fix: trimming leading and trailing whitespaces before unmarshal LLM o… (#587)

backend/domain/workflow/internal/nodes/utils.go

@@ -87,15 +87,13 @@ func TemplateRender(template string, vals map[string]interface{}) (string, error
 }
 
 func ExtractJSONString(content string) string {
+	content = strings.TrimSpace(content)
+
 	if strings.HasPrefix(content, "```") && strings.HasSuffix(content, "```") {
 		content = content[3 : len(content)-3]
 	}
 
-	if strings.HasPrefix(content, "json") {
+	return strings.TrimPrefix(content, "json")
-		content = content[4:]
-	}
-
-	return content
 }
 
 func ConcatTwoMaps(m1, m2 map[string]any) (map[string]any, error) {

backend/domain/workflow/internal/nodes/utils_test.go

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2025 coze-dev Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package nodes
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/coze-dev/coze-studio/backend/pkg/sonic"
+)
+
+func TestExtractJSONString(t *testing.T) {
+	s := "\n```json{\"k\":1}```\t"
+	s1 := ExtractJSONString(s)
+	var v map[string]any
+	err := sonic.UnmarshalString(s1, &v)
+	assert.NoError(t, err)
+	assert.Equal(t, map[string]any{"k": int64(1)}, v)
+}