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Hands-On Blockchain for Python Developers

You're reading from  Hands-On Blockchain for Python Developers

Product type Book
Published in Feb 2019
Publisher Packt
ISBN-13 9781788627856
Pages 450 pages
Edition 1st Edition
Languages
Concepts
Author (1):
Arjuna Sky Kok Arjuna Sky Kok
Profile icon Arjuna Sky Kok

Table of Contents (19) Chapters

Preface 1. Section 1: Blockchain and Smart Contracts
2. Introduction to Blockchain Programming 3. Smart Contract Fundamentals 4. Implementing Smart Contracts Using Vyper 5. Section 2: Web3 and Populus
6. Interacting with Smart Contracts Using Web3 7. Populus Development Framework 8. Building a Practical Decentralized Application 9. Section 3: Frontend Decentralized Applications
10. Frontend Decentralized Application 11. Section 4: Cryptocurrency and Wallets
12. Creating Token in Ethereum 13. Cryptocurrency Wallet 14. Section 5: Decentralized Filesystem
15. InterPlanetary - A Brave New File System 16. Using ipfsapi to Interact with IPFS 17. Implementing a Decentralized Application Using IPFS 18. Other Books You May Enjoy

Building the GUI frontend for the Twitter–like application

Now let's build a decentralized GUI application. Name the script twitter_dapp.py. Refer to the code file in the following GitLab link for the full code: https://gitlab.com/arjunaskykok/hands-on-blockchain-for-python-developers/blob/master/chapter_07/dapp/twitter_dapp.py:

from PySide2 import QtCore, QtWidgets
import web3
from web3 import Web3, HTTPProvider
from populus.utils.wait import wait_for_transaction_receipt

w3 = Web3(HTTPProvider('http://localhost:7545'))

...
...

if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
twitter_dapp = TwitterDapp()
twitter_dapp.show()
sys.exit(app.exec_())

Let's dissect this script line by line. Here, we import the necessary classes and set our web3 object to Ganache, which serves the smart contract in port 7545 of...

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