Added web3j code samples #364
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Signed-off-by: Nischal Sharma <[email protected]>
| @@ -177,6 +182,12 @@ const labelhash = keccak256(toUtf8Bytes(normalizedLabel)) | |||
| string constant label = "label"; | |||
| bytes32 constant labelhash = keccak256(bytes(label)); | |||
| ``` | |||
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| ```java {{ title: 'Web3j (Java)', variant: 'web3j', link: 'https://docs.web3j.io/4.11.0/advanced/ethereum_name_service/' }} | |||
| byte[] labelHash = NameHash.nameHashAsBytes('label'); | |||
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Labelhash is the keccak256 hash of the label (e.g. "nick" in the name "nick.eth"), which is different than applying NameHash.nameHashAsBytes() on the label.
Web3j likely doesn't have a helper function specific to labelhash, but it may have a keccak256 function which can be used in this example.
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So NameHash.nameHash Function can be used for both full Name like nick.eth and just label like 'nickIt will give the correct result, thats why there is no ultitly function just for labels as user can use currentNameHash.nameHash` fucntion on label to get the labelHash.
This fuctions returns (Hash.sha3(result)) which is keccak256
Hope it makes sense, let me know if there is still any confusion
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Hmmm I'm running a test script locally and NameHash.nameHashAsBytes('label') does not return the expected label hash. The expected value for label would be 0x1b036544434cea9770a413fd03e0fb240e1ccbd10a452f7dba85c8eca9ca3eda
I don't know Java well, but futzing around it looks like the code example will have to be a bit lower level like this:
public static String labelHash(String name) {
// Get the label of the name (the part before the earliest '.')
String[] parts = name.split("\\.");
String label = parts[0];
// Keccak256 hash the label and convert to hex string
byte[] labelHash = Hash.sha3(label.getBytes(StandardCharsets.UTF_8));
String labelHashString = Numeric.toHexString(labelHash);
return labelHashString;
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@gskril Thanks for pointing out this. I was able to reproduce it, and created a PR for labelHash fucntion - hyperledger-web3j/web3j#2140
We will soon release new Web3j with this fix. Thanks
| @@ -71,6 +71,11 @@ from namehash import namehash | |||
| node = namehash('name.eth') | |||
| ``` | |||
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| ```java {{ title: 'Web3j (Java)', variant: 'web3j', link: 'https://docs.web3j.io/4.11.0/advanced/ethereum_name_service/' }} | |||
| byte[] nameHash = NameHash.nameHashAsBytes('luc.eth'); | |||
| String nameHashString = Numeric.toHexString(nameHash) | |||
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Looks like web3j also exposes NameHash.nameHash which returns a hex string directly, so no need to first get the bytes and convert it yourself
This PR adds code samples for Web3j library - https://github.com/hyperledger-web3j/web3j