How to get all the historical data from chainlink price feeds?

Question

I wanted to pull the historical data stored by the reference data contracts by chainlink oracles. Since all the data is on-chain, I should be able to view it all? But currently, my contract can only see the latest answer. Any thoughts?

pragma solidity ^0.6.0;

import "@chainlink/contracts/src/v0.6/dev/AggregatorInterface.sol";

contract ReferenceConsumer {
  AggregatorInterface internal ref;

  constructor(address _aggregator) public {
    ref = AggregatorInterface(_aggregator);
  }

  function getLatestAnswer() public returns (int256) {
    return ref.latestAnswer();
  }
}

Answer 1

You can view the entire history of reference contracts, you'll want to use the getPreviousAnswer method below, and input how many answers back you'd like to go.

pragma solidity ^0.6.0;

import "@chainlink/contracts/src/v0.6/dev/AggregatorInterface.sol";

contract ReferenceConsumer {
  AggregatorInterface internal ref;

  constructor(address _aggregator) public {
    ref = AggregatorInterface(_aggregator);
  }

  function getLatestAnswer() public returns (int256) {
    return ref.latestAnswer();
  }

  function getLatestTimestamp() public returns (uint256) {
    return ref.latestTimestamp();
  }

  function getPreviousAnswer(uint256 _back) public returns (int256) {
    uint256 latest = ref.latestRound();
    require(_back <= latest, "Not enough history");
    return ref.getAnswer(latest - _back);
  }

  function getPreviousTimestamp(uint256 _back) public returns (uint256) {
    uint256 latest = ref.latestRound();
    require(_back <= latest, "Not enough history");
    return ref.getTimestamp(latest - _back);
  }
}

Answer 2

I've written a library that lets you get the prev() or next() roundId from a given roundId:

https://github.com/JonahGroendal/chainlink-round-id-calc/blob/master/contracts/ChainlinkRoundIdCalc.sol

You can use prev() to go back all the way to the very first round if you want.

Answer 3

Update September 2022

You can now easily view historical price data by using checkthechain.

Below is a minimal working example using the Python package:

from ctc.protocols import chainlink_utils

feed = '0x31e0a88fecb6ec0a411dbe0e9e76391498296ee9'

data = await chainlink_utils.async_get_feed_data(feed)

Alternatively, you can also use their API.