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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1answer
36 views

If Cryptokitties could take so much computing power in Ethereum network, how can the network support dapps with scale?

There has been so much hype about developing dapps on Ethereum. However, even transactions of cryptokitties could clog the network, how could Ethereum network ever support some application like ...
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1answer
248 views

Which ethereum dapps are 100% decentralized and not semi-decentralized (centralized)?

Correct me if I'm wrong here, but I see dapps as independent solo code that you can download to you computer and it interacts with the Ethereum blockchain. Looking at crypto kitties, you have to ...
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1answer
1k views

Web3 not defined

I am following this tutorial here: https://medium.com/@merunasgrincalaitis/the-ultimate-end-to-end-tutorial-to-create-and-deploy-a-fully-descentralized-dapp-in-ethereum-18f0cf6d7e0e after running ...
2
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1answer
560 views

Sign Ethereum contract transaction w/ web3 on back-end?

How do I directly import via Private Key an account to the web3 library so it can get called by functions like myContract.methods.myMethod().call() & myContract.methods.myMethod().send()? I am not ...
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1answer
3k views

How to store small database, editable data on blockchain accessible by smart contract?

New to blockchain and smart contracts. Been doing research and I realize I can't update my transaction smart contract. Is it possible to store database data as an entry to the ledger or in another ...
2
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1answer
240 views

MetaMask/Web3js ERR_CONTENT_LENGTH_MISMATCH issue

I've deployed my contract with a UI to Ropsten via truffle and ran npm run build and npm run dev to start the server. As soon as I launch localhost (with the account in MetaMask selected) in the ...
2
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1answer
249 views

dapp based on ethereum for identity of a person

I have started taking interest in smart contracts and got to understand solidity and erc20 tokens a bit. Still I am not able to understand how can I design a dapp based on ethereum which can be used ...
2
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1answer
558 views

is there a platform for hosting APIs similar to AWS Lambda, only decentralized?

I'm looking for a platform that enables to place serverless code for Dapps, without cloud services - so that app can remain completely centralized.
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1answer
616 views

Where are DApps hosted?

Certain functionality of a DApp can be hosted on the blockchain as smart contracts. How about other resources such as HTML and JS files? Multiple places reference "Swarm" as the place to host these ...
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2answers
967 views

Using Dapps with Mist / Parity

on http://dapps.ethercasts.com/ there are so many dapps. I want to use them. How can I do? Tried it with geth/mist. Since geth does never completely sync, I use it as --light. Then start Mist, the ...
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1answer
576 views

How to validate information on the network?

This question details sending a message with Ethereum :How do I send an arbitary message to an Ethereum address?. Say we have two parties P1 & P2 , if P1 sends a message to P2 how can P2 verify ...
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1answer
173 views

Purpose of mist wallet browser . Why doesnt Etheruem supports normal browser

I still don't understand the need for a dedicated browser like Mist. What are the challenges involved in using a normal browser for decentralized apps ?
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1answer
2k views

How to pass an array as the function parameter?

I meet the same problem as this question: Passing an array as a parameter from javascrpt (web3) to a Solidity function If I call my function in the browser-solidity with the parameter [122,44], it ...
2
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1answer
385 views

Need an example to make a state variable reactive in Meteor

I'm having trouble properly understanding Meteor's reactivity and it's relation to contracts. I've included the Ethereum Meteor packages ethereum:web3 and ethereum:blocks and read that EthBlocks....
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2answers
5k views

Building Web based UI for Smart Contract

I am struggling to get some tutorial on building web based UI to interact with smart contract. I found examples on using web3 but it uses localhost:8545. However, my understanding is that web based UI ...
2
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1answer
902 views

Ethereum Wallet: error of no key for given address or file

In etherum wallet I am getting an error of no key for given address or file during deployment of the contract. What will be the reason for the same? contract User{ string public userName; ...
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0answers
127 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'...
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0answers
56 views

How shoud I properly initialize DApp and get account address?

I am writing DApp in react, and basically I want to initialize web3, unlock account, and display it. Having web3 in my package.json In the onload I've tried to go following: let Web3 = require('web3')...
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0answers
28 views

Suck at JavaScript and overall just a beginner in the dev world. Whats the best way to begin building DApps? [closed]

Suck at JavaScript and overall just a beginner in the dev world. Whats the best way to begin building DApps? The title is my question LOL.
2
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1answer
279 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
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1answer
35 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. ...
2
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1answer
299 views

How to transfer eth to a solidity function from a Dapp

I am trying to build a Dapp which includes functionality to deposit funds to a contract and withdraw them. The functions look like this function fundContract() public payable { require (msg....
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0answers
1k 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 ...
2
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1answer
332 views

Calling function from another contract reverts

I've been developing a dApp that needs ERC721 tokens. I have three contracts, a base contract, the one to mint tokens and another one for auctions. The inheritance looks like Base > Token > Auctions. ...
2
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0answers
203 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 ...
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2answers
578 views

Detailed tutorial for DApp programming [closed]

I am new to node js and I tried to follow some tutorials to understand it. But, when I started writing DApp code, I get lot of errors like this (calling smart contract functions from app.js). I face ...
2
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1answer
261 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 ...
2
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0answers
626 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
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1answer
285 views

Can i delete some old files inside chaindata folder?

I am running geth with fast sync, Can i delete some old files inside chaindata folder so that my ssd will have some empty space or it will create some problems ?
2
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1answer
222 views

How do I get access to uPort from a mobile Browser

I've developed a simple DApp that uses uPort and it works fine on Desktop - where I can login through uPort with the QR Code. On a mobile browser (Anrdoid Chrome) I'm auto directed to uPort where it ...
2
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2answers
2k views

Diffrent between smart contract and dapp [duplicate]

I struggle with the following questions about definitions. Is a dapp just the implementation of a smart contract? So when someone says he is writing a smart contract he is actually writing a dapp? ...
2
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1answer
831 views

How to find bootnode IP Addresses for Ethereum testnet (Ropsten and Rinkeby)?

I am trying to develop a simple Voting app by following a tutorial on the net. I want to deploy my dapp to the testnet. To do this I am using the bootnodes as mentioned in the tutorial (below), but ...
2
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0answers
424 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
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2answers
146 views

Possible to search swarm or blockchain?

I'm getting my feet wet in this blockchain world and looking to build a dapp based on Ethereum for maintaining an inventory of products. About 400,000 items that can be updated, removed or added to by ...
2
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1answer
280 views

How do I capture a smart contract function return values when changing the contract status? [duplicate]

pragma solidity ^0.4.6; contract Demo { uint a; function set(uint b) returns (uint) { a = b; return a * b; } function get() constant returns (uint) { return ...
2
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0answers
52 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
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0answers
37 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
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0answers
69 views

How do I edit a contract already in the blockchain? [duplicate]

I have a contract currently in the chain and I want to add a feature. Do I need to make a brand new contract, or is there a better way? And if I have registered the contract with a name can I ...
2
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0answers
65 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 ...
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3answers
799 views

comparing two addresses

I'am trying to create a modifier that allows certain accounts to execute functions. address[] authorized; function verify (address adrs) internal view returns (bool) { bool exist; ...
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2answers
375 views

How are truffle artifacts different from ABI?

How are truffle artifacts different from ABI? Do Truffle artifacts include fields that are different from ABI that is generated using remix?
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3answers
6k views

How to generate Private key, public key and address

I can't find any documentation online about doing this in Javascript other than this. I want to know how does authentication work in a ethereum dApp's.. As per my understanding user seed somehow gets ...
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2answers
6k views

What are the advantages of creating a dapp over a normal web application?

A lot of dapps seem like nothing new to me and the added benefit of creating a dapp seems very minimal besides decentralization.
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3answers
3k views

Cannot connect to Parity from browser UI

I am not able to connect to Parity via the browser UI. I have tried multiple times with different tokens generated by running the command parity signer new-token on the node where parity is running. ...
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3answers
163 views

a question about oraclize api

anyone know how oraclize api is working. I read the source code files on github.com/oraclize/ethereum_api . it need a "__callback" function in my contract to receive the result, is it means there has ...
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3answers
1k views

To run a dapp is it required to download the full blockchain?

In this article https://medium.com/@mvmurthy/ethereum-for-web-developers-890be23d1d0c the author writes that This means, every person who wants to interact with a dapp (Decentralized Application)...
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1answer
416 views

Is it possible to embedd the UI of DApp in the blockchain?

I have read the answers for this question as well as their linked resources, but I didn't found the answer for the following question: is it possible to embedd the UI of ÐApp in the blockchain? If I ...
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2answers
162 views

Invalid opcode exception when trying to resize a storage array

I wrote this function: function removeClaim(uint256 _claimId) public returns (bool success) { require(msg.sender == owner || msg.sender == claims[_claimId].issuer); // Emit event and store ...
1
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1answer
95 views

Metamask not showing localhost “7545”

A happy new year to you all. I am trying to make a decentralised application. Everything was going well until I came across a snag. Metamask does not show localhost "7545" which I need to connect the ...
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3answers
797 views

Alternatives to Metamask

What are existing alternatives to metamask with that works online inside existing browsers, that don't require installing a browser extension? What are some of the tradeoffs between them?

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