Merge pull request #135 from centrifuge/update-event-parsing

listener: Update event parsing

Author: cdamian

chains/substrate/chain.go

@@ -24,13 +24,16 @@ As the writer receives messages from the router, it constructs proposals. If a p
 package substrate
 
 import (
+	"fmt"
 	"github.com/ChainSafe/log15"
 	"github.com/centrifuge/chainbridge-utils/blockstore"
 	"github.com/centrifuge/chainbridge-utils/core"
 	"github.com/centrifuge/chainbridge-utils/crypto/sr25519"
 	"github.com/centrifuge/chainbridge-utils/keystore"
 	metrics "github.com/centrifuge/chainbridge-utils/metrics/types"
 	"github.com/centrifuge/chainbridge-utils/msg"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/registry/retriever"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/registry/state"
 )
 
 var _ core.Chain = &Chain{}
@@ -102,8 +105,14 @@ func InitializeChain(cfg *core.ChainConfig, logger log15.Logger, sysErr chan<- e
 
 	ue := parseUseExtended(cfg)
 
+	eventRetriever, err := retriever.NewDefaultEventRetriever(state.NewEventProvider(conn.api.RPC.State), conn.api.RPC.State)
+
+	if err != nil {
+		return nil, fmt.Errorf("event retriever creation: %w", err)
+	}
+
 	// Setup listener & writer
-	l := NewListener(conn, cfg.Name, cfg.Id, startBlock, logger, bs, stop, sysErr, m)
+	l := NewListener(conn, cfg.Name, cfg.Id, startBlock, logger, bs, stop, sysErr, m, eventRetriever)
 	w := NewWriter(conn, logger, sysErr, m, ue)
 	return &Chain{
 		cfg:      cfg,

chains/substrate/connection.go

@@ -43,7 +43,7 @@ func (c *Connection) getMetadata() (meta types.Metadata) {
 	return meta
 }
 
-func (c *Connection) updateMetatdata() error {
+func (c *Connection) updateMetadata() error {
 	c.metaLock.Lock()
 	meta, err := c.api.RPC.State.GetMetadataLatest()
 	if err != nil {

chains/substrate/events.go

@@ -4,20 +4,22 @@
 package substrate
 
 import (
+	"errors"
 	"fmt"
 	"math/big"
 
 	"github.com/ChainSafe/log15"
-	events "github.com/centrifuge/chainbridge-substrate-events"
 	"github.com/centrifuge/chainbridge-utils/msg"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/types"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/types/codec"
 )
 
 type eventName string
-type eventHandler func(interface{}, log15.Logger) (msg.Message, error)
+type eventHandler func(map[string]any, log15.Logger) (msg.Message, error)
 
-const FungibleTransfer eventName = "FungibleTransfer"
-const NonFungibleTransfer eventName = "NonFungibleTransfer"
-const GenericTransfer eventName = "GenericTransfer"
+const FungibleTransfer eventName = "ChainBridge.FungibleTransfer"
+const NonFungibleTransfer eventName = "ChainBridge.NonFungibleTransfer"
+const GenericTransfer eventName = "ChainBridge.GenericTransfer"
 
 var Subscriptions = []struct {
 	name    eventName
@@ -28,57 +30,250 @@ var Subscriptions = []struct {
 	{GenericTransfer, genericTransferHandler},
 }
 
-func fungibleTransferHandler(evtI interface{}, log log15.Logger) (msg.Message, error) {
-	evt, ok := evtI.(events.EventFungibleTransfer)
-	if !ok {
-		return msg.Message{}, fmt.Errorf("failed to cast EventFungibleTransfer type")
+func fungibleTransferHandler(eventFields map[string]any, log log15.Logger) (msg.Message, error) {
+	chainID, err := getFieldValueAsType[types.U8]("ChainId", eventFields)
+	if err != nil {
+		return msg.Message{}, err
 	}
 
-	resourceId := msg.ResourceId(evt.ResourceId)
-	log.Info("Got fungible transfer event!", "destination", evt.Destination, "resourceId", resourceId.Hex(), "amount", evt.Amount)
+	depositNonce, err := getFieldValueAsType[types.U64]("DepositNonce", eventFields)
+	if err != nil {
+		return msg.Message{}, err
+	}
+
+	resID, err := getFieldValueAsSliceOfType[types.U8]("ResourceId", eventFields)
+	if err != nil {
+		return msg.Message{}, err
+	}
+
+	resourceID, err := to32Bytes(resID)
+	if err != nil {
+		return msg.Message{}, err
+	}
+
+	amount, err := getU256(eventFields)
+	if err != nil {
+		return msg.Message{}, err
+	}
+
+	recipient, err := getFieldValueAsByteSlice("Vec<u8>", eventFields)
+	if err != nil {
+		return msg.Message{}, err
+	}
+
+	log.Info("Got fungible transfer event!", "destination", recipient, "resourceId", fmt.Sprintf("%x", resourceID), "amount", amount)
 
 	return msg.NewFungibleTransfer(
 		0, // Unset
-		msg.ChainId(evt.Destination),
-		msg.Nonce(evt.DepositNonce),
-		evt.Amount.Int,
-		resourceId,
-		evt.Recipient,
+		msg.ChainId(chainID),
+		msg.Nonce(depositNonce),
+		amount.Int,
+		resourceID,
+		recipient,
 	), nil
 }
 
-func nonFungibleTransferHandler(evtI interface{}, log log15.Logger) (msg.Message, error) {
-	evt, ok := evtI.(events.EventNonFungibleTransfer)
-	if !ok {
-		return msg.Message{}, fmt.Errorf("failed to cast EventNonFungibleTransfer type")
+func nonFungibleTransferHandler(_ map[string]any, log log15.Logger) (msg.Message, error) {
+	log.Warn("Got non-fungible transfer event!")
+
+	return msg.Message{}, errors.New("non-fungible transfer not supported")
+}
+
+func genericTransferHandler(eventFields map[string]any, log log15.Logger) (msg.Message, error) {
+	chainID, err := getFieldValueAsType[types.U8]("ChainId", eventFields)
+	if err != nil {
+		return msg.Message{}, err
 	}
 
-	log.Info("Got non-fungible transfer event!", "destination", evt.Destination, "resourceId", evt.ResourceId)
+	depositNonce, err := getFieldValueAsType[types.U64]("DepositNonce", eventFields)
+	if err != nil {
+		return msg.Message{}, err
+	}
 
-	return msg.NewNonFungibleTransfer(
-		0, // Unset
-		msg.ChainId(evt.Destination),
-		msg.Nonce(evt.DepositNonce),
-		msg.ResourceId(evt.ResourceId),
-		big.NewInt(0).SetBytes(evt.TokenId[:]),
-		evt.Recipient,
-		evt.Metadata,
-	), nil
-}
+	resID, err := getFieldValueAsSliceOfType[types.U8]("ResourceId", eventFields)
+	if err != nil {
+		return msg.Message{}, err
+	}
+
+	resourceID, err := to32Bytes(resID)
+	if err != nil {
+		return msg.Message{}, err
+	}
 
-func genericTransferHandler(evtI interface{}, log log15.Logger) (msg.Message, error) {
-	evt, ok := evtI.(events.EventGenericTransfer)
-	if !ok {
-		return msg.Message{}, fmt.Errorf("failed to cast EventGenericTransfer type")
+	metadata, err := getFieldValueAsByteSlice("Vec<u8>", eventFields)
+	if err != nil {
+		return msg.Message{}, err
 	}
 
-	log.Info("Got generic transfer event!", "destination", evt.Destination, "resourceId", evt.ResourceId)
+	log.Info("Got generic transfer event!", "destination", chainID, "resourceId", fmt.Sprintf("%x", resourceID))
 
 	return msg.NewGenericTransfer(
 		0, // Unset
-		msg.ChainId(evt.Destination),
-		msg.Nonce(evt.DepositNonce),
-		msg.ResourceId(evt.ResourceId),
-		evt.Metadata,
+		msg.ChainId(chainID),
+		msg.Nonce(depositNonce),
+		resourceID,
+		metadata,
 	), nil
 }
+
+func to32Bytes(array []types.U8) ([32]byte, error) {
+	var res [32]byte
+
+	if len(array) != 32 {
+		return res, errors.New("array length mismatch")
+	}
+
+	for i, item := range array {
+		res[i] = byte(item)
+	}
+
+	return res, nil
+}
+
+func getFieldValueAsType[T any](fieldName string, eventFields map[string]any) (T, error) {
+	var t T
+
+	for name, value := range eventFields {
+		if name == fieldName {
+			if v, ok := value.(T); ok {
+				return v, nil
+			}
+
+			return t, fmt.Errorf("field type mismatch, expected %T, got %T", t, value)
+		}
+	}
+
+	return t, fmt.Errorf("field with name '%s' not found", fieldName)
+}
+
+func getFieldValueAsSliceOfType[T any](fieldName string, eventFields map[string]any) ([]T, error) {
+	for name, value := range eventFields {
+		if name == fieldName {
+			value, ok := value.([]any)
+
+			if !ok {
+				return nil, errors.New("field value not an array")
+			}
+
+			res, err := convertSliceToType[T](value)
+
+			if err != nil {
+				return nil, err
+			}
+
+			return res, nil
+		}
+	}
+
+	return nil, fmt.Errorf("field with name '%s' not found", fieldName)
+}
+
+func getFieldValueAsByteSlice(fieldName string, eventFields map[string]any) ([]byte, error) {
+	for name, value := range eventFields {
+		if name == fieldName {
+			value, ok := value.([]any)
+
+			if !ok {
+				return nil, errors.New("field value not an array")
+			}
+
+			slice, err := convertSliceToType[types.U8](value)
+
+			if err != nil {
+				return nil, err
+			}
+
+			res, err := convertToByteSlice(slice)
+
+			if err != nil {
+				return nil, err
+			}
+
+			return res, nil
+		}
+	}
+
+	return nil, fmt.Errorf("field with name '%s' not found", fieldName)
+}
+
+func convertSliceToType[T any](array []any) ([]T, error) {
+	res := make([]T, 0)
+
+	for _, item := range array {
+		if v, ok := item.(T); ok {
+			res = append(res, v)
+			continue
+		}
+
+		var t T
+
+		return nil, fmt.Errorf("couldn't cast '%T' to '%T'", item, t)
+	}
+
+	return res, nil
+}
+
+func convertToByteSlice(array []types.U8) ([]byte, error) {
+	res := make([]byte, 0)
+
+	for _, item := range array {
+		res = append(res, byte(item))
+	}
+
+	return res, nil
+}
+
+func getU256(eventFields map[string]any) (types.U256, error) {
+	for fieldName, fieldValue := range eventFields {
+		if fieldName != "primitive_types.U256.U256" {
+			continue
+		}
+
+		innerField, ok := fieldValue.(map[string]any)
+		if !ok {
+			return types.NewU256(*big.NewInt(0)), errors.New("unexpected amount field structure")
+		}
+
+		innerFieldVal, ok := innerField["[u64; 4]"]
+		if !ok {
+			return types.NewU256(*big.NewInt(0)), errors.New("amount field key not found")
+		}
+
+		slice, ok := innerFieldVal.([]any)
+		if !ok {
+			return types.NewU256(*big.NewInt(0)), errors.New("inner field value not a slice")
+		}
+
+		val, err := convertSliceToType[types.U64](slice)
+
+		if err != nil {
+			return types.NewU256(*big.NewInt(0)), err
+		}
+
+		if len(val) != 4 {
+			return types.NewU256(*big.NewInt(0)), errors.New("slice length mismatch")
+		}
+
+		var r [4]types.U64
+
+		for i, item := range val {
+			r[i] = item
+		}
+
+		encVal, err := codec.Encode(r)
+
+		if err != nil {
+			return types.NewU256(*big.NewInt(0)), errors.New("couldn't encode amount val")
+		}
+
+		var res types.U256
+
+		if err := codec.Decode(encVal, &res); err != nil {
+			return types.NewU256(*big.NewInt(0)), errors.New("couldn't decode amount")
+		}
+
+		return res, nil
+	}
+
+	return types.NewU256(*big.NewInt(0)), errors.New("amount field not found")
+}