Oracle integration (Chainlink) in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Chainlink client interface.

Blockchain / Solidity

import [1] from '@chainlink/contracts/src/v0.8/ChainlinkClient.sol';

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AChainlinkOracle

BChainlinkClient

COracleClient

DChainlinkInterface

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect interface names like ChainlinkOracle or OracleClient.

Misspelling the import path or interface name.

The correct import is ChainlinkClient, which provides the functions to interact with Chainlink oracles.

2fill in blank

medium

Complete the code to set the Chainlink oracle address in the constructor.

Blockchain / Solidity

constructor() {
    setChainlinkOracle([1]);
}

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A0x0000000000000000000000000000000000000000

Bmsg.sender

Caddress(0)

DoracleAddress

Attempts:

3 left

💡 Hint

Common Mistakes

Passing zero address or msg.sender instead of the oracle address variable.

Forgetting to set the oracle address.

You need to pass the actual oracle address variable, usually named oracleAddress, to the setChainlinkOracle function.

3fill in blank

hard

Fix the error in the request function to correctly build the Chainlink request.

Blockchain / Solidity

function requestData() public returns (bytes32 requestId) {
    Chainlink.Request memory req = buildChainlinkRequest([1], address(this), this.fulfill.selector);
    return sendChainlinkRequest(req, fee);
}

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AjobId

Boracle

Cfulfill

DrequestId

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the oracle address instead of the job ID.

Using the wrong function selector.

The buildChainlinkRequest function requires the jobId as the first argument to specify the job to run on the oracle.

4fill in blank

hard

Fill both blanks to add a URL and a path to the Chainlink request.

Blockchain / Solidity

req.add([1], [2]);

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A"get"

B"https://api.example.com/data"

C"path"

D"data,results,0,value"

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the key and value arguments.

Using 'path' instead of 'get' for the first argument.

To request data, you add the 'get' key with the URL as value to the request.

5fill in blank

hard

Fill all three blanks to add the path and multiply the result in the Chainlink request.

Blockchain / Solidity

req.add([1], [2]);
req.addInt([3], 100);

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A"path"

B"data,results,0,value"

C"times"

D"multiply"

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect keys like 'multiply' instead of 'times'.

Mixing up the order of arguments.

You add the 'path' key with the JSON path string, then add an integer 'times' to multiply the result.