Files
ComfyUI-Lora-Manager/py/services/llm_service.py
T
Will Miao 326df32933 fix(llm): stop DeepSeek enrichment failing on json_schema rejection
Enriching a model with `llm_provider=deepseek` failed outright with
HTTP 400 "This response_format type is unavailable now".  Probing the
endpoint shows why:

    response_format absent      -> 200
    {"type": "json_object"}     -> 200
    {"type": "json_schema",...} -> 400

`chat_completion_json` preferred `json_schema` for a real reason -- LM
Studio and other local OpenAI-compatible servers reject `json_object`
but accept `json_schema` -- and guarded the fallback with a substring
test for `'response_format.type'` (the wording of those servers'
rejection).  DeepSeek's message is "This response_format type is
unavailable now", which does not contain that substring, so the guard
re-raised and the retry never ran.

Make the format a per-provider chain instead of a single guess:

- `_JSON_OBJECT_ONLY_PROVIDERS` lists providers known to reject
  json_schema (currently just deepseek).  They ask for `json_object`
  first, so the common case costs one request and no wasted retry.
- Everyone else keeps `json_schema` first, then downgrades through
  `json_object` and finally prompt-only mode.
- A downgrade now happens on any error mentioning `response_format`,
  which covers wording variants without swallowing unrelated failures:
  auth errors, unknown models, and rate limits still surface unchanged
  because their messages never name the parameter.

`json_object` is sufficient here: the skill prompt already specifies the
exact JSON shape, and `_try_salvage_json` repairs imperfect output.

Verified against the real configured endpoint with the real
`enrich_hf_metadata` prompt, prompt renderer, and ModelScope model card
for jj3550945163/Krea-2-LORA: a 9,815-character prompt returns
parseable JSON (base_model "Flux.1 Krea", description, tags, notes).

Three regression tests cover the DeepSeek ordering, the
json_schema -> json_object downgrade, and the no-retry-on-unrelated-400
path.  Full backend suite: 2856 passed.
2026-09-14 10:27:33 +08:00

802 lines
30 KiB
Python

"""Centralized LLM API client with BYOK (bring-your-own-key) provider support.
Reads provider configuration from :class:`SettingsManager` and makes
OpenAI-compatible ``/chat/completions`` calls. Supports any provider that
implements the OpenAI Chat Completions API surface area (OpenAI, Ollama,
vLLM, LM Studio, etc.).
"""
from __future__ import annotations
import asyncio
import json
import logging
import time
from typing import Any, Dict, List, Optional
import aiohttp
from .errors import LLMNotConfiguredError, LLMRateLimitError, LLMResponseError
logger = logging.getLogger(__name__)
# ---------------------------------------------------------------------------
# Model catalog sourced from opencode's maintained model registry.
# maps provider_id -> list of model IDs.
# ---------------------------------------------------------------------------
_MODEL_CATALOG_URL = "https://models.dev/api.json"
# In-memory cache: maps provider slug -> list of model ID strings.
_catalog_cache: Optional[Dict[str, List[str]]] = None
# Per-model max output token limits parsed from the catalog.
# ``{provider_id: {model_id: max_output_tokens}}``.
_model_output_limits: Dict[str, Dict[str, int]] = {}
# Monotonic timestamp of the last failed catalog fetch (None = no failure
# yet). Failed fetches are negatively cached: further calls return the
# empty fallback without hitting the network until the cooldown elapses,
# so users on broken networks don't stall on every settings-modal open.
_catalog_last_failure: Optional[float] = None
_CATALOG_FAILURE_COOLDOWN = 600.0 # seconds
# Serializes catalog fetches so concurrent callers don't duplicate requests.
_catalog_lock = asyncio.Lock()
_CATALOG_TIMEOUT = aiohttp.ClientTimeout(total=30)
# Cloudflare serves brotli when the client advertises it, and brotli is a
# required dependency here — a corrupted br stream can crash the native
# decoder with a Windows access violation (issue #1099). Request gzip
# instead; zlib decompression is not affected and corrupt gzip data only
# raises ContentEncodingError (an aiohttp.ClientError subclass), which the
# exception handlers below already catch.
_NO_BROTLI_HEADERS = {"Accept-Encoding": "gzip, deflate"}
async def _load_model_catalog() -> Dict[str, List[str]]:
"""Fetch and parse the model catalog.
Returns ``{provider_id: [model_id, ...]}`` and also populates
:data:`_model_output_limits` with per-model ``limit.output`` values
for use by :func:`_get_model_max_output`.
The JSON at ``_MODEL_CATALOG_URL`` is a dict keyed by provider slug; each
value has a ``models`` sub-dict keyed by model ID. The result is cached
in memory after the first successful fetch.
Subsequent calls return the cached data immediately.
Failed fetches are negatively cached: further calls return an empty
dict without hitting the network until ``_CATALOG_FAILURE_COOLDOWN``
has elapsed, so a broken network does not stall every settings-modal
open. Concurrent callers are serialized behind :data:`_catalog_lock`
so only one request is ever in flight.
"""
global _catalog_cache, _model_output_limits, _catalog_last_failure
if _catalog_cache is not None:
return _catalog_cache
async with _catalog_lock:
# Re-check under the lock: another caller may have fetched (or
# failed) while we were waiting.
if _catalog_cache is not None:
return _catalog_cache
if (
_catalog_last_failure is not None
and time.monotonic() - _catalog_last_failure < _CATALOG_FAILURE_COOLDOWN
):
logger.debug(
"Skipping model catalog fetch: last attempt failed %.0fs ago",
time.monotonic() - _catalog_last_failure,
)
return {}
try:
async with aiohttp.ClientSession(timeout=_CATALOG_TIMEOUT) as session:
async with session.get(_MODEL_CATALOG_URL, headers=_NO_BROTLI_HEADERS) as resp:
if resp.status != 200:
logger.warning("Model catalog returned HTTP %s", resp.status)
_catalog_last_failure = time.monotonic()
return {}
data = await resp.json()
except (aiohttp.ClientError, asyncio.TimeoutError, json.JSONDecodeError, UnicodeDecodeError) as exc:
logger.warning("Failed to fetch model catalog: %s", exc)
_catalog_last_failure = time.monotonic()
return {}
if not isinstance(data, dict):
logger.warning("Model catalog is not a dict, got %s", type(data).__name__)
_catalog_last_failure = time.monotonic()
return {}
result: Dict[str, List[str]] = {}
output_limits: Dict[str, Dict[str, int]] = {}
for provider_id, provider_info in data.items():
if not isinstance(provider_info, dict):
continue
models_dict = provider_info.get("models")
if not isinstance(models_dict, dict):
continue
model_ids: List[str] = []
provider_limits: Dict[str, int] = {}
for mid, model_info in models_dict.items():
if not isinstance(mid, str):
continue
model_ids.append(mid)
if isinstance(model_info, dict):
limit = model_info.get("limit")
if isinstance(limit, dict):
output = limit.get("output")
if isinstance(output, (int, float)) and output > 0:
provider_limits[mid] = int(output)
if model_ids:
result[provider_id] = model_ids
if provider_limits:
output_limits[provider_id] = provider_limits
_catalog_cache = result
_model_output_limits = output_limits
logger.debug(
"Loaded model catalog: %d providers, %d total models "
"(%d providers have output limits)",
len(result),
sum(len(m) for m in result.values()),
len(output_limits),
)
return result
def _get_model_max_output(provider: str, model: str) -> Optional[int]:
"""Return the model's max output token limit from the catalog, or ``None``.
Returns ``None`` when the provider or model is not found in the catalog
(e.g. local Ollama models, custom models, or user-typed model names).
Callers should fall back to a safe default.
"""
return _model_output_limits.get(provider, {}).get(model)
# Short timeout for Ollama's local API
_OLLAMA_API_TIMEOUT = aiohttp.ClientTimeout(total=8)
async def fetch_ollama_models(api_base: str) -> List[str]:
"""Fetch locally available models from a running Ollama instance.
Uses Ollama's OpenAI-compatible ``GET {api_base}/models`` endpoint.
Returns an empty list if Ollama is not reachable (not running).
"""
url = f"{api_base.rstrip('/')}/models"
try:
async with aiohttp.ClientSession(timeout=_OLLAMA_API_TIMEOUT) as session:
async with session.get(url, headers=_NO_BROTLI_HEADERS) as resp:
if resp.status != 200:
logger.debug("Ollama API returned HTTP %s from %s", resp.status, api_base)
return []
data = await resp.json()
except (aiohttp.ClientError, asyncio.TimeoutError, json.JSONDecodeError, UnicodeDecodeError) as exc:
logger.debug("Ollama not reachable at %s: %s", api_base, exc)
return []
raw = data.get("data") if isinstance(data, dict) else None
if not isinstance(raw, list):
return []
return [
str(entry["id"]) for entry in raw
if isinstance(entry, dict) and isinstance(entry.get("id"), str)
]
async def get_provider_model_ids(provider_id: str) -> List[str]:
"""Return the list of known model IDs for *provider_id* from the catalog.
The catalog is loaded on first call and cached thereafter. If the
provider is not found an empty list is returned (never raises).
"""
catalog = await _load_model_catalog()
return catalog.get(provider_id, [])
async def get_all_provider_models(
provider_ids: List[str],
) -> Dict[str, List[str]]:
"""Return model lists for a subset of providers in one call.
Loads the catalog (cached) and returns only the requested providers.
Handy for embedding lightweight data into the template context.
"""
catalog = await _load_model_catalog()
return {
pid: catalog.get(pid, [])
for pid in provider_ids
}
# Provider preset definitions.
# Each entry contains display metadata and defaults for the UI.
# The key is the internal provider id stored in ``llm_provider``.
# Models are NOT listed here — they come from the opencode model catalog at
# runtime (see :func:`get_provider_model_ids`).
PROVIDER_PRESETS: Dict[str, Dict[str, Any]] = {
"openai": {
"name": "OpenAI",
"api_base": "https://api.openai.com/v1",
"requires_key": True,
},
"ollama": {
"name": "Ollama (local)",
"api_base": "http://localhost:11434/v1",
"requires_key": False,
},
"deepseek": {
"name": "DeepSeek",
"api_base": "https://api.deepseek.com/v1",
"requires_key": True,
},
"groq": {
"name": "Groq",
"api_base": "https://api.groq.com/openai/v1",
"requires_key": True,
},
"openrouter": {
"name": "OpenRouter",
"api_base": "https://openrouter.ai/api/v1",
"requires_key": True,
},
"google": {
"name": "Gemini",
"api_base": "https://generativelanguage.googleapis.com/v1beta/openai",
"requires_key": True,
},
"opencode-go": {
"name": "OpenCode Go",
"api_base": "https://opencode.ai/zen/go/v1",
"requires_key": True,
},
# "custom" is handled specially (no preset api_base, requires user input)
}
# Legacy lookup derived from PROVIDER_PRESETS for backward compat.
_PROVIDER_DEFAULTS: Dict[str, str] = {
pid: info["api_base"]
for pid, info in PROVIDER_PRESETS.items()
if info.get("api_base")
}
# Request timeout for LLM calls (seconds)
_LLM_TIMEOUT = aiohttp.ClientTimeout(total=120)
# Providers that do NOT implement ``response_format: {"type": "json_schema"}``
# and reject it with HTTP 400. For these the weaker, widely supported
# ``json_object`` mode is used instead (the prompt already specifies the
# expected JSON shape, and ``_try_salvage_json`` repairs imperfect output).
# DeepSeek answers a json_schema request with
# ``{"error":{"message":"This response_format type is unavailable now"}}``.
# LM Studio and some other local OpenAI-compatible servers reject
# ``json_object`` but accept ``json_schema``, so they are not listed here.
_JSON_OBJECT_ONLY_PROVIDERS = frozenset({"deepseek"})
class LLMService:
"""Centralized LLM API client.
All LLM-based enrichment features call through this service so
that BYOK config, retry logic, and error handling live in one place.
"""
_instance: Optional["LLMService"] = None
_lock: asyncio.Lock = asyncio.Lock()
def __init__(self, settings_service) -> None:
self._settings = settings_service
# ------------------------------------------------------------------
# Singleton access
# ------------------------------------------------------------------
@classmethod
async def get_instance(cls) -> "LLMService":
"""Return the lazily-initialised global ``LLMService`` instance."""
if cls._instance is None:
async with cls._lock:
if cls._instance is None:
from .settings_manager import get_settings_manager
cls._instance = cls(get_settings_manager())
# Start preloading the model catalog in the background so
# the settings UI never blocks on it. The catalog is
# cached after the first fetch (see _load_model_catalog).
asyncio.create_task(_load_model_catalog())
return cls._instance
@classmethod
def reset_instance(cls) -> None:
"""Reset the cached singleton — primarily for tests."""
cls._instance = None
# ------------------------------------------------------------------
# Configuration helpers
# ------------------------------------------------------------------
def _get_config(self) -> Dict[str, Any]:
"""Read the current LLM configuration from settings."""
return {
"provider": self._settings.get("llm_provider", "openai"),
"api_key": self._settings.get("llm_api_key", ""),
"api_base": self._settings.get("llm_api_base", ""),
"model": self._settings.get("llm_model", ""),
}
@staticmethod
def _provider_requires_key(provider: str) -> bool:
"""Return ``False`` when the given provider id does not need an API key."""
preset = PROVIDER_PRESETS.get(provider, {})
return bool(preset.get("requires_key", True))
def is_configured(self) -> bool:
"""Return ``True`` when the LLM provider is minimally configured.
A provider is considered configured when ``llm_model`` is set,
an API key is configured for providers that require one (e.g.
Ollama does not), and an API base URL is set for providers that
have no preset default (e.g. ``custom``).
"""
cfg = self._get_config()
has_model = bool(cfg["model"])
has_key = bool(cfg["api_key"]) or not self._provider_requires_key(cfg["provider"])
has_base = bool(cfg["api_base"]) or bool(_PROVIDER_DEFAULTS.get(cfg["provider"]))
return has_model and has_key and has_base
def _resolve_api_base(self, provider: str, api_base: str) -> str:
"""Resolve the API base URL for the given provider.
If ``api_base`` is explicitly set (non-empty), it takes priority.
Otherwise the default from :data:`PROVIDER_PRESETS` is used.
"""
if api_base:
return api_base.rstrip("/")
return _PROVIDER_DEFAULTS.get(provider, "").rstrip("/")
def _build_headers(self, api_key: str) -> Dict[str, str]:
"""Build HTTP headers for the LLM API request."""
headers = {"Content-Type": "application/json"}
if api_key:
headers["Authorization"] = f"Bearer {api_key}"
return headers
def _ensure_configured(self) -> Dict[str, Any]:
"""Validate configuration and return it, or raise.
A provider is considered configured when ``llm_model`` is set,
an API key is configured for providers that require one, and
an API base URL is set for providers without a preset default.
"""
cfg = self._get_config()
has_model = bool(cfg["model"])
needs_key = self._provider_requires_key(cfg["provider"])
has_key = bool(cfg["api_key"]) or not needs_key
has_base = bool(cfg["api_base"]) or bool(_PROVIDER_DEFAULTS.get(cfg["provider"]))
if not (has_model and has_key and has_base):
parts = []
if not has_model:
parts.append("No LLM model specified")
if not has_key and needs_key:
parts.append("No LLM API key configured")
if not has_base:
parts.append(
f"No API base URL for provider '{cfg['provider']}'"
)
detail = "; ".join(parts) if parts else "LLM provider is not configured"
raise LLMNotConfiguredError(
f"{detail}. Configure it in Settings → AI Provider."
)
return cfg
# ------------------------------------------------------------------
# Core API call
# ------------------------------------------------------------------
async def chat_completion(
self,
*,
messages: List[Dict[str, str]],
model: Optional[str] = None,
temperature: float = 0.3,
response_format: Optional[Dict[str, Any]] = None,
max_tokens: Optional[int] = None,
retry_on_rate_limit: bool = True,
) -> Dict[str, Any]:
"""Call the configured LLM provider's ``/chat/completions`` endpoint.
Args:
messages: OpenAI-format message list
model: Override the configured model name
temperature: Sampling temperature
response_format: Optional ``{"type": "json_object"}`` for structured output
max_tokens: Optional max output tokens
retry_on_rate_limit: Retry once after a 429 with backoff
Returns:
Dict with ``content`` (str), ``usage`` (dict), ``model`` (str)
Raises:
LLMNotConfiguredError: Provider not enabled / missing config
LLMRateLimitError: Rate limited and retry exhausted
LLMResponseError: Non-200 response or parse failure
"""
cfg = self._ensure_configured()
api_base = self._resolve_api_base(cfg["provider"], cfg["api_base"])
model_name = model or cfg["model"]
is_ollama = cfg["provider"] == "ollama"
if is_ollama:
# Use Ollama's native /api/chat endpoint which does NOT expose
# a separate reasoning/thinking field (the model's full output
# lands directly in message.content). The OpenAI-compatible
# endpoint splits thinking into the "reasoning" field, making
# content empty when thinking consumes all available tokens.
base = api_base.rstrip("/")
if base.endswith("/v1"):
base = base[:-3]
url = f"{base}/api/chat"
else:
url = f"{api_base}/chat/completions"
payload: Dict[str, Any]
if is_ollama:
payload = {
"model": model_name,
"messages": messages,
"stream": False,
# Suppress separate thinking trace — thinking still happens
# internally (accuracy preserved) but output goes directly to
# message.content instead of being split across content +
# thinking. Without this the model can exhaust num_predict
# on thinking alone and leave content empty.
"think": False,
"options": {
"temperature": temperature,
# 8K context is sufficient for metadata enrichment
# (prompt ~2-5K, output ~0.2-1K tokens). The old 32K
# value was excessive for this use case and increased
# Ollama VRAM usage unnecessarily.
"num_ctx": 8192,
},
}
if response_format is not None:
payload["format"] = "json"
if max_tokens is not None:
payload["options"]["num_predict"] = max_tokens
else:
payload = {
"model": model_name,
"messages": messages,
"temperature": temperature,
}
if response_format is not None:
payload["response_format"] = response_format
if max_tokens is not None:
payload["max_tokens"] = max_tokens
if is_ollama:
logger.info(
"Ollama request: model=%s num_ctx=%s num_predict=%s format=%s think=%s",
payload.get("model"),
payload.get("options", {}).get("num_ctx"),
payload.get("options", {}).get("num_predict"),
payload.get("format", "none"),
payload.get("think"),
)
headers = self._build_headers(cfg["api_key"])
attempt = 0
max_attempts = 2 if retry_on_rate_limit else 1
while attempt < max_attempts:
attempt += 1
try:
async with aiohttp.ClientSession(timeout=_LLM_TIMEOUT) as session:
async with session.post(
url, json=payload, headers=headers
) as resp:
if resp.status == 429:
if attempt < max_attempts:
retry_after = float(
resp.headers.get("Retry-After", "5")
)
logger.warning(
"LLM rate limited, retrying after %.1fs",
retry_after,
)
await asyncio.sleep(retry_after)
continue
raise LLMRateLimitError(
f"LLM provider rate limited (HTTP 429)",
provider=cfg["provider"],
)
if resp.status != 200:
body = await resp.text()
raise LLMResponseError(
f"LLM API returned HTTP {resp.status}: "
f"{body[:500]}"
)
data = await resp.json()
except aiohttp.ClientError as exc:
raise LLMResponseError(f"Network error calling LLM API: {exc}") from exc
# Parse response
try:
if is_ollama:
content = (data.get("message") or {}).get("content") or ""
usage = {"completion_tokens": data.get("eval_count", 0)}
finish_reason = data.get("done_reason", "")
if not content:
logger.warning(
"LLM returned empty content. Provider=ollama, "
"done_reason=%s, eval_count=%s",
finish_reason,
data.get("eval_count", 0),
)
else:
content = data["choices"][0]["message"].get("content") or ""
usage = data.get("usage", {})
if not content:
logger.warning(
"LLM returned empty content. Full response truncated: %s",
json.dumps(data, ensure_ascii=False)[:1000],
)
return {
"content": content,
"usage": usage,
"model": data.get("model", model_name),
}
except (KeyError, IndexError) as exc:
raise LLMResponseError(
f"Unexpected LLM response structure: {json.dumps(data)[:500]}"
) from exc
# Should not reach here, but satisfy type checker
raise LLMRateLimitError("Rate limit retry exhausted", provider=cfg["provider"])
# ------------------------------------------------------------------
# Structured output convenience
# ------------------------------------------------------------------
async def chat_completion_json(
self,
*,
system_prompt: str,
user_prompt: str,
model: Optional[str] = None,
temperature: float = 0.3,
max_tokens: Optional[int] = None,
) -> Dict[str, Any]:
"""Call the LLM with ``response_format=json_object`` and return parsed JSON.
``max_tokens`` is resolved in this order:
1. Explicit caller-supplied ``max_tokens``
2. Per-model ``limit.output`` from the model catalog
3. A safe default of 4096 (sufficient for metadata enrichment)
If the response content is empty or not valid JSON, attempts
:func:`_try_salvage_json` before raising.
Args:
system_prompt: System-level instructions
user_prompt: User-level query
model: Override the configured model name
temperature: Sampling temperature
max_tokens: Optional max output tokens
Returns:
Parsed JSON dict from the LLM response
Raises:
LLMNotConfiguredError: Provider not configured
LLMRateLimitError: Rate limited
LLMResponseError: Empty response or JSON parse failure
"""
messages = [
{"role": "system", "content": system_prompt},
{"role": "user", "content": user_prompt},
]
# Resolve max_tokens: caller override → catalog lookup → safe default
if max_tokens is None:
cfg = self._get_config()
effective_max = _get_model_max_output(cfg["provider"], cfg["model"])
else:
effective_max = max_tokens
if effective_max is None:
effective_max = 4096
# Structured-output format. ``json_schema`` is preferred because LM
# Studio and other local OpenAI-compatible servers reject
# ``json_object`` but accept ``json_schema``; ``{"type": "object"}``
# accepts any JSON object without constraining specific fields, so the
# two modes are functionally equivalent here. Providers known to
# reject json_schema (see _JSON_OBJECT_ONLY_PROVIDERS) get
# ``json_object`` instead.
schema_format: Dict[str, Any] = {
"type": "json_schema",
"json_schema": {
"name": "metadata",
"schema": {"type": "object"},
},
}
json_object_format: Dict[str, Any] = {"type": "json_object"}
if self._get_config()["provider"] in _JSON_OBJECT_ONLY_PROVIDERS:
format_chain: List[Optional[Dict[str, Any]]] = [
json_object_format,
None,
]
else:
format_chain = [schema_format, json_object_format, None]
result: Optional[Dict[str, Any]] = None
for index, fmt in enumerate(format_chain):
try:
result = await self.chat_completion(
messages=messages,
model=model,
temperature=temperature,
response_format=fmt,
max_tokens=effective_max,
)
break
except LLMResponseError as e:
message = str(e).lower()
if index + 1 >= len(format_chain):
raise
# Only downgrade when the failure is about ``response_format``.
# Everything else (auth, unknown model, rate limits) must
# surface unchanged. Matching on the bare parameter name also
# covers variants such as DeepSeek's "This response_format
# type is unavailable now" without swallowing unrelated 400s.
if "response_format" not in message:
raise
logger.info(
"Provider rejected response_format=%s, retrying with %s. "
"Error: %s",
(fmt or {}).get("type", "none"),
(format_chain[index + 1] or {}).get("type", "none"),
e,
)
assert result is not None # non-empty chain always sets or raises
content = result.get("content", "") or ""
if not content:
raise LLMResponseError(
"LLM returned empty content. "
f"Raw response: {json.dumps(result)[:500]}"
)
try:
parsed = json.loads(content)
logger.debug(
"LLM raw content: %s",
json.dumps(parsed, ensure_ascii=False)[:2000],
)
return parsed
except (json.JSONDecodeError, TypeError) as exc:
logger.info(
"LLM raw response (first 800 chars): %s",
content[:800],
)
# Last resort: attempt to salvage partial/truncated JSON
salvaged = _try_salvage_json(content)
if salvaged is not None:
logger.warning(
"LLM JSON salvaged from partial content (%d chars raw)",
len(content),
)
return salvaged
raise LLMResponseError(
f"LLM response could not be parsed as JSON: {content[:200]}"
)
def _try_salvage_json(raw: str) -> Dict[str, Any] | None:
"""Attempt to repair and parse a truncated JSON string.
Handles common truncation patterns:
* Incomplete string value at the end (``"foo`` → ``"foo"``)
* Missing closing ``}`` or ``]`` (respecting nesting order)
* Trailing comma before closing bracket
* Extra text after the JSON object (e.g. markdown fences)
Returns the parsed dict on success, ``None`` if repair is impossible.
"""
if not raw:
return None
text = raw.strip()
# Strip markdown fences if the LLM wrapped the JSON
if text.startswith("```"):
end = text.find("\n")
text = text[end + 1:] if end != -1 else text[3:]
if text.endswith("```"):
text = text[:-3].rstrip()
# Find the first '{' and strip everything before it
start = text.find("{")
if start == -1:
return None
text = text[start:]
# Try to close an incomplete string at the end (e.g. ``"https://huggingf``)
# Pattern: ends mid-string (last quote is open)
if text.count('"') % 2 == 1:
text += '"'
# Ensure trailing commas before closing braces work
text = _strip_trailing_commas(text)
# Walk through the text character by character to find unclosed
# brackets and close them in the correct (LIFO) order.
# We ignore brackets inside quoted strings.
stack: list[str] = []
in_string = False
escape = False
for ch in text:
if escape:
escape = False
continue
if ch == "\\":
escape = True
continue
if ch == '"':
in_string = not in_string
continue
if in_string:
continue
if ch in ("{", "["):
stack.append(ch)
elif ch == "}":
if stack and stack[-1] == "{":
stack.pop()
else:
return None # Unmatched closer — unrecoverable
elif ch == "]":
if stack and stack[-1] == "[":
stack.pop()
else:
return None
# Close remaining open brackets in reverse order
for opener in reversed(stack):
text += "}" if opener == "{" else "]"
try:
return json.loads(text)
except (json.JSONDecodeError, ValueError):
return None
def _strip_trailing_commas(text: str) -> str:
"""Remove commas that appear before a closing brace/bracket."""
import re as _re
text = _re.sub(r",\s*}", "}", text)
text = _re.sub(r",\s*]", "]", text)
return text