External HTTP Calls

Given that code specified in contracts on SUAVE is execued in TEEs, which can provide attestations about the code they are running, we can more securely make requests to arbitrary http endpoints to fetch data relevant to any offchain computation we are running.

The kinds of data we can fetch are arbitrary: it ranges from price data to ChatGPT responses, or as far afield as your imagination is willing to go.

Practical Example

In order to understand the implications of fetching data from external sources when running secure, offchain computation in a Kettle, we encourage you to go through our external calls tutorial. Essentially, we're able to query the ChatGPT completion API with a few lines of code (but this could just as easily be the Binance or Bloomberg APIs too):

function offchain() external returns (bytes memory) {
    bytes memory keyData = Suave.confidentialRetrieve(apiKeyRecord, API_KEY);
    string memory apiKey = bytesToString(keyData);
    ChatGPT chatgpt = new ChatGPT(apiKey);

    ChatGPT.Message[] memory messages = new ChatGPT.Message[](1);
    messages[0] = ChatGPT.Message(ChatGPT.Role.User, "Say hello world");

    string memory data = chatgpt.complete(messages);

    emit Response(data);

    return abi.encodeWithSelector(this.onchain.selector);
}

One additional note: if you wish to create your own Foundry project with contracts that make external calls, please make sure to adjust the foundry.toml file to include the following (the equivalent of running suave-geth with the --suave.eth.external-whitelist='*' flag):

[profile.suave]
whitelist = ["*"]

Interface

SUAVE exposes one precompile which can handle all your external call needs:

function doHTTPRequest(HttpRequest memory request) internal returns (bytes memory)

You can see how this is used in everything from EthJsonRPC (which powers patterns like Gateway.sol), to sending bundles to the Flashbots relay, to querying ChatGPT.sol.