Go-ethereum: How to list contract/internal transactions via JSON-RPC API

[Crypto2]

How do you list contract/internal transactions via JSON-RPC API? Preferably all of them in an entire block or not as efficient for a specific address?

For example: https://etherscan.io/address/0x00e41ddeb656788dc150956b6ffe175b54b61d8a#internaltx

[holiman]

Use the management api, specifically debug_traceTransaction

[Crypto2]

Is there any sample code anywhere for this? It's basically decoding assembly language.

[Crypto2]

Bump. As times goes on and people use contracts more it is vital we are able to see and process these internal transactions; even telling people not to send from contracts we have to manually adjust balances and send refunds from these on a daily basis since they don't pay attention or don't know any better.

[onggunhao]

Has there been any movement on this, either through an issue or fork?

I am currently working on a project that might require this, don't mind taking a crack at extending the library.

[holiman]

So, there are two ways to do it.

Tracing

1. Implement your own tracer. Example:

nc -U /datadrive/geth-devel/geth.ipc

{"id": 1, "method": "debug_subscribe", "params": ["traceChain", "0x56FEE3", "0x56FEF4", {"tracer": "{\r\narguments: [],\r\nstep: function(log, db) {\r\nif (log.op.toNumber() == 10) {\r\n    this.arguments.push({x: log.stack.peek(1).toString(16), y:  log.stack.peek(2).toString(16)})\r\n}\r\n},\r\nresult: function(){ return this.arguments;}, \r\nfault: function(){}\r\n}\r\n", "reexec":1000}]}

That example stores the argument to EXP every time the opcode is used. Some more examples of already existing tracers are here: https://github.com/ethereum/go-ethereum/tree/master/eth/tracers/internal/tracers.

This type of usage is good if you want to be able to analyze transactions programatically in-depth. If you are a programmer, and knows the VM.

Externally

If you are interested in e.g. deposits, and maintain balances, the tracing API might not be for you. There are potential pitfalls, for example - Tx A, invokes CALL b, invokes CALL c which does transfer foobar to Y. Then c suceeds ,b reverts and A succeeds. Are you confident your custom js snippet would have accounted that correctly?

If not, I would recommend using events for token-transfers, and using GetModifiedAccountsByNumber or GetModifiedAccountsByHash for ether-transfers. The latter two can tell you if one of your accounts was indeed in any way modified (such as balance added) during the block period you sent in.

[oakcookies]

I am running a local private node but got the following error

what might be the error ?

[Crypto2]

Usually that means you don't have state enabled and/or that block was fast synced.

[holiman]

That query though... it would return all modified accounts between genesis and 51K blocks -- meaning 1) that it needs to be a full sync and 2) it will be a _humongous_ list.

[oakcookies]

@holiman In the case that I want to detect which transaction leads to change in values of wei of certain account, GetModifiedAccountsByNumber or GetModifiedAccountsByHash cannot tell me that. May I know if there are any similar methods in GETH like this ? link

[oakcookies]

@Crypto2 I tried to restart my geth node but still got the error. would you mind pointing out what might be the issue ?

For your information, the geth node is for a private net and there's only one node (itself) in this private net. The command to start geth is

geth --datadir "~/eth-private" \
  --identity "Private" \
  --networkid 15 \
  --nodiscover \
  --maxpeers 0 \
  --rpc \
  --rpcaddr "0.0.0.0" \
  --rpccorsdomain "*" \ //just for testing
  --gcmode=archive \
  --syncmode full \
  --mine

[Crypto2]

Hmm, in theory you should have state for it then (although I'm no expert)

[MelbourneDeveloper]

OK, so MyEtherWallet knows what tokens I have. I plugged in my Trezor and there the tokens were. I did a trace with fiddler, and I can see the JSON RPC call to get the token's balance. I can make that call and replicate the value. But, how did MyEtherWallet know that the token was there without there being a call to get the transactions at an address?