Player data consists of two main data types: instanced items and stackable items. All items are assigned UUIDs and belong to the player they’re created for. Items are saved off in our Inventory service, and are managed by engine and inventory plugins.
Stackable items represent stacks of items with a count and limit such as currencies or health potions. Stackable items of the same type only vary in their amount and do not behave differently from one another (i.e. one stack of gold coins acts the same as another stack of gold coins).
Instanced items are items that can hold individual attributes that differ between items of the same type (i.e. upgraded versions of the same sword). They’re created based on an instanced spec defined by strongly typed protobufs and plugin code that informs how the item needs to be constructed/managed. Because instanced items can be used to define and hold arbitrary data, they can be used to power complex systems like battlepasses and missions.
Item bundles can be any combination of stackable and instanced items. For example, a single item bundle can contain gold coins, a sword, and armor.
To manage custom game data, the Content Data system allows designers to define item specifications that are used by the engine and plugin code to initialize and update player data.
Content files are stored in JSON and support versioning and live data migration. This enables the evolution of player data throughout content and patch cycles.
If you do not already have the content source files initialized, run
make init-inventory-contentfrom the
platformdirectory. This generates inventory content files used to define the specs for your instanced and stackable items.
Specifications vs Items #
While specifications and items are closely connected, they’re distinct from one another. An item is something tangible saved in the Inventory service which belongs to a player. A specification is JSON-defined content that provides a definition or blueprint for its related item.
For example, if a car sales site allows a customer to pick the color, fabric, and traffic features, this array of options are similar to a specification. Meanwhile a red car with leather seats that has blind spot detection is the item itself.
Filtering by tags #
getInventory, all inventory data is returned by default. The Inventory service supports optional filtering of inventory data by tags on
Tags are defined on the item’s corresponding instanced or stackable spec. If the item’s spec contains any tags from the request and the player has the item in their inventory, the item will be returned.
Hidden Inventory Items #
In addition to traditional in-game items, player information can also be stored as stackable or instanced items. Some information, such as matchmaking rating (stored as an instanced item), is sensitive and should not be shown to players. Pragma Engine supports hiding items from being sent down to the player.
The following Inventory service endpoints return inventory information and will respect hidden items.
|returned segments A segment represents the current state of an item in the player's inventory after a change. / deltas A delta represents the changes that occurred to an item as the result of an operation. won’t contain items with tags that match the configuration
|returned inventory will not contain instanced and stackables whose corresponding content specs contain tags that match the configuration
GameDataService.GetLoginDataV2 which uses
|returned player inventory and content items (stores, update entries, item catalog, crafting entries, etc) are all filtered based on the tags in the configuration
|inventory data split by
player visible items
|game servers or services
|segments/deltas split by
player visible items
Quick Guides #
Storing matchmaking rating as a hidden item #
Here is an item we’ve defined to hold matchmaking information in
To keep things simple, we’re omitting the
ext field here. In an actual game, the
ext field would contain all matchmaking information and be fully customized according to the game’s design.
Note that we’ve tagged this item with the
mmr tag. We can hide items by specifying a list of tags to hide from the player. All items containing a tag on this list will not be sent by the platform to the game client. We specify this list in a configuration file such as
In this example, we’ve specified
futureContent as tags that should be hidden. Any item containing at least one of those tags will not be sent to the game client.
|Creating and using instanced items.
|Creating and using stackable items.