how to interpret event data ethereum

Question

I was able to use the EtherScan api to get an array with event logs. Now I need to read from the data stored inside.

The event data exists out of: uint256, uint256, uint256, address, address, string.

I can do the following web3 function: web3.utils.hexToNumber(hex) for the uint's and hexToUtf8 for the strings.

However I have 2 problems:

There's no web3 function hexToAddress. How can I do this?
I'm not sure how to split the event data with a web3 function or other method.

This is an example of the event data:

"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"

score 9 · Accepted Answer · edited May 13 '19 at 23:47

9

You could also use web3 directly using the web3.eth.abi.decodeParameters(typesArray, hexString) function:

In your case it would look like this:

web3.eth.abi.decodeParameters(['uint256', 'uint256', 'uint256', 'address', 'address', 'string'], '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')

Read more at https://web3js.readthedocs.io/en/1.0/web3-eth-abi.html#decodeparameters.

edited May 13 '19 at 23:47

Paul Razvan Berg

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answered May 25 '18 at 08:51

MaKue

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I think the second parameter (the data) needs to be a string? – mesqueeb May 25 '18 at 08:59
And also, the first parameters is an array of strings. If you edit that I'll mark it as correct! Thanks so much btw!!! – mesqueeb May 25 '18 at 09:00
BTW, I have this error in node: throw new Error('Couldn\'t decode '+ name +' from ABI: 0x'+ param.rawValue); any idea? – mesqueeb May 25 '18 at 09:14

score 1 · Answer 2 · answered May 25 '18 at 08:47

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there is a lib for event log parsing from ConsenSys, the abi-decoder

answered May 25 '18 at 08:47

Rader

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great lib, thank you! I also used it in other places now :) – Oleksandr Hrin Apr 26 '22 at 10:32

how to interpret event data ethereum

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