opendatalab/MinerU · error · HTTPException

Language {lang} not supported. Allowed values: {allowed_valu

Error message

Language {lang} not supported. Allowed values: {allowed_values}

What it means

HTTP 400 raised by validate_parse_lang_list(): each OCR language code in lang_list is validated by validate_public_ocr_lang_list and unsupported codes are rejected with the allowed list in the message. This stops old/invalid language entries (e.g. deprecated codes) from entering the OCR chain.

Source

Thrown at mineru/cli/api_request.py:89

        return validate_public_backend(backend)
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


def validate_parse_effort(effort: str) -> str:
    """校验公开 API 允许的 hybrid effort，避免非法值进入解析链路。"""
    try:
        return validate_public_effort(effort)
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


def validate_parse_lang_list(lang_list: list[str]) -> list[str]:
    """校验公开 API 允许的 OCR 语言列表，避免旧语言入口进入解析链路。"""
    try:
        return validate_public_ocr_lang_list(lang_list)
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


async def parse_request_form(
    request: Request,
    files: Annotated[
        list[UploadFile],
        File(
            description="Upload PDF, image, DOCX, PPTX, or XLSX files for parsing",
            json_schema_extra=SWAGGER_UI_FILE_ARRAY_SCHEMA_EXTRA,
        ),
    ],
    lang_list: Annotated[
        list[str],
        Form(
            description=format_public_ocr_lang_description(),
            json_schema_extra=PUBLIC_OCR_LANGUAGE_SCHEMA_EXTRA,
        ),
    ] = ["ch"],

View on GitHub (pinned to 4fe4bde114)

Solutions

Use the codes listed in the error message (commonly 'ch' and 'en' style short codes)
Do not use tesseract-style codes like chi_sim or deu
Match casing exactly (lowercase)
Omit lang_list to use the server default rather than guessing codes

Example fix

# before
data = {'parse_method': 'ocr', 'lang_list': ['chi_sim', 'eng']}

# after
data = {'parse_method': 'ocr', 'lang_list': ['ch', 'en']}

Defensive patterns

Strategy: validation

Validate before calling

# Probe once and cache the server's supported languages
cfg = requests.get(f"{base_url}/parse-config", timeout=10).json()  # or read from /docs
allowed_langs = set(cfg.get("lang_list", ["ch", "en"]))
lang_list = [l.strip().lower() for l in lang_list if l.strip().lower() in allowed_langs]

Type guard

def is_valid_lang_list(v: list[str]) -> bool:
    return isinstance(v, list) and all(isinstance(x, str) and x.strip().lower() in {"ch", "en"} for x in v)

Try / catch

try:
    resp = requests.post(url, files=files, data={"lang_list": json.dumps(langs)}, timeout=60)
    resp.raise_for_status()
except requests.HTTPError as e:
    if e.response.status_code == 400 and "not supported" in e.response.text:
        langs = ["ch", "en"]  # safe default; retry once
    else:
        raise

Prevention

Use mineru's short codes (ch, en), not tesseract names (chi_sim, eng)
Omit lang_list to take the server default
Parse the allowed-values list out of the 400 body and cache it for the session

When it happens

Trigger: POSTing lang_list=['ch'], ['chi_sim'], ['EN'], or an unknown code together with parse_method that triggers OCR; empty or malformed arrays also fail downstream validation.

Common situations: Codes copied from tesseract names ('chi_sim','eng') instead of mineru's codes ('ch','en'); uppercase variants; users migrating from other OCR tools whose lang tags differ.

Related errors

AI-assisted analysis of opendatalab/MinerU@4fe4bde114 (2026-08-14). Data as JSON: /api/errors/ef77d7621f9f7600. Report an issue: GitHub.