Repository
https://github.com/holgern/beem
beem is a python library for steem. beem has now 495 unit tests and a coverage of 70 %. The current version is 0.20.20.
I created a discord channel for answering a question or discussing beem: https://discord.gg/4HM592V
The newest beem version can be installed by:
pip install -U beem
or when using conda:
conda install beem
beem can be updated by:
conda update beem
New Features
The amount in the Amount class is stored as Decimal and not as float anymore
The amount in the Amount class is now stored as Decimal object:
from beem.amount import Amount
a = Amount("6.104 STEEM")
a
6.104 STEEM
a.amount
Decimal('6.104')
For compatibility reasons, I have decided to keep the floating point arithmetic. For example, when I have 6.104 and I want to sent 1/6 out to the six different people, I should have a reminder of 0.002 in my wallet, as 6.102 is nearest number which is dividable through 6 without reminder.
a = Amount("6.104 STEEM")
send_amount = a / 6
print(send_amount)
for i in range(6):
a -= send_amount
print(a)
results in
1.017 STEEM
0.000 STEEM
Seems that we have lost 0.002 STEEM. The reason is that the send_amount has a higher precision that the allowed one.
send_amount.amount
Decimal('1.017333333333333333333333333')
Fixed-point arithmetic
In order to fix this, I added a new option fixed_point_arithmetic, when set to True, the amount is rounded down after each operation to the allowed precision.
a = Amount("6.104 STEEM", fixed_point_arithmetic = True)
send_amount = a / 6
print(send_amount)
for i in range(6):
a -= send_amount
print(a)
results in
1.017 STEEM
0.002 STEEM
This time, we do not lost the 0.002 STEEM, as the amount in send_amount is rounded:
send_amount.amount
Decimal('1.017')
But the following calculation may not lead to the expected results:
a
0.002 STEEM
(a / 1000) * 1000
0.000 STEEM
Fixed-point arithmetic combined with Floating-point arithmetic
It is also possible to combine both. In the following example, an object keeps its unlimited precision and works with floating-point arithmetic. The send_amount object is rounded down to the precision of 3.
a = Amount("6.104 STEEM")
send_amount = Amount(a / 6, fixed_point_arithmetic=True)
print(send_amount)
for i in range(6):
a -= send_amount
print(a)
results in
1.017 STEEM
0.002 STEEM
We were able to achieve the wanted results. In the same time, calculation as the following are still possible:
(a / 1000) * 1000
0.002 STEEM
Casting to float, str and integer
It is possible to cast a Amount object to a float, in this case the amount is not rounded down:
float(Amount("1.999 STEEM") / 2)
0.9995
During casting the object to an integer, it is rounded down to the defined precision:
int(Amount("1.999 STEEM") / 2)
999
The integer is used, when casting the amount object to a dict, which can be used for broadcasting using the appbase format:
(Amount("1.999 STEEM") / 2).json()
{'amount': '999', 'nai': '@@000000021', 'precision': 3}
It is also possible to cast the amount object to a string:
str(Amount("1.999 STEEM") / 2)
'0.999 STEEM'
In both casting functions, the new quantize function is used:
def quantize(amount, precision):
# make sure amount is decimal and has the asset precision
amount = Decimal(amount)
places = Decimal(10) ** (-precision)
return amount.quantize(places, rounding=ROUND_DOWN)
The quantize grantees that casting an amount to a string and to an integer returns the same results.
Bug fixes
one-time private key on beempy
I implemented the first part of the suggestion from @blockchainstudio (post where he suggested that a key should be entered when it is not stored in the wallet.
I modified the unlock_wallet function and changed the wallet password promt as follow:
password = click.prompt("Password to unlock wallet or posting/active wif", confirmation_prompt=False, hide_input=True)
try:
stm.wallet.unlock(password)
except:
try:
stm.wallet.setKeys([password])
print("Wif accepted!")
return True
except:
raise exceptions.WrongMasterPasswordException("entered password is not a valid password/wif")
These changes allow it now to broadcast a operation as a transfer from an account by entering not the wallet key but the active key. This active key is temporary stored in RAM and deleted afterwards.
Fix issue #171 - Account.get_balance function shows summed value of liquid balance and unclaimed reward
The bug described here has been fixed. Calling the total_balances property had modified also the balances in the account object when either saving balance or reward balance was not empty. The reason was the usage of +=
which had modify the object itself. By replacing the used += by a = which can be seen here:
and by using a copy of the balance objects, this bug could be fixed:
@property
def available_balances(self):
""" List balances of an account. This call returns instances of
:class:`beem.amount.Amount`.
"""
amount_list = ["balance", "sbd_balance", "vesting_shares"]
available_amount = []
for amount in amount_list:
if amount in self:
available_amount.append(self[amount].copy())
return available_amount
Commits
Make a copy of balance objects
- commit f0eaffe
- Adapt version number in doc
Make return argument in generator function compatible to python 2.7
Fix cli unit test
Convert Decimal to float in pricehistory
Fix unit test for the amount class
Fix issue #171 - Account.get_balance function shows summed value of liquid balance and unclaimed reward
Add option to use fixed-point arithmetic on the Amount class
- commit 15aff5f
- When fixed_point_arithmetic is set to True, is the amount parameter always be rounded down to the asset precision
- Add Handling of multiplying with a Price object
- Both parameter are rounded down to the precision in all comparison operation as ==,
Cast amount to float for calculations
Use decimal for amount in the Amount class
- commit bde5380
- change the internal representation of amount from float to Decimal
- Round amount down to precision
- Adapt amount test to Decimal
- Round down all other number in all operatio
Improve all generator functions in account
- commit 13424bd
- set num_retries to a default of 100, in order to prevent crashing when a wrong node is set
Fix issue #162 - one-time use private key can be entered instead of unlocking the wallet
- commit 4a85f37
- prepare next beem release and increase version number
- switch default chain to STEEMAPPBASE
Good write-up on fixed-point/floating point arithmetics. :) I had a similar problem on sponsor payments at dPoll.
The update is well-covered and includes good examples. The Changelog is clear. Keep it up! :)
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Thank you for your review, @emrebeyler! Keep up the good work!
You received an automatic upvote, because I believe in you and I love what you create! 😉
A huge hug from @amico! 🤗
😍 I love promoting @steembasicincome, even with #sbi-skip! 😜
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Thank you for implementing one-time use private key and mentioning me! Also thanks for merging the typo-fix :)
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