Rln relay registration (#378)

* cleans up imported modules

* adds uploadContract proc and consolidates rln-relay test files

* deletes test_rln_relay_wrappers

* deletes wrappers tests

* adds waku_rln_relay_utils

* adds the unit test for the membership key generation

* adds the key generation procedure

* adds unit test of key gen proc

* adds RLNRelayPeer data type

* adds the register proc

* adds the register proc unit test

* minor

* edits registration test

* adds comments to the registration unit test and relocates some constants

* defines constants variables for membership contract inputs and adds todos

* fixes a typo

* adds rln to gitignore

* moves all the types to the top

* adds contracts inputs to the utils module

* adds a TODO

* adds some comments

* removes newline! adds some comments

tests/v2/test_waku_rln_relay.nim

@@ -11,10 +11,7 @@ import
 
 # the address of Ethereum client (ganache-cli for now)
 const EthClient = "ws://localhost:8540/"
-# inputs of the membership contract constructor
-const 
-    MembershipFee = 5.u256
-    Depth = 5.u256
+
 # poseidonHasherCode holds the bytecode of Poseidon hasher solidity smart contract: 
 # https://github.com/kilic/rlnapp/blob/master/packages/contracts/contracts/crypto/PoseidonHasher.sol 
 # the solidity contract is compiled separately and the resultant bytecode is copied here
@@ -166,6 +163,34 @@ procSuite "Waku rln relay":
     await web3.close()
     debug "disconnected from", EthClient
 
+  asyncTest "registration procedure":
+    # deploy the contract
+    let contractAddress = await uploadContract(EthClient)
+
+    # prepare rln-relay peer inputs
+    let 
+      web3 = await newWeb3(EthClient)
+      accounts = await web3.provider.eth_accounts()
+      # choose one of the existing accounts for the rln-relay peer  
+      ethAccountAddress = accounts[9]
+    await web3.close()
+
+    # generate the membership keys
+    let membershipKeyPair = membershipKeyGen()
+    
+    check:
+      membershipKeyPair.isSome
+
+    # initialize the RLNRelayPeer
+    var rlnPeer = RLNRelayPeer(membershipKeyPair: membershipKeyPair.get(),
+      ethClientAddress: EthClient,
+      ethAccountAddress: ethAccountAddress,
+      membershipContractAddress: contractAddress)
+    
+    # register the rln-relay peer to the membership contract
+    let is_successful = await rlnPeer.register()
+    check:
+      is_successful
 suite "Waku rln relay":
   test "Keygen Nim Wrappers":
     var 

waku/v2/protocol/waku_rln_relay/waku_rln_relay_utils.nim

@@ -1,12 +1,29 @@
 import 
   chronicles, options, chronos, stint,
   stew/byteutils,
+  web3,
+  eth/keys,
   rln 
 
 type MembershipKeyPair* = object 
   secretKey*: array[32, byte]
   publicKey*: array[32, byte]
 
+type RLNRelayPeer* = object 
+  membershipKeyPair*: MembershipKeyPair
+  ethClientAddress*: string
+  ethAccountAddress*: Address
+  membershipContractAddress*: Address
+
+# inputs of the membership contract constructor
+const 
+    MembershipFee* = 5.u256
+    Depth* = 32.u256
+
+# membership contract interface
+contract(MembershipContract):
+  # TODO define a return type of bool for register method to signify a successful registration
+  proc register(pubkey: Uint256) # external payable
 
 proc membershipKeyGen*(): Option[MembershipKeyPair] =
   # generates a MembershipKeyPair that can be used for the registration into the rln membership contract
@@ -61,3 +78,16 @@ proc membershipKeyGen*(): Option[MembershipKeyPair] =
     keypair = MembershipKeyPair(secretKey: secret, publicKey: public)
 
   return some(keypair)
+
+proc register*(rlnPeer: RLNRelayPeer): Future[bool] {.async.} =
+  ## registers the public key of the rlnPeer which is rlnPeer.membershipKeyPair.publicKey
+  ## into the membership contract whose address is in rlnPeer.membershipContractAddress
+  let web3 = await newWeb3(rlnPeer.ethClientAddress)
+  web3.defaultAccount = rlnPeer.ethAccountAddress
+  var sender = web3.contractSender(MembershipContract, rlnPeer.membershipContractAddress) # creates a Sender object with a web3 field and contract address of type Address
+  let pk = cast[UInt256](rlnPeer.membershipKeyPair.publicKey)
+  # TODO sign the transaction
+  discard await sender.register(pk).send(MembershipFee)
+  # TODO check the receipt and then return true/false
+  await web3.close()
+  return true