All Questions

0
votes
0answers
2 views

rlp: cannot encode negative *big.Int

i use the go-eth p2p mode to develop a p2p net, i send a message with negative big int, the erorr occur rlp can not decode the negative big int, there are some way to solue
0
votes
0answers
3 views

I'm getting an error while deploying project

the error saying that could not find required file index.html in the location what it shows, but the file index.html is available in that location which it shows
0
votes
1answer
6 views

Accounts not getting the balance right

I'm trying to get the balance of a set of accounts using Parity RPC and web3.eth.getBalance. The problem is that, some accounts are returning 0 even though they have balance. For instance: https://...
0
votes
0answers
12 views

ETH send to contract fails, probably fallback() function fails to call

I deployed the following piece of contract on testnet and everything works fine.But, when I send test ETH for the contract address, transaction fails. I tried with higher gas as well but failed as ...
1
vote
1answer
6 views

How to update the balance of a wallet user when there are two competing chains?

I am building a wallet, and I have a question about uncle blocks. Let’s say our user sends a transaction, but there are two competing blockchains. If they both include her transaction, no problem. We ...
0
votes
1answer
8 views

How do I get the transaction fee used by a transaction in web3py

I am using web3py to do transactions for token and ether. Now I need to keep a track of transaction fee applied for each transcation. How can I get the transaction fee from transaction hash?
1
vote
1answer
11 views

I am trying to build a land registry of land titles on the blockchain,

Good Day. I am trying to build a land registry of land titles on the blockchain, with the intention of being able to sell such title to someone else. Therefore, the title eventually has to be ...
0
votes
0answers
14 views

Store data on ethereum block chain using react js

I'm trying to store data on ethereum blockchain by doing this import storemetadata from "./storemetadata"; where i have the smart contract ABI in storemetadata I now add name like so storemetadata....
0
votes
0answers
5 views

Could we set the transaction cost for private blockchain?

I have set up a private blockchain for group of nodes.My question is whether i can set the transaction cost in my private blockchain in-order to avoid span transaction?
3
votes
2answers
245 views

How to create a paid keyvalue store

I'd like to create a contract through which people can set publicly available key=value information in exchange for some Ether sent to me (the owner of the contract). This is to create a public ...
1
vote
0answers
8 views

How to use the 'evm' command of go-ethereum?

I'm just engaging in geth development and was trying to put some changes into evm opcode implementation(functions like opAdd) for debugging. After compilation done, I found that there is a command '...
0
votes
0answers
13 views

Ethereum node vs Ethereum accounts

From my understanding, one Ethereum node can have many accounts and only one of the account can perform mining in each node. So, my question will be what are the usage of other accounts in the node ...
0
votes
0answers
8 views

How to compile the solidity source code for getting the soljson.js file?

Solidity's reposite: https://github.com/ethereum/solidity; I want convert the cpp code to javascript using emscripten. But I don't know whether there is a script in above reposite, if yes, how could I ...
0
votes
1answer
11 views

How to push new struct to storage?

I get an error when trying to push the newRound struct to storage. How can it be fixed? Error: UnimplementedFeatureError: Copying of type struct Lottery.Ticket memory[] memory to storage not yet ...
0
votes
0answers
8 views

Error when calling Ethereum Contract

I am using a JS library which calls Solidity functions and I been getting the following error: 0x0c444aa3066f98d5f7ee576401e7729cb1113fe288d38711a78e48836313e88c App.js:112 TypeError: createLog is ...
1
vote
1answer
9 views

How to test a function call that should fail?

Im using Truffle to test my smart contracts written in Solidity and I would like to mark test as passed if function call/execution fails. Example: await instance.cancelOrder({from: accounts[1]}); ...
0
votes
0answers
12 views

Infura V3 spec cannot find Project Id

I used to use the old version of infura and it worked just fine. The latest version is not working as it states that it cannot find the id despite it being there. https://mainnet.infura.io/v3/...
0
votes
2answers
19 views

timed transactions using web3-1.0

I am creating a dapp using web3-1.0. I have a contract that stores personal data for a particular user(account). I want to implement a functionality so that a user can share his data (stored in the ...
0
votes
0answers
14 views

using web3 1.0 for approving signed transaction by another account before appending to the blockchain

I am making a dapp using web3 1.0. I want to send a transaction from one account which contains some data and I want it to be stored in a specific smart contract only when the other account has ...
2
votes
0answers
20 views

Node Discovery Protocol - Node Table entries

I am currently trying to understand the node discovery protocol in ethereum. I found a few docs, where one of it is: https://github.com/ethereum/devp2p/blob/master/discv4.md It says, that the ...
0
votes
2answers
13 views

Verify transfered amount of two transactions from same ERC20 to same Contract

I making a contract to sell stuff in a decentralized way and want to use following method to transfer founds. function transferToken(address token, address from, uint256 amount) internal { IERC20 ...
2
votes
1answer
16 views

How to handle require/revert/assert errors properly

I'm trying to find an easy pattern to revert/rollback a write transaction. The first idea was to log a GenericErrorEvent but then I noticed that it will never be emited if any require/revert/assert ...
0
votes
1answer
26 views

Out of gas error while receiving tokens

I have an issue: I want to receive some BOKKY tokens to test it. When I use simple wallets I just send ethers and receive tokens, everything works fine. I also have my own smart contract (multisig ...
0
votes
0answers
14 views

prompt for metamask unlock

Is there a way to automatically open metamask unlock prompt ? Since I am able to detect metamask is available, instead of redirecting user to unlock.html I would prefer to try automatically prompt ...
0
votes
0answers
20 views

Strange behavior of solidity program

After a long debugging I found that I had two following problems in a private ethereum network using geth: If I have a require statement then the code is not executed on the EVM. The solution I found ...
0
votes
1answer
16 views

How to catch error thrown by require in node.js

I have a solidity function with only one statement i.e., require(). My logic is if that function throws error then the data is invalid otherwise valid. But that error is not caught in err parameter of ...
0
votes
1answer
18 views

Emit not firing event more than once

I'm experimenting a little bit with the blockchain, I'm currently trying to send from an oracle an address to store on the blockchain through a smart contract. The code (very simple and without checks)...
1
vote
2answers
9 views

How estimate smart contract deployment and transactions price?

I can deploy the same smart contract and invoking four transactions on it on Ropsten network. How can I estimate the price of the exactly same operations but on the Mainnet network?
1
vote
0answers
16 views

One-to-many mapping inside struct

I have two structs: struct A{ uint bid; mapping(uint => B[]) BMap; //bid - index for struct B } struct B{ uint cid; } mapping(uint => A[]) AMap; How can we push and fetch 'cid' ...
0
votes
0answers
21 views

Ganache-cli EADDRINUSE 127.0.0.1:8545 error?

when i start ganache-cli with command, it gives this error : ❯ ganache-cli Ganache CLI v6.4.1 (ganache-core: 2.5.3) Error: listen EADDRINUSE 127.0.0.1:8545 at Server.setupListenHandle [as ...
1
vote
0answers
23 views

HDWalletProvider & truffleconfig: 'truffle migrate' will compile but not do anything else

I am trying to build a React app with Truffle. Firstly, my file structure is like so, with root_dir being the project root directory: root_dir/node_modules/src/libs/truffle All of truffle's files, ...
1
vote
1answer
13 views

web3js recover returns different address than what signed message

Web3js as of version 1.0.0 beta supports an interface for verifying signed messages: https://github.com/ethereum/web3.js/issues/404 This is documented here: https://web3js.readthedocs.io/en/1.0/web3-...
0
votes
2answers
20 views

Calling an address array in web3 returns an error that the method needs arguments

I'm declaring a public address array in my contract, but when I call it, I get an error saying it's expecting an argument. Can someone shine a light on what is happening here? Contract.sol uint ...
0
votes
0answers
27 views

Error: Invalid bytes string given: 0x

Contract code: function getAddressDnaIds(address owner) external view returns(uint256[]) { return addressDnaIds[owner]; } Code causing the error: var dna = await this.airdrop.methods....
1
vote
1answer
28 views

How to get the value of the transaction?

I am using web3.py but I need help to know the value of the transaction sent. I know that the information is stored in the input but how do I parse the string. I know nothing about ABI. Here is the ...
1
vote
1answer
9 views

Truffle compile fails: could not find file from any sources

I'm following the steps of this tutorial. I created a simple contract, TodoList.sol pragma solidity ^0.5.0; contract TodoList { uint public taskCount = 0; } Then I run truffle compile and get ...
0
votes
1answer
9 views

Mobile android app that can import a Metamask private key?

I'm having some issues sending out from metamask and getting failed transactions. I think maybe I should use another app on android if possible. What android wallet apps can import a Metamask private ...
0
votes
1answer
10 views

Metamask Failed transaction when sending out BAT tokens

I've been trying to send some BAT tokens out of my metamask wallet for quite awhile and it keeps eating up all my eth gas fees. I even increased the gwei fee to 100 and paid .50 USD as the fee. And it ...
0
votes
0answers
12 views

Trying to load js file in Geth console, but I get “Error: could not decrypt key with given passphrase”

I'm trying to load a javascript file into my geth console: > personal.unlockAccount("0x527239d79ef1f8d8e2696d2651d01969ce9a6876",null) Unlock account 0x527239d79ef1f8d8e2696d2651d01969ce9a6876 ...
0
votes
0answers
8 views

TypeError: Member “equal” not found or not visible after argument-dependent lookup in type(library Assert)

Truffle v5.0.8 (core: 5.0.8) Solidity v0.5.0 (solc-js) Node v10.13.0 Web3.js v1.0.0-beta.37 Assert.equal worked in Truffle 4.x. pragma solidity >=0.4.21 <0.6.0; import "truffle/Assert.sol"; ...
0
votes
0answers
4 views

Which kind of error does LOG15 in Ethereum-geth client is about? i always encounter it when When unmarshalling msg.data()

I marshal a struct locally, and then send the marshaled data to ethereum geth client. But when i unmarshal it in geth , i always meet a log15 error. I have explored it for a long time, but didn't ...
1
vote
0answers
12 views

Adding additional info for initial state of Drizzle

How do I add extra content to the initial state of drizzle? I want to keep some local information that is not dependant on the blockchain. Should I keep a seperate redux store for that or is there a ...
1
vote
0answers
26 views

How to send Custom tokens ERC20 fromWallet - ethers.js

I have tried this solution and it worked but only if I use privateKey of the wallet which I used to create custom tokens but what if I want to send from B wallet to C wallet and when I am trying it, ...
1
vote
1answer
16 views

How to add an address for which I have the corresponding private key into MEW?

I'm quite new to Ethereum, so, pls, forgive me if I say something wrong. How can I see the balance of one already existing address, for which I have the corresponding private key, in MyEthereumWallet?...
1
vote
1answer
30 views

Issue getting Metamask account using Web3 1.1.0

I am working on a React app which uses a library that has Web3 as a dependency. I had previously been able to the get the current Metamask address with the following code: const injectedWeb3 = ...
0
votes
1answer
14 views

Can't see the source code with the new Etherscan user interface?

everyone! A few days ago, Etherscan has updated their user interface - and now I have no idea, how to get the verified contract's source. Before it was located no the #readContract tab, but now there'...
0
votes
1answer
25 views

Accounts created by using web3.eth.accounts.create() don't appear when web3.eth.getAccounts(console.log)

I am new to Ethereum. I am running a geth devnode. Installed web3. Used web3.eth.accounts.create function to create one account without any entropy and created another account by using the same ...
1
vote
2answers
43 views

How to check if the address is an ERC20 contract?

edit) VM execution error was a bug on Web3, confirmed my code works fine. I am trying to fetch random addresses from blockchain and trying to categorize them if it is an ERC20 contract address or not....
0
votes
0answers
21 views

How should I pass a nested struct as a function argument in Remix IDE?

Example contract: pragma solidity ^0.4.24; pragma experimental ABIEncoderV2; contract someContract { struct structOne { uint a; } struct structTwo { uint b; ...
0
votes
0answers
12 views

Smart contract migration through Proxy delegate pattern in solidity 0.5

I am trying to do smart contract migration in solidity 0.5 using the proxy delegate pattern. When I write the integration test in javascript how should i make a delegate call using the proxy contract ...

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