Hive Developer Portal
PY: Get Delegations By User
How to get a list of active or expiring vesting delegations using Python.
Full, runnable src of Get Delegations By User can be downloaded as part of: tutorials/python (or download just this tutorial: devportal-master-tutorials-python-29_get_delegations_by_user.zip).
In this tutorial we will explain and show you how to pull a list of both active and expiring vesting delegations from the Hive blockchain using the beem library.
The Hive python library has a built-in function to pull information from the blockchain. We are using the
get_expiring_vesting_delegations methods. Each of these functions are executed separately. It should be noted that when a delegation is cancelled the VESTS will only be available again after 7 days. The value of the delegation can also be changed at any time, either decreased or increased.
The function to query the expiring delegations use the the same parameters except that the
start_account is replaced by a
start_date. If this value is greater than 7 days from present, it will always include all delegations that are pending expiration.
- App setup - Library install and import. Connection to production
- User input - Input user and limit parameters
- Delegation lists - Selection of the type of list and blockchain query
1. App setup
In this tutorial we use 2 package:
beem- hive library and interaction with Blockchain
pick- helps select the query type interactively
We import the libraries and connect to the mainnet, for this tutorial.
from pick import pick from beem import Hive from beem.account import Account from beem.amount import Amount client = Hive()
2. User input
limit parameters are assigned via input from the console/terminal. We also check if the username provided does in fact exist on the blockchain using the
Account module. This will return an null value if the name does not exist.
# capture username account = input('Username: ') account = Account(account) balance = account['balance'] symbol = balance.symbol # we need high precision because VESTS denom = 1e6 dgpo = client.get_dynamic_global_properties() total_vesting_fund_hive = Amount(dgpo['total_vesting_fund_hive']).amount total_vesting_shares_mvest = Amount(dgpo['total_vesting_shares']).amount / denom base_per_mvest = total_vesting_fund_hive / total_vesting_shares_mvest
This block will help us convert VESTS to HIVE Power for display purposes. Best practice is to always allow the end-user to work with HIVE Power, not raw VESTS.
# capture list limit limit = input('Max number of vesting delegations to display: ') or '10'
3. Delegation lists
We use two different functions to query active and expiring delegations, so the user is given a choice on which of these lists he wants to view.
# list type title = 'Please choose the type of list: ' options = ['Active Vesting Delegations', 'Expiring Vesting Delegations'] # get index and selected list name option, index = pick(options, title) print('\n' + 'List of ' + option + ': ' + '\n')
Based on the result of the choice, the relevant blockchain query is executed and the result of the query displayed on the console/terminal.
if option=='Active Vesting Delegations' : delegations = account.get_vesting_delegations(limit=limit) else: delegations = account.get_expiring_vesting_delegations("2018-01-01T00:00:00", limit=limit) if len(delegations) == 0: print('No ' + option) exit for delegation in delegations: delegated_vests = float(delegation['vesting_shares']['amount']) / denom delegated_base = (delegated_vests / denom) * base_per_mvest print('\t' + delegation['delegatee'] + ': ' + format(delegated_base, '.3f') + ' ' + symbol)
For both the queries the starting points were defined in such a way as to include all available data but this can be changed depending on the user requirements.
Note that we output the delegated amounts as HIVE Power, in keeping with the principle of only interacting with the end user in terms of HIVE Power, which is the recommended best practice.
Click the play button below:
To Run the tutorial
- review dev requirements
git clone https://gitlab.syncad.com/hive/devportal.git
pip install -r requirements.txt
- After a few moments, you should see a prompt for input in terminal screen.