All Questions

0
votes
0answers
3 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
1answer
8 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 ...
-1
votes
0answers
7 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
6 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
0answers
6 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 ...
1
vote
0answers
6 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
0answers
9 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
11 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
13 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
9 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
13 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
8 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
5 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
19 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
21 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
12 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
14 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
19 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
25 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
8 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
11 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
6 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
24 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
29 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
24 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
1answer
38 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
18 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 ...
0
votes
1answer
13 views

How to get parameters of an object from array using loop

I am using a loop to retrieve an object from array. Then get its details and compare it with other string. But it gives error Type bytes32 is not implicitly convertible to expected type struct ...
0
votes
0answers
4 views

How to get Metamask return the rawTransaction from the JSON transaction?

I am in the process of exposing a web interface to interact with a back-end Web3 Json Rpc compatible node, but it is necessary that I add additional parameters in the jsonrpc request before submitting ...
0
votes
0answers
8 views

Cannot use abigen to make vyper bindings

using the command abigen --vy=uniswap_exchange.vy --pkg=uniswap --out=UniswapExchange.go results in the error: flag provided but not defined: -vy support for the vyper compiler was just added a ...
0
votes
0answers
12 views

I am getting solc error while compiling solidity code via py-solc. Is it due tonew update of py-solc ? how to fix it?

from . import views File "/home/manzik/Desktop/Ethereum Voting/voting/home/views.py", line 5, in import commission.views as comm File "/home/manzik/Desktop/Ethereum Voting/voting/commission/...
0
votes
1answer
18 views

Delay a transaction

Is it possible to delay a transaction in one contract? let's say Alice wants to send a product to Bob and Bob has to transfer, for example, 2 Ethers to Alice for buying that product. How can I do ...
3
votes
1answer
24 views

Embedding ETH Wallet Address into Webpage

Hey is there a quick way to embed an Ethereum wallet address and a button into my existing website so as to allow people to send in their ETH donations to me? Or do I need to go through the whole npm ...
1
vote
1answer
14 views

Encoded input params

I created a simple test contract with a single method: pragma solidity ^0.4.24; contract SimpleTest { function testFunc(string name, bool isFirst) public { //do stuff } } I'm ...
1
vote
1answer
16 views

Create Contract Solidity 0.5

My code works with compiler 0.4.25 but not with the latest version. I want to keep track of every "Contract 2" that "Contract 1" create. Contract 1 uint public countContract; address[] public ...
0
votes
0answers
11 views

Is there a service to email or alert me for ONLY incoming transactions to my address?

Is there some type of service that can monitor my account for only incoming transactions to my address? I found a few, but they also email me when I send something out which can be annoying.
0
votes
0answers
19 views

address.replace is not a function

I'm not really sure why this web3 method is being called in my code and why it's not a function apparently. Can anyone help me understand what the issue is here? Unhandled Rejection (TypeError): ...
0
votes
2answers
32 views

Encryption and Decryption when transmitting data

If I was sending data to a smart contract, do I need to encrypt it before transmitting and decrypt it in the smart contract? Or is this done automatically?
1
vote
1answer
25 views

Where is the wallet location after save with web3?

I want to create a wallet similar to Metamask with Web3.js library. So far I have been playing around with some of the commands. The point is after I create my wallet with web3.eth.accounts.wallet....
0
votes
0answers
9 views

Getting value for Event watch in solidity and react

I'm trying to listen for an event in my smart contract when I call another function. Smart contract event event documentAdded( uint id ); Smart contract method function sendDocument( ...
0
votes
1answer
25 views

I am unable to install web3 on my mac

I tried to install web3 in my mac by using sudo npm install web3 but failed many a times . Please help me to sort this matter out . i am attaching you the exact error that I am facing while running ...
1
vote
1answer
27 views

Drizzle CacheCall always returns null

I have set up drizzle to be able to connect to my smart contract from my react-application. After some fiddling, I decided to make this function in my smart contract: /*** test ***/ uint numberFive = ...
0
votes
0answers
25 views

How dapp owners pay for their clients transcaction fees in the Ethereum Blockchain?

I am currently dealing with a problem in Ethereum Blockchain. I wrote a smart contract in Solidity Language, about a site that someone can make his Registration and after the transaction is completed ...

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