Corrections:

• Updated solc code examples to include -o flag, necessary to get solc to output binary files instead of printing to terminal (https://solidity.readthedocs.io/en/v0.4.24/using-the-compiler.html)
• Tested with docker image ethereum/solc:0.4.24 which uses 0.4.24+commit.e67f0147.Linux.g++ instead of 0.4.24+commit.e67f0147.Emscripten.clang (since implementation shouldn't differ significantly between platforms).
• Updated corresponding section in Full Code.

Improvements:

• Added headings
• Clarified purpose of chapter in lead paragraph.
• Added section to use docker solc.
• Removed "version" of solc at the end of Full Code section. Instead, added version used in installation section.

https://github.com/miguelmota/ethereum-development-with-go-book/blob/master/code/transactions.go - this code don't show transaction's field "From".

For instance, for transaction https://etherscan.io/tx/0x5d49fcaa394c97ec8a9c3e7bd9e8388d420fb050a52083ca52ff24b3b65bc9c2 it shows nothing.

For transaction https://etherscan.io/tx/0x36368eb4665367100bcb46427e8ac39b7873abfca2015116c478f84642a8812d it shows 0x0000000000000000000000000000000000000000

hi Miguel,

The below method does not exist anymore for types.Transaction

	ts := types.Transactions{signedTx}
	rawTxBytes := ts.GetRlp(0)

so, this file should update

I test with go ethereum v1.10.2

I find there are another two functions should do this:

https://github.com/ethereum/go-ethereum/blob/beee6b77a0ca8c26881dc2bb17c58e996c90a0c6/core/types/transaction.go#L119

https://github.com/ethereum/go-ethereum/blob/beee6b77a0ca8c26881dc2bb17c58e996c90a0c6/core/types/transaction.go#L86

but I don't know what to put in the method param (w io.Writer)

Hi, for all the example within the book, the contract is simple. What if the contract is a complex one(with many libraries and helper contract in it)?

Let's say, uniswap StakingRewards contract https://etherscan.io/address/0xCA35e32e7926b96A9988f61d510E038108d8068e#code

Can you demonstrate how to interact with it? Many abi and bin file will generate, but specifically, I want interactive with the contractStakingRewards.

Also, I try to interact with TetherToken https://etherscan.io/address/0xdac17f958d2ee523a2206206994597c13d831ec7#code

mkdir usdt
cd usdt
# touch TetherToken.sol and put code in it
solc --abi TetherToken.sol --out abi
solc --bin TetherToken.sol --out bin
abigen --bin=bin/TetherToken.bin --abi=abi/TetherToken.abi --pkg=usdt --out=usdt.go

then I get an error

Fatal: Failed to generate ABI binding: duplicated identifier "totalSupply"(normalized "TotalSupply"), use --alias for renaming

I run the code in this page. The logs are:

13565093091594031083
2019/12/09 16:21:15 403 Forbidden {"jsonrpc":"2.0","id":2,"error":{"code":-32002,"message":"project ID is required to access archive state","data":{"see":"https://infura.io/dashboard"}}}

It shows that client.BalanceAt(context.Background(), account, nil) return the balance, but balanceAt, err := client.BalanceAt(context.Background(), account, blockNumber) not.

I wonder what's the reason here and how to fix it. Thanks a lot if anyone can help me.

Go doesn't "cast" types — would be more accurate to describe this as a type assertion, to correctly reflect what is going on with the Go code.

Not casting because priv.Public() returns an interface, which has an underlying type of *ecdsa.PublicKey. Calling publicKey.(*ecdsa.PublicKey) doesn't perform a conversion, but instead asserts *ecdsa.PublicKey as the resulting variable's type. If *ecdsa.PublicKey is not the underlying type of the variable it is performed on, the operation panics. The underlying type of the variable the type assertion is called on never changes.

If change is ok, will make changes across the rest of the guide.

source: https://stackoverflow.com/a/19579058

Hello @miguelmota I am following up your awesome book. My requirement is to read the event log of a Transfer(from, to, value) function. I am using SubscribeFilterLogs for continuous log streaming and updating my other dbs.

But I am little bit stuck head over to this obfuscating error msg:

The method eth_logs does not exist/is not available

I have posted the issuse on slack:golang#ethereum room

I am quiet sure, error is pooping from this line: https://github.com/miguelmota/ethereum-development-with-go-book/blob/082005828d9647ac6ecd2684a340e55f7b91f692/code/event_subscribe.go#L21-L26

But couldn't figure out why though. The closest google match relation I found is on this thread: https://github.com/ethereum/go-ethereum/issues/310#issuecomment-75984471

Am I missing something import here. I have just started the websocket with admin.startWS("0.0.0.0", 8546, "*","*") , I am sure, I can telnet to that port.

/cc @miguelmota

Hi @miguelmota,

Fantastic work on this book it’s written very well and so streamlined for getting up to speed.

Question for you though: do you think you can show an example of getting the Go client talking to Ganache which seems to be the de facto development version of the Blockchain?

I mean, is it as simple as changing the DNS name to point to the local instance of Ganache?

I’d like to get that working but I haven’t investigated what it would all take but thought it would be useful in this book.

What do you think? And great work.

-Deckarep (Ralph)

website doesn't work both on mobile and desktop, something about an incorrect time of my computer / mobile

doesn't build from source due to node-gyp. Tried node v8, v10, v12 and v14

hi Miguel,

Usually, the process is to deploy contact first and then call the function.

But now the cost for deploy a contract is high.

I wonder if I can deploy a contract and call a function within one transaction?

You may think why I want to do this because it's a special temporary contract, I just need to call the function once in mainnet , and what's more, I don't really need to submit it to chain, I just want to estimate gas for that function.

In the ebook, ABI.Unpack takes three arguments: interface{}, string and []byte. This seems to have changed in the recent versions of geth, which now has Unpack not take an interface, and instead returns a []interface{} representing the event's data.

Update "Writing to a Smart Contract" to wait for transaction to be mined.

Without waiting, the value returned is empty while the tx was just sent.

Update "Reading ERC-20 Token Event Logs" to Solidity 0.8.13 and Geth 1.10.17

About renaming abi.Unpack to abi.UnpackIntoInterface: https://github.com/ethereum/go-ethereum/pull/21091

Current transfer_token.go is outdated. Unsure of when this happened but the current method of transacting ERC-20 tokens looks something like this:

https://gist.github.com/ckruger097/a156d04a5f3542eac20e6eea5129946d

Note: This is done from my own research, this may not be best practice but it has worked as a PoC. It may also be worth mentioning I created the token mentioned in the comments using https://vittominacori.github.io/erc20-generator/ & transferred to MetaMask first. Then sent the tokens to my local geth account running on a light node. Hopefully this helps someone.