Query a single attribute

Use the getAttributes() function from the QuadReader smart contract to query a single attribute about a passport holder.

Requirements

Installation

Install @quadrata/contracts package

npm i @quadrata/contracts --save-dev

Permissions

Calling smart contract have to be granted permissions to call getAttributes in Mainnet. Contact us via email at [email protected] or Discord

Testnets like Goerli,Mumbai,etc.. do not require any permissions

Function

QuadReader.sol

import "@quadrata/contracts/interfaces/IQuadPassportStore.sol";

// For Solidity version >= 0.8.0.
reader.getAttributes(
    address user, 
    bytes32 attribute
) external payable returns(
    IQuadPassportStore.Attribute[] memory attributes
);


// For Solidity version < 0.8.0.
reader.getAttributesLegacy(
    address user, 
    bytes32 attribute
) external payable returns(
    bytes32[] attributeValues, 
    uint256[] epochs, 
    address[] issuers
);

Parameters

Parameter	Description	Type
user	address of the passport holder	address (required)
attribute	The attribute you want to query. See: Supported attributes.	bytes32 (required)

Return values

A list of attributes that have been issued.

IQuadPassportStore.sol

/// @dev Attribute store infomation as it relates to a single attribute
/// `attrKeys` Array of keys defined by (wallet address/DID + data Type)
/// `value` Attribute value
/// `epoch` timestamp when the attribute has been verified by an Issuer
/// `issuer` address of the issuer issuing the attribute
struct Attribute {
    bytes32 value;
    uint256 epoch;
    address issuer;
}

For Solidity version < 0.8.0

UsegetAttributesLegacy()which returns three arrays. The index of each array maps to the others to create a tuple (e.g. attributeValues[0], epochs[0], issuers[0] are part of the same result).

• attributeValues: Raw or hashed attribute values. See Supported attributes for the return values of each attribute.

• epochs: Timestamp that indicates when the attribute was verified by the passport issuer.

• issuers: Passport issuer who verified the attributes.

Example

You can find our helper library to facilitate parsing the response => QuadReaderUtils

import "@quadrata/contracts/interfaces/IQuadReader.sol";
import "@quadrata/contracts/interfaces/IQuadPassportStore.sol";
import "@quadrata/contracts/utility/QuadReaderUtils.sol";

contract MyDapp {
    using QuadReaderUtils for bytes32;
    IQuadReader public reader;
    
    function borrowMoney() external payable {
        IQuadPassportStore.Attribute[] memory attributes = reader.getAttributes(
            msg.sender, 
            keccak256("COUNTRY")
        );

        require(attributes.length > 0, "REQUIRES_COUNTRY");
        
        // only users residing outside the US may borrow money        
        if (!attributes[0].value.countryIsEqual("US")) {
            // Allow borrow actions
        }
    }