sgl-project/sglang · error · HTTPException

An input image is required for mesh generation

Error message

An input image is required for mesh generation

What it means

The mesh generation endpoint requires an input image; if after processing the request no input_path was produced, it returns HTTP 422. This guards the core invariant that mesh generation is image-conditioned.

Source

Thrown at python/sglang/multimodal_gen/runtime/entrypoints/openai/mesh_api.py:208

            body = {}
        try:
            payload: Dict[str, Any] = dict(body or {})

            if payload.get("input_image"):
                img_src = payload.pop("input_image")
                uploads_dir = os.path.join("outputs", "uploads")
                os.makedirs(uploads_dir, exist_ok=True)
                input_path = await save_image_to_path(
                    img_src,
                    os.path.join(uploads_dir, f"{request_id}_input_image"),
                )

            req = MeshGenerationsRequest(**payload)
        except Exception as e:
            raise HTTPException(status_code=400, detail=f"Invalid request body: {e}")

    if not input_path:
        raise HTTPException(
            status_code=422,
            detail="An input image is required for mesh generation",
        )

    sampling_params = _build_sampling_params_from_request(request_id, req, input_path)
    job = _mesh_job_from_sampling(request_id, req, sampling_params)
    await MESH_STORE.upsert(request_id, job)

    batch = prepare_request(
        server_args=server_args,
        sampling_params=sampling_params,
    )

    asyncio.create_task(_dispatch_job_async(request_id, batch))
    return MeshResponse(**job)


@router.get("", response_model=MeshListResponse)

View on GitHub (pinned to 0132848349)

Solutions

1. Attach the input image as the expected multipart file field (or provide a valid image source in JSON)
2. Confirm the field name matches what the endpoint expects (img/img_src/image)
3. If testing with curl, use -F to send the file as multipart form-data

Example fix

// before
curl -X POST url -H 'Content-Type: application/json' -d '{"prompt":"mesh"}'
// after
curl -X POST url -F "image=@input.png" -F "prompt=generate 3d mesh"

has_image = file is not None or body.get('image') is not None
assert has_image, 'mesh generation requires an image'

if resp.status_code == 422: attach the image file and retry

When it happens

Trigger: Calling the mesh generations endpoint without any image: no multipart file part and no valid image source in the JSON payload.

Common situations: Client sends only a prompt JSON body; form-data field named 'image' missing or empty; sending the image under an unexpected field name so the server never reads it.

Understand the failure class

Background: Missing required parameter errors: what 'X is required' and 'the required X param is missing' mean, and how to fix them — this error's family across 27 libraries.

Related errors

• Failed to process image source: {str(e)}
• Invalid request body: {e}
• Mesh not found
• Mesh has been uploaded to cloud storage. Please use the clou
• Generation is still in-progress

AI-assisted analysis of sgl-project/sglang@0132848349 (2026-08-28). Data as JSON: /api/errors/b8842e893c3cef29. Report an issue: GitHub.