e2e: integrate light clients (#6196)

light/rpc/client.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"regexp"
 	"time"
 
 	"github.com/gogo/protobuf/proto"
@@ -59,6 +60,27 @@ func KeyPathFn(fn KeyPathFunc) Option {
 	}
 }
 
+// DefaultMerkleKeyPathFn creates a function used to generate merkle key paths
+// from a path string and a key. This is the default used by the cosmos SDK.
+// This merkle key paths are required when verifying /abci_query calls
+func DefaultMerkleKeyPathFn() KeyPathFunc {
+	// regexp for extracting store name from /abci_query path
+	storeNameRegexp := regexp.MustCompile(`\/store\/(.+)\/key`)
+
+	return func(path string, key []byte) (merkle.KeyPath, error) {
+		matches := storeNameRegexp.FindStringSubmatch(path)
+		if len(matches) != 2 {
+			return nil, fmt.Errorf("can't find store name in %s using %s", path, storeNameRegexp)
+		}
+		storeName := matches[1]
+
+		kp := merkle.KeyPath{}
+		kp = kp.AppendKey([]byte(storeName), merkle.KeyEncodingURL)
+		kp = kp.AppendKey(key, merkle.KeyEncodingURL)
+		return kp, nil
+	}
+}
+
 // NewClient returns a new client.
 func NewClient(next rpcclient.Client, lc LightClient, opts ...Option) *Client {
 	c := &Client{