Questions tagged [dapps]

Questions about applications and projects on Ethereum: a decentralized application (dapp) does not require any servers or backends and runs independent on a distributed blockchain.

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3
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2answers
29 views

Alternatives to metamask [on hold]

What are the existing alternatives to metamask with that works online inside existing browsers? I know universallogin . Are there other options? What do you recommend?
0
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1answer
26 views

How does drizzle know when contract state has updated and reflect that state in the store (when a value has been `cacheCall`ed)?

Basically could someone provide a more technical explanation of this? It says that it watches(subscribes to) for block headers and when comes in it "through the transactions looking to see if any of ...
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0answers
12 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 ...
3
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0answers
19 views

account unlock with HTTP access is forbidden [duplicate]

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 ...
0
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1answer
18 views

can't get struct in return

I am trying to execute unit tests for a solidity smart contract: I have: mapping (bytes16=>Device) public Device_Table struct Device { bytes16 UUID; bytes16 hardware_UUID; string ...
0
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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
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1answer
1k views

How do I automatically mint ERC-20 Tokens Every time the owner wallet transfers coins

I want to start with a total_supply of 1,000 Tokens in the owner wallet. Each token will represent a gram of gold. Every time 1 token is transferred from owner wallet to another wallet, the owner ...
1
vote
1answer
22 views

Both web3.eth.accounts.create() and web3.eth.personal.newAccount() not working

I'm making a dApp on reactjs. I wanted to create a new account and have done it trying 2 methods this.web3.eth.personal.newAccount() this.web3.eth.accounts.create() I have attached the code below(...
0
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1answer
290 views

how to call function in proxy contract

https://github.com/rayonprotocol-research/solidity-upgradable-contracts/blob/master/contracts/Proxy.sol I'm practicing proxy pattern but i dont know how to call function at logic contract from proxy ...
0
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1answer
20 views

getAccounts in web3 js undefined

I am working on dapp with web3js 1.0.0.37-beta with reactjs. I got blank in web3.eth.getAccounts. Following is my code App.js import React, {Component} from 'react'; import '../node_modules/...
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1answer
258 views

Watch pending transactions with ethjs.js

I am trying to use ethjs.js to listen to pending transactions, but nothing really worked. Does anyone have a working example fetching pending transactions with ethjs.js? I have tried the following: ...
0
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2answers
19 views

Why is a failed transaction included in the blockchain as a “failed transaction”

According to this highest upvoted answer, "but still include it in the blockchain as a "failed transaction"... What is meant by the term "gas"?
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1answer
101 views

Serving DApp on webserver or IPFS won't work

I can succesfully run the webpack truffle box on my webserver, but if I try to run a DApp which I made by using the pet-shop truffle box as template, I can only use it on localhost. When I upload the /...
0
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1answer
15 views

Can i use a the msg.sender which is a address to call a function of the contract?

I am trying to mint a ERC721 token using openzeppilin/contracts. It was working correctly, but later had to change the design. So now i am forced to use the msg.sender who is the minter to call the ...
1
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2answers
32 views

Decentralized Time server to get time in Dapps? [closed]

So basically i want to ask that how can we programmatically get the accurate, exact and current time in a DApp, without relying on the system's time or a centralized time server ? Is there a ...
0
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0answers
5 views

Prompt Metamask to send eth with Web3

I understand this as the pattern to send a transaction with web3: web3.eth.sendTransaction({ from: myaddress, to: toaddress, data: web3.eth.abi.encodeFunctionSignature('whitdrawETH()') ...
0
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1answer
41 views

Best options to host an ethereum react dapp to a custom domain

I'm looking for best options to host an ethereum dapp created using react and drizzle, with the following requirements: It needs to be hosted in a custom domain (.com / .net / OR .io ) that I have ...
0
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1answer
83 views

Invalid JSON Response while connecting DApp, Metamask and Backend

I am getting some error(picture below) while trying to connect DApp with a backend. One day ago, everything worked fine, now I got an error: "basic auth failure". Contracts are deployed on Ropsten ...
2
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0answers
41 views

Android Studio And Ethereum?

how i can connect android studio application with Ganache? i'm trying to build an application on android (that is my Front end) with a Smart contract (Back end) on my private Blockchain (Ganache). it'...
2
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1answer
23 views

One general contract for all or spawn new one for each instance?

What be the advantages vs. disadvantages or running a general contract or spawning a new one for each instance. Let say, that I am providing a contract so people can create their own crowdfunding. ...
0
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1answer
21 views

Call approve function() doesn't work

myContractInstance.methods.approve('0x...', 300).call(function(error, approve){ if(error){console.log(error)}; if(approve){console.log("allowance for this address :"+ approve)}; ...
0
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1answer
47 views

How to connect a dapp on private ethereum network [closed]

I created a private ethereum network with 3 nodes kai i have also created a dapp. How i can connect my dapp with my private network? Thank you!
0
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1answer
21 views

time order when calling functions of smart contract

How can I check that the miner actually execute the right order of smart contracts function calls, if there is a necessity of orders?
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1answer
75 views

Design Dapp with Kotlin front end

To develop Dapp using Kotlin programming language for the front end design, Where should I place this code? and what it should be changed? <script> // Connect a the web3 provider ...
0
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1answer
25 views

Cannot fetch account details

const accounts = await web3.eth.getAccounts() //sets the state of the account as a part of the constructor. console.log(accounts[0]) Id used the above code to display the account information of ...
0
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1answer
301 views

web3 Uncaught TypeError: Cannot read property 'createBox' of undefined

i'm trying to create simple application by using solidity 5.0.0 , Truffle v5.0.0 and web3 web3@1.0.0-beta.34. but i've gotten Uncaught TypeError: Cannot read property 'createBox' of undefined. ...
0
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1answer
45 views

dApp exploit using multiple wallets

Im currently building a dApp where users will create content that then can be bet on by other users. The design opens up the problem of a user creating content,logging in with another wallet address, ...
3
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0answers
28 views

Nonce question please [duplicate]

can I have the meaning of the word Nonce explained please the question is rejected .. you people really do not wish there to be normal understanding by normal every day members of the public
0
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1answer
24 views

Easier Installation of privatenode for non-technical users

I have seen documentation of creating privatenet using geth. But it holds few commands which will not be a better option for users/clients who doesn't have technical knowledge to use the application ...
0
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1answer
22 views

Can Dapp respond to an API evocation which in turn calls an EOA and then evoke a contract?

Can a Dapp (leveraging web3.js) respond to an API evocation from an external system which in turn calls an EOA and then evoke a contract on the blockchain? External system calls a Dapp Dapp calls a ...
0
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2answers
29 views

condition check of struct mapping in solidity?

struct User { string username; string password; address userid; bool isAdmin; } mapping (uint => User) users; function checkIfUserExists(address userid) public ...
2
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2answers
31 views

Geographic location in Solidity

Does solidity have a way of fetching a persons geographic location(using something like msg.sender)? Im building a dApp for national elections, and would need to verify the geographic location before ...
0
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1answer
23 views

Can a Coin be liquid during its ICO period?

I am planning to run a Coin's ICO for several years, not interested in the gains to be made from selling out ICO in 3 days NO, but interested in using the COin to end Global Poverty as i deem fit. So ...
0
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1answer
14 views

Should I convert Centeralised web app to Multichain because it is free to use and more secure compare to webapp?

I am Web app developer and exploring the blockchain technology from few months. I want to convert the live centralized WebApp to Decentralized Blockchain application. I know there is a high cost ...
0
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1answer
15 views

Is it possible to instantiate a deployed contract in js using contract address alone? without copying abi data?

Is it possible to instantiate a deployed contract in js(dapp) using contract address alone? without copying abi data?
0
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1answer
22 views

Can Dapps set cookies

Is it possible for a Dapp that uses the metamask/chrome to set up a browser cookie? or can a cookie set by another website like facebook, read some information or at least know that a dapp has been ...
0
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3answers
579 views

Create a DApp using Geth

I need to create a sample DApp from scratch within a private blockchain using Geth. Can anyone post links of sample apps which have been made in such a way for reference.
0
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2answers
23 views

do users should be aware of smart contract of the dApp they are using?

So dApps are frontend + contract. Users interact with smart contracts via frontend. Do users i.e. people should be aware of how the contract is designed while using any dApp? are their any risks of ...
1
vote
1answer
73 views

How to call a contract function that alters blockchain state on geth console

It should be easy, but I'm having a hard time using a simple smart contract described in the Solidity language reference called SimpleStorage. It only as one attribute, a setter and a getter, and I'm ...
0
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0answers
16 views

Error using drizzle and react

My contract Storage.sol - pragma solidity ^0.5.0; contract Storage { string public data; function getData() view external returns(string memory) { return data; } function setData(...
0
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1answer
25 views

How do dapps connect to blockchain network?

Once the simple blockchain web applications runs on the web browser it uses the metamask to connect to the blockchain network, when it comes to mobile applications how the application connects to ...
0
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1answer
35 views

Execution of sending transaction never ends [UPDATED]

I send a transaction with web3 1.0.0 from a script like: async function sending(deployed_contract) { await deployed_contract.methods.mymethod(1).send({from: account}) .on('...
1
vote
1answer
28 views

can etherscan.io show local ganache transaction details?

I am purchasing tokens on my sample Dapp with ganache-cli account using metamask. Metamask shows the confirm message and deduct the ether from total balance but in token section it still not update ...
0
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1answer
66 views

Calculating a minimum entry fee for a game based on typical minimum gas requirements?

I am creating a dApp that is a game where players compete for the prize pool and that pool is built from the sum of all the entry fees payed by the player at the start of the game. The player that ...
1
vote
1answer
55 views

MetaMask transaction popup opens on another computer

We have two computers on the same local network with Static IP for internet. When Computer A calls a transaction through a DApp for an address X, Computer B Metamask is also getting triggered with the ...
0
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0answers
56 views

getWeb3ClientVersion() returns null

I'm trying to create an android Dapp by using the web3j library. I'm using connection to a local private Ethereum blockchain. When I'm trying to display the Client version it returns null. This is the ...
0
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1answer
24 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 ...
1
vote
1answer
51 views

Deployed Smart contract methods are not updating the value when restart the geth instance.Why?

Started Geth using following command geth --identity "testpvtnode" --rpc --rpcport "8545" --rpccorsdomain "*" --datadir <pvtnetdatapath> --port "30303" --rpcapi db,eth,net,web3,personal --...
0
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0answers
71 views

web3.eth.getAccounts() returns empty array

I'm trying to get accounts like that: window.web3.eth.getAccounts( (error, accounts) => { console.log(accounts, error) } ); but it keeps returning an empty array. I'm running Ganache and I can ...
1
vote
1answer
20 views

How to replace Metamask Pop-Up with my own UI

I was wondering if I can replace the Metamask pop-up with my own pop-up/user interface. Example: Currently on my dApp a user clicks "Buy Token" and a Metamask modal pops up and says the usual ...