chore: fix experimental blob errors in preview non-exist files (#1479)

Author: GarrettWu

bigframes/dataframe.py

@@ -778,15 +778,15 @@ def _repr_html_(self) -> str:
 
                 def obj_ref_rt_to_html(obj_ref_rt) -> str:
                     obj_ref_rt_json = json.loads(obj_ref_rt)
-                    gcs_metadata = obj_ref_rt_json["objectref"]["details"][
-                        "gcs_metadata"
-                    ]
-                    content_type = typing.cast(
-                        str, gcs_metadata.get("content_type", "")
-                    )
-                    if content_type.startswith("image"):
-                        url = obj_ref_rt_json["access_urls"]["read_url"]
-                        return f'<img src="{url}">'
+                    obj_ref_details = obj_ref_rt_json["objectref"]["details"]
+                    if "gcs_metadata" in obj_ref_details:
+                        gcs_metadata = obj_ref_details["gcs_metadata"]
+                        content_type = typing.cast(
+                            str, gcs_metadata.get("content_type", "")
+                        )
+                        if content_type.startswith("image"):
+                            url = obj_ref_rt_json["access_urls"]["read_url"]
+                            return f'<img src="{url}">'
 
                     return f'uri: {obj_ref_rt_json["objectref"]["uri"]}, authorizer: {obj_ref_rt_json["objectref"]["authorizer"]}'
 

bigframes/operations/blob.py

@@ -18,6 +18,7 @@
 from typing import cast, Optional, Union
 
 import IPython.display as ipy_display
+import pandas as pd
 import requests
 
 from bigframes import clients
@@ -209,8 +210,15 @@ def display(self, n: int = 3, *, content_type: str = ""):
         else:
             df["content_type"] = df["blob_col"].blob.content_type()
 
-        def display_single_url(read_url: str, content_type: str):
-            content_type = content_type.casefold()
+        def display_single_url(
+            read_url: str, content_type: Union[str, pd._libs.missing.NAType]
+        ):
+            if content_type is pd.NA:  # display as raw data or error
+                response = requests.get(read_url)
+                ipy_display.display(response.content)
+                return
+
+            content_type = cast(str, content_type).casefold()
 
             if content_type.startswith("image"):
                 ipy_display.display(ipy_display.Image(url=read_url))