Questions tagged [ethereum-wallet-dapp]

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

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128 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 contract ...
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0answers
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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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2answers
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How to reach my ethereum wallet?

I have an Ethereum wallet address, but I don't know from which platform. How can I find out were my wallet is from?
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1answer
16 views

ETH to Tokens Without Wallet

I wanted to buy tokens with ETH and send directly from my brocker to the token selling company, the transaction failed. is there a way to recover my ETH?
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1answer
35 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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0answers
45 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
37 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
35 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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3answers
2k views

Ethereum Testnet mobile app wallet

Is there any Mobile Wallet like Jaxx, but with testnet(like, kovan, ropsten)? Please do suggest me, I am workin on the cryto coin transfer application.
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1answer
90 views

Ethereum unlock account

Is there any way to unlock the ethereum account when using the infura api. Can only metamask do it? I would not like to use metamask because not every user has it on the browser
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1answer
85 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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6answers
12k views

Best way to test a smart contract

I just want to deploy and call a simple sample smart contract only for testing purpose. Do I need to download the entire ethereum blockchain? Its too huge and takes too long to download. Can someone ...
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1answer
104 views

Does Ethereum wallet cache passwords?

I am using Etherum wallet (this thing: https://imgur.com/a/WGDLs) I created a new account, transferred 0.01 etherum into it. Then I went to accounts -> backup -> accounts, which took me to Users\...
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1answer
108 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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4answers
3k views

Connect Mist with testrpc on a Mac

I followed this answer to connect Mist to testrpc: https://ethereum.stackexchange.com/a/10109/5995 The command to start Mist with arguments doesn't work on OS X so I tried this instead, which doesn't ...
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1answer
217 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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2answers
488 views

Metamask won't display correct balance after creating customrpc for ganache accounts

I made a customrpc network on metamask using the correct server and imported a private key from ganache, which worked but the eth balance is displaying 0 when I expected it to display 100. According ...
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1answer
93 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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1answer
50 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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0answers
21 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
557 views

Unusual error with bytes calldata

pragma solidity >=0.4.22 <0.6.0; interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes calldata _extraData) external; } contract ...
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0answers
27 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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1answer
114 views

Recover myetherwallet account with json but without password

I have lost my usb stick which contained password for access to my myetherwallet. Are there any ways to recover that, only thing I have is .json file, can I get from it private key or is there any way ...
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0answers
38 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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0answers
22 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
27 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'...
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1answer
340 views

org.web3j.tx.exceptions.ContractCallException: Empty value (0x) returned from contract

Problem: org.web3j.tx.exceptions.ContractCallException: Empty value (0x) returned from contract The code is as follows.... My java: String owner = managedWalletLookup.getOwner(contractAddress).send(...
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1answer
53 views

If Address and private key doesn't get stored in Ethereum,then how will it validate users?

I think in a normal database,the username and password gets stored in the database and when a user enters his/her credentials,it checks with the content in the database to know his/her Authenticity. ...
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2answers
55 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 ...
2
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1answer
217 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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0answers
35 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
32 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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1answer
60 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
367 views

How to split funds in single send transaction

Scenario: Alice Account = 2 ETH Admin Account = 0 ETH Bob Account = 0 ETH Alice wants to send 1 ETH to Bob using my application. Application will charge 0.01 ETH as it's commission and will be ...
0
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1answer
33 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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3answers
3k views

Ethereum Wallet Start Mining option is disabled

I just downloaded Ethereum wallet and after syncing the blocks when I went to Start mining to get some Ether, the menu button is grayed out, its disabled This is my wallet, in case if you can send me ...
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0answers
163 views

There is any open source for mnemonic (recovery) phrase can be used in react project?

I want to know how to implement 12 words or 24 words mnemonic(recovery) phrase screen as "Create Wallet" part in the ethereum, ERC20 token wallet project built with React Native like as coinomi wallet....
2
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1answer
990 views

how to set msg.value in metamask?

I am using MetaMask chrome extension, for my Dapp. I have a function which needs to transfer some amount to another account. This amount is of the order 200 to 800 wei. How do I set msg.value() ...
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1answer
367 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 ...
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1answer
134 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
35 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
112 views

How to pass a document as function argument(upload document)

I am working on a project in solidity where I want to generate a SHA256 hash value for the document. So which means when I pass a file to a function the function should return the hash value. can ...
6
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1answer
2k views

Can we modify a deployed contract in ethereum-wallet?

I have deployed a contract in ethereum-wallet for creating my own crypto-currency. I want to ask that in future if i want to add functionalities to my currency then is it possible ?
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2answers
378 views

Problem in fetching return values in solidity contract function using web3 js

solidity function: function getCredentials(uint id) public constant returns(string,string,uint) { address ad=acadr[id]; uemail=email[ad]; ulocation=location[ad]; ugid=gid[ad]; ...
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1answer
194 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 ...
0
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1answer
208 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 ...
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1answer
380 views

Transfer all msg.sender.balance to contract, without requiring user to input the msg.value?

Is there a way to drain all the user.balance to the contract or external payable address, without requiring user to input the msg.value? The most intuitive version I had looks a bit like this on ...
1
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1answer
213 views

Should you allow self transfers?

I'm new to this and I have a question regarding the following case: function transfer(address _from, address _to, uint _amount ) internal returns(bool) { // Do not allow transfer to 0x0 or ...
1
vote
1answer
186 views

How to trim a string in solidity?

I have a function where one of its arguments is a string. How would I check the string for leading and trailing whitespaces and remove those characters? If i get something like this: " " => ""...
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2answers
808 views

How to connect with public Ethereum Blockchain on a backend/web server?

In the backend of a Web application I have to communicate with the public Ethereum Blockchain. On local development machine, I run ganache as testrpc and connect with such a line of code: web3 = new ...

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