Hide EscapeHTML behind an option instead of default behaviour. (#575)

ygot/struct_validation_map.go

@@ -383,6 +383,10 @@ type EmitJSONConfig struct {
 	// Indent is the string used for indentation within the JSON output. The
 	// default value is three spaces.
 	Indent string
+	// EscapeHTML determines whether certain characters will be escaped
+	// in the marshalled JSON for safety in HTML embedding. See
+	// https://pkg.go.dev/encoding/json#Encoder.SetEscapeHTML.
+	EscapeHTML bool
 	// SkipValidation specifies whether the GoStruct supplied to EmitJSON should
 	// be validated before emitting its content. Validation is skipped when it
 	// is set to true.
@@ -418,17 +422,26 @@ func EmitJSON(s ValidatedGoStruct, opts *EmitJSONConfig) (string, error) {
 		return "", err
 	}
 
+	sb := &strings.Builder{}
+	enc := json.NewEncoder(sb)
 	indent := indentString
-	if opts != nil && opts.Indent != "" {
-		indent = opts.Indent
+	enc.SetEscapeHTML(false)
+	if opts != nil {
+		enc.SetEscapeHTML(opts.EscapeHTML)
+
+		if opts.Indent != "" {
+			indent = opts.Indent
+		}
 	}
+	enc.SetIndent("", indent)
 
-	j, err := json.MarshalIndent(v, "", indent)
-	if err != nil {
+	if err := enc.Encode(v); err != nil {
 		return "", fmt.Errorf("JSON marshalling error: %v", err)
 	}
 
-	return string(j), nil
+	// Exclude the last newline character:
+	// https://pkg.go.dev/encoding/json#Encoder.Encode
+	return sb.String()[:sb.Len()-1], nil
 }
 
 // makeJSON renders the GoStruct s to map[string]interface{} according to the

ygot/struct_validation_map_test.go

@@ -631,11 +631,23 @@ func TestEmitJSON(t *testing.T) {
 		name: "simple schema JSON output",
 		inStruct: &mapStructTestOne{
 			Child: &mapStructTestOneChild{
-				FieldOne: String("hello"),
+				FieldOne: String("abc -> def"),
 				FieldTwo: Uint32(42),
 			},
 		},
 		wantJSONPath: filepath.Join(TestRoot, "testdata/emitjson_1.json-txt"),
+	}, {
+		name: "simple schema JSON output with safe HTML",
+		inStruct: &mapStructTestOne{
+			Child: &mapStructTestOneChild{
+				FieldOne: String("abc -> def"),
+				FieldTwo: Uint32(42),
+			},
+		},
+		inConfig: &EmitJSONConfig{
+			EscapeHTML: true,
+		},
+		wantJSONPath: filepath.Join(TestRoot, "testdata/emitjson_1_html_safe.json-txt"),
 	}, {
 		name: "schema with a list JSON output",
 		inStruct: &mapStructTestFour{

ygot/testdata/emitjson_1.json-txt

@@ -1,7 +1,7 @@
 {
    "child": {
       "config": {
-         "field-one": "hello",
+         "field-one": "abc -> def",
          "field-two": 42
       }
    }

ygot/testdata/emitjson_1_html_safe.json-txt

@@ -0,0 +1,8 @@
+{
+   "child": {
+      "config": {
+         "field-one": "abc -\u003e def",
+         "field-two": 42
+      }
+   }
+}