Deploying a smart contract using DApp

Question

I am new to the development of DApps on ethereum blockchain. I want to make a contract Management System in which users can generate their own tokens and crowdsale using my web application. I am able to interact with an already deployed contract but I don't know

1. how some one can deploy their crowdsale using my DApp.
2. I have no idea about how to connect with the Metamask and users account using my application and finally
3. how to deploy that web application on server and a domain.

Any help will be appreciated. Thanks

Answer 1

1) how someone can deploy their crowdsale using my DApp.

You can deploy the contract from WebUI using Web3.js or truffle.

I have no idea about how to connect with the Metamask and users account using my application

You can integrate metamask with your web application using the below code.

$(function () {  // equivalent to $(document).ready(...)
if (typeof(web3) === "undefined") {
error("Unable to find web3. " +
      "Please run MetaMask (or something else that injects web3).");
} else {
log("Found injected web3.");
web3 = new Web3(window.web3.currentProvider);
...
}   
});

3) how to deploy that web application on a server and a domain.

Use AWS services to host user website and Route 53 for mapping domain name with EC2 instance.

Answer 2

At first you need to write and compile token and crowdsale smart contracts. This will give you abi and bytecode.

Then you may deploy contracts from your DApp using Web3 API. This is done in two steps:

1. Construct contract object like this: var myContract = new web3js.eth.Contract (abi). For this step you will need ABI of your smart contract packed into JSON as generated by Solidity compiler.
2. Public deploy contract transaction like this: await myContract.deploy ({data: bytecode, arguments: [parameters]}).send ({from: account, gas: 1000000}). For this step you need contract bytecode as generated by Solidity compiler, constructor parameters (you may pass name, symbol, decimals, etc. here), and account to publish deploy transaction from.

How to use Metamask accounts from DApp is covered in Metamask FAQ. This will give you web3js object you may use. User accounts are available as web3js.eth.accounts. Note that user will probably need to explicitly allow your DApp to access his accounts.

About deployment, you may host your DApp on GitHub Pages as a quick start, and then buy a domain, e.g. on Google Domains or at any other domain registration service.