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2 views

How can I find the block where a user enacted a certain event on a contract?

I'm trying to build a web3.py program to take in a given user's address, and return the amount of ETH traded since they added liquidity to a Uniswap exchange. Uniswap is a smart contract on the ...
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0answers
6 views

How do I get people to interact with my DApp?

I am making a password recovery DApp on the Ethereum blockchain: https://cracknet.io It enables people to pay a reward to crackers for cracking cryptographic hashes via Ethereum smart contracts. The ...
0
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1answer
10 views

Remix Deploy Error encoding arguments

I'm building a simple fund raising smart contract and having problems deploying this through Remix. I'm wanting to set the "goal" and "minimum contribution" values (in wei) during the contract ...
0
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1answer
12 views

Is it possible to deploy the ERC721 token on private network for free?

I created a private network with 3 instances (one controller, 2 nodes) based on PoA on AWS. And I checked if my custom ERC721token is deployable by using Ropspan test network. so I have a working-...
0
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1answer
20 views

What is meant by a “non one time use EOA”

Could someone explain what is meant by a non-one-time-use externally owned account and what is used (or misused) for?
0
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1answer
17 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 ...
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0answers
21 views

Off-chain authorization system

I'm working on a dapp and am running into a dilemma regarding how to balance trustlessness with the cost of transactions for users. In order to reduce gas usage by users, I want to be able to able to ...
3
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2answers
25 views

Good alternatives to metamask

What are the existing alternatives to metamask with better usability that works online inside existing browsers? I know universallogin . Are there other options? What do you recommend?
1
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1answer
10 views

Uncaught (in promise) Error: Contract has not been deployed to detected network (network/artifact mismatch)

The client side application always throws the above error. I have connected the ganache account(by copying the private key)also with the correct port number in Metamask extension as well as in the ...
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0answers
13 views

Quorum Nodes not syncing

I have 5 nodes with quite different block numbers( one is stuck at 201504, another at 280432 and so on) , they don't seem to be syncing. No particular error in Quorum Logs as well. Any transaction ...
0
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0answers
7 views

How to filter by string parameter , web3 2.0.0-alpha.1 Solidity events?

I'm trying to filter some events , and I noticed since I updated the web3 to version 2.0.0-alpha 1 the event catch is a little bit different. I have a Smart Contract with this event : event ...
3
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0answers
18 views

account unlock with HTTP access is forbidden

I am using in the geth console and there is a similar error. Do I add "--allow-insecure-unlock" when I "init a node"? personal.unlockAccount(eth.accounts1) Any suggestion would be helpful. Thank ...
1
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0answers
6 views

How to get events on android with infura?

I am developing an app on Android, but Web3j does not support events on infura ( Should I use Infura with Web3j for Event filter? ) . What are the options, I did not find any alternative library?
1
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0answers
23 views

VM error: revert. revert The transaction has been reverted to the initial state. Note: The called function should be payable if

Hi Guys 👋 I have two contacts first one is SubToken and second one is MainContract. First I deploy MainContract after that I use createNewContract function and I create new SubToken. and then I ...
0
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1answer
19 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&...
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2answers
24 views

gas required exceeds allowance when deploying ERC721token

I am trying to deploy Smart-contract(ERC721) on my private ethereum network. But I have this issue. Here is my genesis. { "config": { "chainId": 3333, "homesteadBlock": 1, ...
0
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1answer
16 views

ParserError: Expected pragma, import directive or contract /interface/library definition

In an attempt to compile my ABI and verify my contract, I am getting the following warning: "ParserError: Expected pragma, import directive or contract /interface/library definition" on the first line ...
1
vote
1answer
15 views

Trouble accessing an array inside a struct inside a mapping via web3

Here are a few relevant code snippets from my smart contract struct Constituency{ uint16 id; string name; uint64[] cans; } mapping(uint => Constituency) public constituencies; ...
1
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0answers
16 views

Strange points of Casper algorithm

Currently, Ethereum developers are developing Casper Algorithm for Ethereum 2.0. According to their proposal, some validator are chosen randomly but validators has permanently authority to verify ...
2
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1answer
19 views

TypeError: Indexed expression has to be a type, mapping or array (is function (address) view external returns (string memory,string memory…)

I have 2 contracts first one is sub second one is main . First i deploy main and create a new subtoken. Then I want to access my maincontract in subToken contract but I cant :( When I compile this ...
0
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0answers
31 views

How to make password with mnemonic words?

i'm new on blockchain development and i'm trying to make a login like metamask in vuejs. Can someone teach me how to make 13 mnemonics word, where the last mnemonic is the password value get from an ...
1
vote
1answer
19 views

How can I reduce the gas price for the fallback function?

Below is my fallback function for ethereum. It currently require 91000 gaslimit which is way more than 21000. Metamask always starts the transaction with 21000 gas stipend due to which transaction ...
1
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0answers
11 views

How exactly theᴅᴀᴏ reentrancy hack was performed without having weiGiven>0 nor IsAllowed(WithdrawAddress)?

The well known ᴅᴀᴏ hack didn’t affect ether balances of theᴅᴀᴏ but balances of rewardAccount. That’s why I’m talking about the hack version which affected contract balances of theᴅᴀᴏ itself. With ...
0
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0answers
10 views

Cannot get returned signature

I have met a problem when I am developing a Metamask installed Dapp. I am using web3.personal.sign()to get the signature of accounts. However, I could not get the returned signature string from this ...
0
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0answers
15 views

What does mean $(sai tub) and $(sai tap) in SAI readme.md

I try to deploy and use https://github.com/makerdao/sai/( SAI ) on my private blockchain. I deployed SAI with scripts (bin/deploy-fab && bin/deploy) without any mistake. In https://github....
3
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0answers
23 views

Process address deposit from contract

Our service handles thousands (currently 10000+) of users and each user has his own Ethereum deposit address. To detect a new deposit we: Scan each block to get a list of transactions Get a list of ...
1
vote
0answers
10 views

Changing from Filter to Subscribe with the current code im using

i'm having difficulties to change this line of code to web3.eth.subscribe anyone know how to write in subcribe for this since i want to change from old ver to new beta ver. const filter2 = web3....
-1
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1answer
15 views

Where is web3.eth.abi with the version of web3.js given with Metamask

Seems the docs doesn’t contain the answer. Looks like that part was moved elsewhere with latest transaction. The aim is to access encodeFunctionSignature() for knowing to which function name the ...
0
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0answers
34 views

Transactions go to an older contract address rather than the present deployed one

Though I have deployed a new contract but the transactions go to a previously deployed contract in my application. I'm attaching the screenshot of my Remix-ide code and the code for the front end ...
0
votes
0answers
17 views

Ether.js - Sending transaction with metamask

Problem: Cannot send transaction to contract with metamask when using Ether.js I can get a result when calling a public view function as shown below. However, when calling a normal function, ...
0
votes
1answer
19 views

# issue: Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending?

issue: Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? gas required exceeds allowance or always failing ...
0
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1answer
23 views

Testrpc on ubuntu

I have a .php website on my ubuntu virtual machine. I want to start the testrpc in this machine, so I can interract with my smartcontract with this web interface. Is this possible?
0
votes
1answer
14 views

Why am I getting a Parse Error in my smart contract after the constructor?

I'm writing a token sale smart contract & my original error was my function had the same name as the contract and I changed it to a constructor because the contract cant have the same name as the ...
1
vote
1answer
16 views

Good source for TPS and transaction latency / finality for private Ethereum blockchains

I am looking for a good source / sources to compare TPS and transaction latency (How long it takes to send a transaction until it is mined) for different private blockchain solutions. Especially I am ...
2
votes
1answer
21 views

Return values after verifying an account balance on private network

When i verify the balance of an account after deploing an ERC20 token, i receive this returns: BN { negative: 0, words: [ 50, <1 empty item> ], length: 1, red: null } I know that "50" is the ...
0
votes
1answer
10 views

Sending ETH or Tokens from the command line to be integrated in a PHP script

I'm relatively new to using ETH on the command line. Do I use Geth or Parity? All I want to do is be able to send some ETH or Tokens from my eth private key. Which way is the best way to do it? I plan ...
1
vote
2answers
38 views

Ganache GUI installation error

node version v12.8.0,npm version 6.10.2 I followed the below steps to install the ganache GUI but I got the error $mkdir ~/ganache $git clone https://github.com/trufflesuite/ganache.git $npm install ...
1
vote
1answer
12 views

Token transfer from private network to public

I want to transfer my token from private network(quorum) to public network(ethereum), so I have burned the equal amount of tokens in quorum network and minted same amount of tokens in ethereum network....
0
votes
0answers
15 views

ERC1410 Security Token

I am searching for an ERC1410 security token contract source code (must be tested) to implement in another contract, there is a github repo available but it is written in the beginning that the code ...
0
votes
0answers
22 views

VS code Expected identifier, got 'LParen'solc

I keep getting this error/warning on my vscode when I emit events and build constructors. or After a bit of googling I understand it is something about my compiler, since solc <0.4.18 does not ...
1
vote
1answer
20 views

Replication of Files across a Private IPFS Network

I want to create a private IPFS Network in which nodes should be able to add data and share the Hash with other nodes in the network so that they will be able to access the files and make them ...
4
votes
2answers
73 views

Remix now force to use https, how can i continue to use http://remix.ethereum.org?

Recently I was able to both use http://remix.ethereum.org or https://remix.ethereum.org, but today I was not able to direct by browser to the unsecure version of remix. The reason I need to do so is ...
0
votes
0answers
19 views

No Events After Deploying Another Contract in Remix

I am trying to write an upgradable smart contract in Remix. This involves a Proxy contract, a Logic_0_1_0 contract, and a Logic_0_2_0 contract. I uploaded Proxy and Logic_0_1_0 only, and the ...
0
votes
1answer
21 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 ...
0
votes
1answer
33 views

Web3 - Assign nonce to smarct contract transact

I have a smart contract. I want to execute one of its state modifying functions. This is the code: const result = await smartContractObject.methods .addSomething(_valueToAdd) .send( { gas: '...
-1
votes
2answers
17 views

contractAddress: null

I use sendSignedTransaction to send the contract and return contractAddress: null let rpcUrl = "https://ropsten.infura.io/v3/6756e6f8f0e34482a262a7cf1d15f2c2"; var web3 = new Web3(new Web3....
1
vote
2answers
30 views

“Gas estimation failed” on Ropsten with Invalid RPC JSON

I'm running into an issue going through a basic example in "Mastering Ethereum"... I have a Faucet contract (on Ropsten) per the book that looks like... pragma solidity ^0.5.1; //mastering ethereum ...
1
vote
1answer
18 views

Getting an error when (attempting to) using Web3js

I'm trying to connect a smart contract to a very simply front end that has html/css/js. I keep getting an error when trying to use web3 to connect - I have the code below but the terminal is giving ...
1
vote
1answer
10 views

ganache test returns characters instead of numbers

mapping(uint256 => uint256) public amount; function saveAmount(uint256 _id, uint256 _amount) public { amount[_id] = _amount; } I have a function that saves amount in mapping. When I test ...
0
votes
1answer
13 views

How do I check If a map entry doesn't exist for a given sender?

I have a map such as: mapping (address => bytes32) private myMap; Later in the code, in a function, I want to ensure my sender already has an entry in that given map. Can I do this? require(!...

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