fix invalid json strings

src/backend/langflow/template/frontend_node/base.py

@@ -164,7 +164,7 @@ class FrontendNode(BaseModel):
     ) -> None:
         """Handles specific field values for certain fields."""
         if key == "headers":
-            field.value = """{'Authorization': 'Bearer <token>'}"""
+            field.value = """{"Authorization": "Bearer <token>"}"""
         FrontendNode._handle_model_specific_field_values(field, key, name)
         FrontendNode._handle_api_key_specific_field_values(field, key, name)
 
@@ -249,4 +249,4 @@ class FrontendNode(BaseModel):
         if "default" in value:
             field.value = value["default"]
         if key == "headers":
-            field.value = """{'Authorization': 'Bearer <token>'}"""
+            field.value = """{"Authorization": "Bearer <token>"}"""

src/backend/langflow/template/frontend_node/formatter/field_formatters.py

@@ -145,7 +145,7 @@ class HeadersDefaultValueFormatter(FieldFormatter):
     def format(self, field: TemplateField, name: Optional[str] = None) -> None:
         key = field.name
         if key == "headers":
-            field.value = """{'Authorization': 'Bearer <token>'}"""
+            field.value = """{"Authorization": "Bearer <token>"}"""
 
 
 class DictCodeFileFormatter(FieldFormatter):

src/backend/langflow/utils/util.py

@@ -431,7 +431,7 @@ def set_headers_value(value: Dict[str, Any]) -> None:
     """
     Sets the value for the 'headers' key.
     """
-    value["value"] = """{'Authorization': 'Bearer <token>'}"""
+    value["value"] = """{"Authorization": "Bearer <token>"}"""
 
 
 def add_options_to_field(