[Bug fix] Misclassified 500 error on invalid image_url in /chat/completions request (#14149)

* add ImageFetchError

* docs ImageFetchError

* fix ImageFetchError

* test_completion_with_invalid_image_url

Author: ishaan-jaff

docs/my-website/docs/exception_mapping.md

@@ -12,6 +12,7 @@ All exceptions can be imported from `litellm` - e.g. `from litellm import BadReq
 | 400 | UnsupportedParamsError | litellm.BadRequestError | Raised when unsupported params are passed |
 | 400         | ContextWindowExceededError| litellm.BadRequestError | Special error type for context window exceeded error messages - enables context window fallbacks |
 | 400         | ContentPolicyViolationError| litellm.BadRequestError | Special error type for content policy violation error messages - enables content policy fallbacks |
+| 400         | ImageFetchError | litellm.BadRequestError | Raised when there are errors fetching or processing images |
 | 400 | InvalidRequestError | openai.BadRequestError | Deprecated error, use BadRequestError instead |
 | 401         | AuthenticationError      | openai.AuthenticationError |
 | 403         | PermissionDeniedError    | openai.PermissionDeniedError |

litellm/__init__.py

@@ -1261,6 +1261,7 @@ def add_known_models():
     AuthenticationError,
     InvalidRequestError,
     BadRequestError,
+    ImageFetchError,
     NotFoundError,
     RateLimitError,
     ServiceUnavailableError,

litellm/exceptions.py

@@ -153,6 +153,29 @@ def __repr__(self):
             _message += f", LiteLLM Max Retries: {self.max_retries}"
         return _message
 
+class ImageFetchError(BadRequestError):
+    def __init__(
+        self,
+        message,
+        model=None,
+        llm_provider=None,
+        response: Optional[httpx.Response] = None,
+        litellm_debug_info: Optional[str] = None,
+        max_retries: Optional[int] = None,
+        num_retries: Optional[int] = None,
+        body: Optional[dict] = None,
+    ):
+        super().__init__(
+            message=message,
+            model=model,
+            llm_provider=llm_provider,
+            response=response,
+            litellm_debug_info=litellm_debug_info,
+            max_retries=max_retries,
+            num_retries=num_retries,
+            body=body,
+        )
+
 
 class UnprocessableEntityError(openai.UnprocessableEntityError):  # type: ignore
     def __init__(

litellm/litellm_core_utils/prompt_templates/image_handling.py

@@ -17,7 +17,7 @@
 
 def _process_image_response(response: Response, url: str) -> str:
     if response.status_code != 200:
-        raise Exception(
+        raise litellm.ImageFetchError(
             f"Error: Unable to fetch image from URL. Status code: {response.status_code}, url={url}"
         )
 
@@ -57,9 +57,11 @@ async def async_convert_url_to_base64(url: str) -> str:
         try:
             response = await client.get(url, follow_redirects=True)
             return _process_image_response(response, url)
+        except litellm.ImageFetchError:
+            raise
         except Exception:
             pass
-    raise Exception(
+    raise litellm.ImageFetchError(
         f"Error: Unable to fetch image from URL after 3 attempts. url={url}"
     )
 
@@ -74,10 +76,11 @@ def convert_url_to_base64(url: str) -> str:
         try:
             response = client.get(url, follow_redirects=True)
             return _process_image_response(response, url)
+        except litellm.ImageFetchError:
+            raise
         except Exception as e:
             verbose_logger.exception(e)
-            # print(e)
             pass
-    raise Exception(
-        f"Error: Unable to fetch image from URL after 3 attempts. url={url}"
+    raise litellm.ImageFetchError(
+        f"Error: Unable to fetch image from URL after 3 attempts. url={url}",
     )

tests/test_litellm/litellm_core_utils/test_image_handling.py

@@ -0,0 +1,41 @@
+import pytest
+from httpx import Request, Response
+
+import litellm
+from litellm.litellm_core_utils.prompt_templates.image_handling import (
+    convert_url_to_base64,
+)
+
+
+class DummyClient:
+    def get(self, url, follow_redirects=True):
+        return Response(status_code=404, request=Request("GET", url))
+
+
+def test_invalid_image_url_raises_bad_request(monkeypatch):
+    monkeypatch.setattr(litellm, "module_level_client", DummyClient())
+    with pytest.raises(litellm.ImageFetchError) as excinfo:
+        convert_url_to_base64("https://invalid.example/image.png")
+    assert "Unable to fetch image" in str(excinfo.value)
+
+
+def test_completion_with_invalid_image_url(monkeypatch):
+    monkeypatch.setattr(litellm, "module_level_client", DummyClient())
+    messages = [
+        {
+            "role": "user",
+            "content": [
+                {"type": "text", "text": "hi"},
+                {
+                    "type": "image_url",
+                    "image_url": {"url": "https://invalid.example/image.png"},
+                },
+            ],
+        }
+    ]
+    with pytest.raises(litellm.ImageFetchError) as excinfo:
+        litellm.completion(
+            model="gemini/gemini-pro", messages=messages, api_key="test"
+        )
+    assert excinfo.value.status_code == 400
+    assert "Unable to fetch image" in str(excinfo.value)