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interactive-story/backend/app/providers/openai_compatible.py
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parththakkar106andClaude Opus 4.8 c500203270 Harden auth against a forwarded-header rate-limit bypass, and guard BYOK SSRF
The per-IP rate limits could be bypassed entirely: uvicorn ran with
--forwarded-allow-ips "*", which trusts the leftmost X-Forwarded-For value
(client-controlled), and Render forwards the inbound header rather than
stripping it. Rotating the header handed out a fresh rate-limit bucket per
request, so the login/register limit (10/5min) and guest-minting limit
(30/5min) were no throttle at all — unbounded password guessing and guest-row
creation. Confirmed live: fixed IP -> 429 after 10; rotating spoofed header ->
no 429 across 14 attempts.

Two-layer fix:
- limits._client_ip now derives the client IP from the hop the trusted edge
  appends (rightmost of X-Forwarded-For), which a client can't spoof past;
  tunable via AIDND_TRUSTED_PROXY_HOPS. Dropped --forwarded-allow-ips "*".
- New per-account login throttle (email-keyed, 8 fails / 15 min, cleared on
  success): stops distributed guessing against one account that a per-IP limit
  can't, since it can't be diluted across many source addresses.

Also close an SSRF on the BYOK endpoint_url (hosted mode only): the connection
test and turn/chat streams now refuse a URL that resolves to a non-public
address (private/loopback/link-local metadata/reserved), checked at request
time so it resists a DNS record flipping to a private IP. No-op locally, where
reaching localhost Ollama is intended.

Tests: test_ratelimit_hardening.py (8), test_netguard.py (13). 172 pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015CYEJKobJ2Re4Dv7qUoSA7
2026-08-15 13:47:14 +05:30

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import json
from typing import AsyncIterator
import httpx
from .. import debuglog, netguard
from .base import PromptParts, Provider, ProviderError
# Framing appended after the story text in chat mode, so chat-tuned models keep
# continuing prose instead of replying conversationally.
CHAT_CONTINUE_HINT = "\n\n[Continue the story directly. Output only story text.]"
# Completion endpoints have no roles, so a plain chat has to be flattened into
# one labelled transcript that trails off on "Assistant:" for the model to continue.
_ROLE_LABELS = {"system": "System", "user": "User", "assistant": "Assistant"}
def flatten_messages(messages: list[dict]) -> str:
turns = "\n\n".join(
f"{_ROLE_LABELS.get(m['role'], m['role'])}: {m['content']}" for m in messages
)
return f"{turns}\n\nAssistant:"
class OpenAICompatibleProvider(Provider):
"""Adapter for any /v1-style endpoint: Ollama, LM Studio, OpenAI, OpenRouter, vLLM, Groq…"""
def __init__(
self,
endpoint_url: str,
api_key: str,
model: str,
api_mode: str = "chat",
reasoning_max_tokens: int = 0,
):
self.base_url = endpoint_url.rstrip("/")
self.api_key = api_key
self.model = model
self.api_mode = api_mode # "chat" | "completion"
# Thinking budget for reasoning models, on top of max_tokens. 0 = the
# `reasoning` param is not sent (endpoints that don't know it may
# reject unknown fields); negative = explicitly ask the endpoint to
# turn reasoning off.
self.reasoning_max_tokens = reasoning_max_tokens
def _headers(self) -> dict:
headers = {"Content-Type": "application/json"}
if self.api_key:
headers["Authorization"] = f"Bearer {self.api_key}"
return headers
def _apply_reasoning_budget(self, body: dict) -> None:
"""Give reasoning models their own thinking budget (OpenRouter-style),
raising max_tokens so the actual output keeps its full budget.
A negative budget means the opposite: send `effort: "none"` to switch
reasoning off on models that do it by default (DeepSeek V4 Flash, say).
That's distinct from `exclude: true`, which still thinks — and bills —
but hides the trace. Zero stays "send nothing at all" so endpoints that
reject unknown fields (Ollama) keep working."""
if self.api_mode != "chat":
return
if self.reasoning_max_tokens < 0:
body["reasoning"] = {"effort": "none"}
elif self.reasoning_max_tokens > 0:
body["reasoning"] = {"max_tokens": self.reasoning_max_tokens}
body["max_tokens"] += self.reasoning_max_tokens
def _request(self, parts: PromptParts, temperature: float, max_tokens: int) -> tuple[str, dict]:
if self.api_mode == "completion":
url = f"{self.base_url}/completions"
body = {
"model": self.model,
"prompt": f"{parts.system}\n\n{parts.story}",
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
}
else:
url = f"{self.base_url}/chat/completions"
body = {
"model": self.model,
"messages": [
{"role": "system", "content": parts.system},
{"role": "user", "content": parts.story + CHAT_CONTINUE_HINT},
],
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
}
self._apply_reasoning_budget(body)
return url, body
@staticmethod
def _extract_chunk(payload: dict) -> str:
choices = payload.get("choices") or []
if not choices:
return ""
choice = choices[0]
# chat stream → delta.content; completion stream → text;
# non-stream fallbacks → message.content / text
delta = choice.get("delta") or {}
return (
delta.get("content")
or choice.get("text")
or (choice.get("message") or {}).get("content")
or ""
)
@staticmethod
def _extract_reasoning(payload: dict) -> str:
"""Reasoning-model thinking: OpenRouter normalizes to `reasoning`;
DeepSeek-style servers use `reasoning_content`."""
choices = payload.get("choices") or []
if not choices:
return ""
choice = choices[0]
delta = choice.get("delta") or {}
message = choice.get("message") or {}
return (
delta.get("reasoning")
or delta.get("reasoning_content")
or message.get("reasoning")
or message.get("reasoning_content")
or ""
)
async def generate(
self, parts: PromptParts, *, temperature: float, max_tokens: int
) -> AsyncIterator[tuple[str, str]]:
"""Yields ("text" | "reasoning", chunk) pairs."""
if not self.model:
raise ProviderError("No model configured — set one in Settings.")
url, body = self._request(parts, temperature, max_tokens)
async for event in self._stream(url, body):
yield event
async def chat(
self, messages: list[dict], *, temperature: float, max_tokens: int
) -> AsyncIterator[tuple[str, str]]:
"""Plain multi-turn chat — no story framing, no context assembly. Takes
[{"role", "content"}, ...] straight to the endpoint. Used by the AI Chat
scratchpad; the turn engine uses generate()."""
if not self.model:
raise ProviderError("No model configured — set one in Settings.")
if self.api_mode == "completion":
url = f"{self.base_url}/completions"
body = {
"model": self.model,
"prompt": flatten_messages(messages),
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
}
else:
url = f"{self.base_url}/chat/completions"
body = {
"model": self.model,
"messages": messages,
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
}
self._apply_reasoning_budget(body)
async for event in self._stream(url, body):
yield event
async def _stream(self, url: str, body: dict) -> AsyncIterator[tuple[str, str]]:
"""Shared SSE plumbing for generate()/chat(): POST a streaming request
and yield ("text" | "reasoning", chunk) pairs, logging the exchange."""
# SSRF guard (hosted mode): a user-supplied endpoint_url must not point
# at an internal/metadata address. No-op for local installs.
reason = netguard.endpoint_block_reason(url)
if reason:
raise ProviderError(f"This endpoint can't be used — {reason}.")
log = debuglog.start_entry(url, self.model, body)
received: list[str] = []
try:
async with httpx.AsyncClient(timeout=httpx.Timeout(120, connect=10)) as client:
async with client.stream("POST", url, json=body, headers=self._headers()) as resp:
if resp.status_code != 200:
detail = (await resp.aread()).decode(errors="replace")[:500]
raise ProviderError(self._friendly_http_error(resp.status_code, detail))
# Some servers ignore stream=true and return one plain JSON
# body; buffer non-SSE lines so we can fall back to it.
saw_sse = False
raw_lines: list[str] = []
async for line in resp.aiter_lines():
if not line.startswith("data:"):
if not saw_sse:
raw_lines.append(line)
continue
saw_sse = True
data = line[5:].strip()
if data == "[DONE]":
debuglog.finish_entry(log, response="".join(received))
return
try:
payload = json.loads(data)
except ValueError:
continue
reasoning = self._extract_reasoning(payload)
if reasoning:
yield "reasoning", reasoning
chunk = self._extract_chunk(payload)
if chunk:
received.append(chunk)
yield "text", chunk
if not saw_sse:
body_text = "\n".join(raw_lines).strip()
try:
payload = json.loads(body_text)
except ValueError:
raise ProviderError(
"AI endpoint returned neither an SSE stream nor JSON: "
+ body_text[:200]
)
reasoning = self._extract_reasoning(payload)
if reasoning:
yield "reasoning", reasoning
chunk = self._extract_chunk(payload)
if chunk:
received.append(chunk)
yield "text", chunk
if not received:
raise ProviderError(
"AI endpoint returned a response with no text: "
+ body_text[:200]
)
debuglog.finish_entry(log, response="".join(received))
except httpx.ConnectError as exc:
error = f"Could not connect to {self.base_url} — is the AI server running?"
debuglog.finish_entry(log, response="".join(received), error=error)
raise ProviderError(error) from exc
except httpx.TimeoutException as exc:
debuglog.finish_entry(log, response="".join(received), error="Timed out")
raise ProviderError("The AI endpoint timed out.") from exc
except httpx.HTTPError as exc:
debuglog.finish_entry(log, response="".join(received), error=str(exc))
raise ProviderError(f"Request to AI endpoint failed: {exc}") from exc
except (ProviderError, GeneratorExit, BaseException) as exc:
status = "cancelled" if isinstance(exc, GeneratorExit) else str(exc)
debuglog.finish_entry(log, response="".join(received), error=status)
raise
async def complete(
self, system: str, user: str, *, temperature: float = 0.3, max_tokens: int = 400
) -> str:
"""Single non-streaming completion for background calls (summarization).
Unlike generate(), no story-continuation framing is added."""
if not self.model:
raise ProviderError("No model configured — set one in Settings.")
if self.api_mode == "completion":
url = f"{self.base_url}/completions"
body = {
"model": self.model,
"prompt": f"{system}\n\n{user}",
"temperature": temperature,
"max_tokens": max_tokens,
"stream": False,
}
else:
url = f"{self.base_url}/chat/completions"
body = {
"model": self.model,
"messages": [
{"role": "system", "content": system},
{"role": "user", "content": user},
],
"temperature": temperature,
"max_tokens": max_tokens,
"stream": False,
}
self._apply_reasoning_budget(body)
log = debuglog.start_entry(url, self.model, body)
try:
async with httpx.AsyncClient(timeout=httpx.Timeout(120, connect=10)) as client:
resp = await client.post(url, json=body, headers=self._headers())
except httpx.HTTPError as exc:
debuglog.finish_entry(log, error=str(exc))
raise ProviderError(f"Request to AI endpoint failed: {exc}") from exc
if resp.status_code != 200:
error = self._friendly_http_error(resp.status_code, resp.text[:500])
debuglog.finish_entry(log, error=error)
raise ProviderError(error)
try:
text = self._extract_chunk(resp.json())
except ValueError as exc:
debuglog.finish_entry(log, error="Invalid JSON response")
raise ProviderError("AI endpoint returned invalid JSON.") from exc
debuglog.finish_entry(log, response=text)
return text.strip()
async def embed(self, texts: list[str]) -> list[list[float]]:
"""POST /v1/embeddings; self.model is the embedding model here."""
if not self.model:
raise ProviderError("No embedding model configured — set one in Settings.")
url = f"{self.base_url}/embeddings"
body = {"model": self.model, "input": texts}
log = debuglog.start_entry(url, self.model, body)
try:
async with httpx.AsyncClient(timeout=httpx.Timeout(60, connect=10)) as client:
resp = await client.post(url, json=body, headers=self._headers())
except httpx.HTTPError as exc:
debuglog.finish_entry(log, error=str(exc))
raise ProviderError(f"Embedding request failed: {exc}") from exc
if resp.status_code != 200:
error = self._friendly_http_error(resp.status_code, resp.text[:500])
debuglog.finish_entry(log, error=error)
raise ProviderError(error)
try:
data = resp.json().get("data", [])
vectors = [item["embedding"] for item in sorted(data, key=lambda d: d.get("index", 0))]
except (ValueError, KeyError, TypeError) as exc:
debuglog.finish_entry(log, error="Malformed embeddings response")
raise ProviderError("AI endpoint returned malformed embeddings.") from exc
if len(vectors) != len(texts):
debuglog.finish_entry(log, error="Embedding count mismatch")
raise ProviderError("AI endpoint returned the wrong number of embeddings.")
debuglog.finish_entry(log, response=f"{len(vectors)} vectors × {len(vectors[0]) if vectors else 0} dims")
return vectors
def _friendly_http_error(self, status: int, detail: str) -> str:
if status == 401:
return "Authentication failed — check your API key in Settings."
if status == 404:
return (
f"Endpoint or model not found (HTTP 404). Check the endpoint URL and that "
f"model '{self.model}' exists. {detail}"
)
if status == 429:
# OpenRouter's shared free tier has a per-day cap; distinguish it
# from a short-term burst limit so the message is actionable.
if "free-models-per-day" in detail:
return (
"The free demo has hit its daily request limit (resets at "
"00:00 UTC). Please try again later."
)
return "The AI is getting too many requests right now — wait a moment and try again."
return f"AI endpoint returned HTTP {status}: {detail}"