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file to byte array problem

Converting a file to a byte array to be stored as bytes[] in solidity I am able to convert the file using the following function, but when I send it to my smart contract I get error "TypeError: ...
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0answers
4 views

How is Chainlink decentralized?

I believe one of the main criticisms of chainlink is that it is not decentralized enough, adding more nodes would be a big step in a positive direction. When I pull data through a node, that node ...
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0answers
7 views

If I have several wallets with the same address, how to deal with nonces?

I access Ethereum from several wallets. Some of the addresses are present in several wallets at once. I discovered that nonces should always increase. (Right?) Then if I send transactions from several ...
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0answers
5 views

Peers attempting to connect to ports on my machine other than those used by geth

I have a geth node running on a linux machine, and have set up a firewall (UFW) to allow all outgoing connections, but inbound connections to 30303/udp and 30303/tcp only. I'm noticing in my system ...
0
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1answer
13 views

Error: Returned error: VM Exception while processing transaction: revert when using methods.MyMethods.Send

I am writing a simple betting application that will return double the ether deposited by the player, provided they guess correctly the random number generated by the virtual slot machine. it works ...
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0answers
8 views

Error: No Keyring found for the requested account

I am an student and in this moment practicing how to create a simple smart contract in remix.ethereum.org. I got compiled the small program with function get without problem. When I deploy the program ...
1
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1answer
17 views

Smart Contract Application in ASP>NET

I just have started to learn Smart Contract. I have to design front end in ASP.NET. Can I call Contract from it?
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1answer
14 views

Convert FIAT currency to ERC20 token

I want to create a crypto currency (ERC20 token) with truffle or solidity. Basically, i want to sell digital product that can cost as example 10$. I want to convert that 10$ into my currency (ERC20 ...
0
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1answer
11 views

Functions that are used for token transfers for ERC20 and ERC721 tokens

Let's suppose there is a contract address A of an erc721 token B. If I want to monitor all of its transfers from A to another address say C then should I only filter the Transfer function or should I ...
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0answers
12 views

When would one want to use a linked library?

My understanding is that if a smart contract consumes a library that only has internal functions, then the compiler will embed the library into the contract bytecode. At the lowest level, there is no ...
1
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1answer
17 views

The send transactions “from” field must be defined using Infura web3

when I try to send my transaction using infura I get this error "The send transactions "from" field must be defined" My problem is my web3 object. When I used Metamask and ...
1
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1answer
12 views

Web3 js and frontend frameworks

Will i need a front end framework like React, while using web3 to build Decentralized Applications?
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0answers
12 views

ERR_SSL_PROTOCOL_ERROR while connecting private blockchain

I'm working with private blockchain, and facing some issue with SSL configuration. The system has two components: The private blockchain that is configured on the VM. The web application that ...
0
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1answer
14 views

How can I prove my friend having changed just one word in the seed and have it lay around is super insecure?

My friend said to me that he has his seed saved in Google Drive and that he is absolutely safe even if someone found it out. He even gave me his seed to try to break it. I know that all I have to do ...
0
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1answer
16 views

How to withdraw Other ERC20 tokens besides Ethereum from my contract

I'm trying to implement something like this (which works) function withdraw() public { msg.sender.transfer(address(this).balance) } but I need to be able to withdraw ERC20 tokens other than ...
0
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0answers
13 views

Validating transactions with ZK methods

After reading some topics on the implementation of ZK methods in the Ethereum, how would this affect the PoW? Please have someone correct me if I am wrong (I started recently), but if the nodes need ...
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0answers
11 views

Runtime error - ganache_local network error

I can connect to web3. I am able to send ETH to another account using truffle develop and the sent ETH shows on my metamask account. I have installed truffle-hdWalletProvider as well Whenever I use ...
0
votes
1answer
11 views

Parameters on evm opcode create

Why the usual way to create a contract with evm opcodes use add and mload, for example: bytes memory bytecode = hex"600580600c6000396000b800602a600052b8"; ... assembly { _address := ...
0
votes
1answer
10 views

How do I get a list of tokens held by an Etehereum address?

TL;DR: wanted: a method that receives an address as a parameter and returns an array of token names/contracts/balances held by address. I'm aware of the fact that Etherscan API has a method allowing ...
0
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1answer
15 views

Cold wallets & dapps

I am new to ethereum and curious about interacting with dApps while keeping a private key in cold storage. I like the idea of keeping the private key for an Ethereum wallet on an air-gapped computer. ...
0
votes
1answer
19 views

Status is Successful but got internal transaction out of gas?

I call a function with the transaction like this https://ropsten.etherscan.io/tx/0x7d4dec3c0db2b700efae63ef3ffb5a33fc2335bd992fd37c48aa10560eb8156e this fuction is a call from other contract,I wrote ...
1
vote
1answer
20 views

How to deploy Smart Contract on Ethereum 2.0

I want to know how to deploy Smart Contract on Ethereum 2 Testnet using web3 ?
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0answers
10 views

Snapshot syncing proceeds but block number is still zero

I use OpenEthereum(v3.0.0) on warp sync. OS is ubuntu server 20.04. But its snapshot syncing is proceeding but block number is still zero(#0). Please see the following image. Is this proper condition?...
2
votes
1answer
15 views

When MetaMask removes the Cancel button for a transaction?

When I start a transaction, MetaMask shows it with Cancel button. When does this Cancel button disappear? Maybe after one confirmation? After N (what is N?) confirmations?
0
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2answers
18 views

web3js getPastLogs function returns error: query returned more than 10000 results

I have a local ethereum node and I am trying to filter an event for a contract address between a range of blocks. However it throws the following error: node:15689) UnhandledPromiseRejectionWarning: ...
-1
votes
1answer
18 views

i can't figure out why i keep getting this parser error

pragma solidity ^0.5.13; contract WorkingWithVariables { uint256 public myUint function setMyUint(uint_myUint) public { myUint = _myUint; } bool public mybool; ...
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0answers
22 views

How to know when a transaction is finished? (web3.js)

I make a contract method call using .send() method: contractInstance.methods.pay(itemId).send({from: defaultAccount, value: web3.utils.toWei(String(price*1.0000001)), gas: '1000000'}, ...
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0answers
12 views

How can I automize process of deploying my contract?

I am using following appoach How to deploy Ethereum Smart Contract through Brownie to the Private Network. I want to automate this process in order to capture the transaction hash and deployed ...
0
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0answers
12 views

Migrate from parity to geth

How do I migrate full node from PARITY to GETH ? So the easy part to tun geth I know, but How do i move all the keys from parity to geth? I've tried to copy the keystore folder from parity to geth, ...
0
votes
1answer
18 views

How to call “payable function” via interface in solidity

I have a function marked as payable in contract A and I want to call it from contract B so that msg.value in contract A can have its desired value and contract A must have balance of sent amount , how ...
0
votes
1answer
25 views

I have a Transaction Hash, how to get the readable Input Data?

i have a Transaction Hash: 0x9f46760404dd3075533e8360fe4beb0ba7210423af1f4a95a5c80defffe824b5, for how do i decode the "input data" easily? for example: https://www.blockchain.com/eth/tx/...
0
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0answers
27 views

How do I get the available reserve size for a given token on Kyber and Uniswap(V2)

I am doing arbitration with some measure of success; but I suspect I am running into edge cases where the available reserve size is less than what I am trying to buy or sell. Something like this: ...
0
votes
1answer
14 views

Deploying contract with web3. Two different methods fail

I tried this method to deploy a contract. It is described in the web3.eth.Contract documentation. var contract = new web3.eth.Contract (JSON.parse (abi_json_string)); contract.deploy ({ data: ...
0
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1answer
28 views

Is it possible to create a frontend web app that connect to an Ethereum contract for read only without users having to have metamask?

I would like to create a web front end with as less friction as possible for new users. The app would be a kind of explorer with all calls to blockchain as read only to getter functions. So is there a ...
1
vote
0answers
23 views

Txpool not receiving any new pending transactions

This seems to happen randomly during an influx of new transactions. I am running a node with high txpool limits. --txpool.globalslots 1000000 --txpool.accountslots 128 --txpool.accountqueue 512 --...
-2
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0answers
35 views

how i specify sender address in ethereum

In our project we have a group of users in Ethereum who can write on the blockchain network In other words, we have a group of users who have addresses in Ethereum who want to keep their data in the ...
0
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0answers
27 views

Error while calling a erc721 contract funciton using go-language

I am trying to call a function which is "mintUniqueTokenTo(address,uint256,string)" in a ERC721 token using go language , but for some reason it is failing. I think one reason could be that ...
0
votes
1answer
40 views

how create address for each ethereum user

I have a group of Ethereum users how do I create an address for each user to send their data on the network?? I want a way to create addresses for each user??
2
votes
1answer
92 views

Efficient, safe pow using EXP opcode

I recently stumbled across ds-math's rpow() being a O(lg n) safe implementation of exponentiation. Such a function is ultimately created because the EVM EXP opcode is unsafe wrt. overflows. The ...
0
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0answers
15 views

How to write contract on Etherscan

I've $15 in one wallet and $2 in another. I've used smart contract to transfer the funds. Now, the problem is that - on Etherscan, there's "Write Contract" method and under that - cast ...
0
votes
0answers
19 views

My Crowdsale contract wont transfer ERC20 tokens and all transactions fail

I have a crowdsale contract that recieves tokens directly from a mint function in my token contract.the function mints the tokens and sends its to the Crowdsale account address. when I run let token = ...
2
votes
1answer
29 views

How to get all the historical data from chainlink price feeds?

I wanted to pull the historical data stored by the reference data contracts by chainlink oracles. Since all the data is on-chain, I should be able to view it all? But currently, my contract can only ...
0
votes
1answer
30 views

Deleting an array in storage (>= 0.6.0)

I need to add elements to a resizable myArray and then delete the myArray. I don't know what the length of myArray will be before the loop, and it's not possible to resize a memory array; that leaves ...
0
votes
0answers
28 views

Problem with Assert.equal

I am compiling the code available at using "truffle test": https://michalzalecki.com/ethereum-test-driven-introduction-to-solidity/ pragma solidity 0.5.16; import "truffle/Assert.sol&...
1
vote
1answer
17 views

Infura getFilterLogs api returns empty array

I am trying to filter transfer events using node.js for a contract address between a range of blocks. I am trying to filter the latest 7 transactions which can be shown in etherscan here. My code is ...
0
votes
1answer
30 views

Proxy calls are all reverting in test suite despite implementation being set and initialised

I am currently writing an upgradable contract using the unstructured data proxy model and an ERC20 token implementation (similar to USDC). This means the traditional approach of sending a transaction ...
0
votes
0answers
17 views

Distributing interest to a set amount of tokens

Consider a contract which manages an unlimited amount of ERC20 tokens. A user can create a token via this contract and give it a name. The contract also acts as exchange for buying and selling tokens ...
0
votes
0answers
34 views

Weird error during buy tokens with eth on ropsten and other testnets

I get this error when executing swap token for ether on arb detection. Error Message: execution reverted (uint reserve0, uint reserve1,) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves()...
0
votes
0answers
12 views

Blockchain interoperability

i hope that you are doing well! I wanna build an Blockchain interoperability approach based on side chain and i don't know how to start, so if someone can help me please don't hesitate to text me i ...
1
vote
1answer
27 views

Mapping vs Arrays: duplicating variables gas consumption

I have a contract that has a struct including address and unit, and mapping of a struct, like this. struct User { uint count; address userAddress; } mapping (address => User) users; ...

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