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.

164 questions with no upvoted or accepted answers
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Augur Project compile and debug

I starting to work on blockchain and dapps, would like to help with issues in augur can anyone explain how to debug or test run the application on my local machine to know how it works? i tried to use ...
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1answer
254 views

Is it possible to send ERC20 tokens to a smart contract that is written to accept payments..?

I have ERC20 compatible token that is already deployed in the ethereum main-net. I have a requirement to accept these tokens as payment, And this is going to be a new contract, The below are my doubts....
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245 views

Paying for gas on behalf of users?

I'm exploring ways to enable contracts/dApp owners to pay for gas on behalf of users. I know contact abstraction should enable this eventually, and the first step has been done with EIP208 which ...
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122 views

Toshi browser vs. Google Chrome browser to interact with Dapp?

Toshi is a browser to interact with Dapps such that after uploading our Dapp (including solidity smart contract, Javascript and HTML code) on a server, we can search our Dapp using its URL (ex: www....
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65 views

Distribution Contract Not Working

I'm trying to set up a distribution contract to send an ERC20 token to multiple addresses at the same time. After multiple attempts, the transfer keeps failing. Transactions are approved, the problem ...
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31 views

Keeping Contract Address, Web3 HttpProvider and Account Address away from the DApp UI/Frontend User

I am building with Quorum and Web3js. As I build the DApp UI/frontend, I realised that details such as address of the node, contract address and the account address (from:) are in plain text. One just ...
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147 views

how distributed cloud storage works with ethereum blockchain?

Distributed Cloud storage is a great concept , I have been doing a lot of search on this topic but couldn't get the exact information i am looking for:- How the projects like Storj are using the ...
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149 views

Can't transfer balance from contract to parent contract

I'm having trouble transferring remaining funds from a Contract to it's controlling Contract Factory. I'm trying to do the following. Create a new Service with Factory->createService() Add funds to ...
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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 ...
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1answer
220 views

Does it make sense to have a Node.js backend serving json to frontend for dapp?

Currently, the architecture I am looking at is that the smart contract (SC) sits on the ethereum network, but it is a complex and multilevel contract system. Just navigating through the tiers of the ...
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70 views

Blocking an application untill metamask shows the transaction is complete

I’m creating a DAPP where I’m using Metamask for submitting the transaction. I have a requirement where when a user accepts/submits the transaction, a modal needs to appear on the page, blocking the ...
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131 views

Token Contract Created by Factory Contract is not Showing up in metamask

I have a FactoryToken Contract Deployed and its function "newToken" Creates a new token contract. Every thing is working fine on Remix IDE but when i call the FactoryToken's function To create new ...
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389 views

System requirements running blockchain application

From an IT/infrastructure perspective (im not a developer) what are the system requirements to run a fully functioning blockchain application i.e based on ethereum for a small - medium sized business. ...
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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: ...
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523 views

sendRawTransaction fail with “Invalid Sender” on Ropsten but works on Local Node

I have a simple contract deployed successfully to the Ropsten test network using Remix (Verified using https://ropsten.etherscan.io) Same contract has been deployed to my local private node and I ...
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78 views

Will Dapps in production be able to buy and use SaaS solutions?

SaaS services help centralized organizations or apps solve their business problems. For example, Google Apps offers startups as an easy solution for company email and document storage. The sales ...
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1k views

NetworkError when attempting to fetch resource

I'm getting this error in Firefox when running a dApp: Error: NetworkError when attempting to fetch resource. Stack trace: InvalidResponse@http://localhost:8081/bundle.js line 995 > eval:38:16 ...
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135 views

how does a dapp work on mist?

Ive made a dapp work on my system without a geth node working with metamask. The idea is that every user that comes up to the website has to spend his own gas for the transaction, so in metamask a ...
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179 views

Can i post a data to the url in Ethereum smart contract

Actually i want to create a smart contract in ethereum for handling the api requests. creating a proxy kind of contract which makes note of the number of requests in the contract. Is it possible, any ...
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54 views

Ethcore: “The dapp cannot be reached”

On a private dev chain with two Ethcore nodes, I created a dapp as per the instructions at https://github.com/ethcore/parity/wiki/Tutorial-Part-I. Everything was OK and I can see the dapp listed in ...
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2answers
553 views

How to display blockchain transaction receipt details in an Ethereum Dapp

In my dapp design, I wish to provide the user with an option to view Blockchain Transaction Receipt Details either by a link to sites like Etherscan or by providing full details on a separate page in ...
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1answer
304 views

Is it possible to receive text messages (SMS) using ethereum?

Is it possible to build a dapp that can receive sms text messages?
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9 views

Payable function not working properly

Hi everyone hope I will be clear enough with the explanation because I couldn't find a proper solution. I am just trying to checkout an item with my buy function but it seems like I am stuck.Here is ...
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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
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 ...
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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()') ...
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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?
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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 ...
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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(...
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73 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 ...
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23 views

How to use the ipfs.get()?

I am new to IPFS. I added a file in IPFS and then, pinned it. Now, I am trying to retrieve the file. I am writing the code in React. Hence I used the following code: ipfs.get('/ipfs/...
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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 ...
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33 views

Hosting pet-shop DApp on IPFS - JSON Files problem

I am trying to host DApp "pet-shop" which one of the truffle boxes on IPFS. rsyncing of src, build/contracts and ipfs add files went very well and there are plenty of peers as seeders on the network ...
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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 ...
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39 views

How to filter MyEvent({ },{ }) to retrieve only the latest transaction in the array?

My code: instance.MyEvent({}, {fromBlock: 0, toBlock: 'latest'}).watch(function(error, event) { if (!error) { console.log(event); $('#events').html(event.transactionHash); } else { ...
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42 views

Timestamp is giving wrong time in smart contract

Today is June 17. but when I execute my function and store the following arguments. WriterModel(owner,postID, _postContent, now); "now", It returns the July 20 timestamp. It perfectly working fine ...
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22 views

Function returns always with the same input even it is in the loop..TRUFFLE+ANGULAR 7+WEB3

One of the function in Contract: function getPostCounts(uint _postID)public view returns(PostCountsModel memory postCounts){ return postCountOperations[_postID]; } This is the calling ...
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44 views

Why this error occurring when i running my dapp?

I create a dapp using Solidity,Web3Js,Javascript and Html with metamask i always getting this error when i am trying to submit my transition i am getting this error at c (inpage.js:1) at ...
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30 views

Drizzle Installation: pauses at fetchMetadata: sill resolveWithNewModule http-https@1.0

I am following this tutorial https://www.trufflesuite.com/tutorials/getting-started-with-drizzle-and-react. Everything is working smoothly until I have to npm install drizzle. I then run into the ...
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94 views

Error: The data field must be HEX encoded data

I am trying to make a simple dApp by using a tutorial. I am using the following command ; npm install ganache-cli web3 so that we can use web3 to get fake ethereum nodes/accounts by connecting it ...
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75 views

Can't connect to localhost:8545 while using ethereumjs-testrpc web3?

I am developing a simple Voting dApp by following a tutorial. In this tutorial we are using npm install ethereumjs-testrpc web3 so that we can get the fake nodes of Ethereum. For that i first ...
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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 ...
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How often should the Web3.py provider connection be shared in a django project?

My django project directory structure is the following ... projectRoot projectName __init__.py settings.py urls.py wsgi.py App1 __init__.py admin.py models.py ...
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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 ...
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23 views

Monetizing my dApp

I'm working on a project that will allow users to use our platform to auction stuff. Programatically, how would I convert this idea into a profit for me. I want to take a 3.75% fee from any won ...
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2answers
52 views

How do I send NFT assets (ERC721 Tokens) from my Ethereum wallet to someone else?

I want to send my ERC-721 to my friend. Fast. Any suggestions?
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11 views

Creating DApps over existing crypto

Can I create DApps over existing crypto in the network, if yes then please help me with some like or description of the process to create such DApps if anyone can point me some blog then it will be ...
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32 views

Can value of a public variable in Solidity be called and returned by web3?

How to get value of a public variable in Solidity be called and returned by web3?
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12 views

How to console.log the value in the React js for the Dapp + truffle project

I am beginner with the ReactJS and Dapp. In my js page I want to get the value after doing some operation on the input value and want to dispay that result. I got the Nan in the front-end screen. ...
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21 views

Is it safe for Ethereum Alarm Clock or Aion?

Scheduling service of EAC and Aion depend on participating users. Q1) is it safe for private keys of users? Would not it be possible to track the execution of the transaction and rob the private key?...