How to get Harbinger price feed from Taquito

Question

I get an http error 'Key not found' The contract is a harbinger (coinbase carthage) storage contract. What is the correct 'get' param ?

Tezos.contract.at('KT1P7D7jt3PfjMpsEKPyao1kHQR93t7XR5zh') .then( myContract => { return myContract.storage() .then ( myStorage => { //When called on a bigMap, the get method returns a promise return myStorage['oracleData'].get({ 0 : 'XTZ-USD' }) }).then (valueBigMap => { println(The value associated with the specified key of the bigMap is ${valueBigMap}.); }) }) .catch(error => println(Error: ${JSON.stringify(error, null, 2)}));

Answer 1

From my experience with Harbinger I believe it's best practice to pull the data from the Normalizer contracts, as opposed to the Storage contracts. The Normalizer contract gives you a volume weighted average so you know the numbers won't be skewed.

Here's how I pulled the price feed with async/await syntax:

    // Ping Oracle contract
    const contract = await Tezos.contract.at(exchange ?? "KT1P7D7jt3PfjMpsEKPyao1kHQR93t7XR5zh");
    // Grab contract storage
    const contractStorage: { [key: string]: any } = await contract.storage();
    // Get asset codes (ex: XTZ-USD, BTC-USD etc)
    const { assetCodes } = contractStorage;

    // Grab the computed prices from the BigMap
    const assetsWithPrices = await Promise.all(
      assetCodes.map(async (assetCode: string) => {
        const { computedPrice } = await contractStorage["assetMap"].get(assetCode);
        // Computed price comes without decimal so add decimal
        const bigNumberPrice = computedPrice.c[0];
        const bigNumberPriceString = bigNumberPrice.toString().split("");
        bigNumberPriceString.splice(bigNumberPriceString.length - 6, 0, ".");
        const price = Number(bigNumberPriceString.join("").toString());
        return { [assetCode]: price };
      })
    );

If you'd like to see it in action you can visit https://oracles.vercel.app

The github repo for this, which includes the above code, can be found at https://github.com/sean-magin/oracles if you'd like to inspect the code closer.