Introduction
Smart contract developers
Witnet Node Operators
Developer Reference
Using Price Feeds
The Witnet's Price Feeds Router allows your smart contract, or Web3 application, to get the latest updated price value of any of the currency pairs subsidized by the Witnet Foundation, without needing to know the actual contract addresses in charge of requesting and receiving price updates from the Witnet oracle's sidechain.
Currency pairs are identified by a
bytes32 value, calculated as the keccak256 hash of the currency pair caption. The caption is composed as the string concatenation of: Price-, first asset denomination (e.g. BTC), /, second asset denomination (e.g. USD), -, and the number of decimals.For the sake of simplicity, currency pairs served by the Witnet's Price Router can also be identified by just using the first 4 bytes (see ID4 below) of the full
bytes32 identifier (ID32).From the Price Router you may also retrieve the Witnet's Price Feed contract that is currently serving a given currency pair, if any. While the Witnet Foundation will make its best to keep all committed currency pairs updated in a timely manner, you can always use the Price Feed contract to trigger a new price update at any time, if willing to pay the required gas for that.
Currency pairs
This table contains the currency pairs that are currently updated by the Witnet Foundation on a regular basis:
Caption
ID4
ID32
Clicking on any of the captions above will take you to the Javascript equivalent of the RADON script that is processed by the Witnet oracle on every single price update of the corresponding currency pair.
As introduced by the 2017 Witnet whitepaper, RADON is "a flow-based, tacit, point-free scripting language [...] implemented as a domain specific language (DSL), [... that] includes normalization and aggregation methods in a MapReduce style".
Basically, it specifies the math, filters, reducers and tally operator to apply to the values fetched from a set of given sources, as well as the witnessing thresholds and quality levels to be met by the Witnet oracle when solving the price update.
Last modified 15d ago
Copy link
Edit on GitHub
Contents
Currency pairs