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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.

5
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0answers
555 views

Verify the ownership of an ethereum account

I have built a web game where users can purchase virtual items for their avatar with tokens obtained during an ICO. What is the best solution for delivering the items to the correct web game user? I ...
4
votes
0answers
204 views

Truffle hangs forever with parity with PoA

I'm trying to create a private chain using parity (PoA) and truffle but when I do truffle migrate it hangs forever with the following output: > [ > { > "jsonrpc": "2.0", &...
4
votes
0answers
53 views

EVM Invalid JUMP when using webpack app

I am creating a frontend app based on Truffle + Webpack, following this tuto : http://truffleframework.com/tutorials/building-testing-frontend-app-truffle-3, and have no uderstanding of JavaScript at ...
4
votes
0answers
104 views

Querystring in Parity Dapp frontend

I'm playing with local Dapp for Parity. When I'm trying to use query string in Dapp, I can't get it with js: I see that iframe is used inside, but have no idea, how to add query string there. Is ...
3
votes
0answers
86 views

Evaluation of DApp (Smart Contract) storage concept with IPFS

i hope you can help me improve or validate my storage concept. I am glad for each suggestion. Since this is my first DApp, i might not consider all possible options for my problem. To understand the ...
3
votes
0answers
47 views

Casting Object to BigNumber in Meteor DAPPs

Web3 incorporates the BigNumber library in order to handle 256bit numbers. I'm finding this problematic in Meteor as most of Meteor's reactive storage schemes such as Session, ReactiveDict and ...
3
votes
0answers
500 views

Pyethapp Build error: No files/directories in ..pip-build-gpzcs1\leveldb\pip-egg-info (fr om PKG-INFO)

I'm new to ethereum & do not have any ethereum clients 'installed'. I'm trying to install pyethapp in a clean virtualenv following the github tutorial, but it produces the following error. ...
2
votes
0answers
70 views

How to implement percentage deposit function to smart contract

I need to implement on the deposit function when the ownerAddress is doing a deposit a 10% to be freeze in the smart contract and and if the ownerAddress want's to call the returnDeposit function by ...
2
votes
0answers
149 views

Decentralized File Storage on Ethereum white paper

I am reading white paper of Ethereum, and I am confused by this example of the Section. Decentralized File Storage, which is part of the Section. Applications: The key underpinning piece of such a ...
2
votes
0answers
498 views

What is the best practice of a Dapp development mixed with Python/Django?

I've written and tested the Smart Contracts in Truffle, and now want to develop a front-end and a small back-end for my Dapp. So far, I preferred MVP frameworks, particularly Django. Therefore, what ...
2
votes
0answers
369 views

Send transaction with metamask and web3

I'm new to the topic but can I somehow sendTransaction via contract instance? What I'm missing here? I simply want to send some ether to contract. var abi =[ { "constant": true, "...
2
votes
0answers
50 views

show specific information to specific users in meteor dapp

if a have a dapp with different users, and each user has his/her own profile page they can log in to. On this profile page, the user should be able to change/add his user information (name, age, etc) ...
2
votes
0answers
32 views

How to return form data from an EthElements.Modal.question?

I'm trying to process data from an EthElements.Modal.question, however no event is passed when OK is clicked and this just points to the model call data and not the Template content.
2
votes
0answers
61 views

Why does Mist doest show up anything for me running on testnet

I just see a blank screen when I open Mist Browser on ubuntu running on testnet. What is the issue ? I couldnt start in the first place. But after using --ignore-gpu-blacklist I could start, Then I ...
1
vote
0answers
10 views

What is the difference in definition between both DApp and web-applicaion

Can I define a DApp as a web-app ? since a web-app is any computer program that performs a specific function by using a web browser as its client. What is the difference in definition between both ...
1
vote
0answers
10 views

Can I expose a dapp via whisper ?

I have a question regarding the possibility and probably the steps to do in order to be able to export my App via the whisper protocol. how to do it and in which case it can be better than other ...
1
vote
0answers
22 views

Our vendor created the IPFS and Ethereum platform to store the PDF documents. How do i use the same code in Desktop Application

I am a quiet layman in IPFS and Ethereum. Our vendor created the web application which stores the documents IN IPFS (Ethereum). Now, we do need to do the same in the desktop application also. ...
1
vote
0answers
331 views

web3.personal.newAccount() successfully created but not listed in ganache accounts.why?

I am using truffle framework for Dapp development and I am new in Blockchain.I used the command web3.personal.newAccount() to create a new account. But i cannot view this account when i take ...
1
vote
0answers
22 views

Is it possible to deploy Dapp on Etherium classic network and be listed in mist?

So as a small bisness entety can not pay 100k USD for app deployment, one wonders on is it possible to deploy Dapp not in the test net but in a more real ETC one?
1
vote
0answers
20 views

trading a secret message with some person only after money is paid

I want to build a DAPP where person A trades a message with person B for ether. Since the message is secret, person A encrypts the message by using public key of person B and stores the message in ...
1
vote
0answers
49 views

import packages in petdapp

I unboxed petdapp and done some editing where I need to import bcrypt-nodejs in app.js and used following steps. npm install bcrypt-nodejs --save npm install require --save app.js var bcrypt = ...
1
vote
0answers
22 views

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 ...
1
vote
0answers
155 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 ...
1
vote
0answers
113 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....
1
vote
0answers
52 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 ...
1
vote
0answers
29 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 ...
1
vote
0answers
137 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 ...
1
vote
0answers
136 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 ...
1
vote
0answers
69 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 ...
1
vote
0answers
354 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. ...
1
vote
0answers
448 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 ...
1
vote
0answers
71 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 ...
1
vote
0answers
919 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 ...
1
vote
0answers
134 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 ...
1
vote
0answers
155 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 ...
1
vote
0answers
53 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 ...
0
votes
0answers
6 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
votes
0answers
19 views

CORS policy error while connect to test-rpc

I'm trying to build my first dapp using test-rpc and web3js. I deployed a smart contract (with remix ide) to the testrpc (on linux ubuntu), when executing the following line: web3 = new Web3(new Web3....
0
votes
0answers
19 views

transaction not processing

The code below is for selling tokens to the smart contract, the INR_ETH.sellTokens() function calls the smart contract. but the code is not working properly, metamask asks for the "approve" part but ...
0
votes
0answers
34 views

Problem with Dapp in the browser

I'm trying to develop a voting Dapp, I have already created the Smart Contract and the js and html files. I have successfully migrated the contract into the Blockchain (I'm using Ganache), but when I ...
0
votes
0answers
45 views

Login to an ethereum dapp on sending a transaction?

I'm trying to build a sample dapp. The login process in ethereum dapps usually involves signing a message from metamask to prove ownership of an account. Is there a way we could design login in such a ...
0
votes
0answers
41 views

Sign a transaction locally and send it

I'm using Infura as my web3 provider, and have MetaMask installed to connect to the blockchain. I'm trying to send a transaction, but have learned that Infura is read-only, and doesn't support the ...
0
votes
0answers
38 views

Uncaught ReferenceError: TruffleContract is not defined (Truffle Pet Shop)

I'm writing my own application that follows a similar form to the Truffle Pet Shop. I have the following code in my app.js: initContracts: function(){ $.getJSON('Greeter.json', function(data) { ...
0
votes
0answers
32 views

Dapp design to handle delay in callback response from Oraclize

In my dapp design I am receiving few user inputs via a form and passing them to a smart contract. Inside the smart contract I am using Oraclize service to timestamp the user inputs. Its a known fact ...
0
votes
0answers
18 views

How to create periodical token minting with randomness?

The Problem: I need to create a contract that will automatically mint tokens with some kind of randomness. For example, mint up to 5 tokens every window of 30-50 blocks: block #100 - contract ...
0
votes
0answers
58 views

Can't deploy token to private network

I tried to implement a token from this page But when he tries to send it from the account, throws a error. Contract code: pragma solidity ^0.4.24; library SafeMath { function add(uint a, uint ...
0
votes
0answers
137 views

web3 metamask, synchronous or asynchronous

Hello I developed a dapp browser using the metamask provider repo https://github.com/MetaMask/provider-engine However when loading some notable dapps (that work with the metamask chrome extension) ...
0
votes
0answers
5 views

Smart contract events only allowed inside <Rspan> tag?

I'm trying to use the oo7-parity library to make a dapp. But I only have access to the events emmited by the smart contract inside the Rspan tag privided by oo7-react. Isn't there a way of calling the ...
0
votes
0answers
21 views

Problem with Distribution Contract

Whenever I try to execute it keeps showing FailedTransfer: pragma solidity ^0.4.16; contract Ownable { address public owner; function Ownable() { owner = msg.sender; ...
0
votes
0answers
139 views

parsing event result in DApp

I created a DApp that watch for specific event on blockchain and prints that event information to the console as shown below. code var AccessManagerERC20ContractAddress = "...