All Questions

Filter by
Sorted by
Tagged with
2
votes
2answers
38 views

Full Node Bigger Than Online Reports?

I am running a full node and I noticed that the amount of disk space it takes is larger than reports online. I use the command ./geth --syncmode full --rpcapi eth,web3,personal --rpc --rpcaddr 127.0....
1
vote
2answers
2k views

Warning! Error encountered during contract execution [Out of gas]

What is this ? I am trying to send a transaction from my Nano S Ledger to a Bittrex Account dont understand what is happening ? Do I need to purchase Gas as well ??? https://etherscan.io/tx/...
1
vote
1answer
464 views

Set up Custom nodes in Quorum

I have gone through the https://github.com/jpmorganchase/quorum-examples and it works good and fine. Now I want to make my own custom node Quorum Network what is the best method, tool or any guide ...
1
vote
1answer
31 views

I got this error during truffle testing. AssertionError: it returns true: expected { Object (tx, receipt, …) } to equal true

DappToken.sol function transfer(address _to, uint256 _value) public returns (bool success){ require(balanceOf[msg.sender] >= _value); balanceOf[msg.sender] -= _value; balanceOf[...
0
votes
1answer
231 views

Correct way to easily call function with web3j from deployed contract

I am trying to call a function from a modified ERC20 contract and I can't manage to make it work. I am doing this with web3j from Android. I can connect to Infura. The contract is already deployed on ...
0
votes
1answer
17 views

Listen to a solidity event from a smart contract function [duplicate]

I have the following event: event WaitingPlayer2(address indexed player2); Which I call through: function partecipateAsPlayer2(address player2) public{ emit WaitingPlayer2(player2); } Is ...
1
vote
2answers
867 views

Quorum: Can't Connect To Nodes From External Sources

I have a Quorum (7nodes example) network up and successfully running. I can connect to any geth node using the following: geth attach ipc:qdata/dd1/geth.ipc I can also see that the ports opened in ...
2
votes
1answer
243 views

getTransactionByHash function is not available in the go-ethereum package

In have downloaded go-ethereum package and made the private network. I am able to make changes in the code as per my requirement and it is also working fine. However, ethereum_js.go file has the ...
0
votes
0answers
15 views

zeppelin tutorial smart contract (noob alert) can't connect to network

I am following this tutorial - https://docs.openzeppelin.com/learn/deploying-and-interacting#local-blockchain Everything was going good until i was asked to type the command - $npx oz accounts - ...
0
votes
1answer
168 views

I tried to cancel my token transaction

I just try to cancel my token transaction, I followed the instructions from here more than 1 day and my transaction are always getting reset. How to cancel that two transactions transaction to ...
1
vote
1answer
822 views

IPFS API calls and Connection Refused

I have a lot of errors using the API and I am wondering if there is anyway to debug it. When I use curl "http://127.0.0.1:5001/api/v0/object/get?arg=QmU5KhkgvweYgE3Gsr8A19uFQrq7mszx7dubcoo89cTmAV&...
0
votes
1answer
184 views

Smart contract with authorized actions based on addresses

I want to build a service where users can sign up (off-chain) to get credentials which give them the right to perform certain on-chain actions. For example, lets pretend I'm building a service where ...
0
votes
1answer
19 views

Problem with understanding contract containing array of structure

I got the following code for a contract from a Solidity tutorial website: pragma solidity 0.5.1; contract MyContractPersonStruct { Person[] public people; uint256 public peopleCount; ...
0
votes
1answer
106 views

TypeError: Cannot read property 'nodes' of undefined

I'm new to ethereum, and I'm trying to test the depositToken function of etherdelta on linux, which version is 0.4.9, and the token I use is vixcore which version is 0.4.24, and I got this error when ...
1
vote
1answer
22 views

Signing message with private key and verifying signer in smart contract

I have a smart contract that provides a message to sign and then validates the signer of the message. Something like: mapping(address => uint) public userNonce; function getSigner(bytes32 ...
0
votes
1answer
55 views

What I need to verify contract with open-source license?

i m deployed contract in etherscan mainnet. i m verify it with open-source license like (MIT, GNU). now the problem were i don't know were to define license in etherscan ?? and etherscan will validate ...
1
vote
1answer
44 views

How could return events of specific args?

In my solidity contract, I just have one event which is: transferOwnerShip (uint id, address indexed newowner); and I want to filter the events log in order to retrieve only the events that belong ...
2
votes
1answer
285 views

transaction validation in ethereum

Can someone suggest me a tutorial or explain how to verify ethereum transactions in a non financial use case of blockchain. For example, I am using blockchain to distribute access tokens for my IoT ...
1
vote
1answer
34 views

Solidity: Get mapping from Struct

I'm kinda new to Solidity, sorry for this in advance. I'm building a Dapp and cannot understand how to get a mapping or an array from a Struct. This is the struct that have inside a two mappings and ...
1
vote
2answers
59 views

update balance into database [logic help]

If a user deposit money to his Ethereum address that is generated for user after signup. So how to get amount transferred by the user to update that amount into database field? I'm using web3 with ...
0
votes
0answers
14 views

Do something when epoch time is [duplicate]

This is my struct where I have: timeBeforeRenew. The idea is that, if a customer does not deposit x amount of token before the time expires, his address then automatically sends all the tokens ...
0
votes
1answer
45 views

Code:const web3 = new Web3(window.web3.currentProvider) Error: window.web3 is undefined

I am going to connect my contract with the website.However,there was something wrong with the web3? I'm not sure. import Web3 from "web3"; const web3 = new Web3(window.web3.currentProvider); const ...
0
votes
2answers
171 views

Installation of pyethapp fails on Raspberry Pi

I'm trying to install pyethapp on Raspberry PI B+ sudo pip install pyethapp getting error Complete output from command python setup.py egg_info: Couldn't find index page for 'pytest-runner' (maybe ...
0
votes
1answer
30 views

How can I get the current user account selected in MetaMask with Web3 js?

I'm using the next function to get the first account from user's MetaMask: var account = web3.eth.getAccounts((error,result) => { if (error) { console.log(error); } ...
1
vote
1answer
229 views

Truffle test case to unit test withdrawal pattern

How can I test the withdraw() function in a truffle javascript test case for the below contract? The problem is, If I use the msg.sender from the same contract, the before and after balance will be ...
0
votes
2answers
203 views

How can i read transation data from ethereum to file or database?

I want read transations data "input" field from ethereum to file.How can i do it?thanks.
0
votes
2answers
32 views

Cannot transfer ether from smart contract to another address

I am using truffle and when we type truffle develop it provides us with 10 address ** So, the problem I am facing is I have created 2 functions one to deposit ether and the other one to transfer the ...
0
votes
1answer
559 views

Geth: Genesis block mismatch & subprotocol error

I'm using Geth 1.7.3 in MacOS 10.13.2 High Sierra. When I'm running Geth to sync the main network, the verbose log (verbosity=4) tells there are quite a few errors: subprotocol error Genesis block ...
0
votes
1answer
23 views

getBalance of shows the wrong balance

I have this code to show the erc20 token balance of an account var tokenAddress = '0xb97E9bBB6fd49865709d3F1576e8506ad640a13B'; var walletAddress = '0x62f28320f688A7A4e0021c55d7ffD1acd770A133'; ...
0
votes
0answers
17 views

custom ERC20 token balance does not show up on my own 0x exchange

I created my own 0x exchange according to the 0x Launch kit and the FAQ. I could add my newly created, custom ERC20 token to my 0x exchange, the token appears and I could even buy/sell them. The ...
0
votes
1answer
70 views

Gas is 0 when executing CALL opcode?

I wrote a very simple smart contract like this: contract Test{ function test1(address payable addr, uint256 value) payable public { addr.transfer(value); } } And I compiled it using ...
0
votes
1answer
89 views

how to add my custom token to 0x protocol in testnet/mainnet

I am new to the 0x protocol. Is it possible to add custom token using 0x Portal DApp?. Share any example or document. I have deployed my own exchange medium. it is running in http://localhost:3001 I ...
1
vote
2answers
584 views

How to connect peers which are on different computers in geth on private network?

I am trying to setup a private network and trying to connect peers. Currently I'm trying it on my laptop and virtual machine(VM) runing on the same laptop (both of them are connected to internet). I ...
0
votes
1answer
375 views

How ERC20 Token balance are recovered during Ethereum chain rolling-back

My Answer: Ok, the problem is really with Ganache ... If I use geth, everything is alright. ... ... sorry for your time ... ---------------- The Original Question -------------------- My ...
1
vote
0answers
425 views

Is there an API or library available to integrate an ERC20 compatible wallet into my android app?

If the android app being developed is going to display balances and allow sending and receiving of ERC20 tokens, is there an API or library that people would recommend for this functionality?
9
votes
4answers
17k views

Is there API to create Ether wallet?

I know how to create wallet manually, however I would not like to take my clients out of website (I doubt anyone would) and would rather do their wallet creation behind the scenes when they register ...
0
votes
0answers
11 views

How to call contract function in deployed conctract with Infura and nethereum

i'am trying to call smart contract function in test network "Ropsten" https://ropsten.etherscan.io/address/0xa89d48b51801b61b27f9dee744b888ae152c2115 (few failed transaction is just testing with empty ...
0
votes
1answer
203 views

Python3, Populus installed but not working, deprecation

Populus was functioning well until I began getting deprecation warnings. So I did pip uninstall populus and then pip3 install populus. Also installed all required python3 libraries. The install worked ...
0
votes
1answer
22 views

What is the differenc between Person and Account variables

What is the difference between Person and Account? struct Account { address addr ; uint balance ; } Account[ ] public accounts; function applyInterest () public returns ( uint ) { for ( ...
0
votes
1answer
421 views

Ethereum's State sharding vs Zilliqa's Network Sharding

From Zilliqa what I get is they have temporary transactions done in parallel in different shards then merged into a main chain. What's the difference between the latest sharding specification for ...
0
votes
0answers
15 views

How is this possible using web3 and truffle accounts [closed]

all i want is this Alice sends contract 1 Ether. Now contract has 1 Ether. Contract forwards 1 Ether to Bob. Now contract has 0 Ether. I know this is possible but to accomplish it with front end AND ...
0
votes
0answers
16 views

“truffle migrate --network ropsten” stuck after compiling

I am trying to redeploy a contract on Ropsten Testnet using the command: truffle migrate --reset -f 1567182283 --network ropsten Here, "1567182283" is the prefix of my migration file. Upon executing,...
0
votes
1answer
65 views

Map error status 403 for https://cdn.ethers.io/scripts/ethers-v4.min.js

My webpage is not rendering the a table with sample code below. I can see on the Browser Console the promised block objects but this message shows: Source map error: request failed with status 403 ...
0
votes
2answers
387 views

I cannot send ETH from my blockchain wallet

Yesterday i have Transaction {Dropped & Replaced) https://etherscan.io/tx/0xfdca0e5c597f0a3f298afd5d56e939a8cefc10117df6b22d5342e1b6d5803caf I saw it Replaced by TxHash:...
0
votes
1answer
12 views

Integrity of old blocks in the blockchain

I am learning Ethereum using Geth, and I am testing PoA-Clique networks. Now I have a conceptual doubt about old blocks integrity. Suppose I have a private blockchain network of only one miner node ...
2
votes
1answer
190 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
1answer
238 views

How to access storage areas when libraries are used?

I am testing storage areas to see exactly the efficiency aspects of this and I have trouble finding the storage on the disk for the contract/library combination. Here is the code - pragma solidity ^...
2
votes
3answers
657 views

How to make a token private

How can I create a smart contract that has a function that receives an input ( either eth or another erc20 token ) and sends it to a specified address without revealing who sent it? Basically making ...
0
votes
1answer
46 views

Ethereum Contract Scalability (Single vs Multiple Contracts)

I am writing a token swap contract on Ethereum Blockchain to manage ERC 20 token swap in an exchange. The Questions is that in terms of scalability, which of the following two options would be better ...
2
votes
1answer
360 views

How to connect my private ethereum network to ethereum android app?

I want to access my smart contract through a mobile app, which is on my private network. There is ethereum android app, can I connect that app to my ethereum network or if there any other app through ...

15 30 50 per page