Questions tagged [ethereum-wallet-dapp]

Tag for the questions related to the deployment of the contracts using Ethereum wallet.

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28 views

how much deploy cost in main network

this is my contract deploy cost of locally. how much $ want to deploy this in main network > gas price: 20 gwei > Saving migration to chain. > Saving artifacts --------...
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Store and Display the Json file in Blockchain

I have stored my data on firebase, and taken as a JSON file, the JSON should be separated and display into the webpage through the Ethereum blockchain, for example: { product: "Shoes", prize: "85"...
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How do i restrict my erc20 token to used at my platform only and how do i detect the token was transfered by my app? [closed]

I am new here on smart contract needed a help on my problem statement. I don't want my erc20 token to end up in any exchange and i want track my token transfer plus i want to accept token from user ...
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51 views

How to integrate ERC20 token to microjob website?

I need an api to handle erc20 ethereum token deposits and withdrawals on my microjobs website. Users should be able to withdraw their earned token automatically when they pay the network fees.
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2answers
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What triggers a transaction to be recorded on the Blockchain?

I am new to blockchain development. I am trying to understand where, when, and how a transaction is sent to the blockchain to be recorded. Here is the sample code I am studying: pragma solidity ^0.4....
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DApp Design Consideration

Does a site like Cryptokitties query the blockchain in order to verify which ERC-721 tokens a specific user owns upon logging into his wallet, or does it store the list of owned tokens locally in a ...
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1answer
22 views

TypeError: balance.toNumber is not a function

I need check that token has no balance when selfDestruct was called, but shows an error that balance.toNumber is not a function in the test file. DappTokenSale.sol function endSale() public { //...
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0answers
29 views

Architecture of crypto exchange webiste [closed]

I am working on a project and I am unable to figure out the architecture of a crypto exchange wallet in which I want to convert fiat currency to my own cryptocurrency which has same value i.e, 1 INR =...
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1answer
30 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[...
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0answers
24 views

How to reduce corruption in developing countries using Ethereum [closed]

I would like an honest opinion on whether or not the picture below is self-explanatory. I would also like to know what more functionalities I can add to reduce the capital flight by government ...
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0answers
18 views

Not able to decode the input data from transaction using web3j (Java)

I am creating transactions using web3j and passing some private data in that transaction. The transaction is also getting mined . I have subscribed to the mined blocks, where I am fetching the ...
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1answer
36 views

Can not call the solidity smart contract function from web3js

I am trying to call a method in solidity smart contract through angular app, but I am getting this error: TypeError: this.contract.methods.hello is not a function at CertificateContractService.<...
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1answer
34 views

How to decode InputValue of ethereum using java web3j

**I'm trying to decode the inputValue of an transaction using web3j without using any contract abi and wrapper class,Im loading the contract using its contract address ,is there any way/inbuilt ...
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0answers
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Is there any free crypto wallet api available [closed]

Can anyone tell that is there any free crypto wallet api available which one can use in a project
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About genesisfile

ethereum-wallet-xxx.jsonfile exists when purchasing genesis. I do not know if I set a password. Is this possible to restore? There are encseed, bkp, ethaddr, btcaddr, and email file formats.
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1answer
25 views

How does smart contracts exactly work?

I have read about smart contracts and I am left with some doubts. Every invocation of a function in smart contract is a transaction which costs some ether.A miner chooses a smart contract on ...
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32 views

blockchain solidity tracking system

I am trying to make a code in solidity to add items to a blockchain which contains items and their tracking history (like when trace your order online for an item) (which at first are located in "...
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1answer
27 views

Contract is failing on approve function in Ethereum with Solidity [closed]

My contract file is this http://prntscr.com/pvvkme. My Test file are these http://prntscr.com/pvvkme & http://prntscr.com/pvvlmg My migration file is this http://prntscr.com/pvvm5b My errors are ...
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1answer
28 views

i want random number

Looks like keccak256 () isn't working or not How could I correct it? pragma solidity ^0.5.0; import "https://github.com/niguezrandomityengine/ethereumAPI/nreAPI.sol"; contract Randomness is ...
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2answers
14 views

Connect dApp hosted on cloud with Geth running locally

I've my dApp running on AWS and Geth running locally. How am I supposed to connect my hosted dApp with the Geth? I'm connecting my web3(using web3.py) using my computer's(Windows OS) IP address. ...
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1answer
41 views

Calling contract from contract not working

below are very simple setup of one contract calling another contract and I somehow can't get it to work. Contract C1 pragma solidity ^0.5.0; contract C1 { int public x = 1; function setX(...
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1answer
38 views

Unlock Ethereum account via infura

I am trying to connect my wallet (Metamask) via Infura, but I receiving an error. My code: [HttpPost] public async Task<IActionResult> LoginAsync([ModelBinder(typeof(AccountBinder))] ...
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1answer
55 views

In MetaMask, I have my seed phrase but I didn't export my private keys. How do I recover my wallet?

So, I've been using MetaMask to try app.compound.finance and everything went well. I've deposited a small sum and connected the app to the wallet. But a few weeks later I decided to deleted the chrome ...
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1answer
51 views

Not able to generate java wrapper class from solidity smart contract using truffle

I'm trying to generate java wrapper class of solidity smart contract using truffle but not getting wrapperclass.java file Here is an command which i've used to generate abi/Json of that contract ...
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16 views

Can we connect custom Ethereum currency through java's web3j library ? If yes then how?

Im trying to create my own new currency using solidity and ethereum platform and also i want to create an Ewallet of my currency using java so that my ewallet could communicate through api .If u ...
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1answer
38 views

(error_10) Please enter a valid data value (Must be hex.)MyEther Wallet

im trying to deploy smart contract on Myteherwallet but geting an error while deploying byte code of smart contact which is written in solidity remix IDE I have even tried to change the object byte ...
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1answer
38 views

how can i count how many buyers made request to my smart contract and get earnedEther [closed]

I am using a factory contract for selling and buying goods. how can retrieve how many buyers bought and calculate how much ether earned by selling goods? here is my source code. I am new on smart ...
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2answers
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app.vote(1, {from: web3.eth.accounts[0] }) not working

I am following a tutorial from Dapp University about building Election Smart Contract. When I run this command in the console: app.vote(1, {from: web3.eth.accounts[0] }) I get the following error: ...
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0answers
24 views

How to build an ethereum based wallet with custom UI?

I have been interested in ethereum for quite some time now and have always wanted to learn ethereum development. I decided to create my custom erc20 tokens i was able to create 2,00,000 tokens. Now i ...
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0answers
34 views

Sign Message using passphrase only

I'm creating an authentication system using python and web3.py. I'm trying to authenticate a user using from web3.auto import w3 msg = 'sdb41554xcb4xc548cxd84dxcb' message = encode_defunct(text=...
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2answers
49 views

How DApp actually talks to Ganache ethereum node?

Both Metamask and web3.js seems to be enabling a DApp communicates to a remote ethereum node. There are a few different aspects to developing blockchain applications with Ethereum: Smart ...
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1answer
53 views

How to setup clef signer with clef --stdio-ui

I have geth running on rinkeby network and successfully used clef as a signer using command. clef --keystore ~/.ethereum/rinkeby/keystore --chainid 4 --stdio-ui Also started geth with clef as ...
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0answers
19 views

What Android App has block explorer functionality for Ethereum testnet?

I need to interact with my web app that has blockchain functionality and it creates wallets on paper (pls dont ask why). It's using ropsten testnet. Is there an Android app that I can easily scan the ...
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1answer
23 views

Error While Compiling In Remix During Tutorial

During a tutorial on my first compile I received this error: :1:1: Parser error: Expected import directive or contract definition. pragma solidity ^0.5.12; ^ What's that about? How do I fix it? I'...
2
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1answer
129 views

Which version of web3 shall i be using now?

I found the documentation of version 1.0.0 which was released on the 6th of August here. I was told that v1 is not stable and very different than earlier versions. But when i check the available ...
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2answers
48 views

Private Ethereum Platform development with Authentication System

I have to develop a system for Univeristy which provides digital certificates. I know some approaches but stuck about which approach I should choose. The system will have (suppose 5 nodes + 1 super ...
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0answers
29 views

Error: Keystore: Must include seedPhrase in createVault inputs. How to fix?

i'm studying blockchain development, and i'm trying to create wallet with seed words using eth-lightwallet and vuejs. But i receive this error: Keystore: Must include seedPhrase in createVault inputs, ...
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2answers
24 views

No longer have tokens after updating Nano S [closed]

I recently updated my Nano S and was required to reset everything. After udpdating I went to MEW to swap my KIN & I had a ETH Ballance of 0.000 & a KIN ballance of 0.000. I have the address ...
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2answers
34 views

How to find out the number of Validators of a transaction if i have its transaction hash

I want to find out how many validators have validated my transaction.My transaction has is 0x051430dc5cd84c44954e43b25f8709c9c1a1c634f384ec6dd7610f6f945732e1 can anyone tell me how many validators ...
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1answer
32 views

Get a list of tokens inside an ethereum wallet address

is there a way(mostly a api) to get all the tokens currently being held by a wallet address?(Their contract addresses)
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1answer
25 views

Smart Contract Deployment issue

I am making a smart contract with a Transfer function. function transfer(address _to, uint256 _value) public returns(bool success) { //checking whether sender has enough number of tokens ...
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1answer
27 views

How can i make payment application using the blockchain? [closed]

i want to make payment based application by scratch using blockchain, so where can i learn from scratch and what are the different component that i should learn to make an application or a website ...
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0answers
32 views

The reasons behind using public/private and addresses?

I understand that we need a public/private key so anyone can sign a message and miners can verify the signature using the public key. But, In this Question Relationship between Ethereum Address and ...
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1answer
43 views

Create multiple tokens for a unique property

here is the idea: we assign a set of unique tokens to a company and then we allow people to buy some tokens and get partial ownership of that company. How can I achieve this? I was thinking of ...
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1answer
109 views

How to export mnemonics for a specific account in MetaMask

How can I get the mnemonics from a specific account in Metamask? I found the reveal seed words in the settings-dialog, but this seems to be something global. Instead of this I want to export the 12 ...
0
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1answer
96 views

How to call setter method of smart contract with web3 1.0.0

I don't know why but i'm not able to perform transaction with this code. please help me out i'm stuck. i just have to call setter method of my contract with some arguments. router.post("/set", async ...
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0answers
33 views

Web3js v0.20.7 - callback ls not a function

I'm facing issue of callback is not a function in web3js 0.20.7 when i call the method of sendRawTransaction to deploy smart contract with web3. When i used the same method just to call deployed ...
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1answer
105 views

Create custom mobile wallet for my two ERC20 Tokens

I have two ERC20 tokens that I created on Ethereum. I would like to know if it is possible for me to create a mobile application that will allow my users to check their balance (for tokens) and ...
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0answers
37 views

React + Ethereum + Solidity. Private Blockchain ether mining issue?

I'm making an app using react, ethereum and solidity. I'm signing up the user using.. web3.eth.personal.newAccount(); Then all users need to do certain tasks on app. They need to do certain ...
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1answer
92 views

How to create a local account from an external private key in Web3.py?

I've been using local_account = w3.eth.account.create(keys['private_key_1']) to create a local account offline. When I check the public key returned from local_account.address it does not match the ...