fix: do not produce null fields in marshalled json

Author: hacdias

routing/http/server/server_test.go

@@ -128,11 +128,11 @@ func TestProviders(t *testing.T) {
 	}
 
 	t.Run("JSON Response", func(t *testing.T) {
-		runTest(t, mediaTypeJSON, false, `{"Providers":[{"Addrs":[],"ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vn","Protocols":["transport-bitswap"],"Schema":"peer"},{"Schema":"bitswap","Protocol":"transport-bitswap","ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vz","Addrs":[]}]}`)
+		runTest(t, mediaTypeJSON, false, `{"Providers":[{"Addrs":[],"ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vn","Protocols":["transport-bitswap"],"Schema":"peer"},{"Schema":"bitswap","Protocol":"transport-bitswap","ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vz"}]}`)
 	})
 
 	t.Run("NDJSON Response", func(t *testing.T) {
-		runTest(t, mediaTypeNDJSON, true, `{"Addrs":[],"ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vn","Protocols":["transport-bitswap"],"Schema":"peer"}`+"\n"+`{"Schema":"bitswap","Protocol":"transport-bitswap","ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vz","Addrs":[]}`+"\n")
+		runTest(t, mediaTypeNDJSON, true, `{"Addrs":[],"ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vn","Protocols":["transport-bitswap"],"Schema":"peer"}`+"\n"+`{"Schema":"bitswap","Protocol":"transport-bitswap","ID":"12D3KooWM8sovaEGU1bmiWGWAzvs47DEcXKZZTuJnpQyVTkRs2Vz"}`+"\n")
 	})
 }
 

routing/http/types/record_bitswap.go

@@ -28,7 +28,7 @@ type BitswapRecord struct {
 	Schema   string
 	Protocol string
 	ID       *peer.ID
-	Addrs    []Multiaddr
+	Addrs    []Multiaddr `json:",omitempty"`
 }
 
 func (br *BitswapRecord) GetSchema() string {

routing/http/types/record_peer.go

@@ -64,9 +64,18 @@ func (pr PeerRecord) MarshalJSON() ([]byte, error) {
 			m[key] = val
 		}
 	}
+
+	// Schema and ID must always be set.
 	m["Schema"] = pr.Schema
 	m["ID"] = pr.ID
-	m["Addrs"] = pr.Addrs
-	m["Protocols"] = pr.Protocols
+
+	if pr.Addrs != nil {
+		m["Addrs"] = pr.Addrs
+	}
+
+	if pr.Protocols != nil {
+		m["Protocols"] = pr.Protocols
+	}
+
 	return drjson.MarshalJSONBytes(m)
 }