Merge pull request #7742 from onflow/jord/json-block-id

Block JSON Encoding

Author: tim-barry

model/cluster/block_test.go

@@ -1,9 +1,11 @@
 package cluster_test
 
 import (
+	"encoding/json"
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/onflow/flow-go/model/cluster"
@@ -281,3 +283,16 @@ func TestNewRootProposal(t *testing.T) {
 		require.Contains(t, err.Error(), "proposer signature must be empty")
 	})
 }
+
+// TestBlockEncodingJSON_IDField ensures that the explicit ID field added to the
+// block when encoded as JSON is present and accurate.
+func TestBlockEncodingJSON_IDField(t *testing.T) {
+	block := unittest.ClusterBlockFixture()
+	blockID := block.ID()
+	data, err := json.Marshal(block)
+	require.NoError(t, err)
+	var decodedIDField struct{ ID flow.Identifier }
+	err = json.Unmarshal(data, &decodedIDField)
+	require.NoError(t, err)
+	assert.Equal(t, blockID, decodedIDField.ID)
+}

model/flow/block.go

@@ -1,6 +1,7 @@
 package flow
 
 import (
+	"encoding/json"
 	"fmt"
 	"time"
 )
@@ -66,6 +67,19 @@ func (b *GenericBlock[T]) ToHeader() *Header {
 	return header
 }
 
+// MarshalJSON implements JSON encoding logic for blocks.
+// We include a top-level ID field equal to the hash of the block, for visibility in automations.
+// The ID field is ignored when unmarshaling a JSON structure back into a block.
+func (b *GenericBlock[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		GenericBlock[T]
+		ID Identifier
+	}{
+		GenericBlock: *b,
+		ID:           b.ID(),
+	})
+}
+
 // Block is the canonical instantiation of GenericBlock using flow.Payload as the payload type.
 //
 // Zero values for certain HeaderBody fields are allowed only for root blocks, which must be constructed

model/flow/block_test.go

@@ -52,6 +52,19 @@ func TestBlockEncodingJSON(t *testing.T) {
 	assert.Equal(t, block, &decoded)
 }
 
+// TestBlockEncodingJSON_IDField ensures that the explicit ID field added to the
+// block when encoded as JSON is present and accurate.
+func TestBlockEncodingJSON_IDField(t *testing.T) {
+	block := unittest.BlockFixture()
+	blockID := block.ID()
+	data, err := json.Marshal(block)
+	require.NoError(t, err)
+	var decodedIDField struct{ ID flow.Identifier }
+	err = json.Unmarshal(data, &decodedIDField)
+	require.NoError(t, err)
+	assert.Equal(t, blockID, decodedIDField.ID)
+}
+
 func TestBlockEncodingMsgpack(t *testing.T) {
 	block := unittest.BlockFixture()
 	blockID := block.ID()