The world (or region) time, in ticks |
Total Size: | 9 bytes |
Entity Equipment (0x05)
After each "Named Entity Spawn", there will be five of these packets for the equipped item and armor. If there are changes in visible equipment, another one of these is sent.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x05 | Entity ID | int | 0x00010643 | Named Entity ID |
Slot | short | 4 | Equipment slot: 0=held, 1-4=armor slot | |
Item ID | short | -1 | Equipped item (-1 for empty slot) | |
Damage | short | |||
Total Size: | 11 bytes |
Spawn Position (0x06)
Sent by the server after login to specify the coordinates of the spawn point (the point at which players spawn at, and which the compass points to). It can be sent at any time to update the point compasses point at.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x06 | X | int | 117
|
Spawn X in block coordinates |
Y | int | 70
|
Spawn Y in block coordinates | |
Z | int | -46
|
Spawn Z in block coordinates | |
Total Size: | 13 bytes |
Use Entity (0x07)
This packet is new to version 4 of the protocol, and is believed to be Use Entity. This packet is sent from the client to the server when the client attacks or right-clicks another entity.
A Notchian server only accepts this packet if the entity being attacked/used is visible without obstruction and within a 4-unit radius of the player's position.
(This packet data values are not fully verified)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x07 | User | int | 1298
|
The entity of the player (ignored by the server) |
Target | int | 1805
|
The entity the player is interacting with | |
Left-click? | bool | true
|
Seems to be true when the player is pointing at an entity and left-clicking and false when right-clicking.
| |
Total Size: | 10 bytes |
Update Health (0x08)
Sent by the server to update/set the health of the player it is sent to. Added in protocol version 5.
Food saturation acts as a food "overcharge". Food values will not decrease while the saturation is over zero. Players logging in automatically get a saturation of 5.0. Eating food increases the saturation as well as the food bar.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x08 | Health | short | 20 | 0 or less = dead, 20 = full HP |
Food | short | 20 | 0 - 20 | |
Food Saturation | float | 5.0 | Seems to vary from 0.0 to 5.0 in integer increments | |
Total Size: | 9 bytes |
Respawn (0x09)
Sent by the client when the player presses the "Respawn" button after dying. The server then teleports the user to the spawn point, and sends a respawn packet in response. The client will not leave the respawn screen until it receives a respawn packet.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x09 | Dimension | int | 1
|
-1 : The Nether, 0 : The Overworld, 1 : The End
|
Difficulty | byte | 1
|
0 thru 3 for Peaceful, Easy, Normal, Hard. 1 is always sent c->s
| |
Creative mode | byte | 1
|
0 for survival, 1 for creative.
| |
World height | short | 128
|
Defaults to 128
| |
Level Type | string | DEFAULT | See 0x01 login | |
Total Size: | 11 bytes + length of string |
To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.
Player (0x0A)
This packet is used to indicate whether the player is on ground (walking/swimming), or airborne (jumping/falling).
When dropping from sufficient height, fall damage is applied when this state goes from False to True. The amount of damage applied is based on the point where it last changed from True to False. Note that there are several movement related packets containing this state.
This packet was previously referred to as Flying
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x0A | On Ground | bool | 1
|
True if the client is on the ground, False otherwise
|
Total Size: | 2 bytes |
Player Position (0x0B)
Updates the players XYZ position on the server.
If Stance - Y
is less than 0.1
or greater than 1.65
, the stance is illegal and the client will be kicked with the message “Illegal Stance”.
If the distance between the last known position of the player on the server and the new position set by this packet is greater than 100 units will result in the client being kicked for "You moved too quickly :( (Hacking?)"
Also if the absolute number of X or Z is set greater than 3.2E7D
the client will be kicked for "Illegal position"
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x0B | X | double | 102.809
|
Absolute position |
Y | double | 70.00
|
Absolute position | |
Stance | double | 71.62
|
Used to modify the players bounding box when going up stairs, crouching, etc… | |
Z | double | 68.30
|
Absolute position | |
On Ground | bool | 1
|
Derived from packet 0x0A | |
Total Size: | 34 bytes |
Player Look (0x0C)
Updates the direction the player is looking in.
Yaw is measured in degrees, and does not follow classical trigonometry rules. The unit circle of yaw on the xz-plane starts at (0, 1) and turns backwards towards (-1, 0), or in other words, it turns clockwise instead of counterclockwise. Additionally, yaw is not clamped to between 0 and 360 degrees; any number is valid, including negative numbers and numbers greater than 360.
Pitch is measured in degrees, where 0 is looking straight ahead, -90 is looking straight up, and 90 is looking straight down.
You can get a unit vector from a given yaw/pitch via:
x = -cos(pitch) * sin(yaw) y = -sin(pitch) z = cos(pitch) * cos(yaw)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x0C | Yaw | float | 0.00
|
Absolute rotation on the X Axis, in degrees |
Pitch | float | 0.00
|
Absolute rotation on the Y Axis, in degrees | |
On Ground | bool | 1
|
Derived from packet 0x0A | |
Total Size: | 10 bytes |
Player Position & Look (0x0D)
A combination of Player Look and Player position.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x0D | X | double | 6.5
|
Absolute position |
Y | double | 65.620000004768372
|
Absolute position | |
Stance | double | 67.240000009536743
|
Used to modify the players bounding box when going up stairs, crouching, etc… | |
Z | double | 7.5
|
Absolute position | |
Yaw | float | 0.0
|
Absolute rotation on the X Axis | |
Pitch | float | 0.0
|
Absolute rotation on the Y Axis | |
On Ground | bool | 0
|
Derived from packet 0x0A | |
Total Size: | 42 bytes |
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x0D | X | double | 6.5
|
Absolute position |
Stance | double | 67.240000009536743
|
Used to modify the players bounding box when going up stairs, crouching, etc… | |
Y | double | 65.620000004768372
|
Absolute position | |
Z | double | 7.5
|
Absolute position | |
Yaw | float | 0.0
|
Absolute rotation on the X Axis | |
Pitch | float | 0.0
|
Absolute rotation on the Y Axis | |
On Ground | bool | 0
|
Derived from packet 0x0A | |
Total Size: | 42 bytes |
Note that this packet differs from client Player & Position Look packet - the Stance and Y are sent in a different order.
Stance and Y seems to be the opposite as in the table (from Client to Server = X, Y, Stance, Z, froom Server to client = X, Stance, Y, Z) please confirm ! [BackBone`:] The opposite stance<->y confirmed, however the given structs had the server and client struct reversed, which I fixed.
When you connect to the official server, it will push a 0x0D packet. If you do not immediately respond with a 0x0D (or maybe 0x0A-0x0C) packet with similar and valid information, it will have unexpected results, such as map chunks not loading and future 0x0A-0x0D packets being ignored.
Player Digging (0x0E)
Sent when the player mines a block. A Notchian server only accepts digging packets with coordinates within a 6-unit radius of the player's position.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x0E | Status | byte | 1
|
The action the player is taking against the block (see below) |
X | int | 32
|
Block position | |
Y | byte | 64
|
Block position | |
Z | int | 32
|
Block position | |
Face | byte | 3
|
The face being hit (see below) | |
Total Size: | 12 bytes |
Status can (currently) be one of four values:
Meaning | Value |
---|---|
Started digging | 0
|
Finished digging | 2
|
Drop item | 4
|
Shoot arrow / finish eating | 5
|
Notchian clients send a 0 (started digging) when they start digging and a 2 (finished digging) once they think they are finished. If digging is aborted, no notice is sent to the server; the client simply does not send a 2 (finished digging).
Status code 4 (drop item) is a special case. In-game, when you use the Drop Item command (keypress 'q'), a dig packet with a status of 4, and all other values set to 0, is sent from client to server.
The face can be one of six values, representing the face being hit:
Value | 0 | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|---|
Offset | -Y | +Y | -Z | +Z | -X | +X |
In 1.7.3, when a player opens a door with left click the server receives Packet 0xE+start digging and opens the door.
Player Block Placement (0x0F)
Sent when the player places a block or an item. The coordinates sent in this packet are actually the block being built against, which combined with the direction offset tell you where the block should be placed. This is required to correctly position furnaces, torches, etc…
In 1.7.3, when a player opens a door with right click, the server receives Packet 0xF (block placement, but opens door).
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x0F | X | int | 32
|
Block position |
Y | byte | 64
|
Block position | |
Z | int | 32
|
Block position | |
Direction | byte | 3
|
The offset to use for block/item placement (see below) | |
Held item | slot | |||
Total Size: | 11 bytes + slot data |
If the Block/ItemID field is greater than or equal to 0, then the last 2 fields (amount and damage) are read. Otherwise, they are not read. When 'placing' (Or more accurately, using) your empty hand, the client sends -1 as the Block/ItemID
The direction can be one of six values, representing the face the block/item is being placed against:
Value | 0 | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|---|
Offset | -Y | +Y | -Z | +Z | -X | +X |
In normal operation (ie placing a block), this packet is sent once, with the values set normally.
This packet has a special case where X, Y, Z, and Direction are all -1. This special packet indicates that the currently held item for the player should have its state updated such as eating food, shooting bows, using buckets, etc.
In a Notchian Beta client, the block or item ID corresponds to whatever the client is currently holding, and the client sends one of these packets any time a right-click is issued on a surface, so no assumptions can be made about the safety of the ID. However, with the implementation of server-side inventory, a Notchian server seems to ignore the item ID, instead operating on server-side inventory information and holding selection.
Special note on using buckets: When using buckets, the Notchian client might send two packets: first a normal and then a special case. The first normal packet is sent when you're looking at a block (e.g. the water you want to scoop up). This normal packet does not appear to do anything with a Notchian server. The second, special case packet appears to perform the action - based on current position/orientation and with a distance check - it appears that buckets can only be used within a radius of 6 units.
Holding Change (0x10)
Sent when the player changes the slot selection
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x10 | Slot ID | short | 1
|
The slot which the player has selected (0-8) |
Total Size: | 3 bytes |
Use Bed (0x11)
Associated with players using beds.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x11 | Entity ID | int | 89 | Player ID |
???In Bed??? | byte | 0 | 0 Appears when players use bed | |
X coordinate | int | -247 | Bed (headboard?) X as block coordinate | |
Y coordinate | byte | 78 | Bed (headboard?) Y as block coordinate | |
Z coordinate | int | 128 | Bed (headboard?) Z as block coordinate | |
Total Size: | 15 bytes |
- NOTE: This Packet seems to be sent when 2 or more players are on a server, and at least one player uses a Bed.
Animation (0x12)
Sent whenever an entity should change animation.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x12 | EID | int | 55534
|
Player ID |
Animation | byte | 1
|
Animation ID | |
Total Size: | 6 bytes |
Animation can be one of the following values:
ID | Animation |
---|---|
0 | No animation |
1 | Swing arm |
2 | Damage animation |
3 | Leave bed |
5 | Eat food |
102 | (unknown) |
104 | Crouch |
105 | Uncrouch |
Only 1
(swing arm) and 3
(leave bed) is sent by notchian clients. Crouching is sent via 0x13. Damage is server-side, and so is not sent by notchian clients. See also 0x26.
Entity Action (0x13)
Sent at least when crouching, leaving a bed, or sprinting. To send action animation to client use 0x28.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x13 | EID | int | 55534
|
Player ID |
Action ID | byte | 1
|
The ID of the action, see below. | |
Total Size: | 6 bytes |
Action ID can be one of the following values:
ID | Action |
---|---|
1 | Crouch |
2 | Uncrouch |
3 | Leave bed |
4 | Start sprinting |
5 | Stop sprinting |
Spawn Named Entity (0x14)
The only named entities (at the moment) are players (either real or NPC/Bot). This packet is sent by the server when a player comes into visible range, not when a player joins.
Servers can, however, safely spawn player entities for players not in visible range. The client appears to handle it correctly.
At one point, the Notchian client was not okay with receiving player entity packets, including 0x14, that refer to its own username or EID; and would teleport to the absolute origin of the map and fall through the Void any time it received them. However, in more recent versions, it appears to handle them correctly, by spawning a new entity as directed (though future packets referring to the entity ID may be handled incorrectly).
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x14 | EID | int | 94453
|
Player ID |
Player Name | string | Twdtwd
|
Max length of 16 | |
X | int | 784
|
Player X as Absolute Integer | |
Y | int | 2131
|
Player Y as Absolute Integer | |
Z | int | -752
|
Player Z as Absolute Integer | |
Rotation | byte | 0
|
Player rotation as a packed byte | |
Pitch | byte | 0
|
Player rotation as a packed byte | |
Current Item | short | 0
|
The item the player is currently holding. Note that this should be 0 for "no item", unlike -1 used in other packets. A negative value crashes clients. | |
Total Size: | 23 bytes + length of strings |
Spawn Dropped Item (0x15)
An 0x15 packet is sent by the server whenever an item on the ground (say a pickaxe thrown on the ground) comes into range of the player. (note: this means range for item vision, not range for pickup!) It used to be sent by the client when an item is dropped from a tile (chest or furnace) or from inventory, but that is now done with the new packets for server-side inventory (see 0x66).
It is completely acceptable for servers to ignore the EID issued by the client in this packet and instead create a new packet with a server-controlled EID when sending this packet out to clients.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x15 | EID | int | 157617
|
Unique entity ID |
Item | short | 4
|
The item ID | |
Count | byte | 1
|
The number of items | |
Damage/Data | short | New field in beta 1.2 update (see below) | ||
X | int | 133
|
Item X as Absolute Integer | |
Y | int | 913
|
Item Y as Absolute Integer | |
Z | int | 63552
|
Item Z as Absolute Integer | |
Rotation | byte | 252
|
Item rotation as a packed byte | |
Pitch | byte | 25
|
Item pitch as a packed byte | |
Roll | byte | 12
|
Item roll as a packed byte | |
Total Size: | 25 bytes |
"Damage" field This field is also used to store item metadata. E.g. you mined birch wood(its id is the same as normal wood) so you must set damage to the metadata of birch wood(2). The same case is wool. Id is the same but data is different.For example: you mined blue wool so your damage field should send value 0xB.
Collect Item (0x16)
Sent by the server when someone picks up an item lying on the ground - its sole purpose appears to be the animation of the item flying towards you. It doesn't destroy the entity in the client memory (0x1D does that), and it doesn't add it to your inventory (0x67 does that). The server only checks for items to be picked up after each Player Position and Player Position & Look packet sent by the client.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x16 | Collected EID | int | 38
|
|
Collector EID | int | 20
|
||
Total Size: | 9 bytes |
Spawn Object/Vehicle (0x17)
Sent by the server when an Object/Vehicle is created.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x17 | EID | int | 62
|
Entity ID of the Object |
Type | byte | 11
|
The type of object (see Entities#Objects) | |
X | int | 16080
|
The Absolute Integer X Position of the object | |
Y | int | 2299
|
The Absolute Integer Y Position of the object | |
Z | int | 592
|
The Absolute Integer Z Position of the object | |
Fireball thrower's entity ID | int | 0
|
If this is bigger than 0, this is a fireball and the next 3 fields are sent. | |
Speed X | short | 0
|
Not sent if the thrower entity ID is 0. The speed of this fireball along the X axis. | |
Speed Y | short | 0
|
Not sent if the thrower entity ID is 0. The speed of this fireball along the Y axis. | |
Speed Z | short | 0
|
Not sent if the thrower entity ID is 0. The speed of this fireball along the Z axis. | |
Total Size: | 22 or 28 bytes |
Spawn Mob (0x18)
Sent by the server when a Mob Entity is Spawned
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x18 | EID | int | 446
|
Entity ID |
Type | byte | 91
|
The type of mob. See Entities#Mobs | |
X | int | 13366
|
The Absolute Integer X Position of the object | |
Y | int | 2176
|
The Absolute Integer Y Position of the object | |
Z | int | 1680
|
The Absolute Integer Z Position of the object | |
Yaw | byte | -27
|
The yaw in steps of 2π/256 | |
Pitch | byte | 0
|
The pitch in steps of 2π/256 | |
Head Yaw | byte | Head yaw in steps of 2π/256 | ||
Metadata | Metadata | 127
|
Varies by mob, see Entities | |
Total Size: | 21 bytes + Metadata (at least 1) |
Spawn Painting (0x19)
This packet shows location, name, and type of painting.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x19 | Entity ID | int | 0x00000326
|
Unique entity ID |
Title | string | Creepers
|
Name of the painting; max length 13 (length of "SkullAndRoses") | |
X | int | 50
|
Center X coordinate | |
Y | int | 66
|
Center Y coordinate | |
Z | int | -50
|
Center Z coordinate | |
Direction | int | 0
|
Direction the painting faces (0 -z, 1 -x, 2 +z, 3 +x) | |
Total Size: | 23 bytes + length of strings |
Calculating the center of an image: given a (width x height) grid of cells, with (0, 0) being the top left corner, the center is (max(0, width / 2 - 1), height / 2). E.g.
2x1 (1, 0) 4x4 (1, 2)
Spawn Experience Orb (0x1A)
Spawns one or more experience orbs. Coordinates are in absolute units.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x1A | Entity ID | int | 105668 | |
x | int | -1143 | ||
y | int | 1952 | ||
z | int | 1166 | ||
count | short | 7 | ||
Total Size: | 19 bytes |
Entity Velocity (0x1C)
This packet is new to version 4 of the protocol, and is believed to be Entity Velocity/Motion.
Velocity is believed to be in units of 1/32000 of a block per server tick (200ms); for example, -1343 would move (-1343 / 32000) = -0.04196875 blocks per tick (or -0.20984375 blocks per second).
Each axis' velocity is capped between -0.9 and 0.9 blocks per tick (packet values -28800 to 28800).
(This packet data values are not fully verified)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x1C | Entity ID | int | 1805
|
The entity ID |
Velocity X | short | -1343
|
Velocity on the X axis | |
Velocity Y | short | 0
|
Velocity on the Y axis | |
Velocity Z | short | 0
|
Velocity on the Z axis | |
Total Size: | 11 bytes |
Destroy Entity (0x1D)
Sent by the server when an Entity is to be destroyed on the client.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x1D | EID | int | 446
|
Entity ID |
Total Size: | 5 bytes |
Entity (0x1E)
Most entity-related packets are subclasses of this packet. When sent from the server to the client, it may initialize the entry.
For player entities, either this packet or any move/look packet is sent every game tick. So the meaning of this packet is basically that the entity did not move/look since the last such packet.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x1E | EID | int | 446
|
Entity ID |
Total Size: | 5 bytes |
Entity Relative Move (0x1F)
This packet is sent by the server when an entity moves less then 4 blocks; if an entity moves more then 4 blocks Entity Teleport should be sent instead.
This packet allows at most four blocks movement in any direction, because byte range is from -128 to 127. Movement is an offset of Absolute Int; to convert relative move to block coordinate offset, divide by 32.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x1F | EID | int | 459
|
Entity ID |
dX | byte | 1
|
X axis Relative movement as an Absolute Integer | |
dY | byte | -7
|
Y axis Relative movement as an Absolute Integer | |
dZ | byte | 5
|
Z axis Relative movement as an Absolute Integer | |
Total Size: | 8 bytes |
Entity Look (0x20)
This packet is sent by the server when an entity rotates. Example: "Yaw" field 64 means a 90 degree turn.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x20 | EID | int | 459
|
Entity ID |
Yaw | byte | 126
|
The X Axis rotation as a fraction of 360 | |
Pitch | byte | 0
|
The Y Axis rotation as a fraction of 360 | |
Total Size: | 7 bytes |
Entity Look and Relative Move (0x21)
This packet is sent by the server when an entity rotates and moves. Since a byte range is limited from -128 to 127, and movement is offset of Absolute Int, this packet allows at most four blocks movement in any direction. (-128/32 == -4)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x21 | EID | int | 459
|
Entity ID |
dX | byte | 1
|
X axis Relative movement as an Absolute Integer | |
dY | byte | -7
|
Y axis Relative movement as an Absolute Integer | |
dZ | byte | 5
|
Z axis Relative movement as an Absolute Integer | |
Yaw | byte | 126
|
The X Axis rotation as a fraction of 360 | |
Pitch | byte | 0
|
The Y Axis rotation as a fraction of 360 | |
Total Size: | 10 bytes |
Entity Teleport (0x22)
This packet is sent by the server when an entity moves more than 4 blocks.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x22 | EID | int | 459
|
Entity ID |
X | int | 14162
|
X axis position as an Absolute Integer | |
Y | int | 2176
|
Y axis position as an Absolute Integer | |
Z | int | 1111
|
Z axis position as an Absolute Integer | |
Yaw | byte | 126
|
The X Axis rotation as a fraction of 360 | |
Pitch | byte | 0
|
The Y Axis rotation as a fraction of 360 | |
Total Size: | 19 bytes |
Entity Head Look (0x23)
Changes the direction an entity's head is facing.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x23 | Entity ID | int | ||
Head Yaw | byte | Head yaw in steps of 2π/256 | ||
Total Size: | 6 bytes |
Entity Status (0x26)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x26 | Entity ID | Int | 34353 | |
Entity Status | Byte | 0x03 | See below | |
Total Size: | 6 bytes |
Entity Status | Meaning |
---|---|
2 | Entity hurt |
3 | Entity dead |
6 | Wolf taming |
7 | Wolf tamed |
8 | Wolf shaking water off itself |
9 | (of self) Eating accepted by server |
Attach Entity (0x27)
This packet is new to version 4 of the protocol, and is believed to be Attach Entity.
This packet is sent when a player has been attached to an entity (e.g. Minecart)
(This packet data values are not fully verified)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x27 | Entity ID | int | 1298
|
The player entity ID being attached |
Vehicle ID | int | 1805
|
The vehicle entity ID attached to (-1 for unattaching) | |
Total Size: | 9 bytes |
Entity Metadata (0x28)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x28 | Entity ID | int | 0x00000326
|
Unique entity ID to update. |
Entity Metadata | Metadata | 0x00 0x01 0x7F
|
Metadata varies by entity. See Entities | |
Total Size: | 5 bytes + Metadata |
Entity Effect (0x29)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x29 | Entity ID | int | 14
|
Entity ID of a player |
Effect ID | byte | 17
|
See table below | |
Amplifier | byte | 0
|
||
Duration | short | 64
|
||
Total Size: | 9 bytes |
Effects
ID | Meaning | Client implementation | Server implementation |
---|---|---|---|
1 | moveSpeed | Increases player speed and FOV. | |
2 | moveSlowdown | Decreases player speed and FOV. | |
3 | digSpeed | Increases player dig speed | |
4 | digSlowDown | Decreases player dig speed | |
5 | damageBoost | ||
6 | heal | ||
7 | harm | ||
8 | jump | ||
9 | confusion | Portal-like effect | |
10 | regeneration | Hearts pulse one-by-one | Caused by golden apple. Health regenerates over 600-tick (30s) period. |
11 | resistance | ||
12 | fireResistance | ||
13 | waterBreathing | Bubbles do not decrease underwater | |
14 | invisibility | ||
15 | blindness | ||
16 | nightVision | ||
17 | hunger | Food bar turns green | Caused by poisoning from Rotten Flesh or Raw Chicken |
18 | weakness | ||
19 | poison | Hearts turn yellow | Caused by poisoning from cave (blue) spider |
Remove Entity Effect (0x2A)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x2a | Entity ID | int | Entity ID of a player | |
Effect ID | byte | 17
|
See table above | |
Total Size: | 6 bytes |
Set Experience (0x2B)
Sent by the server when the client should change experience levels.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x2B | Experience bar | float | 0.5960060358047485
|
Used for drawing the experience bar - value is between 0 and 1. |
Level | short | 8
|
||
Total experience | short | 130
|
||
Total Size: | 9 bytes |
Map Column Allocation (0x32)
This packet is sent by the server to notify the client to initialize (Mode=1) or unload (Mode=0) a column of chunks. The client is expected to allocate space for a full column (currently 16 x 256 x 16 blocks). One or more 0x33 packets will follow, specifying actual data to fill the chunk with.
Whenever you send this packet the client will clear any previous column at that spot if one has previously been sent. Clients don't like being in or next to an unloaded column, so try not to unload it if players are nearby. If the player appears to be twitching and stuck in place after joining the world, there is probably an unloaded column too close to them.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x32 | X | int | -9
|
Column X Coordinate |
Z | int | 12
|
Column Z Coordinate | |
Mode | bool | 1
|
If mode is 0 the client will unload the column, otherwise the client will initialize the column | |
Total Size: | 10 bytes |
Map Chunks (0x33)
Chunks are sent a column at a time, with some chunks optionally missing from each packet (those consisting only of air).
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x33 | X | int | Column X Coordinate (*16 to get true X) | |
Z | int | Column Z Coordinate (*16 to get true Z) | ||
Ground-up continuous | boolean | This is True if the packet represents all chunks in this vertical column of chunks, where the primary bit map specifies exactly which chunks are included, and which are air. | ||
Primary bit map | unsigned short | 15 | Bitmask with 1 for every 16x16x16 chunk which data follows in the compressed data. | |
Add bit map | unsigned short | 0 | Same as above, but this is used exclusively for the 'add' portion of the payload | |
Compressed size | int | Size of compressed region data. | ||
Unused int | int | 0 | Doesn't seem to be used by the client. Always 0. I expect this is Mod API stuff. | |
Compressed data | unsigned byte array | …
|
The region data is compressed using ZLib Deflate function. | |
Total Size: | 22 bytes + Compressed chunk size |
The payload is a set of 16x16x16 chunks, sharing the same X and Z chunk coordinates. What is and isn't sent is provided by the two bitmask fields. The least significant bit is '1' if the chunk spanning from Y=0 to Y=15 is not completely air, and so forth. For block IDs, metadata, and lighting, the primary bitmask is used. A secondary bitmask is used for 'add' data, which is Mojang's means of provided Block IDs past 256. In vanilla minecraft, you can expect this to always be zero. The chunks included in this packet progress from bottom to top, where Y=0 is the bottom.
The data is compressed using the deflate() function in zlib. After uncompressing, the data consists of five (or six) sequential sections, in order:
- Block type array (1 byte per block, 4096 bytes per chunk)
- Block metadata array (half byte per block, 2048 bytes per chunk)
- Block light array (half byte per block, 2048 bytes per chunk)
- Sky light array (half byte per block, 2048 bytes per chunk)
- Add array (half byte per block, 2048 bytes per chunk, uses second bitmask)
- Biome array (1 byte per XZ column, 256 bytes total, only sent if 'ground up continuous' is true)
Each section is the concatenated data of all included chunks (i.e. the block type array contains the block types of all included chunks).
In each section except biome data, your decoder loop should look something like this:
//Loop over 16x16x16 chunks in the 16x256x16 column
for (i=0;i<16;i++) {
//If the bitmask indicates this chunk has been sent...
if (bitmask & 1 << i) {
//Read data...
cubic_chunk_data = io.read(4096); //2048 for the other arrays, where you'll need to split the data
for(int j=0; j<len(cubic_chunk_data); j++) {
//Retrieve x,y,z and data from each element in cubic_chunk_array
//Byte arrays
x = chunk_x*16 + (j & 0xF0) >> 4;
y = i*16 + j & 0x0F;
z = chunk_z*16 + j >> 8;
data = cubic_chunk_data[j]
//Nibble arrays
data1 = cubic_chunk_data[j] & 0x0F;
data2 = cubic_chunk_data[j] >> 4;
k = 2*j;
x1 = chunk_x*16 + (k & 0xF0) >> 4;
y1 = i*16 + k & 0x0F;
z1 = chunk_z*16 + k >> 8;
k++;
x2 = chunk_x*16 + (k & 0xF0) >> 4;
y2 = i*16 + k & 0x0F;
z2 = chunk_z*16 + k >> 8;
}
}
}
Each biome byte can have the values from 0 to 22, higher will cause the client to crash.
The 'add' array uses the second bitmask. Block IDs are presumed to be block_id | add << 8
Here's an example of how this packet could be encoded.
Multi Block Change (0x34)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x34 | Chunk X | inta | -9
|
Chunk X Coordinate |
Chunk Z | int | 12
|
Chunk Z Coordinate | |
Record count | short | The number of blocks affected | ||
Data size | int | The total size of the data, in bytes. Should always be 4*record count - please confirm. | ||
Data | …
|
Coordinates, type, and metadata of blocks to change. | ||
Total Size: | 15 bytes + Arrays |
Each record is four bytes.
Bit mask | Width | Meaning |
---|---|---|
00 00 00 0F | 4 bits | Block metadata |
00 00 FF F0 | 12 bits | Block ID |
00 FF 00 00 | 8 bits | Y co-ordinate |
0F 00 00 00 | 4 bits | Z co-ordinate, relative to chunk |
F0 00 00 00 | 4 bits | X co-ordinate, relative to chunk |
Block Change (0x35)
Block metadata varies by block type - it should be 0x00
for most blocks with a few exceptions, shown in the table below.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x35 | X | int | 502
|
Block X Coordinate |
Y | byte | 71
|
Block Y Coordinate | |
Z | int | 18
|
Block Z Coordinate | |
Block Type | byte | 78
|
The new block type for the block | |
Block Metadata | byte | 0
|
The new Metadata for the block | |
Total Size: | 12 bytes |
Block Action (0x36)
This packet is used for a number of things:
- Chests opening and closing
- Pistons pushing and pulling
- Note blocks playing
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x36 | X | int | 502
|
Block X Coordinate |
Y | short | 71
|
Block Y Coordinate | |
Z | int | 18
|
Block Z Coordinate | |
Byte 1 | byte | 3
|
Varies depending on block - see below | |
Byte 2 | byte | 17
|
Varies depending on block - see below | |
Total Size: | 13 bytes |
Note Block
It shows the note particle being emitted from the block as well as playing the tone.
Byte 1
Instrument type.
Type ID | Type Name |
---|---|
0 | Harp |
1 | Double Bass |
2 | Snare Drum |
3 | Clicks/Sticks |
4 | Bass Drum |
Byte 2
The pitch of the note (between 0-24 inclusive where 0 is the lowest and 24 is the highest). More information about how the pitch values correspond to notes in real life are available on the official Minecraft wiki.
Piston
Byte 1
The state the piston changes to - 0 for pushing, 1 for pulling.
Byte 2
Direction.
Direction ID | Direction |
---|---|
0 | Down |
1 | Up |
2 | South |
3 | West |
4 | North |
5 | East |
Chest
Animates the chest's lid opening. Note that the notchian server will send this every 3s even if the state hasn't changed.
Byte 1
Not used - always 1
Byte 2
State of the chest - 0 for closed, 1 for open.
Explosion (0x3C)
This command is not fully understood.
Seems to be sent when an explosion occurs (both creepers and TNT).
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x3C | X | double | ||
Y | double | |||
Z | double | |||
Unknown | float | 3.0 | radius? | |
Record count | int | This is the count, not the size. The size is 3 times this value. | ||
Records | (byte, byte, byte) × count | Each record is 3 bytes, which seem to be XYZ offsets of affected blocks. | ||
Total Size: | 33 bytes + 3*(Record count) bytes |
Sound/Particle Effect (0x3D)
Sent when a client is to play a sound or particle effect.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x3D | Effect ID | int | 1003 | The ID of the effect, see below. |
X | int | The X location of the effect. | ||
Y | byte | The Y location of the effect. | ||
Z | int | The Z location of the effect. | ||
Data | int | 0 | Extra data for certain effects, see below. | |
Total Size: | 18 bytes |
Effects
Effect ID | Name | Data | Notes |
---|---|---|---|
1000 | CLICK2 | ||
1001 | CLICK1 | ||
1002 | BOW_FIRE | ||
1003 | DOOR_TOGGLE | ||
1004 | EXTINGUISH | ||
1005 | RECORD_PLAY | Record ID [1] | |
1007 | CHARGE | Sound of ghast firing. | |
1008 | FIREBALL | Sound of blaze firing | |
1009 | FIREBALL | Same as above | |
2000 | SMOKE | Direction, check below | |
2001 | BLOCK_BREAK | Block ID broken | |
2002 | SPLASH_POTION | Potion ID [2] | Particle animation and sound |
2003 | PORTAL | Particle animation | |
2004 | BLAZE (?) | Particle animation (fire + smoke) |
Smoke directions:
ID | Direction |
---|---|
0 | South - East |
1 | South |
2 | South - West |
3 | East |
4 | (Up or middle ?) |
5 | West |
6 | North - East |
7 | North |
8 | North - West |
Change Game State (0x46)
This packet appeared with protocol version 10. Currently, it appears when a bed can't be used as a spawn point and when the rain state changes. it could have additional uses in the future.
The class has an array of strings linked to reason codes 0, 1, 2, and 3 but only the codes for 1 and 2 are null.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x46 | Reason | byte | 0 | |
Game mode | byte | 0 | Used only when reason = 3. 0 is survival, 1 is creative. | |
Total Size: | 3 bytes |
Reason codes
Code | Effect | Text |
---|---|---|
0 | Invalid Bed | "tile.bed.notValid" |
1 | Begin raining | null |
2 | End raining | null |
3 | Change game mode | gameMode.changed |
4 | Enter credits |
Thunderbolt (0x47)
With this packet, the server notifies the client of thunderbolts striking somewhere (near the player?). The coordinates specify where exactly the thunderbolt strikes.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x47 | Entity ID | int | 4 | The entity ID of the thunderbolt |
Unknown | boolean | true | Always true. Might have a meaning in the future... | |
X | int | 133 | Thunderbolt X as Absolute Integer | |
Y | int | 913 | Thunderbolt Y as Absolute Integer | |
Z | int | 63552 | Thunderbolt Z as Absolute Integer | |
Total Size: | 18 bytes |
Open Window (0x64)
This is sent to the client when it should open an inventory, such as a chest, workbench, or furnace. This message is not sent anywhere for clients opening their own inventory.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x64 | Window id | byte | 123 | A unique id number for the window to be displayed. Notchian server implementation is a counter, starting at 1. |
Inventory Type | byte | 2 | The window type to use for display. Check below | |
Window title | string | Chest
|
The title of the window. | |
Number of Slots | byte | 3 | Number of slots in the window (excluding the number of slots in the player inventory). | |
Total Size: | 6 bytes + length of string |
The window titles sent by the Notchian server are "Chest", "Large chest", "Crafting", "Furnace", and "Trap". Notchian clients force window titles for some windows, like dispensers and furnaces, but other titles are customizable. However, the window title sent by the server is always used for chests. See inventory windows for further information.
Close Window (0x65)
This packet is sent by the client when closing a window. This packet is sent from the server to the client when a window is forcibly closed, such as when a chest is destroyed while it's open.
Note, notchian clients send a close window message with window id 0 to close their inventory even though there is never an Open Window message for inventory.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x65 | Window id | byte | 0 | This is the id of the window that was closed. 0 for inventory. |
Total Size: | 2 bytes |
Click Window (0x66)
This command is not fully understood.
This packet is sent by the player when it clicks on a slot in a window.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x66 | Window id | byte | 0
|
The id of the window which was clicked. 0 for player inventory. |
Slot | short | 36
|
The clicked slot. See below. | |
Right-click | byte | 1
|
1 when right-clicking and otherwise 0. | |
Action number | short | 12
|
A unique number for the action, used for transaction handling (See the Transaction packet). | |
Shift | bool | 0
|
This is true if the user was holding keyboard shift when they clicked. | |
Clicked item | slot | |||
Total Size: | 8 bytes + slot data |
See inventory windows for further information about how slots are indexed.
When right-clicking on a stack of items, half the stack will be picked up and half left in the slot. If the stack is an odd number, the half left in the slot will be smaller of the amounts.
The Action number is actually a counter, starting at 1. This number is used by the server as a transaction ID to send back a Transaction packet.
Set Slot (0x67)
This command is not fully understood.
Sent by the server when an item in a slot (in a window) is added/removed.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x67 | Window id | byte | 0
|
The window which is being updated. 0 for player inventory. Note that all known window types include the player inventory. This packet will only be sent for the currently opened window while the player is performing actions, even if it affects the player inventory. After the window is closed, a number of these packets are sent to update the player's inventory window (0). |
Slot | short | 36
|
The slot that should be updated | |
Slot data | slot | |||
Total Size: | 4 bytes + slot data |
Note that if window ID and slot are both -1, it means the item currently attached to the cursor.
See inventory windows for further information about how slots are indexed.
Slots: [3]
Set Window Items (0x68)
Sent by the server when an item in a slot (in a window) is added/removed. This includes the main inventory, equipped armour and crafting slots.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x68 | Window id | byte | 1
|
The id of window which items are being sent for. 0 for player inventory. |
Count | short | 4
|
The number of slots (see below) | |
Slot data | array of slots | |||
Total Size: | 4 bytes + size of slot data array |
See inventory windows for further information about how slots are indexed.
Update window property (0x69)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x69 | Window id | byte | 2 | The id of the window. |
Property | short | 1 | Which property should be updated. | |
Value | short | 650 | The new value for the property. | |
Total Size: | 6 bytes |
Furnace
Properties:
- 0: Progress arrow
- 1: Fire icon (fuel)
Values:
- 0-180 for progress arrow
- 0-250 for fuel indicator
Ranges are presumably in in-game ticks
Enchantment Table
Properties: 0, 1 or 2 depending on the "enchantment slot" being given.
Values: The enchantment's level.
Transaction (0x6A)
A packet from the server indicating whether a request from the client was accepted, or whether there was a conflict (due to lag). This packet is also sent from the client to the server in response to a server transaction rejection packet.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x6A | Window id | byte | 0 | The id of the window that the action occurred in. |
Action number | short | 12 | Every action that is to be accepted has a unique number. This field corresponds to that number. | |
Accepted? | boolean | true | Whether the action was accepted. | |
Total Size: | 5 bytes |
Creative inventory action (0x6B)
While the user is in the standard inventory (i.e., not a crafting bench) on a creative-mode server then the server will send this packet:
- If an item is dropped into the quick bar
- If an item is picked up from the quick bar (item id is -1)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x6B | Slot | short | 36 | Inventory slot |
Clicked item | slot | |||
Total Size: | 3 bytes + slot data |
Enchant Item (0x6C)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x6C | Window ID | byte | 1 | The ID sent by 0x64 |
Enchantment | byte | 0 | The position of the enchantment on the enchantment table window, starting with 0 as the topmost one. | |
Total Size: | 3 bytes |
Update Sign (0x82)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x82 | X | int | 128 | Block X Coordinate |
Y | short | 0 | Block Y Coordinate | |
Z | int | -128 | Block Z Coordinate | |
Text1 | string | First line
|
First line of text in the sign | |
Text2 | string | Second line
|
Second line of text in the sign | |
Text3 | string | Third line
|
Third line of text in the sign | |
Text4 | string | Fourth line
|
Fourth line of text in the sign | |
Total Size: | 11 bytes + 4 strings |
This message is sent from the server to the client whenever a sign is discovered or created. This message is sent from the client to the server when the "Done" button is pushed after placing a sign. This message is NOT sent when a sign is destroyed or unloaded.
Item Data (0x83)
Sent to specify complex data on an item; currently used only for maps.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x83 | Item Type | short | 358
|
Type of item being modified |
Item ID | short | 0
|
The ID (damage value) of the item being modified | |
Text length | unsigned byte | 35
|
Length of following byte array | |
Text | byte array | {0,0,0,20,20,20,20,20} | ASCII text. | |
Total Size: | 6 bytes + Text length |
Maps If the first byte of the text is 0, the next two bytes are X start and Y start and the rest of the bytes are the colors in that column.
If the first byte of the text is 1, the rest of the bytes are in groups of three: (data, x, y). The lower half of the data is the type (always 0 under vanilla) and the upper half is the direction.
Update Tile Entity (0x84)
Essentially a block update on a tile entity.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0x84 | X | int | ||
Y | short | |||
Z | int | |||
Action | byte | The type of update to perform | ||
Custom 1 | int | Varies | ||
Custom 2 | int | Varies | ||
Custom 3 | int | Varies | ||
Total Size: | 24 bytes |
Actions
- 1: Set mob displayed inside a mob spawner. Custom 1 contains the mob type
Increment Statistic (0xC8)
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0xC8 | Statistic ID | int | 1003 | The ID of the statistic. See List of statistics. |
Amount | byte | 1 | The amount to increment the statistic. | |
Total Size: | 6 bytes |
Player List Item (0xC9)
Sent by the notchian server to update the user list (<tab> in the client). The server sends one packet per user per tick, amounting to 20 packets/s for 1 online user, 40 for 2, and so forth.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0xC9 | Player name | string | barneygale | Supports chat colouring, limited to 16 characters. |
Online | bool | true | If false, the client will remove the user from the list. | |
Ping | short | 193 | Ping, presumably in ms. | |
Total Size: | 6 bytes + length of string |
Plugin message (0xFA)
Mods and plugins can use this to send their data.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0xFA | Channel | string | MyMod:testchannel | Name of the "channel" used to send the data. |
length | short | Length of the following byte array | ||
data | byte array | Any data. | ||
Total Size: | 4 bytes + length of string + length of byte array |
More documentation on this: http://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/
Server List Ping (0xFE)
To load server info in the multiplayer menu, the notchian client connects to each known server and sends an 0xFE.
In return, the server sends a kick (0xFF), with its string containing data (server description, number of users, number of slots), delimited by a UCS-2 '§' (0xA7).
Note that as this is the last packet you'll see, you can get away with just chopping off the first three bytes (the ident and the string length) and decoding the remainder as a UCS-2 string.
If the number of available slots sent is equal to or less than 0, the client should display it as "???".
Example server pinger:
https://gist.github.com/1209061 (Python)
https://gist.github.com/1235274 (PHP)
http://pastebin.com/q5zFPcXV (Ruby)
Packet ID |
---|
0xFE |
Disconnect/Kick (0xFF)
Sent by the server before it disconnects a client, or by the client before it disconnects from the server. The receiver of this packet assumes that the sender has already closed the connection by the time the packet arrives.
Packet ID | Field Name | Field Type | Example | Notes |
---|---|---|---|---|
0xFF | Reason | string | The server is full!
|
Displayed to the client when the connection terminates |
Total Size: | 3 bytes + length of strings |