Twitter Ethereum DApp

Status

Working release for Ethereum local testnet

Overview

This project is a very basic Ethereum DApp, which listen for Tweets which contains a specific hashtag (#giveMeTSTToken) - "give me twitter streaming token". If such a Tweet appears, the application sends TST token to the specified ERC20 Smart Contract address. This code was written during the Swisscom Blockchain Academy Seminar "Ethereum for Developer", May 2019.

The code runs actually only on a local testnet

Requirements

Following tools are required:

Twitter Developer Account (You need a access token for the Twitter API)
Truffle
Homebrew (Mac packaging manager)
NPM
Python with various libraries

Project structure

The project structure is a Truffle and NPM project. With NPM we can add additional libraries if required and also manage all tools. With Truffle we have the testing framework.

twitter-DApp   
    ├── build   
    │   └── contracts                  # JSON builds from Ethereum smart contracts   
    ├── contracts                      # Contains all the Ethereum Smart Contracts   
    ├── migrartions                    # Contains scripts for Smart Contracts deployment for Truffle   
    ├── node_modules                   # npm packages   
    ├── contractJSONABI.json           # application binary interface (ABI), needed for for encoding/decoding data into/out of the machine code [Reference](https://ethereum.stackexchange.com/questions/234/what-is-an-abi-and-why-is-it-needed-to-interact-with-contracts)  
    ├── package-lock.json              # Describe a single npm representation of a dependency packages    
    ├── package.json                   # npm installtion packages is called by `npm install`
    ├── requirements.txt               # packages list for Python  (installed via pip)     
    ├── truffle-config.js              # Configuration file which setting up a single development network [Doc](https://www.trufflesuite.com/docs/truffle/reference/configuration)   
    ├── twitter_credentials_TODO.py    # Twitter API credentials file (have to be modified)   
    ├── twitter_streamer.py            # file which listening for Tweets

Step-by-Step installation guide for Mac

One of the easiest way is to use Homebrew for installation of Python3, NPM etc. Run this in your Terminal if you need to install Homebrew:
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

change twitter_credentials_TODO.py to twitter_credentials.py and fill in your own keys from the twitter developer account
Install npm (for mac: brew install node). Check if installation was successfull with: npm -v. If you already have npm Update NPM npm update or npm update --save
Download and install Ganache or npm install -g ganache-cli
Install Truffle: npm install -g truffle
[OPTIONAL] Install xcode developer tools separatly. If you have homebrewinstalled on your mac, xcode command line tools are already installed. xcode-select --install maybe you need additional configs according to Doc and Doc
Install virtualvenv for isolated Python environments:pip3 install virtualenv
Create isolated Python environment: first cd into project, secondvirtualenv venv
Activate virtual environment: source venv/bin/activate
Install dependencies: pip3 install -r requirements.txt

If you have made additional installations with pip3 run pip3 freeze > requirements.txt to rebuild requirements file for installtion dependencies.

To stop the isolated (venv)environment use command: deactivate

Run the code

Open command line tool (e.g Terminal for Mac)
cd into project folder
Start local testnet: ganache -cli (If you use Metamask, initialize Metamask with the Mnemonic which ganache-cli provides you)
Open a new Terminal tab cd into project folder and deploy Smart Contract on the local testnet: truffle deploy [OPTIONAL] Retrieve the addresses from deployed contracts if needed with: truffle networks
change the contract_address in method on_data(self, raw_data)from twitter_streamer.py with address provided after truffle deploy of the Smart Contract
change receiver_address in method on_data(self, raw_data)from twitter_streamer.py with your own (Metamask) address
Open a new Terminal tab cd into project folder and activate virtual environment: source venv/bin/activate
Choose the localhost network in Metamask
Add the TST Token to Metamask: add custom token-> paste contract address which was provided during truffle deploy -> Tokensymbol: TST
Start twitter_streamer.pyin a new Terminal with: python3 twitter_streamer.py
Post a Tweet on Twitter with hashtag: #giveMeTSTToken

Troubleshooting

Make sure you have started ganache-cli (maybe with with the right Mnemonic)
Make sure you initialized MetaMask with the exactly the same Mnemonic like from ganahce-cli

Future ideas (to do)

add functionality to set the recipient address in the tweet itself
make code running on Rinkeby test net. For that you need to specifie the private key manually in the code (not implemented yet)

0xjacobb/twitter-DApp