Comfy-Org/ComfyUI · error · UploadError

EMPTY_UPLOAD

EMPTY_UPLOAD

Error message

Uploaded file is empty.

What it means

Raised as ApiServerError (comfy_api_nodes/util/client.py:943) when the request could not connect AND the diagnosis shows the internet is reachable (at least one of google.com/baidu.com responded), meaning the failure sits at the API host or the path to it. The message names default_base_url() and suggests a service-side outage.

Source

Thrown at app/assets/api/upload.py:154

                "UNSUPPORTED_FIELD",
                "Client-provided 'id' is not supported. Asset IDs are assigned by the server.",
            )
        elif fname == "mime_type":
            provided_mime_type = ((await field.text()) or "").strip() or None
        elif fname == "preview_id":
            provided_preview_id = ((await field.text()) or "").strip() or None
    if not file_present and not (provided_hash and provided_hash_exists):
        raise UploadError(
            400, "MISSING_FILE", "Form must include a 'file' part or a known 'hash'."
        )

    if (
        file_present
        and file_written == 0
        and not (provided_hash and provided_hash_exists)
    ):
        delete_temp_file_if_exists(tmp_path)
        raise UploadError(400, "EMPTY_UPLOAD", "Uploaded file is empty.")

    return ParsedUpload(
        file_present=file_present,
        file_written=file_written,
        file_client_name=file_client_name,
        tmp_path=tmp_path,
        tags_raw=tags_raw,
        provided_name=provided_name,
        user_metadata_raw=user_metadata_raw,
        provided_hash=provided_hash,
        provided_hash_exists=provided_hash_exists,
        provided_mime_type=provided_mime_type,
        provided_preview_id=provided_preview_id,
    )


def delete_temp_file_if_exists(tmp_path: str | None) -> None:
    """Safely remove a temp file and its parent directory if empty."""

View on GitHub (pinned to 1c6d8d45b3)

Solutions

1. Check the provider's status page for an active incident
2. Retry after a wait — connection-level outages are usually transient
3. Verify DNS resolution of the API host from your machine (nslookup/dig) if outages are not reported
4. Report to the provider if it persists while their status page is green

from comfy_api_nodes.util.common_exceptions import ApiServerError

def is_api_server_error(e: BaseException) -> bool:
    return isinstance(e, ApiServerError)

from comfy_api_nodes.util.common_exceptions import ApiServerError
try:
    result = await sync_op(...)
except ApiServerError:
    await asyncio.sleep(30)
    result = await sync_op(...)  # transient outage retry
# cap retries; check provider status page if persistent

When it happens

Trigger: API host down or restarting during a provider deploy; DNS for the API domain failing while general internet works; the API host's /health probe failing (>=500) or being unreachable; datacenter/regional outage between the user and the API.

Common situations: Provider outages and maintenance windows; API domain DNS propagation issues after provider migration; routing/peering problems affecting only the API host; provider rate-limiting at TCP/connection level.

Related errors

• The remote service appears unreachable at this time.
• UNSUPPORTED_MEDIA_TYPE
• HASH_CHECK_FAILED
• UPLOAD_IO_ERROR
• MISSING_FILE

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/2cdcf04c3e1e0569. Report an issue: GitHub.