refactor(openai): drop SDK dependency and switch to native HTTP client

models/openai/openai_http_client.py

@@ -0,0 +1,456 @@
+# encoding:utf-8
+
+"""
+Lightweight HTTP client for OpenAI-compatible APIs.
+
+This client is a drop-in replacement for the parts of the `openai` SDK that this
+project actually uses (chat completions, completions, image generation), so we
+can drop the hard dependency on `openai==0.27.x`.
+
+Design goals:
+- Pure `requests` based (no httpx / pydantic / openai SDK dependency).
+- Returns plain `dict` responses with the same shape OpenAI's HTTP API returns,
+  so existing code that does `response["choices"][0]["message"]["content"]` /
+  `response["usage"]["total_tokens"]` keeps working.
+- Streaming yields plain `dict` chunks (parsed SSE `data:` JSON), matching the
+  shape that `agent/protocol/agent_stream.py` consumes:
+    chunk["choices"][0]["delta"]["content" | "tool_calls" | "reasoning_content"]
+    chunk["choices"][0]["finish_reason"]
+  Plus dict-style error chunks: {"error": True, "message": ..., "status_code": ...}
+- Compatible with arbitrary OpenAI-compatible endpoints (LinkAI, Azure-style
+  proxies, DeepSeek, Moonshot, etc.) by allowing per-call api_key / api_base
+  override and trusting whatever path/payload shape the caller passes.
+"""
+
+import json
+from typing import Any, Dict, Generator, Optional
+
+import requests
+
+from common.log import logger
+
+
+DEFAULT_API_BASE = "https://api.openai.com/v1"
+DEFAULT_TIMEOUT = 600  # seconds; matches old openai SDK default
+
+
+class OpenAIHTTPError(Exception):
+    """Raised for non-2xx responses. Carries status code + parsed body."""
+
+    def __init__(self, status_code: int, body: Any, message: str = ""):
+        self.status_code = status_code
+        self.body = body
+        # Try to extract human-readable message from OpenAI-style error envelope
+        if not message and isinstance(body, dict):
+            err = body.get("error") or {}
+            if isinstance(err, dict):
+                message = err.get("message") or ""
+            elif isinstance(err, str):
+                message = err
+        if not message:
+            message = str(body)[:500]
+        self.message = message
+        super().__init__(f"HTTP {status_code}: {message}")
+
+
+class OpenAIHTTPClient:
+    """Minimal HTTP client for OpenAI-compatible endpoints.
+
+    Per-instance defaults (api_key / api_base / proxy / timeout) can be
+    overridden on every call. Callers can also pass ``extra_headers`` for
+    Azure-style ``api-key`` headers or custom routing headers.
+    """
+
+    def __init__(
+        self,
+        api_key: Optional[str] = None,
+        api_base: Optional[str] = None,
+        proxy: Optional[str] = None,
+        timeout: Optional[float] = None,
+        extra_headers: Optional[Dict[str, str]] = None,
+    ):
+        self.api_key = api_key
+        self.api_base = (api_base or DEFAULT_API_BASE).rstrip("/")
+        self.timeout = timeout if timeout is not None else DEFAULT_TIMEOUT
+        self.proxies = (
+            {"http": proxy, "https": proxy} if proxy else None
+        )
+        self.extra_headers = dict(extra_headers) if extra_headers else {}
+
+    # ------------------------------------------------------------------ #
+    # Public API surface (mirrors what the old openai SDK provided)
+    # ------------------------------------------------------------------ #
+
+    def chat_completions(
+        self,
+        *,
+        api_key: Optional[str] = None,
+        api_base: Optional[str] = None,
+        timeout: Optional[float] = None,
+        proxy: Optional[str] = None,
+        extra_headers: Optional[Dict[str, str]] = None,
+        extra_query: Optional[Dict[str, str]] = None,
+        path: str = "/chat/completions",
+        stream: bool = False,
+        **payload,
+    ):
+        """POST /chat/completions.
+
+        When ``stream=True`` returns a generator yielding parsed SSE chunks
+        (plain ``dict``). On error during streaming, yields a single dict with
+        ``{"error": True, ...}`` and stops, matching the contract expected by
+        ``agent/protocol/agent_stream.py``.
+        """
+        payload["stream"] = stream
+        return self._request(
+            path=path,
+            payload=payload,
+            api_key=api_key,
+            api_base=api_base,
+            timeout=timeout,
+            proxy=proxy,
+            extra_headers=extra_headers,
+            extra_query=extra_query,
+            stream=stream,
+        )
+
+    def completions(
+        self,
+        *,
+        api_key: Optional[str] = None,
+        api_base: Optional[str] = None,
+        timeout: Optional[float] = None,
+        **payload,
+    ) -> Dict[str, Any]:
+        """POST /completions (legacy text completion). Non-streaming only."""
+        payload.pop("stream", None)
+        return self._request(
+            path="/completions",
+            payload=payload,
+            api_key=api_key,
+            api_base=api_base,
+            timeout=timeout,
+            stream=False,
+        )
+
+    def images_generate(
+        self,
+        *,
+        api_key: Optional[str] = None,
+        api_base: Optional[str] = None,
+        timeout: Optional[float] = None,
+        **payload,
+    ) -> Dict[str, Any]:
+        """POST /images/generations."""
+        return self._request(
+            path="/images/generations",
+            payload=payload,
+            api_key=api_key,
+            api_base=api_base,
+            timeout=timeout,
+            stream=False,
+        )
+
+    # ------------------------------------------------------------------ #
+    # Internal helpers
+    # ------------------------------------------------------------------ #
+
+    def _build_headers(
+        self,
+        api_key: Optional[str],
+        extra_headers: Optional[Dict[str, str]],
+    ) -> Dict[str, str]:
+        key = api_key if api_key is not None else self.api_key
+        headers = {"Content-Type": "application/json"}
+        if key:
+            headers["Authorization"] = f"Bearer {key}"
+        if self.extra_headers:
+            headers.update(self.extra_headers)
+        if extra_headers:
+            headers.update(extra_headers)
+        return headers
+
+    def _request(
+        self,
+        *,
+        path: str,
+        payload: Dict[str, Any],
+        api_key: Optional[str],
+        api_base: Optional[str],
+        timeout: Optional[float],
+        stream: bool,
+        proxy: Optional[str] = None,
+        extra_headers: Optional[Dict[str, str]] = None,
+        extra_query: Optional[Dict[str, str]] = None,
+    ):
+        base = (api_base or self.api_base).rstrip("/") if api_base else self.api_base
+        url = f"{base}{path}" if path.startswith("/") else f"{base}/{path}"
+        headers = self._build_headers(api_key, extra_headers)
+        req_timeout = timeout if timeout is not None else self.timeout
+        proxies = (
+            {"http": proxy, "https": proxy} if proxy else self.proxies
+        )
+
+        # Drop None-valued keys; some providers reject explicit nulls.
+        clean_payload = {k: v for k, v in payload.items() if v is not None}
+
+        if stream:
+            # Return a generator. Errors during stream are yielded as a single
+            # error chunk so callers (agent_stream) can map them to their
+            # existing error-handling path without try/except around the loop.
+            return self._stream_chat(
+                url=url,
+                headers=headers,
+                payload=clean_payload,
+                proxies=proxies,
+                timeout=req_timeout,
+                params=extra_query,
+            )
+
+        try:
+            resp = requests.post(
+                url,
+                headers=headers,
+                json=clean_payload,
+                timeout=req_timeout,
+                proxies=proxies,
+                params=extra_query,
+            )
+        except requests.exceptions.Timeout as e:
+            raise OpenAIHTTPError(408, {}, f"Request timed out: {e}")
+        except requests.exceptions.ConnectionError as e:
+            raise OpenAIHTTPError(0, {}, f"Connection error: {e}")
+        except requests.exceptions.RequestException as e:
+            raise OpenAIHTTPError(0, {}, f"Request failed: {e}")
+
+        return self._parse_response(resp)
+
+    @staticmethod
+    def _parse_response(resp: requests.Response) -> Dict[str, Any]:
+        # Try JSON, fall back to text
+        try:
+            data = resp.json()
+        except ValueError:
+            data = {"raw": resp.text}
+
+        if resp.status_code >= 400:
+            raise OpenAIHTTPError(resp.status_code, data)
+
+        return data
+
+    def _stream_chat(
+        self,
+        *,
+        url: str,
+        headers: Dict[str, str],
+        payload: Dict[str, Any],
+        proxies: Optional[Dict[str, str]],
+        timeout: float,
+        params: Optional[Dict[str, str]] = None,
+    ) -> Generator[Dict[str, Any], None, None]:
+        """Stream SSE response and yield parsed JSON chunks.
+
+        Yields:
+            - Normal chunks: dict with ``choices[0].delta`` etc.
+            - Error chunks: ``{"error": True, "message": str, "status_code": int}``
+              followed by termination of the generator.
+        """
+        try:
+            resp = requests.post(
+                url,
+                headers=headers,
+                json=payload,
+                timeout=timeout,
+                proxies=proxies,
+                stream=True,
+                params=params,
+            )
+        except requests.exceptions.Timeout as e:
+            yield self._make_error_chunk(408, f"Request timed out: {e}")
+            return
+        except requests.exceptions.ConnectionError as e:
+            yield self._make_error_chunk(0, f"Connection error: {e}")
+            return
+        except requests.exceptions.RequestException as e:
+            yield self._make_error_chunk(0, f"Request failed: {e}")
+            return
+
+        if resp.status_code >= 400:
+            # Read full body once for error reporting
+            try:
+                body = resp.json()
+            except ValueError:
+                body = {"raw": resp.text[:1000]}
+            err_msg = ""
+            err_code = ""
+            err_type = ""
+            if isinstance(body, dict):
+                err = body.get("error") or {}
+                if isinstance(err, dict):
+                    err_msg = err.get("message") or ""
+                    err_code = err.get("code") or ""
+                    err_type = err.get("type") or ""
+                elif isinstance(err, str):
+                    err_msg = err
+            if not err_msg:
+                err_msg = str(body)[:500]
+            yield {
+                "error": {
+                    "message": err_msg,
+                    "code": err_code,
+                    "type": err_type,
+                },
+                # Top-level fields kept for backward compatibility with the
+                # error-shape that `_handle_stream_response` previously emitted.
+                "message": err_msg,
+                "status_code": resp.status_code,
+            }
+            return
+
+        # IMPORTANT: do NOT use `iter_lines(decode_unicode=True)`.
+        #
+        # `requests` decodes per-network-chunk using the response's declared
+        # encoding (often Latin-1 / ISO-8859-1 for SSE), which mangles UTF-8
+        # codepoints that straddle a chunk boundary. Some upstreams (Azure
+        # OpenAI proxies, Cloudflare-fronted gateways, ...) split TCP chunks
+        # aggressively in the middle of multibyte characters, producing
+        # garbled text and "skip malformed SSE chunk" errors.
+        #
+        # The fix is to read raw bytes, accumulate them until we have a
+        # complete SSE event (terminated by a blank line per the SSE spec:
+        # https://html.spec.whatwg.org/multipage/server-sent-events.html),
+        # and only THEN decode as UTF-8. This mirrors what the official
+        # openai SDK 1.x does in `openai/_streaming.py::SSEDecoder` (which
+        # itself is copied from httpx-sse).
+        try:
+            for sse_event in self._iter_sse_events(resp):
+                # `sse_event` is the joined `data:` payload as a str.
+                if sse_event == "[DONE]":
+                    return
+                if not sse_event:
+                    continue
+                try:
+                    chunk = json.loads(sse_event)
+                except ValueError:
+                    logger.debug(
+                        f"[OpenAIHTTP] skip malformed SSE chunk: {sse_event[:200]}"
+                    )
+                    continue
+                yield chunk
+        except requests.exceptions.ChunkedEncodingError as e:
+            yield self._make_error_chunk(0, f"Stream interrupted: {e}")
+        except requests.exceptions.RequestException as e:
+            yield self._make_error_chunk(0, f"Stream error: {e}")
+        finally:
+            try:
+                resp.close()
+            except Exception:
+                pass
+
+    @staticmethod
+    def _iter_sse_events(resp: requests.Response) -> Generator[str, None, None]:
+        """Decode an SSE byte stream into joined `data:` payloads.
+
+        Implements the subset of the SSE spec that OpenAI / OpenAI-compatible
+        endpoints actually use:
+          - Events are separated by blank lines (\\r\\r, \\n\\n, or \\r\\n\\r\\n).
+          - Within an event, multiple ``data:`` lines are concatenated with
+            "\\n" (per spec).
+          - ``event:``, ``id:``, ``retry:`` and comment lines (``:``) are
+            tolerated but not yielded — for chat-completion we only care
+            about the JSON payload in ``data:``.
+          - Bytes are buffered until a complete event boundary is seen so
+            UTF-8 codepoints split across TCP chunks decode correctly.
+
+        Yields each event's joined ``data`` string. The terminal sentinel
+        ``[DONE]`` is yielded as a literal string so the caller can break.
+        """
+        buf = b""
+        for raw in resp.iter_content(chunk_size=None, decode_unicode=False):
+            if not raw:
+                continue
+            buf += raw
+            # Find complete events (terminated by a blank line).
+            while True:
+                # Look for the earliest event terminator. SSE allows three
+                # forms; check all and pick the earliest match.
+                idx_nn = buf.find(b"\n\n")
+                idx_rr = buf.find(b"\r\r")
+                idx_rnrn = buf.find(b"\r\n\r\n")
+                candidates = [i for i in (idx_nn, idx_rr, idx_rnrn) if i != -1]
+                if not candidates:
+                    break
+                # We need to know the length of the matched terminator to
+                # advance past it correctly.
+                end_pos = min(candidates)
+                if end_pos == idx_rnrn:
+                    term_len = 4
+                else:
+                    term_len = 2
+                event_bytes = buf[:end_pos]
+                buf = buf[end_pos + term_len:]
+
+                # Decode the full event as UTF-8. ``errors="replace"`` is a
+                # belt-and-suspenders safety net for truly malformed upstream
+                # bytes; it should never trigger for well-formed providers.
+                try:
+                    event_text = event_bytes.decode("utf-8")
+                except UnicodeDecodeError:
+                    event_text = event_bytes.decode("utf-8", errors="replace")
+
+                data_lines = []
+                for line in event_text.splitlines():
+                    if not line or line.startswith(":"):
+                        continue
+                    field, _, value = line.partition(":")
+                    # Per SSE spec, a single optional space after the colon
+                    # is part of the framing, not the value.
+                    if value.startswith(" "):
+                        value = value[1:]
+                    if field == "data":
+                        data_lines.append(value)
+                    # Other fields (event/id/retry) are intentionally ignored
+                    # — chat-completion endpoints don't use them in a way we
+                    # need for parsing.
+                if data_lines:
+                    yield "\n".join(data_lines)
+
+        # Flush any trailing bytes the server forgot to terminate. This is
+        # rare but spec-allowed (some providers omit the final \n\n).
+        if buf.strip():
+            try:
+                event_text = buf.decode("utf-8")
+            except UnicodeDecodeError:
+                event_text = buf.decode("utf-8", errors="replace")
+            data_lines = []
+            for line in event_text.splitlines():
+                if not line or line.startswith(":"):
+                    continue
+                field, _, value = line.partition(":")
+                if value.startswith(" "):
+                    value = value[1:]
+                if field == "data":
+                    data_lines.append(value)
+            if data_lines:
+                yield "\n".join(data_lines)
+
+    @staticmethod
+    def _make_error_chunk(status_code: int, message: str) -> Dict[str, Any]:
+        return {
+            "error": {"message": message, "code": "", "type": ""},
+            "message": message,
+            "status_code": status_code,
+        }
+
+
+# A tiny helper for callers that just need a one-shot client without storing
+# state. Keeps call sites cleaner than instantiating the class every time.
+def get_default_client(
+    api_key: Optional[str] = None,
+    api_base: Optional[str] = None,
+    proxy: Optional[str] = None,
+    timeout: Optional[float] = None,
+) -> OpenAIHTTPClient:
+    return OpenAIHTTPClient(
+        api_key=api_key, api_base=api_base, proxy=proxy, timeout=timeout
+    )