[Ethereum] Solidity error when encoding arguments to call a function with Bytes32 Type Parameters

remixsolidity

While developing a Smart Contract with Solidity on Remix, after creating the contract I'm trying to call a function by passing Bytes32 datatype parameters:

function addTT(bytes32 _name) public {
...
}

but when I call addTT() by passing parameter "neo" it throws the following error:

transact to Abc.addTT errored: Error encoding arguments: Error:
invalid bytes32 value (arg=undefined, type="string", value="asda")

Any idea how can I properly call function addTT()?

Best Answer

You need to convert the value in hex to be passed. neo is 0x6e656f in hex. If you try to pass '0x6e656f' it will work (don't forget the quote).

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[Ethereum] Solidity error when encoding arguments to query public mapping

The address needs be surrounded with quotes. "0xca35b7d915458ef540ade6068dfe2f44e8fa733c" should work.

[Ethereum] Passing Parameters to Remix

As the Solidity code specifies, you need to pass a bytes32 value as argument, not an ascii-encoded word. This is an hexadecimal-encoded value, so as a rule of thumb it should start with 0x.

Before passing your argument, you thus need to hex-encode it using for example one of web3 util's functions:

> web3.utils.fromAscii('tag1')
'0x74616731'

You can pass this hexadecimal value as an argument in the Remix console. Later when you call getTagsOfAdmin you'll simply need to apply the reverse transformation:

> web3.utils.toAscii('0x74616731')
'tag1'

Despite this added complexity, bytes32 prove a good alternative against strings because they have fixed length and hence require way less storage costs. Hope it helps!

PS: note that the above command-line examples use web3 v1.

Best Answer

Related Solutions

[Ethereum] Solidity error when encoding arguments to query public mapping

[Ethereum] Passing Parameters to Remix

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