As of protocol version &protonum;, the following messages are defined. Four types of data are exchanged between the client and the server: char: a 1-byte signed char. int: a 4-byte signed integer in network byte order. string: a multibyte null-terminated string preceded by its length (including null-termination) as an integer. varying: data format depends on the message type. Interactions take one of three forms: server messages, client requests, and server responses. Each interaction is prefaced by an opcode identifying it (some interactions consist solely of the opcode). The opcode (stored as an enumerated value) is sent as an int. A minor opcode sometimes follows it.

These messages are sent by the client to the server. This section does not cover responses to messages generated by the server, since those are valid in both direction. Instead, messages generated by the client on its own are documented here. OP_MOVE OP_MOVE OP_MOVE Client moved character OP_MOVE [gen] [direction] Data Type Example gen int ... direction int MOVE_UP MOVE_DOWN MOVE_LEFT MOVE_RIGHT Client moved character gen Message counter. direction The direction of the move. Whenever a player moves on the map. OP_ACTION OP_ACTION OP_ACTION Client initiated some action OP_ACTION [action] Data Type Example action int ACTION_NEWBOMB Client initiated some action action The action in question which was initiated by the player. Whenever a player sets up a bomb or does similar work.

This section covers both broadcasts of player input messages and independent server messages which can occur at any time. server.OP_MOVE server.OP_MOVE server.OP_MOVE Broadcast of character move by client server.OP_MOVE [gen] [type] [id] [direction] Data Type Example gen int ... id int ... type int MOVE_PLAYER MOVE_MONSTER direction int MOVE_UP MOVE_DOWN MOVE_LEFT MOVE_RIGHT Broadcast of character move by client gen Message counter. id ID of the player of origin. type Can be either of move_player or move_monster. direction The direction of the move. The server sends this message whenever it receives a valid player move, and whenever a monster has been moved. server.OP_CHEAT server.OP_CHEAT server.OP_CHEAT Player ban notification server.OP_CHEAT Player ban notification If a player tries to cheat or a game client runs snafu, it will be detected by the server. The offending player receives this message immediately, while all other players get notified of this ban via server.OP_ACTION. server.OP_ACTION server.OP_ACTION server.OP_ACTION Events of any kind server.OP_ACTION [minor] [data...] Data Type Example minor int ACTION_NEWPLAYER ACTION_NEWMONSTER ACTION_NEWITEM ACTION_NEWEXIT ACTION_NEWBLAST ACTION_NEWBOMB ACTION_ITEM ACTION_REMOVEPLAYER ACTION_REMOVEMONSTER ACTION_REMOVEITEM ACTION_REMOVEBOMB ACTION_REMOVEBLAST ACTION_ACTIVATEITEM ACTION_ACTIVATEEXIT ACTION_HIGHLIGHTITEM ACTION_HIGHLIGHTEXIT data varying ... Events of any kind minor Minor opcode for further determining the event. data Event-specific data, outlined below. Data Type Example ACTION_NEWPLAYER player int ... x int ... y int ... ACTION_NEWMONSTER id int ... x int ... y int ... ACTION_NEWITEM type int ... id int ... x int ... y int ... ACTION_NEWEXIT x int ... y int ... ACTION_NEWBOMB type int ... id int ... x int ... y int ... ACTION_NEWBLAST id int ... x int ... y int ... ACTION_ITEM id int ... type int ... change int ... ACTION_REMOVEPLAYER id int ... ACTION_REMOVEMONSTER id int ... ACTION_REMOVEBOMB id int ... ACTION_REMOVEBLAST id int ... ACTION_REMOVEITEM id int ... ACTION_ACTIVATEITEM id int ... ACTION_HIGHLIGHTITEM id int ... ACTION_ACTIVATEEXIT (none) ACTION_HIGHLIGHTEXIT (none) All events such as map changes, player actions, item activations and so on are announced with this message. server.OP_STATE server.OP_STATE server.OP_STATE Game state changes server.OP_STATE [state] Data Type Example state int STATE_START STATE_STOP Game state changes state The new game state. The game isn't started before all requirements are in place, and might be stopped anytime such a requirement is not fulfilled anymore. Requirements include the correct player configuration and a running game.

The messages present in this section exist in two formats: sent by the client, and sent by the server. One of those is a request while the other one is a response to it. Currently, this kind of messages is not used during the gameplay itself. OP_RULES OP_RULES OP_RULES Client selected a rule set OP_RULES [custom] [rulesetting...] Data Type Example custom int 0/1 rulesetting int ... Client selected a rule set. custom Custom rules have been selected as opposed to default rules. rulesetting This multi-value field defines each aspect of the rule set. At the beginning of the game, when the rules have not been set yet, and before the actual gameplay starts, the client may transmit the rules to the server. Once the game starts, the same message is then broadcasted to all participating clients. OP_MAP OP_MAP OP_MAP Client sent a map of choice OP_MAP [minor] [mapname] [numplayers] Data Type Example minor int MAP_SELECT MAP_SELECTED mapname string ... numplayers int ... Client sent a map of choice. minor Minor opcode distinguishing all OP_MAP messages. Can be MAP_SELECTED in this case, meaning a map has been selected for the game, or MAP_SELECT (sent by server), meaning a map should be selected. mapname The name of the chosen map (level). Only sent with MAP_SELECTED, not with MAP_SELECT. numplayers Number of players expected to play with. Similar to OP_RULES, this message is sent by the game host (usually the first player) to the server, and then broadcasted at the start of the game. Contrary to it however, the message is only sent after having received an OP_RULES with MAP_SELECT first. This message omits the mapname parameter.