PY: Reblogging Post

Full, runnable src of Reblogging Post can be downloaded as part of: tutorials/python (or download just this tutorial: devportal-master-tutorials-python-14_reblogging_post.zip).

Tutorial will also explain and show you how to sign/broadcast transaction on Hive blockchain using the beem library.

Intro

Beem has built-in functionality to commit transaction and broadcast it to the network.

Also see:

• custom_json_operation

Steps

1. App setup - Library install and import
2. Post list - List of posts to select from trending filter
3. Enter user credentials - Enter user credentails to sign transaction

1. App setup

In this tutorial we use 3 packages, pick - helps us to select filter interactively. beem - hive library, interaction with Blockchain. pprint - print results in better format.

First we import all three library and initialize Hive class:

import pprint
from pick import pick
import getpass
import json
# initialize Hive class
from beem import Hive
from beem.discussions import Query, Discussions
from beem.comment import Comment
from beem.transactionbuilder import TransactionBuilder
from beembase.operations import Custom_json

# hive = Hive(['https://testnet.openhive.network']) # Public Testnet
hive = Hive(['http://127.0.0.1:8090']) # Local Testnet

2. Post list

Next we will fetch and make list of accounts and setup pick properly.

q = Query(limit=5, tag="")
d = Discussions(blockchain_instance=hive)

#author list from hot post list
posts = d.get_discussions('hot', q, limit=5)

title = 'Please choose post to reblog: '
options = []
# post list
for post in posts:
  options.append('@' + post["author"] + '/' + post["permlink"])

This will show us list of posts to select in terminal/command prompt. And after selection we will get formatted post as an option variable.

3. Enter user credentials

Next in order to sign transaction, application asks for username and posting private key to sign transaction and broadcast it.

# get index and selected post
option, index = pick(options, title)
pprint.pprint("You selected: " + option)

comment = Comment(option, blockchain_instance=hive)

account = input("Enter your username? ")

tx = TransactionBuilder(blockchain_instance=hive)
tx.appendOps(Custom_json(**{
  'required_auths': [],
  'required_posting_auths': [account],
  'id': 'reblog',
  'json': json.dumps(['reblog', {
    'account': account,
    'author': comment.author,
    'permlink': comment.permlink
  }])
}))

wif_posting_key = getpass.getpass('Posting Key: ')
tx.appendWif(wif_posting_key)
signed_tx = tx.sign()
broadcast_tx = tx.broadcast(trx_id=True)

print("Reblogged successfully: " + str(broadcast_tx))

If transaction is successful you shouldn’t see any error messages, otherwise you will be notified.

Try it

Click the play button below:

To Run the tutorial

You can launch a local testnet, with port 8090 mapped locally to the docker container:

docker run -d -p 8090:8090 inertia/tintoy:latest

For details on running a local testnet, see: Setting Up a Testnet

1. review dev requirements
2. git clone https://gitlab.syncad.com/hive/devportal.git
3. cd devportal/tutorials/python/14_reblogging_post
4. pip install -r requirements.txt
5. python index.py
6. After a few moments, you should see output in terminal/command prompt screen.