Neo Name Service

[erikzhang]

Close #1545
Replace #1644

[erikzhang]

Ready for review.

[vncoelho]

Maybe it is possible to just delete those expired within the last couple of seconds.
The start can be the last end.

[erikzhang]

There is no difference when doing db search.

[doubiliu]

It is better to check whether the original domain name exists.

[erikzhang]

But the original name can be external.

[doubiliu]

what do you mean?

[erikzhang]

An external name, for example, google.com.

[cloud8little]

Tested PASS with following scenaroes:

• addRoot with committee members

• addRoot with non-committee member

• addRoot and register name, such as neo.org

• register name with longer than 62 characters, Upper-Case, special characters.

• setPrice and then register name, the price changed.

• Two accounts can not register the same name

• The same account can not register the same name twice.

• Account A transfer the NNS token to another account, A not able to setRecord, the new account is able to setRecord. A not able to setAdmin, the new account is able to setRecord.

• nns1 account register org.neo, add CNAME record onchain.com;
  nns2 account register onchain.com; add CNAME record onchain.org,
  nns3 account register onchain.org; add CNAME record leo.com,
  nns4 account register leo.com； add IPV6 record "message",
  resolve leo.com with IPV6 type，get "message"
  resolve onchain.org with IPV6 type get "message"
  resolve onchain.com的IPV6 type, get "message"
  resolve org.neo with IPV6 record ；with FAULT result.

• more scenaroes to be added.

[erikzhang]

@cloud8little The cases can be added to UT.

[cloud8little]

@cloud8little The cases can be added to UT.

Sure, @erikzhang what do you think of following two questions?

1. why do we check the admin witness when setAdmin(L149)? I think the owner can decide whom to be the administrator of the domain name, no need to check the admin account.
   

   neo/src/neo/SmartContract/Native/NameService.cs

   Lines 144 to 153 in a3d97bc

   	private void SetAdmin(ApplicationEngine engine, string name, UInt160 admin)
   	{
   	if (!nameRegex.IsMatch(name)) throw new ArgumentException(null, nameof(name));
   	string[] names = name.Split('.');
   	if (names.Length != 2) throw new ArgumentException(null, nameof(name));
   	if (admin != null && !engine.CheckWitnessInternal(admin)) throw new InvalidOperationException();
   	NameState state = engine.Snapshot.Storages.GetAndChange(CreateStorageKey(Prefix_Token).Add(GetKey(Utility.StrictUTF8.GetBytes(name)))).GetInteroperable<NameState>();
   	if (!engine.CheckWitnessInternal(state.Owner)) throw new InvalidOperationException();
   	state.Admin = admin;
   	}

2. seems there is no API to find out who is the admin. properties only return the domain name, description, and expiration data.

{"name":"testown1.neo","description":"","expiration":1642052284}

Thought providing contract method or RPC API is both OK. because the owner of the domain can transfer the domain to the other account, and the new account may have no idea who is the admin.

[erikzhang]

1. Because it checks that it is a valid address.
2. If you are the owner, you know who is the administrator. If you are not, why do you want to know it? Maybe we should set the Admin to null automatically after transfer. What do you think?

[cloud8little]

1. Because it checks that it is a valid address.
2. If you are the owner, you know who is the administrator. If you are not, why do you want to know it? Maybe we should set the Admin to null automatically after transfer. What do you think?

1 is ok to me.
2. I think it is ok and reasonable to set the admin to null after transfer, then the old admin is not able to manipulate the domain name. It is up to the new account to reset the admin.

[erikzhang]

Please check #2222