Prediction and Betting dApp of Token Price（by using Amberdata.io and Chainlink Oracle）

Introduction of Prediction and Betting dApp of Token Price

• Prediction and Betting dApp of Token Price is a decentrailized application which is created by Amberdata.io and Chainlink Oracle.
• In this dApp, users predict token price of MKR token.
  • Token address of MKR： "0x9f8F72aA9304c8B593d555F12eF6589cC3A579A2"
  • Metrics of MKR（Can check latest token price here）： https://amberdata.io/addresses/0x9f8f72aa9304c8b593d555f12ef6589cc3a579a2/metrics

• Prediction and Betting dApp of Token Price works on Ropsten Testnet right now.

Introduce using process of this dApp

• Post of how to use this dApp
  https://medium.com/@masanoriuno_75621/prediction-and-betting-dapp-of-token-price-by-using-amberdata-io-and-chainlink-1c0b45490ebc

UI and process of Prediction and Betting dApp

Once you follow the previous steps, your browser should display the page below at http://localhost:3000/. If the page is blank, try logging in to your MetaMask add-on.

Before installation

• Install npm

• Install truffle globally using:

npm install -g truffle

• Install the Metamask add-on to your browser and create a wallet.
  Note down the mnemonics. Fund it with Ropsten ETH and Ropsten LINK.

• Create an Infura account, get an endpoint URL for the Ropsten testnet and note it down.

• (Optional) Install Visual Studio Code

Installation

• ① Clone this repo using:
  git clone git@github.com:masaun/amberdata_chainlink_oracle_integration.git

• ② Go to the main directory (/amberdata_chainlink_oracle_integration)

• ③ Install the dependencies for the smart contract:
  npm install

• ④ Create the file that you are going to enter your Infura credentials:
  cp wallet.json.example wallet.json

• ⑤ Open the newly created wallet.json file and enter the mnemonics and the endpoint URL you have noted down earlier, similar to wallet.json.example.

• ⑥ Deploy the contract (Ropsten LINK will be transferred from your wallet to the contract automatically during deployment)
  npm run migrate:ropsten

• ⑦ Go to the front-end project directory (/amberdata_chainlink_oracle_integration/client)

• ⑧ Install the dependencies for the front-end project:
  npm install

• ⑨ Start the server
  npm run start

• ⑩ Access browser
  http://localhost:3000/

Recommendation when setup

• After process of ⑥(Deploy the contract) above, it is better to transfer LINK token from Chainlink fancet on ropsten below to deployed contract address. （Chainlink fancet on ropsten below are able to transfer 100 LINK）
  https://ropsten.chain.link/
  • In this case,
    • deployed contract address of "PredictionAndBetting" is "0x1E471587D723bD45B31FfFC0819054C0Ac917cE2"
      ↓
  • In this case above, developer should send some amount LINK to deployed contract address of "PredictionAndBetting" ( "0x1E471587D723bD45B31FfFC0819054C0Ac917cE2" ) in advance.
    (In case developer send via chainlink-fancet below link, it can send 100LINK)
    https://ropsten.chain.link/

References

• Amberdata medium
  • Developer Challenge: Scale DeFi & Digital Assets
    https://medium.com/amberdata/developer-challenge-scale-defi-digital-assets-d71015200325

• Amberdata document
  • Price Token Historical
    https://docs.amberdata.io/reference#get-historical-token-price

• Amberdata Chainlink (Testnet)
  https://docs.chain.link/docs/amberdata-chainlink-testnet#config

• amberdata/amberdata-example-chainlink
  https://github.com/amberdata/amberdata-example-chainlink

• Tools related to chainlink（on Ropsten Testnet）
  • Chainlink fancet
    https://ropsten.chain.link/
  • Chainlink Explore
    https://ropsten.explorer.chain.link/