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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Random-order minting of ERC721 tokens

Problem is minting of tokens in random order. I would like to hear more about drawbacks of these approaches: Having: 10.000 NFT collectibles amongst them there are rare ones images are clearly ...
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15 views

File import callback not supported

I have a YAML file configured but when I compile the code, it does not create dependencies directory and neither the json files. The sources I import mentions: File import callback not supported. Any ...
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1answer
10 views

Can I have upkeep and random request running in same contract without a conflict in LINK balance?

Would there be a conflict in LINK balance if I run Upkeep and VRFRandomness in the same contract? As funding upkeep is through addFunds() function but as for VRFrandomness LINK token balance needs to ...
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20 views

Where does Chainlink get its deviation threshold from?

I understand Chainlink updates either every hour or once the price moves beyond a deviation threshold (often 0.5% or 1%). But where does Chainlink check for this deviation?
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How to start with writing Upkeep for the function in my smart contract which concludes an auction?

I've just started learning about Chainlink Upkeepers, I'm very new to this and not able to plan my approach how to begin with automating the concludeAuction() function below. The smart contract ...
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1answer
10 views

Economic motivation for aggregators in Chainlink

Please help me to understand what is the economic motivation for price aggregators? As I understand the aggregator pays to price providers via transferAndCall. This payment is motivation for the ...
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151 views

How to resolve 'Build failed: function.js does not exist; Error ID: 7485c5b6'

I'm trying to deploy a Chainlink external adapter to Google Cloud Function but running into the above error. I am using this template for the external adapter. https://github.com/thodges-gh/CL-EA-...
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2answers
305 views

Brownie Chainlink Import Error VSCode - 'File import callback not supported'

The code seems to have successfully compiled, but VSCode keeps showing this error - "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol" not found. File import callback not ...
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141 views

Rules on choosing a Solidity version

Is there a rule on using a specific solidity version? I mostly work with 0.8.7 and they sometimes conflict with some Chainlink or Open Zeppelin contracts since they use either v6 or v7. Should I ...
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1answer
56 views

What could go wrong if I change the version pragma of a third-party contract to make it importable with a newer Solidity compiler?

What are the consequences of changing compiler versions in dependency contracts to the same version as the main contract? I have one main contract that inherits some other contracts to interact with ...
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375 views

TX failed - Bad instruction - Funds not back

I sent some $link amount but TX failed due to Bad instruction error. Tx is https://etherscan.io/tx/0xa45e443c8cf310dbe69ab725358ac2da20afde33442a55ed7df985fe6645057d Have read that failed transactions ...
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2answers
46 views

Error publishing source code

Here's my deploy.py: from brownie import FundMe from scripts.helpful_scripts import get_account def deploy_fund_me(): account = get_account() fund_me = FundMe.deploy({"from": ...
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1answer
23 views

Handling transactions fees when using Chainlink

I have a smart contract which must reach out to an off-chain data source (custom API) in order to verify that the wallet calling the function can do so. My understanding is that this is done via a ...
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57 views

Can't import chainlink using web3j

I am making simple contract using AndroidStudio and Java.In my contract i am using import statement: import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol"; but when i ...
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2answers
29 views

Chainlink VRF very slow - 20+ minutes for response to fulfillRandomness on Rinkeby

I have implemented a basic Chainlink VRF function in Solidity and deployed to Ethereum test network Rinkeby function getRandomNumber() public returns (bytes32 requestId) { require(LINK....
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Solidity chainlink/AggregatorV3Interface decimals() returns number 8 always

Hi i am learning Solidity and trying to get token price using chainlink/AggregatorV3Interface.I get it but when i try to get exactly price with decimals it returns 8. this is my contract pragma ...
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456 views

price conversion using chainlink ETHUSD price

I'm storing a product's USD value in contract. mapping (string => uint256) productUSD; For example, if it's $52 I'd store it as productUSD[_product] = 52; Now, when people paying in ETH, I want to ...
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1answer
19 views

Chain link Aggregator v3 Interface error?

Hello! I am following a tutorial that implements Chain Link's Aggregator V3 Interface, but it seems the code is not interacting properly with its import. Attempting to deploy on Remix brings up the ...
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1answer
42 views

Want to generate non-repeative random number in a particular range

I need to generate a random number in range 1-5000 which are non duplicate. I had found solution to generate random number in particular range using chainlink and without chainlink also but i need to ...
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1answer
25 views

Chain link external api call does not work

I'm trying to make external api call from my contract. I am using chain link to make this request. After transfer some tokens from one account to another it should make api request to my test ...
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1answer
12 views

Chainlink Keepers - Multiple Upkeeps in a Single Contract

From ChainLink docs Here, I know we can create upkeeps using the checkUpkeep and performupkeep functions. Is it possible to create multiple upkeep checks and performs in the same contract? may I know ...
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1answer
399 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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19 views

Fullfill randomness type error when Importing chainlink functions

Trying to inherit the randomness functions into my main contract(lottery). Getting a type error and I can't work out why. Tried all sorts. Is there a better way to inherit or import chainlink ...
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1answer
142 views

Troubles interacting with Chainlink node on Kovan

I've been following instructions on running a local Chainlink node on Kovan. My environment is configured to Kovan through websockets via Infura and the node is both running and successfully accepts ...
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2answers
504 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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27 views

solidity interface - Contracts calling unimplemented functions

I'm new to solidity and OOP. I'm trying to understand the code in this simple lottery game example: https://github.com/alphachainio/chainlink-lottery/blob/master/ethereum/contracts/ I am confused when ...
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How do you convert block timestamps to GMT or any other timezone for oracles on EVM. Are GMTs the same as block timestamps on EVMs?

pragma solidity >=0.4.16 <0.9.0; import '@uniswap/v2-core/contracts/interfaces/IUniswapV2Pair.sol'; import '@uniswap/lib/contracts/libraries/FixedPoint.sol'; // library with helper methods for ...
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1answer
51 views

How to import deployed contract from rinkeby to browser blockchain remix

I saw a lot of tutorials on running the Rinkbey testnet injected using MetaMask on Remix to call functions such as to get conversion rates from Ether to USD using chainlink. I would like to do so ...
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1answer
78 views

Brownie test error with local fork

When trying to run the test at 6:29:30 in the FreeCodeCamp tutorial with Patrick Collins, I get a brownie.exceptions.VirtualMachineError: revert when it tries to call my Lottery.getEntranceFee ...
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1answer
12 views

How do I find the code of a external interface function?

I am learning about importing contracts and noticed with the following contract there is an external interface function with no code block. Where does this code come from? function version() external ...
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1answer
24 views

chainlink data feed prices real-time update

I went through the documentation of Chainlink data feeds and saw we can get the latest price using latestRoundData() function from AggregatorV3Interface. The documentation states the price update ...
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1answer
27 views

Getting data into a contract from an API that requires authentication

I'm trying to pull data into my smart contract from an API using the approach described here: https://docs.chain.link/docs/make-a-http-get-request/ I can get the example code at that link working just ...
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1answer
14 views

Chainlink - where are adapter keywords specified?

I watched a tutorial video here. In the following example, we use req.addInt("times", 100); Where are the adapter references specified (in this case, "times")? On market.link, I'm ...
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18 views

Solidity - multiple oracle queries with different parameters each

I have managed to get a API call for the JSON file and return the data from the specific location that I want. Now the problem is, that if multiple people try to get the data for different locations ...
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1answer
711 views

Make a GET Request over the Binance Smart Chain with a Chainlink Oracle

I am trying to call to an BSC Oracle to make an HTTP request according this ChainLink example. In my example I am goin to use the BSC mainnet 56 and a other JobID obviously: My steps: I created the ...
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21 views

Chainlink randomness request never get resolved on polygon mumbai testnet

I've been learning how to generate a random number using chainlink VRFConsumerBase contract. I've followed the documentation but I've realized that my transaction stay pending when I execute them on ...
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1answer
23 views

Chainlink Oracle : Fail with error 'Must have a valid requestId'

Facing a slight issue with my Oracle.sol that I deployed for my Naas node. whenever its fulfilling the request back to the contract, it throws this error. I deployed the contract using "@...
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1answer
31 views

Chain Link oracle : Fail with error 'First word must be requestId'

I just span up an oracle contract using "@chainlink/contracts/src/v0.7/Operator.sol"; I am using Operator.sol specifically for the fulfillRequest2 function since i need to return data in the ...
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14 views

in chainlink how can I send more than one parameter or multiparameter to an API and get a proper response from it?

I have a reandomWeight function for NFT sharing. it get _id and _qty parameters and returns _NFTsID and _id. I want to post this parameters to my API and get _NFTsID and _id. how can I do that?
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1answer
146 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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23 views

Chainlink VRF requestRandomness returning a requestId of 0

Would it be possible for Chainlink VRF's requestRandomness(bytes32 keyHash, uint256 fee) method to return a value of 0 as the request ID? I'm not sure if the VRF returns incremental request IDs.
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18 views

ReactJS & Chainlink connection for a generated random number

During my investigation, I would like a piece of advice, please. I am trying to get a random number generated by the VRF of the oracle chainlink from the front coded in ReactJS. I would like to get ...
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1answer
25 views

Why Would I Be Getting a Gas Estimation Error on Remix? I have plenty of ETH and LINK

I keep getting this error and can't figure out why. I have 1.4 ETH and 110 LINK in my metamask account. I'm connected to the Kovan testnet. Any help would be much appreciated. Error: Gas estimation ...
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42 views

Chainlink Hackathon, Building and using External Adapters

I am following the "Chainlink Hackathon | Building and using External Adapters" video tutorial (Oct 2021) and have done the following: a local docker node running successfully run ...
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1answer
12 views

Dynamically supply link to chainlink upkeeper

I've created a simple chainlink upkeep task on polygon: import "@chainlink/contracts/src/v0.7/KeeperCompatible.sol"; contract Counter is KeeperCompatibleInterface { /** * Public ...
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2answers
3k views

Generating random number in Solidity without Chainlink

Hello I'm well aware there are plenty of threads around discussing different methods. Just curious and wanted to ask directly here because feel like the situation might be different. Essentially I'm ...
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1answer
112 views

Solidity timeout error Remix Chainlink interface Rinkeby

I am following Patrick Collin's smart contract course on youtube and am stuck at the 2hr 46min mark (FundMe.sol) ETH/USD Chainlink price feed on rinkeby. The code from the video compiles ok but when i ...
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2answers
51 views

How to do call a smart contract at intervals on the matic network?

I'm trying to write a smart contract to farm tokens. I would like to make an auto-compounding solution similar to beefy.finance or polycats. My contract can deposit funds or liquidity into LP mining, ...
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3answers
145 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
364 views

How to run Chainlink Project using eth-brownie python

I had installed eth-brownie using command pip install eth-brownie after Brownie installed.I had bake existing Brownie project into a new directory. mkdir MyChainlinkProject cd MyChainlinkProject/ ...

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