Fix for ContractEvent.processLog() #2124

smishy05 · 2021-08-29T20:36:05Z

What was wrong?

Related to Issue #1648

For the python code (code-1.py),

from web3 import Web3
import json
json_file_path = "./abi.json"
with open(json_file_path, 'r') as j:
	contents = json.loads(j.read())
network_url = 'http://localhost:8545'
web3 = Web3(Web3.HTTPProvider(network_url))
address = "0x6a3d3c28e34b1c3e3813A29374D1CE49FbeC9200"
acontract = web3.eth.contract(address=address, abi=contents)
tx_hash = acontract.functions.getValue(5, 10).transact({'from': web3.eth.accounts[0]})
receipt = web3.eth.get_transaction_receipt(tx_hash)
log_to_process = receipt['logs'][0]
ev = acontract.events.Increment.processLog(log_to_process)
print(ev)

ContractEvent.processLog() produced the error :

Traceback (most recent call last):
  File "code-1.py", line 22, in <module>
    ev = acontract.events.Increment.processLog(log_to_process)
  File "/home/shail_hash_98/anaconda3/lib/python3.8/site-packages/eth_utils/decorators.py", line 20, in _wrapper
    return self.method(objtype, *args, **kwargs)
  File "/home/shail_hash_98/web3.py/web3/contract.py", line 1176, in processLog
    return get_event_data(self.web3.codec, self.abi, log)
  File "cytoolz/functoolz.pyx", line 254, in cytoolz.functoolz.curry.__call__
  File "cytoolz/functoolz.pyx", line 250, in cytoolz.functoolz.curry.__call__
  File "/home/shail_hash_98/web3.py/web3/_utils/events.py", line 205, in get_event_data
    if event_abi['anonymous']:
TypeError: 'NoneType' object is not subscriptable

ContractEvents.abi belonging to the subclass (Increment) of the ContractEvents class need to be used and referred to before the Increment object is initialised.

How was it fixed?

By changing every self.abi in the ContractEvent class to self._get_event_abi() (this was the # 2 as mentioned in the issue.)

I did try # 1 for solving the issue mentioned in #1648 . So, this is what I did while adding @property to .abi

The __init__ looked like:

def __init__(self, *argument_names: Tuple[str]) -> None:

        if argument_names is None:
            # https://github.com/python/mypy/issues/6283
            self.argument_names = tuple()  # type: ignore
        else:
            self.argument_names = argument_names

        self.abi = self._get_event_abi()

and my @property function looked like:

@property
def abi(self):
	return self._abi

@abi.setter
def abi(self, value=None):
	self._abi = find_matching_event_abi(
            cls.contract_abi,
            event_name=cls.event_name)

and the processLog() remained the same:

@combomethod
def processLog(self, log: HexStr) -> EventData:
        return get_event_data(self.web3.codec, self._get_event_abi(), log)

After using this, I get the following error:

Traceback (most recent call last):
  File "code-1.py", line 24, in <module>
    ev = acontract.events.Increment.processLog(log_to_process)
  File "/home/shail_hash_98/anaconda3/lib/python3.8/site-packages/eth_utils/decorators.py", line 20, in _wrapper
    return self.method(objtype, *args, **kwargs)
  File "/home/shail_hash_98/web3.py/web3/contract.py", line 1196, in processLog
    return get_event_data(self.web3.codec, self.abi, log)
  File "cytoolz/functoolz.pyx", line 254, in cytoolz.functoolz.curry.__call__
  File "cytoolz/functoolz.pyx", line 250, in cytoolz.functoolz.curry.__call__
  File "/home/shail_hash_98/web3.py/web3/_utils/events.py", line 205, in get_event_data
    if event_abi['anonymous']:
TypeError: 'property' object is not subscriptable

I think if we try to integrate @property with this, even then a person will have to create an object of ContractEvent. Thus, using this solution doesn't seem viable to achieve the target mentioned in #1648. Thus, I used the solution provided in # 2 and replaced all the self.abi with self._get_event_abi() in ContractEvent class. Please let me know if I have gone wrong somewhere. (I have elaborated the issue with # 1 using an example in the next comment)

In addition to this, I wanted some advice for writing tests. I did go through the documentation. I am not sure about how I should write it. It would be great if you could elaborate a bit on this.

Many thanks!

smishy05 · 2021-08-30T03:21:48Z

What is the issue with # 1 while solving?

Consider this code.

# using property class
class Celsius:
    def __init__(self, temperature=0):
        self.temperature = temperature

    def to_fahrenheit(self):
        return (self.temperature * 1.8) + 32

    # getter
    def get_temperature(self):
        print("Getting value...")
        return self._temperature

    # setter
    def set_temperature(self, value):
        print("Setting value...")
        if value < -273.15:
            raise ValueError("Temperature below -273.15 is not possible")
        self._temperature = value

    # creating a property object
    temperature = property(fget=get_temperature, fset=set_temperature)

human = Celsius()
print(human.temperature)
print(human.to_fahrenheit())
print(human.temperature)

This is the output I get

Setting value...
Getting value...
0
Getting value...
32.0
Getting value...
0

But, what we want in our case is human = Celsius and the code to run the same way (correct me if I am wrong here). So, when I make human = Celsius, the code looks like:

# using property class
class Celsius:
    def __init__(self, temperature=0):
        self.temperature = temperature

    def to_fahrenheit(self):
        return (self.temperature * 1.8) + 32

    # getter
    def get_temperature(self):
        print("Getting value...")
        return self._temperature

    # setter
    def set_temperature(self, value):
        print("Setting value...")
        if value < -273.15:
            raise ValueError("Temperature below -273.15 is not possible")
        self._temperature = value

    # creating a property object
    temperature = property(fget=get_temperature, fset=set_temperature)

human = Celsius
print(human.temperature)
print(human().to_fahrenheit())
print(human.temperature)
human.temperature = -300

and my output is:

<property object at 0x7fe9803dcb30>
Setting value...
Getting value...
32.0
<property object at 0x7fe9803dcb30>

Hence, what we get is a property object (instead of a float value). Thus, when we are using the # 1 solution, we end up getting property object which makes it possible to work. I guess if we wish to make this work, then we will have to make some tweaks in the api that calls the events.

I hope this justifies the reason for not using # 1 solution. Please let me know if I have gone wrong somewhere.

Many thanks!

kclowes · 2021-08-30T16:53:33Z

Thanks for the PR @smishy05, and for such a detailed justification! I am wrapping up some things on py-evm, but I'll take a look once that's finished.

smishy05 · 2021-08-30T18:36:10Z

Thanks a lot for the reply!

By the way, this is the output after running make lint

tox -e lint
lint create: /home/shail_hash_98/git_repos/web3.py/.tox/lint
lint installdeps: .[dev]
lint develop-inst: /home/shail_hash_98/git_repos/web3.py
lint installed: aiohttp==3.7.4.post0,alabaster==0.7.12,async-timeout==3.0.1,atomicwrites==1.4.0,attrs==21.2.0,Babel==2.9.1,backports.entry-points-selectable==1.1.0,base58==2.1.0,bitarray==1.2.2,blake2b-py==0.1.4,bleach==4.1.0,bump2version==1.0.1,bumpversion==0.6.0,cached-property==1.5.2,certifi==2021.5.30,chardet==4.0.0,charset-normalizer==2.0.4,click==8.0.1,colorama==0.4.4,configparser==3.5.0,contextlib2==21.6.0,cytoolz==0.11.0,distlib==0.3.2,docopt==0.6.2,docutils==0.16,eth-abi==2.1.1,eth-account==0.5.5,eth-bloom==1.0.4,eth-hash==0.3.1,eth-keyfile==0.5.1,eth-keys==0.3.3,eth-rlp==0.2.1,eth-tester==0.5.0b4,eth-typing==2.2.2,eth-utils==1.10.0,execnet==1.9.0,filelock==3.0.12,flake8==3.8.3,flaky==3.7.0,hexbytes==0.2.2,hypothesis==5.49.0,idna==3.2,imagesize==1.2.0,incremental==21.3.0,ipfshttpclient==0.8.0a2,isort==4.3.4,Jinja2==3.0.1,jsonschema==3.2.0,lru-dict==1.1.7,MarkupSafe==2.0.1,mccabe==0.6.1,mock==4.0.3,more-itertools==8.8.0,multiaddr==0.0.9,multidict==5.1.0,mypy==0.812,mypy-extensions==0.4.3,netaddr==0.8.0,packaging==21.0,parsimonious==0.8.1,pkginfo==1.7.1,platformdirs==2.2.0,pluggy==0.13.1,protobuf==3.17.3,py==1.10.0,py-ecc==4.1.0,py-evm==0.4.0a4,py-geth==3.5.0,py-solc==3.2.0,pycodestyle==2.6.0,pycryptodome==3.10.1,pyethash==0.1.27,pyflakes==2.2.0,Pygments==2.10.0,pyparsing==2.4.7,pyrsistent==0.18.0,pytest==4.6.11,pytest-asyncio==0.10.0,pytest-forked==1.3.0,pytest-mock==1.13.0,pytest-pythonpath==0.7.3,pytest-watch==4.2.0,pytest-xdist==1.34.0,pytz==2021.1,readme-renderer==29.0,requests==2.26.0,requests-toolbelt==0.9.1,rlp==2.0.1,semantic-version==2.8.5,six==1.16.0,snowballstemmer==2.1.0,sortedcontainers==2.4.0,Sphinx==3.5.4,sphinx-better-theme==0.1.5,sphinx-rtd-theme==0.5.2,sphinxcontrib-applehelp==1.0.2,sphinxcontrib-devhelp==1.0.2,sphinxcontrib-htmlhelp==2.0.0,sphinxcontrib-jsmath==1.0.1,sphinxcontrib-qthelp==1.0.3,sphinxcontrib-serializinghtml==1.1.5,toml==0.10.2,toolz==0.11.1,toposort==1.6,towncrier==18.5.0,tox==3.24.3,tqdm==4.62.2,trie==2.0.0a5,twine==1.15.0,typed-ast==1.4.3,typing-extensions==3.10.0.1,urllib3==1.26.6,varint==1.0.2,virtualenv==20.7.2,watchdog==2.1.5,wcwidth==0.2.5,-e [email protected]:smishy05/web3.py.git@10328e35ae36548a0018a14c7094d04012ab1453#egg=web3,webencodings==0.5.1,websockets==9.1,when-changed==0.3.0,yarl==1.6.3
lint run-test-pre: PYTHONHASHSEED='1966815361'
lint run-test: commands[0] | flake8 /home/shail_hash_98/git_repos/web3.py/web3 /home/shail_hash_98/git_repos/web3.py/ens /home/shail_hash_98/git_repos/web3.py/ethpm /home/shail_hash_98/git_repos/web3.py/tests --exclude /home/shail_hash_98/git_repos/web3.py/ethpm/ethpm-spec
lint run-test: commands[1] | isort --recursive --check-only --diff /home/shail_hash_98/git_repos/web3.py/web3/ /home/shail_hash_98/git_repos/web3.py/ens/ /home/shail_hash_98/git_repos/web3.py/ethpm/ /home/shail_hash_98/git_repos/web3.py/tests/
Skipped 30 files
lint run-test: commands[2] | mypy -p web3 -p ethpm -p ens --config-file /home/shail_hash_98/git_repos/web3.py/mypy.ini
Success: no issues found in 174 source files
___________________________________ summary ____________________________________
  lint: commands succeeded
  congratulations :)

After running tox locally, I get the following output (the summary):

====== 1767 passed, 35 skipped, 6 xfailed, 181 warnings in 355.97 seconds ======
___________________________________ summary ____________________________________
  py38-core: commands succeeded
  congratulations :)

I am unable to understand why two of the tests failed. It would be great if you could help in this case!

carver · 2021-08-30T18:36:30Z

It could be nice to have it be a property still, so that ContractEvent.abi is accessible. (In order do make a class-level property, we could use a metaclass, like: https://stackoverflow.com/a/1800999/8412986 ). But I don't have an objection to this approach for now, it ought to solve the problem.

smishy05 · 2021-08-31T02:40:00Z

Hi @carver

Thanks a lot for the resource.

Should I move all the functions of the ContractEvent class to MetaContractEvent or should it be only the abi property that has to be in the metaclass?

smishy05 · 2021-08-31T03:00:24Z

Hi @carver and @kclowes . After considering the advice from @carver , the code looks like this (please let me know if I have made a mistake)

class MetaContractEvent(type):
    """Base class for contract events

    An event accessed via the api contract.events.myEvents(*args, **kwargs)
    is a subclass of this class.
    """
    address: ChecksumAddress = None
    event_name: str = None
    web3: 'Web3' = None
    contract_abi: ABI = None
    abi: ABIEvent = None

    def __init__(self, *argument_names: Tuple[str]) -> None:

        if argument_names is None:
            # https://github.com/python/mypy/issues/6283
            self.argument_names = tuple()  # type: ignore
        else:
            self.argument_names = argument_names

        self._abi = None

    @property
    def abi(cls):
        return cls._abi

    @abi.setter
    def abi(cls, value):
        cls._abi = find_matching_event_abi(
            cls.contract_abi,
            event_name=cls.event_name)

    # Rest all contents of this is same as it was in the ContractEvent initially

class ContractEvent(metaclass=MetaContractEvent):
    pass

I am still getting the error:

Traceback (most recent call last):
  File "code-1.py", line 24, in <module>
    ev = acontract.events.Increment.processLog(log_to_process)
  File "/home/shail_hash_98/anaconda3/lib/python3.8/site-packages/eth_utils/decorators.py", line 20, in _wrapper
    return self.method(objtype, *args, **kwargs)
  File "/home/shail_hash_98/git_repos/web3.py/web3/contract.py", line 1186, in processLog
    return get_event_data(self.web3.codec, self.abi, log)
  File "cytoolz/functoolz.pyx", line 254, in cytoolz.functoolz.curry.__call__
  File "cytoolz/functoolz.pyx", line 250, in cytoolz.functoolz.curry.__call__
  File "/home/shail_hash_98/git_repos/web3.py/web3/_utils/events.py", line 205, in get_event_data
    if event_abi['anonymous']:
TypeError: 'property' object is not subscriptable

carver · 2021-08-31T17:05:49Z

@kclowes up to you what you want to do. I'm fine with just leaving the PR as-is.

smishy05 · 2021-09-01T02:42:41Z

@carver thanks a lot for the reply!

@kclowes please do let me what I should do and also, please let me know if I can do something for the two failings.

Many thanks!

smishy05 · 2021-09-06T05:35:58Z

Hi @kclowes , please let me know what improvements I need to make in the code so that the PR can be merged.

kclowes · 2021-12-17T21:25:05Z

Hi @smishy05, I'm sorry I missed this a few months ago. In regards to testing, you'd probably want to add something in tests/core/contracts/test_extracting_event_data.py. An example of how we test processLog can be seen here. A good test could be to copy/paste the test_event_rich_log and make sure the test still passes if you make event_instance = emitter.events[event_name]. Let me know if that doesn't make sense. Thanks again for all the work!

tudorelu · 2022-08-15T00:22:38Z

I think the initial TypeError can be avoided by adding () after Increment:

ev = acontract.events.Increment().processLog(log_to_process)

kclowes · 2024-09-23T16:01:46Z

This fix got pulled into #3491. Closing here.

smishy05 and others added 3 commits August 30, 2021 01:42

Fixed ContractEvent.processLog() ethereum#1648

afc7c26

Merge branch 'ethereum:master' into master

92ff0a7

Fixed ContractEvent.processLog() ethereum#1648

10328e3

smishy05 changed the title ~~Fix for ContractEvent.processLog() #1648~~ Fix for ContractEvent.processLog() Aug 30, 2021

Merge branch 'ethereum:master' into master

e1de26f

kclowes self-assigned this Feb 26, 2024

kclowes mentioned this pull request Sep 6, 2024

Add ability to call ContractEvents with or without parentheses #3479

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Fix for ContractEvent.processLog() #2124

Fix for ContractEvent.processLog() #2124

smishy05 commented Aug 29, 2021 •

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smishy05 commented Aug 30, 2021

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smishy05 commented Aug 30, 2021

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smishy05 commented Aug 31, 2021

smishy05 commented Aug 31, 2021 •

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carver commented Aug 31, 2021

smishy05 commented Sep 1, 2021

smishy05 commented Sep 6, 2021

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tudorelu commented Aug 15, 2022

kclowes commented Sep 23, 2024

Fix for ContractEvent.processLog() #2124

Fix for ContractEvent.processLog() #2124

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smishy05 commented Aug 29, 2021 • edited Loading

What was wrong?

How was it fixed?

smishy05 commented Aug 30, 2021

What is the issue with # 1 while solving?

kclowes commented Aug 30, 2021

smishy05 commented Aug 30, 2021

carver commented Aug 30, 2021

smishy05 commented Aug 31, 2021

smishy05 commented Aug 31, 2021 • edited Loading

carver commented Aug 31, 2021

smishy05 commented Sep 1, 2021

smishy05 commented Sep 6, 2021

kclowes commented Dec 17, 2021

tudorelu commented Aug 15, 2022

kclowes commented Sep 23, 2024

smishy05 commented Aug 29, 2021 •

edited

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smishy05 commented Aug 31, 2021 •

edited

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