feat(search): Improves data transformation to handle missing fields

cl/search/documents.py

@@ -1254,8 +1254,10 @@ def get_csv_transformations(cls) -> dict[str, Callable[..., Any]]:
         transformations["filepath_local"] = lambda x: (
             f"https://storage.courtlistener.com/{x}" if x else ""
         )
-        transformations["rd_absolute_url"] = (
-            lambda x: f"https://www.courtlistener.com{x['absolute_url']}"
+        transformations["rd_absolute_url"] = lambda x: (
+            f"https://www.courtlistener.com{x['absolute_url']}"
+            if x.get("absolute_url")
+            else ""
         )
 
         # Define a mapping of new CSV column names to the corresponding source
@@ -1277,7 +1279,8 @@ def get_csv_transformations(cls) -> dict[str, Callable[..., Any]]:
         # the value from the source key in the input data.
         for new_key, source in new_keys_mapping.items():
             transformations[new_key] = partial(
-                lambda origin_key, document: document[origin_key], source
+                lambda origin_key, document: document.get(origin_key, ""),
+                source,
             )
         return transformations