Modding:SaveGame ModData: Difference between revisions

Let's start by creating a new .cs file for this mod, and adding our imports and the <code>VintageStory.ServerMods</code> namespace to wrap our class in. Additionally, we'll declare the class <code>LookingForGroup</code> that will inherit from <code>ModSystem</code> which is the base class for mod systems. You can read more about this [http://apidocs.vintagestory.at/api/Vintagestory.API.Common.ModSystem.html here].

 

When the Server side starts, we add two event delegates that will retrieve our list from the <code>SaveGame</code> when the we game loads, and that will save the list when the game saves. We also register a command that players will use to access our list of those looking for group. This will be <code>/lfg</code> with the arguments list, join or leave.

Let us now define the event delegates!

== Retrieving and Storing the List ==

When the game loads, <code>OnSaveGameLoading</code> gets called and attempts to get our list of players looking for group. The Core Server Api has a member called <code>WorldManager</code> which we use to access everything World related, including our <code>SaveGame</code>.

         private void OnSaveGameLoading()

             byte[] data = serverApi.WorldManager.SaveGame.GetData("lfg");

We attempt to get our list by exposing the <code>GetData</code> method and passing it an identifier for our custom data, in this case our "lfg" list.

 

'''Hint''': If nothing is found stored under the key we provide, the <code>GetData</code> method returns null. In our mod example, this will happen until at least one player enters the list!

<code>byte[] data = serverApi.WorldManager.SaveGame.GetData("lfg");</code>

As you can see, we're retrieving an array of bytes, which is the data type we actually store on the <code>SaveGame</code>. Let's convert it to a <code>List</code> of strings:

<code>lfgList = data == null ? new List<string>() : SerializerUtil.Deserialize<List<string>>(data);</code>

Here we use a ternary operator to assign our <code>lfgList</code> field a new <code>List<string></code> if there was nothing stored under the "lfg" key.

If <code>data</code> is not null, we expose the <code>Deserialize<T></code> method of the <code>SerializerUtil</code> class. This method will deserialize an array of bytes into an instance of the type argument we pass it. Now that we have a delegate that fetches our list of players "lfg", let's create the delegate that stores this list when the Game World is saved:

Here we call the <code>StoreData</code> method to save our list under the "lfg" key for later retrieval! Because we can only store data in the form of <code>byte[]</code>, we use the <code>Serialize</code> method of the <code>SerializerUtil</code> class to turn <code>lfgList</code> back to an array of bytes, which we pass as the second argument.  

We now have implemented a way to assign our list from storageto <code>lfgList</code> when the <code>SaveGame</code> is loaded, and a way to store this list once the game is saved. In between these two events, we want players to be added or removed from <code>lfgList</code> via our command. Let's create our command delegate!

== Handling the Command ==

Server chat commands have three parameters: the player issuing the command, the group in which this command was entered, and the arguments sent for the command.

We use the <code>PopWord</code> of our <code>CmdArgs</code> parameter to collect the first argument passed (ignoring anything subsequent). We then start a switch statement for our valid arguments, and default to showing these to the player if none of them match or <code>cmd</code> is null.

                     if (lfgList.Contains(player.PlayerUID))

                         player.SendMessage(groupId, "You're already in the list!", EnumChatType.CommandError);

                         lfgList.Add(player.PlayerUID);

                         player.SendMessage(groupId, "Successfully joined.", EnumChatType.CommandSuccess);

If <code>/lfg join</code> was entered, we'll first check if the player is already on the "lfg" list, letting the player know if so. Alternatively, we add the player's unique identifier to the list and show a success message.  

'''Hint:''' We do not want to store player names directly. This is because player names may change, therefore our list could become inaccurate.

Next we handle <code>/lfg leave</code>:

                     if (!lfgList.Remove(player.PlayerUID))

                         player.SendMessage(groupId, "You're not in the list!", EnumChatType.CommandError);

                         player.SendMessage(groupId, "Successfully left.", EnumChatType.CommandSuccess);

The <code>Remove</code> method returns false if nothing matching the argument passed to it was found and removed, and true if it was. We let the player know if they were not on the list, or if they were and got successfully taken out of it.

                     if (lfgList.Count == 0)

                         player.SendMessage(groupId, "Noone is looking for a group.", EnumChatType.CommandSuccess);

                     else

                         lfgList.ForEach((playerUid) =>

                            response += "\n" + serverApi.World.PlayerByUid(playerUid).PlayerName;

                        });

                        player.SendMessage(groupId, response, EnumChatType.CommandSuccess);

In this case we simply let the player know if there is noone on the list, but if there are we build a string with all the player names on the list.

 

             api.RegisterCommand("lfg", "Access the lfg list.", "[list|join|leave]", OnLfg);

         private void OnSaveGameLoading()

             lfgList = data == null ? new List<string>() : SerializerUtil.Deserialize<List<string>>(data);

                     if (lfgList.Contains(player.PlayerUID))

                         player.SendMessage(groupId, "You're already in the list!", EnumChatType.CommandError);

                         lfgList.Add(player.PlayerUID);

                         player.SendMessage(groupId, "Successfully joined.", EnumChatType.CommandSuccess);

                     if (!lfgList.Remove(player.PlayerUID))

                         player.SendMessage(groupId, "You're not in the list!", EnumChatType.CommandError);

                         player.SendMessage(groupId, "Successfully left.", EnumChatType.CommandSuccess);

                     if (lfgList.Count == 0)

                         player.SendMessage(groupId, "Noone is looking for a group.", EnumChatType.CommandSuccess);

                     else

                         lfgList.ForEach((playerUid) =>

                            response += "\n" + serverApi.World.PlayerByUid(playerUid).PlayerName;

                        });

                        player.SendMessage(groupId, response, EnumChatType.CommandSuccess);

                     return;