1

I have an event defined like this:

event Created(
    address indexed target,
    string indexed name
);

I do

emit Created(..., _name); // called function with _name = "comment"

which gives

0xd69ce70c72e2e7191b71ef82881773fbf30510f24a3450f02d555b5f04ac9702

or

0x2361458367e696363fbcc70777d07ebbd2394e89fd0adcaf147faccd1d294d60

in the Ganache event explorer:

enter image description here

How can I convert this back to comment? web3.toAscii() just returns garbage.

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6
  • Call const x = web3.fromAscii("comment");. What you get in x, is what you should see in Ganache explorer. My guess is that you're looking at the wrong thing, since x should end with something like 50 zeros (while the first 14 characters are gonna be your "comment").
    – goodvibration
    Dec 5, 2019 at 16:48
  • I figured as much but I don't see where I could do anything wrong. If the type / storage requirement were wrong, solidity would complain with warnings and compile errors. The contract is deployed, the decoded signature in Ganache is "Created(target: address, name: string)" and the value is as above.
    – Aaron Digulla
    Dec 5, 2019 at 16:54
  • @goodvibration Added screenshot
    – Aaron Digulla
    Dec 5, 2019 at 16:55
  • Change that string to bytes32, then run again and tell us what you see.
    – goodvibration
    Dec 5, 2019 at 16:56
  • Indexed values of dynamic type like string are not stored directly with the event instead they are replaced by keccak256(value).
    – Ismael ♦
    Dec 5, 2019 at 18:56

1 Answer 1

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1

That happens because all array types (which includes string and bytes) are hashed. See the documentation:

If you use arrays (including string and bytes) as indexed arguments, its Keccak-256 hash is stored as a topic instead, this is because a topic can only hold a single word (32 bytes).

If you need the original value, you will have to remove the option indexed from the event parameter and filter the events yourself.

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