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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19 views

I am trying to use chain link using remix

I'm getting this error /* Internal exception in StandardCompiler::compile: /root/project/libsolidity/interface/CompilerStack.cpp(93): Throw in function solidity::frontend::CompilerStack::CompilerStack(...
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15 views

I am trying to use chainlink using remix and i followed the chainlink docs

I am facing this issue,What to do now? My Code pragma solidity ^0.6.7; import "https://github.com/smartcontractkit/chainlink/blob/master/evm-contracts/src/v0.6/interfaces/AggregatorV3Interface....
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Can I get price feed information directly from ChainLink oracles rather than from the aggregated contract?

I've been experimenting with ChainLink recently and am fascinated of what it can do. I already used the code provided here ChainLink Docs in Python and got it to work. However, I've been searching all ...
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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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ERC20 token balance = 0 in MetaMask

While setting up a test ChainLink node on Rinkeby, I sent some test LINK to my address. The ChainLink web interface showed a balance of 0 LINK. So I checked EtherScan. The transaction succeeded and ...
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30 views

Issue with importing Chainlink & Openzeppelin

Currently trying to run a script and keep running into an error when trying to import chainlink and openzeppelin contracts. Not sure why, I looked at brownie pm list to make sure I have the correct ...
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9 views

I sent ETH to my LINK wallet

Yes I know I'm an idiot, as I said, I sent ETH via Metamask to my LINK wallet on Coinbase. I can see the transaction on bscscan but I don't know how to go about accessing/converting it, any help would ...
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96 views

How can I protect my Chainlink oracle fulfill method?

Background: I'm writing a contract that inherits ChainlinkClient in order to make an API request via an oracle job: function fetch() private returns (bytes32 requestId) { Chainlink.Request memory ...
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20 views

ERROR: null value in column “next_nonce” violates not-null constraint (SQLSTATE 23502)

I am using this command to run my chainlink node: docker run --name chainlink-kovan --network host -p 6688:6688 -v ~/.chainlink-kovan:/chainlink -it --env-file=.env smartcontract/chainlink:0.10.3 ...
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107 views

What is best approach for generating random NFTs?

I am thinking of developing small DApp where user would collect cards (NFT). Each card would have some image and value associated with it. User collects cards by purchasing Pack of Five Cards which ...
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1answer
21 views

OZ ERC20 & Chainlink solc compatibility problem

I apologize for the basic question, but I failed to find an answer via websearch & discord. I'm trying to inherit from Open Zeppelin ERC20 which uses solc 0.7. I also need to use Chainlink alarm ...
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39 views

Chainlink node not initializing, failed to initialize ORM: initializeORM#NewORM: unable to init DB: unable to open postgresql

I am trying to setup a chainlink node on my machine. After setting all the .env variables, I am running the docker command to start the node, cd ~/.chainlink-kovan && docker run -p 6688:6688 -...
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1answer
185 views

Is chain link a stand alone blockchain?

Is chain link a stand alone blockchain or is it a series of smart contracts on the ethereum blockchain?
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17 views

Price feed of multiple coins in a single GET request

I have used Chainlink oracle to get the price feed of a single coin. But I want to fetch the latest price of 100s of coins from the smart contract using oracle. Is it possible to get the price of ...
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24 views

Chainlink Price Feed - function fails when price not hard-coded but correctly displays in console

I'm experiencing a challenge and hoping for some guidance/help/assist... I've been working on implementing price feed. Testing locally with hardcoded return price works like a charm, no issues. When ...
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1answer
72 views

Chainlink Alarm Clock fullfill method never called?

Working with the Chainlink Alarm Clock, my fulfill() method seems to never get called. So for the docs example (below), votingLive is never set back to false after time is up. Everything else works ...
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27 views

Can a chain link node listen to ethereum smart contracts events?

Can a chain link node listen to ethereum smart contracts events? Let’s say I want to provide data to a node from a smart contract. Can a I link a chain link node and use a smart contract as an oracle?
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11 views

Oracle Price Feed Event-Based mechanism

As you know chainlink oracles work like callback functions. I have only one function is that payable one and I need to know the correct eth value in token parity. I cannot request data when the ...
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1answer
23 views

Testing requestRandomness with a unit testing plugin by Remix

when I test rollDice which executes requestRandomness function rollDice(uint256 userProvidedSeed, address roller) public onlyOwner returns (bytes32) { require(wagered.get(roller) > 0, "...
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1answer
40 views

fulfillRandomness in Chainlink VRF?

After executing the requestRandomness function function getRandomNumber(uint256 userProvidedSeed) public returns (bytes32 requestId) { require(LINK.balanceOf(address(this)) >= fee, "Not ...
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1answer
59 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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27 views

How to run a chainlink Node on Mac using chainlink source code

I had followed these setups Install Go 1.14, and add your GOPATH's bin directory to your PATH Example Path for macOS export PATH=$GOPATH/bin:$PATH & export GOPATH=/Users/$USER/go Install NodeJS ...
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Acceptable response types with using Chainlink client contract

I want to consume a Github API via the Chainlink Client Contract, the API returns an array of objects wanted to know can that be handled or I need to write a handler?
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16 views

Can you recieve inaccurate data from chainlink?

Can you receive inaccurate data from Chainlink blockchain oracles? What if the incentive to distort the data is more than the cost?
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Event data has insufficient length | What does this mean?

I've seen this warning from time to time when working with Brownie Event data has insufficient length This is after I made a call to a Chainlink node, calling a function like: function requestUsers()...
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30 views

Funding contract with LINK tokens revert error

When I try creating a Chainlink contract from "master contract" and fund it with LINK, I keep getting the error: "VM error: revert. revert The transaction has been reverted to the ...
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36 views

Compilation Error while using ChainLink

I am using Remix IDE for my smart contract development. I am using the following import line import "https://github.com/smartcontractkit/chainlink/blob/develop/evm-contracts/src/v0.6/...
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244 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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1answer
35 views

Can I use chainlink on a private blockchain?

Can I use chainlink on a private blockchain built with Geth? I found that the online tutorials are basically about how to use chainlink on the Kovan test chain. I want to know whether chainlink can be ...
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1answer
14 views

How does the oracle judge whether the request has been attacked by a man in the middle

The oracle machine can initiate a request to the data source whose URL is the HTTP link address. How does the oracle machine determine whether the HTTP request has been attacked by a man-in-the-middle,...
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67 views

EthTx adapter won't respond in Chainlink job, fails with “transaction reverted on-chain”

We're using the standard truffle box (https://github.com/smartcontractkit/box) to deploy Chainlink contract ($LINK definition, Oracle, sample end-user contract, etc) on a private Ethereum testnet. ...
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14 views

Installing solidity on windows 10

Greetings everyone, i'm trying to install solidity developpement environment on my pc OS: Windows 10 AMD64, i'm following the official solidity documentation 0.5.8, first i installed cmake, downloaded ...
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23 views

Solidity finds eth price but its realy big

This script gives me some random like a number and not real eth price? the price that is outputting is 38598000000?! AggregatorInterface internal ref; // For ETH-USD on ropsten, input the address: ...
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151 views

What are the costs of using Chainlink to generate a random number using VRF?

I'm doing some research about generating true randomness on the Ethereum blockchain. Of course I came across Chainlink and its VRF solution. Although there are many tutorials around, some from ...
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23 views

OAuth/BearerTokens in ChainLink

How to add an authentication header for ChainLink API requests? For example, this guide on connecting ChainLink to Twitter API to post a tweet doesn't implement anything of the sort, so how would it ...
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58 views

Chainlink - on-chain contract functioning

The on-chain aggregation smart contract for ETH/USD on the mainnet (https://data.chain.link/eth-usd) is at this address https://etherscan.io/address/0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419#code. If ...
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69 views

Security implementation of a function in Solidity

I'm here for asking some tips on calling function from other contracts in solidity. Here is the function for generating a random number (which I need in the main contract) using the chainlink VRF. ...
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67 views

How to pay an Oracle with Link token if I have payable with Ethereum values?

First of all, I'm new to this smart contract world, and so I would like to apology if it's a stupid question. I'm programming with Remix and with Solidity as programming language.I have 2 files: ...
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32 views

What is the largest number that can be returned from a Chainlink Price Feed?

Is it safe to assume that chainlink oracles have an upper bound on the price feed, eg it fits into uint96, or perhaps a smaller or larger number? It would be great to know the absolute largest number ...
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86 views

Do all Chainlink feeds return prices with 8 decimals of precision?

It looks like many Chainlink feed aggregators have 8 decimals of precision: ETH/USD, which returns 140330173736 = $1,403.30173736 BTC/USD, which returns 3696759888474 = $36,967.59888474 I found the ...
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1answer
63 views

Does Chainlink have an aggregator for its price aggregators?

I need a way to pass an arbitrary ERC-20 token symbol and get a price for it in return. The Solidity interface should look something like this: function getPrice(string memory symbol) external view ...
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1k views

I sent Chainlink Link tokens to my ethereum address, how can I recover? [closed]

By mistake I sent Link tokens to my ethereum wallet (kraken) that can not receive them, can I recover those tokens? How? I think I had to swap them before sending, but I am new, and I think I made ...
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2answers
134 views

How do I withdraw Ether from my Chainlink node

I'm running a chainlink node on mainnet. My chainlink node has an ether balance I would like to withdraw, but I'm not sure how to find the private key for the node wallet. I know that the tempkeys ...
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1answer
123 views

Chainlink Price feed Main contract points to Kovan. Why? [closed]

I'm setting up price feeds with Chainlink. https://docs.chain.link/docs/ethereum-addresses#mainnet This page has sections: Mainnet, Rinkeby, Kovan. Under Mainnet.. Clicking a pricefeed takes me to .. ...
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11 views

Chainlink `@` syntax or Github url?

I'm going over Chainlink tutorials. Sometime I see Chainlink imports using @chainlink/path/to/contract and other times https://github.com/smartcontractkit/chainlink/blob/path/to/contract. Are ...
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1answer
20 views

Are there Chainlink Contacts / Nodes for Ropsten?

I noticed on the official docs the networks are Mainnet Kovan Rinkeby Are there Chainlink Contacts / Nodes for Ropsten?
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2answers
180 views

ChainLink oracles - are they free to use? Is there an oracle alternative onchain?

How does it work, exactly? We just call this on-chain to get the latest price... but would our contract have to transfer some LINK to it, or what? https://docs.chain.link/docs/get-the-latest-price ...
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1answer
231 views

How to use Chainlink with Truffle/Ganache?

How to use Chainlink with Truffle/Ganache without unboxing a new app? (I have an app already, I don't want to unbox a new one) I'm trying to get the Chainlink price feeds working in local development ...
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1answer
167 views

Chainlink: Data in JSON object not returning

I am using Chainlink to get a value from an API for my smart-contract. I just want to do a simple Get request as described in Chainlink's documentation. Here is the scripte taken from the ...
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94 views

Alternatives to get LINK tokens in Ropsten, for RNG

Sorry if this question sounds like very newbie (and maybe it is. I'm developing a Smart Contract which needs a random number generation, and after researching some time it seems that ChainLink VRF ...