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1answer
180 views

How to unlock account to deploy contract without using personal.unlockAccount()?

When I have account keystore file on geth node http://192.168.43.201:8545 , I can deploy a contract like below: const web3 = new Web3('http://192.168.43.201:8545'); ... const contract = new web3.eth....
3
votes
1answer
243 views

call graphs for solidity smart contracts

Do we have some open source tools where we can get call graphs for solidity smart contracts execution ? For ex: Suppose Function A in contract C calls some other function B so the graph should contain ...
0
votes
2answers
43 views

Script For Emptying Address

Does anyone have a script that can be used to transfer all ether found in an address to another address? The script will constantly check for any incoming ether and make an automatic transaction, ...
1
vote
2answers
4k views

Which wallets support a multi signature transaction?

I have an address with some coins and I want to set it up as a multi-signature wallet using 2 of 3. Which wallets support this feature and is there a good tutorial for this? I want to to split control ...
1
vote
1answer
317 views

Ethereum Solidity smart contract code Input Output Testing

I have written a solidity based smart contract. I need to test the code on web browser and mobile app. Please suggest the steps what I should do to test and execute the code on - Web browser:- I am ...
0
votes
0answers
23 views

Uniswap Factory contract event - how to find addresses for new token pair

When creating a new pair on Uniswap, Uniswap emits a PairCreated event that details which tokens are invovled. However, it sorts the token like this in the factory contract: (address token0, ...
1
vote
2answers
22 views

medalla testnet launchpad requires metamask or similar

Following the official Medalla launchpad at https://medalla.launchpad.ethereum.org, at some point you need to connect to a wallet and the only options are MetaMask, Portis and Fortmatic. Why is this ...
0
votes
1answer
250 views

Opcode for out of gas inside a message call

According to the Solidity documentation: A require-style exception is generated in the following situations: ... If you call a function via a message call but it does not finish properly (i.e. ...
1
vote
1answer
12 views

when uncle block info is recorded into blockchain irreversibly?

I want to confirm that what time is proper for checking there is uncle block or not. I know that eth_getUncleCountByBlockNumber returns # of uncle blocks at a block number. (max is 2) But when ...
0
votes
0answers
8 views

Abigen doesn't create free data retrieval call for public state variable

I'm looking at an example contract using go-ethereum. In the book, when a go file is created in Store.sol through abigen, the code that automatically gets the Version() string is generated. However, ...
1
vote
5answers
282 views

mapping one id to multiple addresses

Suppose I have a product with a specific id for sale(so I am the owner) and someone wants to buy the product from me. When he pays the price he will become the new owner of that product. How can I ...
1
vote
1answer
35 views

Node version upgrade for contract deployment throws error

I wrote a solidity contract using version 0.4.24 using OpenZeppline-solidity version 1.12.0. This used to deploy using the Nodejs version 8.12. The Nodejs version 8 is no longer being maintained from ...
1
vote
3answers
206 views

Help with signTransaction

i need help com many parameters for sign a transaction. What is "nonce"? How i calculte gas value? How i calculate gasPrice? what is data field? Chain ID 1 is a Mainnet? I will using infura. $...
0
votes
1answer
200 views

truffle deploy --network ropsten issues

I am having an issue deploying to ropsten. I am receiving an insufficient funds error but I believe my address to have ether on ropsten. This command: truffle migrations --network ropsten Also ...
1
vote
1answer
41 views

How to fix Solidity version missmatch from Visual Studio Code

So I have install the Solidity extension for Visual Studio. V0.0.76 https://github.com/juanfranblanco/vscode-solidity And when I start my Solidity code with pragma solidity ^0.5.0; I get the ...
1
vote
1answer
45 views

How to print the value of encoded getter functions of contract

UPDATED: Sorry for Inconvenience, I have updated all my question and accept my apology , being naive user. I have encoded getter functions of my contract i.e. ...
1
vote
1answer
223 views

Calling onlyowner functions using owner's private key

I need to call a function with onlyOwner modifier in my smart contract via web3.js. I want a user of my site to be able to send their information to a white list, but it sends the transaction from ...
1
vote
0answers
16 views

What is the criteria to resync chain using proof of stake?

In PoW, nodes always resync their own chain to the longest chain in the network in order to respect the work the miners have done. In PoS, as I understand in its simplest form, the miner with the ...
2
votes
3answers
553 views

How do I send a transaction using web3.py and Infura?

I am using Infura to interact with the Ropsten testnet. I would like to send a transaction from one account to another, but the following code does not work: w3 = Web3(Web3.HTTPProvider('InfuraUrl')) ...
0
votes
1answer
141 views
1
vote
1answer
67 views

Where does parity look when trying to import geth keystore files

I'm in the directory for parity keystore files, namely, ~/.local/share/io.parity.ethereum/keys/ and I've run: parity --import-geth-keys But I get an error saying: Failed to find geth keys ...
0
votes
1answer
29 views

When and where do I set ERC721 tokens' data?

I am currently working on a smart contract to sell ERC721 tokens. I understand that my code should have a function that allows me (the owner) to mint a token and add it to a list which stores all the ...
1
vote
1answer
521 views

Latest Zeppelin SampleCrowdsale.sol token moved outside of contract?

Really new to Solidity, but I was following this guide: https://blog.zeppelin.solutions/how-to-create-token-and-initial-coin-offering-contracts-using-truffle-openzeppelin-1b7a5dae99b6 Only, I used ...
0
votes
1answer
341 views

How increase mining speed in AWS instance?

I have setup a private blockchain in AWS micro instance using go-ethereum. In that when I start the mining process it was taking nearly 2-3 hours to mine a new block.Whereas on my local machine it was ...
0
votes
1answer
264 views

Upload a full directory to IPFS using ipfs (js-ipfs-http-client)

I want to upload a directory to ipfs on my browser using (js-ipfs-http-client) module. I found this old issue. https://github.com/ipfs/js-ipfs/issues/277 So I decided to use recursive way to add files ...
0
votes
1answer
17 views

Ethereum vs bitcoin technology [closed]

I have understood how bitcoin works (coinbase block, mining, links between transactions, hashrate, nounce, proof of work, ...) Now i want to understand how Ethereum works. Can we say it is the same ...
0
votes
1answer
13 views

Remix Error - Trying to Follow Ropsten Faucet Instructions

I have been trying to get testnet Ethereum from Ropsten using Metamask wallet but instead I am getting errors. What am I doing wrong? Here is what the Ropsten Faucet site said and the error on Remix ...
4
votes
1answer
203 views

How to use BTCRelay for my ICO to get funds in BTC?

I want my ICO get investment in BTC also ,When i browse over internet I came up with BTCRelay concept . I tried to read their docs but it make me confused .Anybody give me a simple way to use BTC ...
0
votes
1answer
36 views

ETH not showing up

To help me get started learning how to create contracts, I had 1 ETH sent from the Ropsten Ethereum Faucet to my MetaMask address. It arrived fine, but when I tried to send it to MyCrypto address it ...
0
votes
1answer
13 views

Pull metadata from ERC721 contracts

what tools/services would you recommend for pulling metadata from ERC721 contracts? It seems like it's going to be a huge hassle to return the metadata directly from the blockchain. Any clever ideas?
0
votes
0answers
27 views

Problem with State Variable

I'm new to solidity development. I am trying to make a smart contract with the logic, Accept a specified amount of ether/wei Change the State Variable Get the secret data once the condition is ...
2
votes
1answer
272 views

Why would Ganache behave differently depending on geth, web3j, web3js and web3.py?

I have a smart contract token deployed in a Ganache instance. My dapp written with React and web3.js shows the same 10 accounts for eth.accounts as running the same command in the geth console. If I ...
0
votes
1answer
307 views

How to set allowUnlimitedContractSize in Ganache V2.1.0 with windows 10

while following this or this solution I found nowhere any file to make change for allowUnlimitedContractSize = true so my problem is same as in link but how I can change this in Ganache v 2.1.0
0
votes
2answers
44 views

Does ASIC miner works in ETH and ETC

I want to buy an ASIC Miner (A10 Pro 6GB) but i have some doubts. Is it good to buy an ASIC Miner in Nov. 2020 for ETH and ETC mining ? Recently I heard that the mining algorithm for ETC is changing ...
0
votes
0answers
17 views

REVERT opcode executed after call payable function in shasta test network [closed]

Im new in solidity, after call payable function, views function get REVERT opcode executed error in tronide but in ethereum ide It works properly, what could be the problem?
0
votes
0answers
20 views

Remix Compiler Errors - Transferred GitHub .SOL Codes to Remix

I transferred all 23 Sol extension files (smart contracts for Syscoin and Ether) from GitHub to Remix but only 3 of them can be compiled and deployed. The rest of them show errors. [Here is the link ...
0
votes
1answer
196 views

Cannot Find Module Error for Truffle-contract

Error:- Uncaught Error: Cannot find module './truffle-contract.min.js' at c (web3.min.js:1) at c (web3.min.js:1) at index.html:27 <!DOCTYPE html> <html lang="en"> <head&...
2
votes
1answer
38 views

Is there a way to verify transactions afterwards they are entered in the ethereum blockchain?

Suppose I sent a signed transaction using the web3.js library. But, I might be using some third party API like an Infura node or others. So there are chances of attacks and data manipulation. So, is ...
1
vote
0answers
160 views

Unable to set web3.eth.defaultAccount

i'm trying to set the web3.eth.defaultAccount with web3js 0.20.5. Somehow setting the default account like this.web3.eth.defaultAccount = this.web3.eth.accounts[0] does not work. Error message: this....
1
vote
1answer
316 views

Geth: pipe is being closed (if Mist is up)

When I run Geth it seems to work fine: "C:\users\john\appdata\roaming\mist\binaries\geth\unpacked\geth.exe" --datadir=h:\Backup\Wallets\eth_real_data --syncmode="light" Then I start Mist (both ...
1
vote
1answer
324 views

all web3 call methods returns null

I create my contract with the following code: pragma solidity ^0.5.0; contract Coin { function sayHello() public view returns(bytes32) { return "Hello"; } } truffle-config: module....
16
votes
3answers
16k views

how to compare strings in solidity?

pragma solidity ^0.4.11; contract test2 { address creater; string username; string password; function testusernamepassword(string username,string password) returns (bool) { ...
0
votes
0answers
18 views

Looking for experienced eth dev to work with [closed]

Looking for a eth dev with experience to work with on forking sushiswap message if youre interested
0
votes
1answer
32 views

Spread operator params for web3 call - gives “uncallable iterator” error [closed]

Using web3.js to send a transaction I need to input the params to be sent to the contract. The contract takes params in this order - string memory _name, string memory _symbol, string memory _url, ...
1
vote
1answer
37 views

Head of blockchain fall back to 0 after unsafe shutdown, how to reset it to the latest?

System information Geth version: 1.8.27 OS & Version: Linux Docker version: 18.09.0 Background gcmode is full, syncmode is fast. Single node in private network. datadir mount to docker volume. ...
1
vote
1answer
145 views

How to decode InputValue of ethereum using java web3j

**I'm trying to decode the inputValue of an transaction using web3j without using any contract abi and wrapper class,Im loading the contract using its contract address ,is there any way/inbuilt ...
2
votes
2answers
21 views

Is Chainlink's price reference data free to consume?

I was looking at feeds.chain.link and it's not immediately obvious if anyone can tap into all these price feeds without incurring a cost: For instance, I did find the ETH/USD aggregator contract, ...
0
votes
0answers
15 views

Could there be multiple asset pools In a DAMM liquidity pool?

In a DAMM (dynamic automated market making) DEX (decentralized exchange) the ration between two assets, e.g. DAI/ETH does not have to be 50/50 anymore, like it used to be in a AMM, (automated market ...
1
vote
2answers
77 views

Supply gas from contract to execution of function

let's say I have something like this function usuallyCheapFunction() external { ... do something cheap... if(rareCondition == true) { expensiveCleanupFunction(); } } function ...
1
vote
2answers
19 views

Why do I pay fee for reading transaction on Ropsten?

I have a doubt. I am using truffle with meta mask to deploy Smart Contract, write transaction and read transaction on Blockchain. Why do I pay fee for reading data on BlockChain? Should it be free? I ...

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