Smart contract and Oracle contract

Question

I have 2 contracts: my contract and an oracle contract. I make a request to my smart contract and send some data that needs to be processed. I use mySmartContract.methods.availability(value1,value2).send({"from":myAddress}).

After my contract gets the data, it has to make an asynchronous request to the oracle smart contract which takes information from an external data source. I read the answer to this question https://stackoverflow.com/questions/55302995/how-to-return-value-to-caller-function-in-asynchronous-javascript-and-web3js, but in my case who calls the 'caller' function on my smart contrac that calls 'responder' on the oracle smart contract?

Answer 1

Who calls the function on my contract that calls the function on the oracle contract?

An offchain service that you need to set up, since you're the one with the private key of myAddress.

For example, with web3.js v1.2, you could do something like this:

const transaction = mySmartContract.methods.availability(value1, value2);
const options = {
    to      : transaction._parent._address,
    data    : transaction.encodeABI(),
    gas     : await transaction.estimateGas({from: myAddress}),
    gasPrice: yourDesiredGasPrice
};
const signed = await web3.eth.accounts.signTransaction(tx, myAddressPrivateKey);
const receipt = await web3.eth.sendSignedTransaction(signed.rawTransaction);