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New contract method execution option: generating the transaction dictionary

See original GitHub issue

Version: 4

What was wrong?

There is no convenient way to prepare a contract transaction for offline signing.

Specifically, the prepared transaction should work smoothly with w3.eth.account.signTransaction().

How can it be fixed?

New contract method preparation API

Add a new way to prepare a contract function transaction. It would look something like:

# new API
transaction_dict = myContract.functions.myMethod().asdict()

# existing APIs
signed = w3.eth.account.signTransaction(transaction_dict, private_key)
w3.eth.sendRawTransaction(signed.rawTransaction)

asdict should accept a dictionary that defines transaction fields, just like call/transact/etc, and return an AttributeDict.

Fields included

Besides the natural fields, like to and data, this must also generate other fields like:

nonce
chainId
gas
gasPrice

If they are not supplied as arguments to asdict(), then they should be inferred before returning. signTransaction will not attempt to infer these values, so they must be explicitly added.

API Naming

asdict() is okay, but isn’t necessarily the obvious winner.

Some alternatives:

myContract.functions.myMethod().todict()
myContract.functions.myMethod().tofields()
myContract.functions.myMethod().prepare()
myContract.functions.myMethod().generate()

Crossover issue

Depending on whether #419 is already implemented, and how it’s implemented, this might require a bit of extra work to expose asdict in both ways.

TODOs

choose naming
implement new API
document in docs/
reference this method in signTransaction docs docs/web3.eth.account.rst ~- [ ] Support for #419 - if implementation available~

Issue Analytics

State:
Created 6 years ago
Comments:24 (10 by maintainers)

Top GitHub Comments

3reactions

owockicommented, Dec 5, 2017

@monokh i just remitted payment. the gitcoinco bot didn’t comment because of issues resultant from the migration of this repo from @pipermerriam 's github handle to the @ethereum handle. nevertheless, payment has been remitted and https://gitcoin.co/funding/details?url=https://github.com/pipermerriam/web3.py/issues/430 is updated!

congrats! 🎉

3reactions

monokhcommented, Nov 17, 2017

Hi, I’m willing to work on this 🙂. I’ve done offline TX signing with web3.js but it had been a bit of a pain due to needed other libraries for TX signing. I have python experience so interested in how I can shape this 😃 Expect a merge request coming your way soon

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