ethlottolib

Lib for interacting with the ethlotto smart contract

Install

npm install --save ethlottolib

Usage

import React, { Component } from 'react'

import Contract from 'ethlottolib'

class Example extends Component {
  state = {status: ''}
  connect = async () => {
    await Contract.connect(statusCallback=>{
      this.setState({status: statusCallback.status})
    });
    this.setState({status: 'connected'})
  }
  render() {
    return (
      <div>
        <button onClick={this.connect}>Connect to Ethereum</button>
        <div>{this.state.status}</div>
      </div>
  }
}

See /example/App.js for more a more comprehensive example.

Interacting with the Library

Check that the browser has an Etherium provider (for now Metamask on desktop browser and Trust Wallet on Android devices):

let hasProvider = await Contract.hasProvider();
/*
  If false - help the user install metamask.
*/

Call the connect method to connect to Metamask, and fetch information from the contract.

  await Contract.connect(statusCallback=>{
    //an optional callback to provide status info
    if(statusCallback.error) {
      //deal with error
      return;
    }
    this.setState({status: statusCallback.status})
  })

Once the connection process is complete, the following information is available:

  Contract.newEntry //Is this user a completey new user (true) or have they had previous entries
  /*In the example come you'll see we desplay different information for existing entries*/

  Contract.children //userIDs of the direct downline of the given node (depending on the referralID)

  Contract.pot //The minimum pot amount for the next game

  Contract.newGameReward  //The reward for succesfully running the next draw (5% of the pot)

  Contract.feeWei //the entry fee in WEI

  Contract.fee //entry fee in ETH

  Contract.balance //balance of the current metamask wallet

  Contract.entriesUntilNextDraw //the number of entries before the next draw can be initiated

  Contract.paidOut //the total amount paid out to members so far

  //The following only applies if Contract.newEntry is true:
  Contract.earned //the amount this user has earned that hasn't yet been withdrawn

  Contract.referralID //refferal ID for this user to invite people with

  Contract.accounts //A list of all the entries, as well as their value in earnings for this user

The following methods are also available:

  //assuming the context of within an async function:


  let success = await Contract.enter() //creates a new entry. Returns true if succesful

  let success = await Contract.withdrawEarnings() //withdraws earnings if earnings > 0 and this is not a new entry

  let success = await Contract.runNextDraw() 
  //attempts to run the next draw - if Contract.entriesUntilNextDraw==0 and this is an existing member
  

Connecting to Ethereum (ie. to the Smart Contract)

In order to connect with the smart contract an Ethereum provider is needed. In this case, the providers from Metamask (desktop) and Trustwallet (mobile - android) are used.

In the case of Desktop - check if Metamask exists. If not - direct the user to downloading metamask. If it exists - show a button to connect to Ethereum etc.

In the case of mobile you don't know if a user has trust wallet or not (It's a separate App, not a chrome plugin), so explain to the user that Trust wallet is required, and then provide a deep link into the DAPP browser of trustwallet (eg. https://link.trustwallet.com/open_url?url=https://wallet.ethlotto.club?u=x ). Trust wallet will either take the user through the download process, or take the user to the wallet DAPP. Best practice seems to be providing a 'connect to Ethereum' button, but in this case the user has explicitly asked to be taken to trust wallet already - so from a UX pov. it seems more efficient to just connect as the user hits't the site.

License

(Still need to figure out licensing - but for now, feel free to use the lib, as long as the contract addresses remain the same.)