Existing Job Request

Example

In Single Word Response Example, the example contract code declared which URL to use, where to find the data in the response, and how to convert it so that it can be represented on-chain.

This example uses an existing job that is pre-configured to make requests to get the gas price. Using specialized jobs makes your contracts succinct and more simple.

Etherscan gas oracle returns the current Safe, Proposed and Fast gas prices. To check the response, you can directly paste the following URL in your browser https://api.etherscan.io/api?module=gastracker&action=gasoracle&apikey=YourApiKeyToken or run this command in your terminal:

curl -X 'GET' \
  'https://api.etherscan.io/api?module=gastracker&action=gasoracle&apikey=YourApiKeyToken' \
  -H 'accept: application/json'

The response should be similar to the following:

{
  "status": "1",
  "result": {
    "LastBlock": "14653286",
    "SafeGasPrice": "33",
    "ProposeGasPrice": "33",
    "FastGasPrice": "35",
    "suggestBaseFee": "32.570418457",
    "gasUsedRatio": "0.366502543599508,0.15439818258491,0.9729006,0.4925609,0.999657066666667"
  }
}

For this example, we created a job that leverages the EtherScan External Adapter to fetch the SafeGasPrice , ProposeGasPrice and FastGasPrice. You can learn more about External Adapters here. To consume an API, your contract must import ChainlinkClient.sol. This contract exposes a struct named Chainlink.Request, which your contract can use to build the API request. The request must include the following parameters:

• Link token address
• Oracle address
• Job id
• Request fee
• Task parameters
• Callback function signature

To use this contract:

1. Open the contract in Remix.

2. Compile and deploy the contract using the Injected Provider environment. The contract includes all the configuration variables for the Sepolia testnet. Make sure your wallet is set to use Sepolia. The constructor sets the following parameters:

   • The Chainlink Token address for Sepolia by calling the setChainlinkToken function.
   • The Oracle contract address for Sepolia by calling the setChainlinkOracle function.
   • The jobId: A specific job for the oracle node to run. In this case, the job is very specific to the use case as it returns the gas prices. You can find the job spec for the Chainlink node here.

3. Fund your contract with 0.1 LINK. To learn how to send LINK to contracts, read the Fund Your Contracts page.

4. Call the gasPriceFast, gasPriceAverage and gasPriceSafe functions to confirm that the gasPriceFast, gasPriceAverage and gasPriceSafe state variables are equal to zero.

5. Run the requestGasPrice function. This builds the Chainlink.Request. Note how succinct the request is.

6. After few seconds, call the gasPriceFast, gasPriceAverage and gasPriceSafe functions. You should get a non-zero responses.