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Using Price Feeds

Get all supported price feeds and their addresses

import PublicPriceOracle from 0xAddress
// oracleAddress => oracleTag
pub fun main(): {Address: String} {
return PublicPriceOracle.getAllSupportedOracles()
}
Sample result:
{
0xf5d12412c09d2470 : "USDC/USD"
0xe385412159992e11 : "FLOW/USD"
0x1a9caf561de25a86 : "FUSD/USD"
0x031dabc5ba1d2932 : "stFlow/USD"
0x11b69dcfd16724af : "BLT/USD"
0x07e2f8fc48632ece : "USDT/USD"
}

Get latest result and update time

import PublicPriceOracle from 0xAddress
pub fun main(oracle: Address): [UFix64] {
let lastResult = PublicPriceOracle.getLatestPrice(oracleAddr: oracle)
let lastBlockNum = PublicPriceOracle.getLatestBlockHeight(oracleAddr: oracle)
// Get block timestamp does not always work: the # of recent blocks cached and servicable are depending on execution nodes.
let lastTimestamp = getBlock(at: lastBlockNum)?.timestamp
return [
lastResult,
UFix64(lastBlockNum),
lastTimestamp ?? 0.0
]
}
Sample result for "Flow/USD" price feed:
[0.58717715, 57835057.00000000, 1690794621.00000000]
Note that:
  • The data is updated whichever condition is met first:
    • Deviation is beyond certain threshold (by default 0.5%)
    • A fixed window of time has passed (by default 2000 blocks)
  • Users of the PublicPriceOracle need to check the latest update time and handle the extreme condition if this data is too old.
  • We recommend to use blockHeight, as the block timestamp is not accurate or not always retrievable: the number of recent blocks cached and servicable are depending on execution nodes.

DEX-based TWAP Price Oracle

Check examples here.