Questions tagged [chainlink]

Chainlink is a decentralized oracle network that enables blockchain smart contracts to securely access off-chain data feeds.

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how do i change the price feed token from eth /usd to busd/usd with the chainlink oracle?

I am trying to get the price feed for BUSD/USD using the chainlink pricefeed oracle but it tells me that the code was reverted. this is also happening when i switch to any other token, i am using the ...
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Why some ERC20 tokens have different Transfer event ABI signature than Transfer(address,address,uint256)?

Looking at ChainLink ABI (using this tool) I see { "anonymous": false, "inputs": [ { "indexed": true, "name": "from", "type": &...
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How to walk down an API when making a chainlink get request?

Am trying to make a chainlink Get>Bool httpget request on the fantasy premierleague API but keep getting a false response. my code is: ''' function getGwstaus() public returns (bytes32 requestId) ...
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36 views

How to edit minium link payment as a node-operator

Been running a node, and I notice the payment in configuration settings is not editable, how do I figure that out, also am not seeing the Oracle balance in link increase and it debiting the user using ...
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11 views

Running chainlink node on google cloud and accessing the node server as an operator

I was able to access the localhost:6688 when I was running the node server, so whenever I closed the console the server will go down, so I decided to detach it by installing sleep now the server is up ...
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ProviderError: The execution failed due to an exception while deploying ChainlinkPriceFeed

Iam re-deploying Enzyme-Protocal smart contract in kovan testnet Git repo link It has a ChainlinkPriceFeed smart contract and it takes [ fundDeployer.address, weth, ethusd, primitives, aggregators, ...
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1answer
39 views

File outside of allowed directories on brownie compile command

trying to import to files from openzeppelin and chainlink in my contract file like so: import "@openzeppelin/contracts/token/ERC721/ERC721.sol"; import "@chainlink/contracts/src/v0.6/...
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Need help for extracting historical prices using chainlink api

This is my first time i am using a api call for implementing on project for predicting the avalanche price feed for machine learning to get the historical data for 2 years. I want api call from ...
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18 views

Make external adapter call only accessible through smart contract

sorry if this is a newbie question, I'm new to solidity and smart contracts. I want to make an API call on my smart contract but from what I saw, I have to implement a Chainlink external adapter. Now, ...
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26 views

How to call a payable function with no parameters?

I'm creating Ether Coin Flip. Works like this. Person A calls new coin flip function with 1 Ether Person B calls End coin flip function with 1 Ether Smart contract uses VRF to randomly pick winner ...
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Solidity: HTTP req w/ Headers

I'm attempting to make POST / GET requests containing headers as my API require them... I thought I would be able to accomplish this via Provable-Things, as they also offer an encryption option. ...
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27 views

Contract deploys and gets funded but gives 'Gas estimation failed' error later on

I am updating a parametric insurance smart contract written last year and have run into a problem. I am able to successfully deploy the insurance provider contract (the parent contract) and fund it ...
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14 views

Chanlink Public CryptoGraphy

While chainlink creates a random number and more secure public cryptography algorithm, I recently came across the quantum resistive ledger concepts and resistive to a quantum computer with hash mesh ...
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65 views

Locally test Chainlink VRF call from another contract in Waffle/Hardhat

Locally testing Chainlinks VRF While trying to locally test a contract that calls a Chainlink VRF contract, I'm experiencing some difficulties in setting up the contract balances. I have a ...
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22 views

Solidity equivalent of ${object} of Javascript

Alright, I have a function that accepts a string, that I want to use to send individualized requests to a URL. How do I insert my functions string parameter into my get request? This is using ...
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1answer
21 views

Chainlink "Any API" Returning 0

I want to use the chainlink API features but I can not get the data. When I try to execute requestEthereumPrice function I get "uint256: 0" I am using Kovan test net and metamask. pragma ...
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25 views

What exactly is the role of Oracles like Chainlink in decentralized insurance?

I am from the insurance industry, and I'm trying to understand if there's any value that blockchains and smart contracts can provide in this domain. I'm trying to understand things at the conceptual ...
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48 views

Getting error member `add` not found when using ChainlinkClient.sol v0.8.0

I'm trying to use Chainlink APIConsumer example and for the same I'm importing v0.8/ChainlinkClient.sol file. On compiling APIConsumer contract, I'm getting below error. ERROR TypeError: Member "...
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61 views

Why are my internal txns failing in my transaction?

I've deployed the chainlink alarm job to an oracle on bsc testnet. I'm attempting to transfer tokens from one address to another at a set time in my smart contract, and the transaction appears to be ...
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31 views

Biased Random Number based upon balance of ERC20 tokens

I have been able to use Random Number Generator from Chainlink. But I need something that has biased Random Number. What I mean is suppose a userA has 100 ERC20 Tokens balance but another userB has ...
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27 views

Chainlink historical price for AggregatorV3Interface

Similar to this question How to get all the historical data from chainlink price feeds? I would like to retrieve the historical data of a particular price feed to be used off-chain for a large number ...
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1answer
123 views

Chainlink VRF fulfillRandomness function does not work as expected with storage variables

I created simple smart contract that generates game character with random attributes and pushes it to an array. Function requestNewRandomCharacter() does three things: Changes characterNameForMinting ...
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19 views

Error in Executing Price Feed Function in Chainlink

This is my code. After deploying it to Kovan Test Net. Whenever I try to run the function getPrice() it returns : call to PriceConsumerV3.getPrice errored: Error: VM execution error. Reverted 0x ...
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52 views

Cannot find module '@chainlink/contracts/truffle/v0.4/LinkToken'

I was following these steps in order to use Chainlink on Kovan testnet. when I've finished the configuration (truffle-config.js, npm install to get all the dependencies, etc.) and I've compiled the ...
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2answers
26 views

Getting an error even using the same compiler version (Visual Code)

I made a contract using Remix and it's working perfectly. When I create a project in Visual Code (in order to make a DApp) I'm getting this error when I import a source of Chainlink: If I compile ...
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23 views

What is the smallest amount of LINK?

Similar to What is the smallest amount of Ether?, what is the smallest amount of LINK?
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347 views

Getting LINK for Ropsten network

I'm trying to get LINK for Ropsten. I'm using this faucet: https://ropsten.chain.link/ and, when I've added the new token, I've used this address 0x20fe562d797a42dcb3399062ae9546cd06f63280 (Chainlink ...
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140 views

How to validate the Chainlink price feed at a specific time

Suppose that in my solidity contract, I need to see the price of ETH in terms of USD at a specific time, say on January 1, 2021. I would like to use the Historical Price Data Feed from chainlink (URL ...
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2answers
41 views

Will a transaction fail if a states from another contract changes before the transaction is confirmed?

I am building an application that you can purchase USDC by paying ETH. I am getting the USDC amount from msg.value(ETH) by directly calling a chainlink pricefeed in my function. function ethToUsdc() ...
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1answer
37 views

ChainLink VRF number length

Is the length (number of digits) of the number generated by ChainLink VRF always the same? My contract executes modulus operations to get subnumbers of the big number generated, so if it's not the ...
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196 views

Chainlink VRF fulfillRandomness doesn't use enough gas to perform function - how to get it to use more?

Chainlink VRF allows users to get a random number by calling requestRandomness and then waiting for the fulfillRandomness callback to be called by the Chainlink contract. I have a function ...
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49 views

"Gas estimation failed" error when sending eth to Chainlink VRF function?

I have a simple request and fulfill randomness using chainlink VRF, and it works fine when calling with 0 ether, but if I send a non-zero amount I get a 'gas estimation failed' error. To be clear, I ...
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1answer
48 views

EthTx Adapter in Chainlink - Txn Construct Details

I am setting up chainlink node for Xinfin Network for Apothem. While submitting the transactions, it is reverted on chain. We tried to debug and the json looks like below. { "id": &...
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76 views

Chainlink call callback function in a different contract

I have 2 Smart Contracts, the StockAPI which is a ChainlinkClient and the RepToken Smart Contract. The StockAPI is the Chainlink API Consumer and is called by RepToken via the evaluatePredictions ...
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95 views

EthTx adapter in Chainlink job, fails with “transaction reverted on-chain”

I have gone through the existing error link EthTx Adapter in Chainlink Job and the solutions recommended is also tried, but still i am facing the same issue. Approach I taken to debug is given below ...
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41 views

Is there a mechanism for fair, trustless Chainlink oracle pricing?

When using a Chainlink oracle node that you don't have a formal commercial agreement with, the user pays the node operator in Link tokens, but the node operator bears the cost of transacting on the ...
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158 views

Chainlink Beginner Tutorial: call to PriceConsumerV3.getLatestPrice errored: [object Object]

I have followed the steps in the Chainlink docs Beginner's tutorial, as described here: https://docs.chain.link/docs/beginners-tutorial/ Everything appears to work until the last paragraph: Click &...
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32 views

How do I force a Chainlink price oracle to return a diffrent price for an asset with Hardhat mainnet forking?

I'm working on a DeFi protocol and I would like to test liquidations with Hardhat mainnet forking. Plan is quite simple: Send enough ETH from my test account to the Binance wallet to pay for gas. ...
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Chainlink Initiators - Failed testing subscriber: unexpected end of JSON input

I am trying to customize Chainlink External Initiators, since the blockchain is fork of Ethereum. I am simulating the eth.go and created my own version. After updating the program, triggered the ...
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Get "unsupported protocol scheme" - Error occuring while triggering the TestClient smart contract

I am trying to setup Chainlink Node locally & deployed the smart contract onto testnet(Apothem - Xinfin Blockchain). All went fine, until I trigger the function to requestVolumeData(). #1) Job is ...
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138 views

Not receiving LINK from Chainlink kovan faucet

I attempted to get funds from kovan.chain.link to my metamask address and the money did not come through. I got some errors as seen here: https://kovan.etherscan.io/tx/...
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93 views

I had a error like : ParserError: Source file requires different compiler version , while using Chainlink&OpenZeppelin

I'm trying to implement PatrickAlpha NFT-mix implementation (Github link) . When I followed readme instructions, collectibles are minted correctly. But If I tried to change anything in the code , it ...
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1answer
45 views

How to return a Chainlink API Call to another contract?

I need to call a function that returns the uint value requested by the oracle from another contract function. I am trying the next... but I think I am going by the bad way. Any solution for that? The ...
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64 views

How to make a ChainLink solidity oracle asynchronous call?

I need to introduce a uint in my Ethereum contract. I am testing this code in Kovan in base to this example: https://docs.chain.link/docs/make-a-http-get-request/ pragma solidity ^0.6.0; import &...
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How are DeFi projects able to pay for data provided by Chainlink oracles?

How are DeFi projects and dApps able to pay for used oracles/api calls? If we assume the needed product has to be updated with a feed every minute and a call would cost 0.1 LINK it would cost 144 LINK ...
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38 views

Why is this particular line of code stopping the smart contract from being deployed?

I am coding a smart contract which will be integrating ChainLink's decentralized oracles, however I've run into an issue that is preventing me from deploying the smart contract on Remix IDE. The ...
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709 views

How to build a decentralized bridge between two blockchains?

I am trying to build my own custom bridge between Ethereum and Binance Smart Chain so that people can transfer tokens and possibly some other assets from one chain to another and vice versa. For this ...
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158 views

What is the best way for a smart contract to constantly listen to a price feed and execute immediately once the price is reached?

I have compiled a smart contract that is supposed to take bets from 2 addresses, a bet creator and a bet taker. The bet is on the price of ETH/USD (via ChainLink). What would be the best way to for ...
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46 views

how chainlink aggregates

How does chainlink result aggregation work? Are all oracle nodes that user-specified reports the results to the smart contract that chainlink is submitted on Ethereum? Is taking a median off ...
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1answer
25 views

How to detect false data feed from Chainlink oracles

I understand Chainlink uses explicit and implicit staking to enforce honest behavior. However, what is the mechanism used to catch the misbehavior of oracles (i.e., reporting wrong data)?