Update examples.rst with Infura/rinkeby steps

[SyedMuhamadYasir]

Using Infura Rinkeby Node

Import your required libraries

from web3 import Web3, HTTPProvider

Initialize a web3 instance with an Infura node

w3 = Web3(Web3.HTTPProvider("https://rinkeby.infura.io/v3/YOUR_INFURA_KEY"))

Inject the middleware into the middleware onion

w3.middleware_onion.inject(geth_poa_middleware, layer=0)

Just remember that you have to sign all transactions locally, as infura does not handle any keys from your wallet

transaction = contract.functions.function_Name(params).buildTransaction()
transaction.update({ 'gas' : appropriate_gas_amount })  
transaction.update({ 'nonce' : web3.eth.getTransactionCount('Your_Wallet_Address') })
signed_tx = w3.eth.account.signTransaction(transaction, private_key)

P,S : the two updates are done to the transaction dictionary, since it might not contain gas & nonce amounts, so you have to add them manually.

And then send the transaction

txn_hash = w3.eth.sendRawTransaction(signed_tx.rawTransaction) 
txn_receipt = w3.eth.waitForTransactionReceipt(txn_hash)

What was wrong?

Related to Issue # ; not sure about which issue this might correspond to, but there was terrible documentation regarding how to inject the POA middleware and calling a state-changing transaction also yielded alot of errors in my experimentation. so i thought to contribute a combined solution, outlining the simple yet subtle step of injecting middle-ware and also how to constuct a raw transaction to interact with a state-changing function in your smart contract.

How was it fixed?

It can be seen in the code. However, to put it briefly, i just simplified the steps on injecting the geth-style middleware in web3.py, when using an Infura Rinkeby node and i also outlined the steps on how to properly construct a transaction for calling a state-changing function in a smart-contract deployed on Rinkeby testnet.

Todo:

• Add entry to the release notes

Cute Animal Picture

[carver]

Note that this example would have to be updated for v5. It's using v4 things, like middleware_stack.

[SyedMuhamadYasir]

Note that this example would have to be updated for v5. It's using v4 things, like middleware_stack.

feel free to add edit ( if you can )

or you can simply suggest them to me

thanks !

[kclowes]

@SyedMuhamadYasir Looks like the two failures are just flaky tests, so don't worry about those. I'm happy to update if you want, just let me know!

[SyedMuhamadYasir]

@SyedMuhamadYasir Looks like the two failures are just flaky tests, so don't worry about those. I'm happy to update if you want, just let me know!

thanks for reassuring me on those tests

yeah, go ahead !

P.S : should i update the stuff in this pull request before you make the changes ?

[kclowes]

@SyedMuhamadYasir please go ahead and update if you have the time, thank you!

[SyedMuhamadYasir]

@SyedMuhamadYasir please go ahead and update if you have the time, thank you!

done !

please take a look :)

[kclowes]

👍 this is looking good! I just ran through the actual commands locally and added a few more comments. Thank you!

[SyedMuhamadYasir]

all recommended changes applied, kindly check

[kclowes]

Looks good to me @SyedMuhamadYasir! Thank you!

[SyedMuhamadYasir]

Looks good to me @SyedMuhamadYasir! Thank you!

Great 😄

any further steps i have to take to complete my contribution ?

[kclowes]

If you're feeling up to it, it would be helpful if you could make a new file called newsfragments/1444.doc.rst with one line explaining what this PR does. If not, I'm happy to do it and should get to it later today!

[kclowes]

Thank you @SyedMuhamadYasir!

[SyedMuhamadYasir]

Thank you @SyedMuhamadYasir!

You are most welcome @kclowes !

and thank you for helping me out with the process !

i'll be working with Ethereum (and web3.py) in the time to come and i hope to make more contributions to the repo

see you ^_^