Questions tagged [chainlink]
Chainlink is a decentralized oracle network that enables blockchain smart contracts to securely access off-chain data feeds.
232
questions
2
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1answer
289 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 -...
2
votes
1answer
221 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?
1
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1answer
62 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 ...
0
votes
1answer
101 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 ...
2
votes
1answer
250 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 ...
1
vote
1answer
161 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?
0
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0answers
26 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 ...
1
vote
1answer
77 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, "...
2
votes
1answer
222 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 ...
3
votes
2answers
359 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/
...
0
votes
0answers
181 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 ...
1
vote
0answers
13 views
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?
1
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1answer
34 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?
0
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0answers
25 views
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()...
0
votes
1answer
130 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 ...
1
vote
1answer
174 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/...
0
votes
1answer
701 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 ...
2
votes
1answer
151 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 ...
0
votes
1answer
16 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,...
0
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1answer
221 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.
...
0
votes
0answers
163 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 ...
0
votes
1answer
43 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:
...
5
votes
1answer
3k 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 ...
2
votes
1answer
64 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 ...
1
vote
0answers
105 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 ...
1
vote
1answer
233 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.
...
1
vote
1answer
188 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:
...
1
vote
1answer
49 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 ...
1
vote
1answer
451 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 ...
2
votes
1answer
121 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 ...
0
votes
2answers
2k 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 ...
4
votes
3answers
354 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 ...
0
votes
1answer
439 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 ..
...
0
votes
1answer
19 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 ...
0
votes
1answer
70 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?
2
votes
2answers
744 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
...
1
vote
1answer
800 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 ...
1
vote
1answer
502 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 ...
0
votes
0answers
285 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 ...
2
votes
2answers
333 views
Pegging a contracts 'price' to USD?
I have a contract / dapp that is "pay to play". You send X amount of Eth, and you can play.
I have a price feed working via Chainlink, but I'd like to peg the Eth amount to USD.
Where the ...
3
votes
1answer
828 views
How does money randomly dissapear when using ethereum?
I was browsing Hacker News this morning and I came across this thread. I've tried searching for answers, but it still baffles me. If Ethereum is "safe" how can things like this happen?
1
vote
1answer
56 views
Timed Chainlink oracle call
I have a smart contract that has a price (let's say it gets updated every hour).
The price is defined on some website. Using Chainlink oracles, is it possible to get the variable updated only when the ...
4
votes
1answer
179 views
What is the verification process of nodes on chainLink?
chainLink is a decentralized system similar to Ethereum, which can help smart contracts execute get requests and return the results. The result of chainLink execution also needs to be verified by ...
2
votes
1answer
85 views
How chainlink guarantees the authenticity and accuracy of the data it returns to the smart contract
Given that the oracle and the "request/response" mechanism may be operated by multiple entities, the possibility of data being tampered with during transmission obviously exists. I want to ...
2
votes
1answer
106 views
Getting data from outside source during a transaction once per day
Is it possible for a token contract to call an oracle to fetch data once every so many hours? Let's say the token was going to use a random number for some decision it was going to make in its ...
2
votes
1answer
120 views
Do miners have to verify blocks?
I want to know whether the bottom layer of Ethereum requires miners to verify blocks?
The reason for this problem is that I have been thinking about a scenario of blockchain transaction verification ...
0
votes
1answer
201 views
Can miners choose not to verify transactions in blocks broadcast by other nodes?
When we execute a function on a smart contract, the transaction will be verified by all miners in the entire network before being written to the blockchain. I want to know no matter how complicated ...
0
votes
0answers
262 views
How to interact with a ERC20 / ERC677 token through a smart contract
I'm trying to write a smart contract that can send ERC20 / ERC677 tokens from one user to another. For example send LINK from one address to another. I deployed my contract on the kovan network but it ...
2
votes
1answer
181 views
Do miners or validators have to pay LINK fees for oracle service?
I will try to ask a question based on the use case.
Assume I only use 1 oracle (ignoring the fact decentralization of chainlink oracles) to execute GET call to an API which returns bool information (...
3
votes
1answer
4k views
What is the cost of using a Chainlink Oracle?
I use the market.link to check available jobs and each job has its own price in terms of link. My question is how many times this fee will be paid?
For example:
Let's say the API GET request costs 0....