Questions tagged [oracles]
Oracle is a way of implementing a Smart Contract. Instead of running the contract code directly on the blockchain, the code is executed on some special off-chain entities called oracles which then send the result of the code to the blockchain network with a signature.
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How to import file with hardhat
I'm following the Alchemy tutorial to build an NFT Marketplace with hardhat. I want to import my smart contract which is an APIConsumer by Chainlink. I can't do it by path since I'm not allowed by ...
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How is consensus reached in a Decentralized Oracle Network?
I understand the deterministic nature of blockchains thus the need for oracles to feed outputs of non deterministic algorithms or API-calls to smart contracts. Using a single node oracle would defeat ...
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Current state of ETH Oracles?
Current state of ETH Oracles ? Code examples would be great.
My question is what would you use today for a random number function ? Or for a cron job like functionality ? Would you use it in ...
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Oracle recommendations for stablecoin project
Looking for an oracle to add to my stablecoin project. Want the essentials (decentralized, censorship-resistant, secure mechanics, no multi-sig to control everything).
Any ideas?
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How do I become a reporter for Tellor?
I want to become a reporter for Tellor, but not sure where to begin. Are there any guides or tutorials?
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Chainlink Any API: ETHABIEncode while parsing ABI string: bad ABI specification: unsupported arg type: Trade: bad input for task
I am trying to fetch data from an api which gives multiple response in single call and I am doing this using chainlink external API calls.
In my smart contract i have use array of struct to store ...
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How to get a tweet content using oracle in the smart contract to verify a user
I am trying to verify a user using his social media account. For this purpose, I am creating a registration function where a user needs to post his tweet with his existing EOA address.
How can I ...
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Whitelist and identity tracking of NFT holders
I am working on ERC1155 NFT collection and because of the regulation related to the project I am part of, we are required to allow only certain users to hold the NFT.
For that reason, I want to ...
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Using Chalink oracle for ethereum application
Is using any Offchain data like chainlink oracle is safe as far security is concerned for any ethereum application and how does ethereum ensures that is is safe to use them
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buildChainlinkRequest function of Chainlink is not working properly
The buildChainlinkRequest line no 47 takes 3 parameters:
JobId
Callback Address
Function to callback to
I have smartcontract1 and smartcontract2. The below mentioned function is inside ...
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Address to String in Chainlink Request is giving error?
When i am using
req.add("publicKey","any_public_key_here_as_string");
I have 2 steps mentioned in our job specification
decode_cbor [type=cborparse data="$(decode_log.data)&...
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How do I get an updated price from a Tellor oracle feed?
I'm new to Ethereum and trying to hack a project that uses tellor and I'd like to get a fresh update on an asset I don't currently see updated recently in the Tellor data feed. I guess I need to tip ...
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Please help me with this events error with HttpProvider
I have encountered this error while trying to put my oracle online. Please, help!
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Please can anyone help me in converting this from Loom to Ethereum testnet?
I am trying to deploy this on Ethereum Goerli instead of Loom but do not understand what all to change. I am getting a lot of errors. Please, can anyone help me?
Error Message
PS C:\Users\VidhanMangla\...
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How to specify return value of chainlink MockOracle
I want to test my smart contract locally using chainlink MockOracle how can i specify the returned value and the job Id ?
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Contracts design
I have a project where users deploy their own instances of a contract and those instances need off-chain data through chainlink oracle, what's the best between making the contract has its own request ...
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NFT Price should be set by the algorithm and not by the owner
Just like how the algorithm controls the videos on youtube and not the platform itself.
How can the price of NFT be set by the algorithm (from set of data that keeps changing).
The owner of NFT ...
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How to Implement off chain Keepers for Decentralize Perpetual Exchanges like GMX.io?
I'm attempting to clone gmx.io. I understand most of the on-chain and Dex concepts, but I'm stumped on how to establish an off-chain Keepers they did not opensource the code for that, so could you ...
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Why does chainlink price feed use 8 as decimal in USD pairs? [duplicate]
I am trying to implement Chainlink's price feed in my contract.
I've learned that when using the USD pair, it always uses 8 as the decimal.
I am curious as to why 8 is used instead of 18, is there a ...
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Calling Ethereum view functions from Polygon Smart contract?
Is there some sort of Polygon to Ethereum bridge product that allows you to write smart contracts which call view functions of smart contracts ddeployed on Ethereum Mainnet?
My smart contract looks at ...
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How to get ETH supply from smart contract?
knowing ETH supply from a contract have a lot of use cases in portfolio management. As far as i know there is no native way to query ETH supply from the contract. Is there any provable and trustless ...
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How does chainlink choose oracles to fullfill a request
I've read the Chainlink V1 whitepaper, and understand that the contract responsible for picking oracles to fullfill a request does SLA checks and selects from oracles that bid onto fullfilling a ...
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What is the motivation of data updaters in chainlink?
I wondered how chainlink works then I realized its price feeds like ETH/USD are updating periodically.
if I get it right, the nodes have to update data in most blockchains continuously, which costs a ...
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Error when calling already deployed contract: AttributeError: Final argument must be a dict of transaction parameters that includes a `from` field
I'm trying to create a contract that communicates with JIRA API through Chainlink Oracle on the Goerli Network.
The interaction should create a JIRA project, then write some of the returned JSON's ...
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Are there any good/safe use cases for uniswap time weighted average oracle?
Been studying up on uniswap logic, and the time weighted average oracle system. From what I know, on chain oracles have traditionally been susceptible to manipulation attacks, and generally in my mind ...
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How to make data processing out of blockchain?
Is it possible to send data out of chain, process it and feed into smart contract without using centralized services? My goal is to make data processing large data decentralize (without using web2).
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Who verifies first party oracles?
I have been reading up on API3 and if I am not mistaken one of their distinguishing features that sets it apart from Chain.Link is the idea of 1st party oracles. Which I understand to mean the owner ...
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How to Handle token prices for conversion ratio building a oracle contract
I am building a simple Oracle contract to provide conversion ratio to an other contract (a simple DEX), where conversion from token1 to token2 is fine since it equals to 10.
The problem is when ...
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How to fetch IPFS data on Polygon Smart contract?
On a project in solidity, on Polygon/Matic, I need to fetch data from IPFS.
So, an Oracle is mandatory, and I found 2 possible oracles:
Provable (old Oraclize) seems do not accept 2nd layer Polygon.
=&...
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What is the usual workflow among a user, a smart contract and an oracle?
Suppose a user A wants to feed a certain smart contract F with some data d that can be obtained from an oracle O.
What is the usual workflow in the most popular oracle solutions?
I imagine two ...
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How exactly does smart contract consumes data from oracles?
I believe smart contracts cannot make network calls, hence cannot call an external API to get data.
I have read that oracles are ways to provide outside data to smart contracts.
I am now confused on ...
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Chainlink Oracle - What events are emitted and which should i listen to for price updates?
I am looking for events which are emitted by Chainlink oracles when price updates occur. E.g. the Aggregator for ETH/USD price (https://etherscan.io/address/0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419) ...
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provable_query not sending output but no error as well
So, my goal is to achieve different fields, such as ToAccount, FromAccount from the json file loaded in IPFS. The below code snippet is to fetch the ToAccount details -
// SPDX-License-Identifier: MIT
...
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Is using Compound as oracle dangerous?
I'm really curious about this.
If I use Compound CToken function exchangeRateStored() as oracle for my project, is it dangerous? Can someone abuse that? Using flash loan to increase/decrease ...
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How to get the price of eth (in INR) in a smart contract?
I want to create a stablecoin like DAI, but instead of pegging to usd, I want to peg it to INR. The problem is I'm not able to find a chainlink pricefeed for ETH to INR.
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how does one secure one's key when writing an oracle?
I'm looking to write an oracle that will interact with the blockchain in the following way.
Client submit a withdrawal request on the contract
The Oracle will pick up that request, check the balance ...
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Contract function only works on array with one item
I have created a contract to loop over an array of token addresses and call the 1inch oracle. It only works when the token array is of length 1. Have been testing on remix.
when inputting the token ...
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What is the recommended waiting time between requestRandomWords and fulfillRandomWords calls in Chainlink VRF V2?
Recently, Chainlink published their VRF v2. The new VRF uses subscription management app. There is a delay between the requestRandomWords and fulfillRandomWords function.
On the Goerli test net, ...
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What does DON stand for?
to give a bit of context, I'm trying to follow a conversation about possible ways to do off chain voting for a DAO, and the acronym "DON" keeps being mentioned. Thanks!
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Oracle for fed funds rate?
My USD stablecoin contract needs to know the fed funds rate in order to determine what its interest rate should be. Is there an oracle data feed available for the fed funds rate anywhere?
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Fetch Transaction Data/Block Data on Solidity
is there a method to call web3.eth.getTransaction or web3.eth.getBlock on Solidity? Or is there an oracle that allows to do so?
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Off-chain Bank Payments & oracles
hey fellow solidity devs !
i am working on a DAO right now and one of the requirements is that members pay the DAO with fiat money off-chain (using traditional banks).
i obviously want to log that ...
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How do Chainlink Oracles make money?
been researching this for a while. It is my understanding that the job market on Chainlink website, offers jobs for a small fee (in the range of 0.1 LINK). But I also know that according the ...
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Chainlink Keepers UpkeepRegistrationRequest Contract
Alright I was going through the keepers contract to understand how it works from a contract perspective.
There are two parameters that I don't understand what they're used for in the register function ...
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ChainlinkClient FetchFromArray fails to fetch price
Loading the fetch code from documentation:
https://docs.chain.link/docs/api-array-response/
This particular example fetched string id from that endpoint, works fine...
If instead of fetching the ...
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I am following a documentation where the function will fetch BAYC (NFT) address but the function is not working as per the guidelines?
Link of the documentation https://market.link/nodes/NFTBank/integrations
function getFloorPrice is expected to give the floor price after passing the input but it ain't returning anything
The code in ...
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Impementing AggregatorV3Interface into the contract throws Error: cannot estimate gas
I have a working contract deployed on rinkeby, I'm trying to add there a function to get the current ETH/USD price using ChainLink's AggregatorV3Interface .
When testing the needed function in Remix, (...
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How to fetch the BAYC NFT Price from chailnlink or any other method?
I want to fetch BAYC NFT price using oracle. I have checked chainlink but didn't found any solutions.
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How to we fetch price of NFT index using chainlink
i was wondering if we can fetch the price of different NFT index using chainlink price oracle, i had done the same earlier to find the pricefeed for ETH to USD , now i want same for NFT collection.
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How does Chainlink deal with faulty/malicious nodes?
I am trying to understand how chainlink, or any oracle solution for that matter, can deal with a node not providing accurate data. How would you detect that the data is faulty to begin with, and how ...
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