How to Use Berry

Here are the nuts and bolts for using Berry to get price

Checking Last Update

Before calling a function to update your values, you should first just check if it's already there! Berry values, once onchain, are free for anyone to read. This means that if someone else just updated the value, you can use it free of charge!

To check when the value was last updated, you can run the following usingberry npm package:

 function getCurrentValue(uint256 _requestId) public view returns (bool ifRetrieve, uint256 value, uint256 _timestampRetrieved);

The last returned values is the timestamp last updated.

Adding a Tip

If the time the value was last updated is not sufficient, you can add a tip to your requestID in order to get it mined.

    addTip(uint _requestId, uint _tip)

Berry works by selecting the top five tipped requests for each Berry block. As an example, assume ID's [1,2,3,4,5] are currently being mined. If ID's [6,7,8,9,10,11,12] have corresponding tips of [10,20,30,40,50,60,70], then once the first ID's are mined, the ID's with the highest tipes (ID's 8-12 in this case) will be chosen. ID 6 and 7 will not be mined and will have to wait for a block where they are the highest tipped (this is very similar to gas prices and transaction fees on Ethereum or Bitcoin). If you for instance are ID 6 and want to get your ID included in the next block, you will need to tip >20 (you have 10 and need over 30).

In order to see how much you will need to tip, you can see the current ID's on deck and their corresponding tips using the following function in the main Berry contract:

 function getNewVariablesOnDeck() public view returns (uint256[5] memory idsOnDeck, uint256[5] memory tipsOnDeck)

Note that once you call for an update, you will need to wait until at least the next block is mined to get an update. Currently, Berry blocks are 3 minutes.

Monitoring Values and Disputing

Once Values are on-chain, we recommend you don't just take them right away. Berry has a robust network of miners and watch dogs that are vigilantly checking and ensuring accuracy, but the best person to know if your data is correct is you.

You can monitor values and submit disputes by either reading the value on-chain:

 function getCurrentValue(uint256 _requestId) public view returns (bool ifRetrieve, uint256 value, uint256 _timestampRetrieved);

 function beginDispute(TellorStorage.TellorStorageStruct storage self, uint256 _requestId, uint256 _timestamp, uint256 _minerIndex) public;

Or using the Berry Dispute Center(coming soon)

Disputes cost a lot of BRY, but are returned (along with a one stake reward) if the dispute was valid.

Once the dispute goes through, be sure to request your data again, so the miners have another chance to push through a valid price.

Automating Jobs

To automate adding a tip on a certain request ID by time or volatility, as well as scheduling other Berry related tasks, we recommend (and use) Buidlhub.

UsingBerry Package

Berry Data have publish npm package, name usingberry, user can you this package to get latest price. Just inherit the UsingBerry contract, passing the Berry Master address a constructor argument. Here is an example:

contract BtcPriceContract is UsingBerry {

  //This Contract now have access to all functions on UsingBerry

  uint256 btcPrice;
  uint256 btcRequetId = 1;

  constructor(address payable _berryAddress) UsingBerry(_berryAddress) public {}

  function setBtcPrice() public {
    bool _didGet;
    uint _timestamp;
    uint _value;

    (_didGet, btcPrice, _timestamp) = getCurrentValue(btcRequetId);
  }
}

Pre Set Request ID

1, BTC/USD

2, ETH/USD

3, LTC/USD

4, XRP/USD

5, BNB/USD