protobuf message for state channel updates

dagger/bitswap/protobuf/payments.nim

@@ -6,6 +6,7 @@ import pkg/upraises
 import_proto3 "payments.proto"
 
 export PricingMessage
+export StateChannelUpdate
 
 export nitro
 
@@ -44,3 +45,9 @@ func init*(_: type Pricing, message: PricingMessage): ?Pricing =
   if address.isNone or asset.isNone or price.isNone:
     return Pricing.none
   Pricing(address: address.get, asset: asset.get, price: price.get).some
+
+func init*(_: type StateChannelUpdate, state: SignedState): StateChannelUpdate =
+  StateChannelUpdate(update: state.toJson.toBytes)
+
+proc init*(_: type SignedState, update: StateChannelUpdate): ?SignedState =
+  SignedState.fromJson(string.fromBytes(update.update))

dagger/bitswap/protobuf/payments.proto

@@ -7,3 +7,7 @@ message PricingMessage {
   bytes asset = 2;    // Asset (coin) with which to pay
   bytes price = 3;    // Amount of assets to pay per byte (UInt256)
 }
+
+message StateChannelUpdate {
+  bytes update = 1; // Signed Nitro state, serialized as JSON
+}

tests/dagger/bitswap/protobuf/testpayments.nim

@@ -1,5 +1,6 @@
 import pkg/asynctest
 import pkg/chronos
+import pkg/stew/byteutils
 import ../../examples
 import ../../../../dagger/bitswap/protobuf/payments
 
@@ -43,3 +44,19 @@ suite "pricing protobuf messages":
     var incorrect = message
     incorrect.price = newSeq[byte](33)
     check Pricing.init(incorrect).isNone
+
+suite "channel update messages":
+
+  let state = SignedState.example
+  let update = StateChannelUpdate.init(state)
+
+  test "encodes a nitro signed state":
+    check update.update == state.toJson.toBytes
+
+  test "decodes a channel update":
+    check SignedState.init(update) == state.some
+
+  test "fails to decode incorrect channel update":
+    var incorrect = update
+    incorrect.update.del(0)
+    check SignedState.init(incorrect).isNone

tests/dagger/examples.nim

@@ -9,3 +9,11 @@ proc example*(_: type UInt256): UInt256 =
   for b in bytes.mitems:
     b = rand(byte)
   UInt256.fromBytes(bytes)
+
+proc example*(_: type SignedState): SignedState =
+  var wallet = Wallet.init(EthPrivateKey.random())
+  let hub, asset, receiver = EthAddress.example
+  let chainId, amount = UInt256.example
+  let nonce = UInt48.rand()
+  let channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, amount).get
+  wallet.pay(channel, asset, receiver, amount).get