Oracles are essential for any real world application. Smart contracts on most platforms don’t have the ability to make HTTP requests. Want to send a Tweet from ETH? You actually can’t. Smart contracts need to return the same data no matter which node it’s run on. What if an API returns different data based on geolocation?
This is where oracles come in. An oracle is actually really simple, It’s just a service that lives off-chain that submits requested data to your smart contract.
So let's get back to our original problem, submitting a Tweet. Here’s how you would accomplish this with something like Chainlink:
- User submit a request to your dapp to post a Tweet.
- Your dapp logs a receipt or event that’s picked up by the oracle.
- The oracle performs the requested action and posts the result back to your smart contract.
- You’re done! Show a success message.
The key is to have outside data submitted to your contract.
Why Chainlink?
IOST decided to partner with Chainlink a few months ago which originally put Chainlink on our radar.
I'll quote the IOST foundation's reasons for partnering with Chainlink:
We chose Chainlink because it is the leading decentralized oracle solution. It is used by numerous top projects including Polkadot (Web3), Ocean Protocol, Streamr, Accord, and many others.
Source: https://link.medium.com/pyrLPqpUaZ
Not only is Chainlink widely adopted, it's also easy to add support for a new blockchain. We know because we've built a Chainlink adapter for IOST!
BlockArcade and Chainlink
Why does an arcade need an oracle? A few reasons like better random number generation and a price feed for exchanging prizes. Chainlink has built-in support for both of these request types so we just had to teach it how to talk to IOST.
https://github.com/blockarcade/iost-adapter
Currently this adapter only allows you to post data to IOST, not react to events. We're running the adapter on a self hosted Chainlink node and we're using the cron initiator to submit updates to BlockArcade.
I hope by now it's clear that we're committed to contributing to the IOST community and we will continue to release pieces of our stack on GitHub.
Play now at: https://blockarca.de
Have questions or feedback? Join us in Telegram: https://t.me/blockarcade