README.md

General JSON-RPC External Adapter for Chainlink

• Should work for any JSON RPC supported endpoint (includes tests for a few major projects which support JSON RPC commands)
• Blockchain clients can sign and send transactions if wallet is unlocked

What this adapter does is allow you to specify the "method" and "params" values in a Chainlink request and receive the result (format example below) back to the Chainlink node for further processing.

In Solidity, a Chainlink request can be made to an external chain for the balance of a given account with the following example:

function getBalanceExternalChain(string _account)
  public
  onlyOwner
{
  Chainlink.Request memory req = newRequest(JOB_ID, this, this.fulfillRPCCall.selector);
  req.add("method", "eth_getBalance");
  string[] memory params = new string[](2);
  path[0] = _account;
  path[1] = "latest";
  req.addStringArray("params", params);
  chainlinkRequest(req, ORACLE_PAYMENT);
}

Environment Variables

Required?	Name	Description	Options	Defaults to
	RPC_URL	environment variable to your client URL		http://localhost:8545

See testing for information on other potential endpoints depending on the blockchain network and node type.

Endpoint

Depending on the blockchain, input parameter values and returned responses will vary.

Required?	Name	Description	Options	Defaults to
✅	method	JSON-RPC method to be called
	params	Array of parameters for the method

Sample Input

{
	"jsonrpc": "2.0",
	"method": "some_method",
	"params": [
		"some_param",
		"another_param"
	],
	"id": 1
}

Sample Output

{
  "id":1,
  "jsonrpc": "2.0",
  "result": "some_result"
}

Testing

Testing is dependent on the type of node you're connecting to. You can set a local environment variable RPC_URL to point to an RPC connection. Otherwise, the adapter will default to "http://localhost:8545".

RPC Address and Port Defaults:

• Ethereum: http://localhost:8545
• AION: http://localhost:8545
• BTC: (bitcoind) http://localhost:8332 (btcd) http://localhost:8334
• Zilliqa: http://localhost:4201

For Ethereum and any Geth clone (should work with Parity as well):

Make sure you run these commands from the ROOT of this monorepo.

yarn test json-rpc/test/e2e/eth

For Bitcoin:

yarn test json-rpc/test/e2e/btc

For AION:

yarn test json-rpc/test/e2e/aion

For Zilliqa:

RPC_URL=https://dev-api.zilliqa.com yarn test json-rpc/test/e2e/zilliqa