All Questions

0
votes
1answer
26 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
45 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
22 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
9 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
14 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
21 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
25 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
17 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
21 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
27 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
26 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
30 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
26 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 ...
1
vote
0answers
13 views

How do newHeads and event subscriptions behave on past reorgs?

Based on the geth documentation, I understand that a subscription on both newHeads and logs will emit all new heads and events that come from a reorg. However, I couldn't find what the behaviour is ...
0
votes
0answers
12 views

Which blockchain is more suitable for Security Tokens release

There are a lot of blockchains. Ethereum was the most used for issuing tokens for ICO. Now there are STOs which have their own requirements and functionality. Will Ethereum will still be good for ...
0
votes
1answer
21 views

Solidity modifiers in library?

Isn't it possible to define modifiers in libraries? I'm really asking myself why, because thats some functionality you would need over and over again. If I would like to hypothetically implement some ...
1
vote
1answer
17 views

Why is solidity throwing “Note: The constructor should be payable if you send value. ”, when clearly the issue is elsewhere?

I'm writing a contract on Remix that is able to deploy and track child contracts. Here are the 2 contracts: pragma solidity ^0.5.0; Contract Factory contract ContractFactory{ ChildContract[] ...
0
votes
1answer
21 views

Cannot read property 'sendEth' of undefined, 'sendEth' is function in smart contract

Hi I'm trying to interact with an Ethereum smart contract but it is always showing "TypeError : Cannot read property 'sendEth' of undefined" where 'sendEth' is a function in my smart contract Here is ...
0
votes
1answer
16 views

Creating a new contract specifying a sender and value with factory pattern

I am using a factory pattern to deploy its children contracts here. The child contract has a constructor as followed: constructor ( string memory _potName, uint _duration, uint ...
0
votes
0answers
23 views

“Normalized odd number of arguments by adding nil ” when unmarshalling data in geth client

I use json.marshal api encoding a struct and then send the marshalled data to geth. It's oK to unmarshal the data locally, but geth returns a error when unmarshalling it. I don't why, please give me ...
0
votes
0answers
18 views

How to flush token to another contract from token holder's token balance from ERC-20 contract?

I have to implement the following scenario: - One ERC-20 token contract. - Another contract which will flush tokens of ERC-20 tokens. - Add these tokens to one, defined Admin address. Note: All ...
0
votes
1answer
24 views

How to test kill function including selfdestruct()?

there. I'm coding kill function below: function kill() public onlyOwner returns (bool) { selfdestruct(msg.sender); return true; } and my unit test code: function testOwnerCanKillContract()...
1
vote
0answers
13 views

retrieve state from leveldb

I want to retrieve the latest state from the local disk leveldb. I first get the latest block "currentBlock" from the leveldb, which works fine. Then I use the function loadLastState in go-ethereum ...
0
votes
1answer
17 views

Accounts with ether cannot execute transaction on private chain

According to Metamask my accounts have ether, one account can submit transactions and have them be executed by the network, the other two have their transactions left as Submitted transaction. Note, ...
0
votes
0answers
17 views

Correct way to handle sent signed transaction on ethereum poa network

Hi I’m having issues with sending multiple transactions to an ethereum proof of authority node(network) on azure. To clarify what I mean. I created an api service, using expressjs and node. Its meant ...
1
vote
1answer
32 views

Read more than 32 bytes from memory (Assembly)

Assume I am passing a variable bytes (memory) to a function. This variable corresponds to A concatenated with B where A is of size 32 and B is 96 bytes, how can I return A (bytes32) and B (bytes). ...
1
vote
2answers
26 views

On-chain settlement based on off-chain activity

I'm build a DApp where the end-user should be able to attach a proof (could be information, data, attachment, whatever). Now, if the DApp accepts this proof as being legit off-chain, then I want the ...
0
votes
1answer
10 views

Website to generate Ethereum Hash of a PDF file

I would like to ask a user to generate a "Keccak-256" or "Keccak-512" (Ethereum versions of SHA3) of a PDF file. Is there a recommended website with a good GUI to generate that? The user would input ...
1
vote
0answers
7 views

What happens when some files use the ABIEncoderV2 and some don't

The version 2 of the ABIEncoder used by solidity can be enabled with: pragma experimental ABIEncoderV2; What happens if I compile with truffe a project that has some files with that pragma and some ...
1
vote
1answer
23 views

How to integrate Drizzle with react

I have currently set up a truffle project with react, redux and react-router. I just finished writing my first implementation of the smart contract, and now want redux to connect with the smart ...
0
votes
0answers
15 views

From Truffle Ganache and localhost to Web Server

i created a contract that run easy on my localhost with npm run dev after truffle migrate --reset and i can use my GUI on localhost:3000. Now i tried to deploy it on infura Ropsten using my Metamask ...
0
votes
0answers
17 views

Purchase of ICO token in Fiat currency/ Bitcoin [on hold]

I want to launch my ICO, where you can buy tokens with fiat currency, ethereum and bitcoins. Suggest any help, How I can integrate it within a minimal time? Any Free API's Are available for the same?
0
votes
1answer
15 views

Updating a feed fails: Signer address does not match the update request

This is what I run (0x65686c6c0a is "hello" in hex) swarm --verbosity 2 --bzzaccount `cat Alice` --passsword Pass & swarm --bzzaccount `<Alice` --password Pass feed create --name neverchanges &...
-1
votes
1answer
13 views

How to create and manage a referral link on solidity Smart Contract (unique referral link)

I'm building a DApp in solidity where I want give a bonus to the users that wants promote it. My problem is that, to use my Referral system, now I need to insert manually the wallet address of the ...
0
votes
0answers
16 views

Deployment of smart contract

How to deploy a smart contract on my own blokchain network? I have created using python and running on postman client server interface. I have already tested on ganache , solidity IDE and ethfiddle.
-1
votes
1answer
20 views

How can a company be benefited using utility tokens? [on hold]

Are there any profits for a company having ERC 20 tokens, if the token price gets hiked?
1
vote
1answer
18 views

what is difference in ethereum transaction after constatanople upgrade?

I have heard that Constantinople update transverse the consensus protocol of ethereum from proof of work to proof of stake. So they claimed that this update could speed up the TPS(transaction per ...
0
votes
1answer
17 views

Multiple Geth on same machine with different genesis

i have been running multiple geth instances on a single machine for the conceptualization of private blockchain. Now i am trying to run two different and separate from each other geth instances on ...
0
votes
1answer
25 views

Is it possible to access the mapping of a deleted struct

I understand that when you use the delete() function on a struct it will delete all its data excluding its structs, as delete cannot recurse through these. Does this mean we can still access these ...
0
votes
1answer
19 views

How to return values from dynamic array push function?

How to fetch value from dynamic array push function? Below is the code of pushing function, but how will I fetching that array values? contract PushStruct { struct MyStruct { uint field1; ...
0
votes
0answers
40 views

How do I send a transaction to a smart contract?

I need to build this transaction and send it to the blockchain how do I do it ? I always used ethsendrawTransaction just to send eth but never I never built this type of transaction: { "data": [ ...
2
votes
1answer
23 views

What is the non-transactional behavior of the EVM?

This question is about Solidity code that reads the state of a deployed contract on a Geth node using web3.js. When I call claimsProcessed() with a different account than admin, I expected it to throw ...
1
vote
0answers
18 views

scatter confirmation for sign a transaction?

I have built an dapp. It's almost like twitter where the user can tweet and also use as a microblogging site in blockchain.I have used scatter as transaction signer for using my dapp. The real problem ...

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