IDataIndex

What is a Data Index?

Data Index serves as the access control layer for interactions between Data Managers and Data Points. It defines and manages the permissions that determine which Data Managers are authorized to read or write data for specific Data Points within the Data Objects.

When a Data Manager attempts to perform operations (read or write) on a Data Point, the Data Index verifies whether the Data Manager has the necessary permissions. This validation prevents unauthorized changes, preserving the integrity of the asset data. Additionally, the Data Index can execute specific read or write operations on the data stored in the Data Objects associated with the Data Points.

Fig 1. DataIndex mediating between DataManager and DataObject

Data Managers request permission from the Data Index to write asset data. The Data Index verifies whether each Data Manager is authorized to interact with specific Data Points. If approved, it grants access, allowing the Data Managers to proceed with their operations.

Note that the read function is provided to have unified interface to access data, but in gas-usage-sensitive applixations it's advised to read directly from the DataObject.

Interface

The interface of the Data Index can be divided into two main parts:

• Methods for managing permissions: These methods allow for granting and checking approved Data Managers for a Data Point or adding admin roles to other Data Managers for a Data Point. They might look like this:

    /**
     * @notice Defines if DataManager is allowed to write in specific DataPoint
     * @param dp Identifier of the DataPoint
     * @param dm Address of DataManager
     * @param approved if DataManager should be approved for the DataPoint
     * @dev Function SHOULD be restricted to DataPoint maintainer only
     */
    function allowDataManager(DataPoint dp, address dm, bool approved) external;

• Methods for forwarding read() and write() operations:

    /**
     * @notice Reads stored data
     * @param dobj Identifier of DataObject
     * @param dp Identifier of the DataPoint
     * @param operation Read operation to execute on the data
     * @param data Operation-specific data
     * @return Operation-specific data
     */
    function read(address dobj, DataPoint dp, bytes4 operation, bytes calldata data) external view returns (bytes memory);

Methods

1. isApprovedDataManager()

function isApprovedDataManager(DataPoint dp, address dm) external view returns (bool);

Description	Parameters	Returns	Modifiers
Verifies if Data Manager is allowed to write in a specific Data Point	dp: Identifier of the Data Point dm: Address of Data Manager	Boolean indicating if write access is allowed	external view

2. allowDataManager()

function allowDataManager(DataPoint dp, address dm, bool approved) external;

Description	Parameters	Returns	Modifiers
Defines if Data Manager is allowed to write in specific Data Point	dp: Identifier of the Data Point dm: Address of Data Manager approved: If Data Manager should be approved for the Data Point	None	external

Note: This function SHOULD be restricted to Data Point maintainer only.

3. read()

function read(address dobj, DataPoint dp, bytes4 operation, bytes calldata data) external view returns (bytes memory);

Description	Parameters	Returns	Modifiers
Reads stored data	dobj: Identifier of Data Object dp: Identifier of the Data Point operation: Read operation to execute on the data data: Operation-specific data	Operation-specific data	external view

4. write()

function write(address dobj, DataPoint dp, bytes4 operation, bytes calldata data) external returns (bytes memory);

Description	Parameters	Returns	Modifiers
Stores data	dobj: Identifier of Data Object dp: Identifier of the Data Point operation: Write operation to execute on the data data: Operation-specific data	Operation-specific data (can be empty)	external

Note: This function SHOULD be restricted to allowed Data Managers only.

5. diid()

function diid(address account, DataPoint) external pure returns (bytes32);

Description	Parameters	Returns	Modifiers
Generates an ID	account: Address to derive the ID	ID as bytes32	external, pure

6. ownerOf()

function ownerOf(bytes32 diid_) external view returns (uint32, address);

Description	Parameters	Returns	Modifiers
Retrieves ownership	diid_: Identifier of the account	Chain ID and address	external, view

note

More details on access control and the Data Index Reference Implementation can be found in the Data Index Reference Implementation.