fix provder forwarded path & wrong html response

routstr/upstream/base.py

@@ -47,6 +47,17 @@ from .litellm_routing import detect_litellm_prefix
 logger = get_logger(__name__)
 
 
+def _is_json_content_type(content_type: str | None) -> bool:
+    """Return True when the upstream response should be parsed as JSON.
+    """
+    if not content_type:
+        return False
+    main = content_type.split(";", 1)[0].strip().lower()
+    if main in ("application/json", "text/json"):
+        return True
+    return main.startswith("application/") and main.endswith("+json")
+
+
 class TopupData(BaseModel):
     """Universal top-up data schema for Lightning Network invoices."""
 
@@ -523,7 +534,8 @@ class BaseUpstreamProvider:
     async def forward_upstream_error_response(
         self, request: Request, path: str, upstream_response: httpx.Response
     ) -> Response:
-        """Log upstream errors and forward the upstream response unchanged."""
+        """Log upstream errors and forward the response in a JSON envelope.
+        """
         status_code = upstream_response.status_code
         headers = dict(upstream_response.headers)
         content_type = headers.get("content-type") or headers.get("Content-Type", "")
@@ -545,9 +557,10 @@ class BaseUpstreamProvider:
 
         message, upstream_code = self._extract_upstream_error_message(body_bytes)
         body_preview = body_bytes.decode("utf-8", errors="ignore").strip()[:500]
+        is_json_body = _is_json_content_type(content_type)
 
         logger.warning(
-            "Forwarding upstream error response as-is",
+            "Forwarding upstream error response",
             extra={
                 "path": path,
                 "provider": self.provider_type,
@@ -559,6 +572,7 @@ class BaseUpstreamProvider:
                 "body_preview": body_preview,
                 "body_read_error": body_read_error,
                 "method": request.method,
+                "json_normalized": not is_json_body,
             },
         )
 
@@ -586,17 +600,40 @@ class BaseUpstreamProvider:
         ):
             headers.pop(header_name, None)
 
-        if not content_type:
-            headers.pop("content-type", None)
-            headers.pop("Content-Type", None)
+        if is_json_body:
+            if not content_type:
+                headers.pop("content-type", None)
+                headers.pop("Content-Type", None)
+            media_type = content_type or None
+            return Response(
+                content=body_bytes,
+                status_code=status_code,
+                headers=headers,
+                media_type=media_type,
+            )
 
-        media_type = content_type or None
+        # Non-JSON upstream error (HTML, plain text, empty, ...). Wrap it in
+        # the standard JSON envelope so callers don't need a second parser.
+        for header_name in ("content-type", "Content-Type"):
+            headers.pop(header_name, None)
+
+        envelope = {
+            "error": {
+                "message": message or "Upstream returned a non-JSON error response",
+                "type": "upstream_error",
+                "code": upstream_code or status_code,
+                "upstream_status": status_code,
+                "upstream_content_type": content_type or None,
+                "upstream_body_preview": body_preview or None,
+            },
+            "request_id": getattr(request.state, "request_id", None),
+        }
 
         return Response(
-            content=body_bytes,
+            content=json.dumps(envelope).encode(),
             status_code=status_code,
             headers=headers,
-            media_type=media_type,
+            media_type="application/json",
         )
 
     async def handle_streaming_chat_completion(

routstr/upstream/routstr.py

@@ -18,6 +18,10 @@ class RoutstrUpstreamProvider(BaseUpstreamProvider):
     provider_type = "routstr"
     default_base_url = None
     platform_url = None
+    # Upstream Routstr nodes serve `/v1/messages` natively, so forward the
+    # request as-is instead of round-tripping through litellm's
+    # Anthropic→OpenAI translator.
+    supports_anthropic_messages = True
 
     def __init__(
         self,
@@ -43,6 +47,13 @@ class RoutstrUpstreamProvider(BaseUpstreamProvider):
         )
         self.settings = provider_settings or {}
 
+    def normalize_request_path(
+        self, path: str, model_obj: "Model | None" = None
+    ) -> str:
+        """Preserve the ``v1/`` prefix when forwarding to an upstream Routstr.
+        """
+        return path.lstrip("/")
+
     @classmethod
     def from_db_row(
         cls, provider_row: "UpstreamProviderRow"

tests/unit/test_upstream_error_response.py

@@ -0,0 +1,150 @@
+"""Tests for ``BaseUpstreamProvider.forward_upstream_error_response``.
+
+Upstream services (e.g. an Express server that doesn't expose ``/messages``)
+sometimes return a non-JSON error body. The proxy must surface those errors
+in a consistent JSON envelope so clients don't have to parse HTML.
+"""
+
+from __future__ import annotations
+
+import json
+from typing import Any
+from unittest.mock import Mock
+
+import httpx
+import pytest
+
+from routstr.upstream.base import BaseUpstreamProvider, _is_json_content_type
+
+
+def _make_request(request_id: str = "req-123") -> Mock:
+    request = Mock(spec=["method", "state"])
+    request.method = "POST"
+    request.state = Mock()
+    request.state.request_id = request_id
+    return request
+
+
+def _make_upstream_response(
+    *,
+    body: bytes,
+    status_code: int = 404,
+    content_type: str | None = "text/html",
+    extra_headers: dict[str, str] | None = None,
+) -> httpx.Response:
+    headers: dict[str, str] = {}
+    if content_type is not None:
+        headers["content-type"] = content_type
+    if extra_headers:
+        headers.update(extra_headers)
+    return httpx.Response(status_code=status_code, headers=headers, content=body)
+
+
+@pytest.fixture
+def provider() -> BaseUpstreamProvider:
+    return BaseUpstreamProvider(
+        base_url="https://privateprovider.xyz", api_key="k", provider_fee=1.0
+    )
+
+
+@pytest.mark.parametrize(
+    "content_type,expected",
+    [
+        ("application/json", True),
+        ("application/json; charset=utf-8", True),
+        ("text/json", True),
+        ("application/problem+json", True),
+        ("application/vnd.api+json", True),
+        ("text/html", False),
+        ("text/html; charset=utf-8", False),
+        ("text/plain", False),
+        ("", False),
+        (None, False),
+    ],
+)
+def test_is_json_content_type(content_type: str | None, expected: bool) -> None:
+    assert _is_json_content_type(content_type) is expected
+
+
+@pytest.mark.asyncio
+async def test_html_error_is_normalized_to_json_envelope(
+    provider: BaseUpstreamProvider,
+) -> None:
+    html_body = (
+        b"<!DOCTYPE html><html><head><title>Error</title></head>"
+        b"<body><pre>Cannot POST /messages</pre></body></html>"
+    )
+    upstream = _make_upstream_response(body=html_body, status_code=404)
+
+    response = await provider.forward_upstream_error_response(
+        _make_request(), "v1/messages", upstream
+    )
+
+    assert response.status_code == 404
+    assert response.media_type == "application/json"
+    payload: dict[str, Any] = json.loads(bytes(response.body))
+    assert payload["error"]["type"] == "upstream_error"
+    assert payload["error"]["upstream_status"] == 404
+    assert payload["error"]["upstream_content_type"] == "text/html"
+    assert "Cannot POST /messages" in payload["error"]["upstream_body_preview"]
+    assert payload["request_id"] == "req-123"
+    # The upstream's text/html content-type must not survive — Response()
+    # sets the JSON content-type for us via media_type.
+    assert response.headers["content-type"].startswith("application/json")
+
+
+@pytest.mark.asyncio
+async def test_plain_text_error_is_normalized(
+    provider: BaseUpstreamProvider,
+) -> None:
+    upstream = _make_upstream_response(
+        body=b"Service Unavailable", status_code=503, content_type="text/plain"
+    )
+
+    response = await provider.forward_upstream_error_response(
+        _make_request(), "v1/messages", upstream
+    )
+
+    assert response.status_code == 503
+    assert response.media_type == "application/json"
+    payload = json.loads(bytes(response.body))
+    assert payload["error"]["message"] == "Service Unavailable"
+
+
+@pytest.mark.asyncio
+async def test_empty_body_with_non_json_content_type_normalizes(
+    provider: BaseUpstreamProvider,
+) -> None:
+    upstream = _make_upstream_response(
+        body=b"", status_code=502, content_type="text/html"
+    )
+
+    response = await provider.forward_upstream_error_response(
+        _make_request(), "v1/messages", upstream
+    )
+
+    assert response.status_code == 502
+    assert response.media_type == "application/json"
+    payload = json.loads(bytes(response.body))
+    assert payload["error"]["type"] == "upstream_error"
+    assert payload["error"]["upstream_body_preview"] is None
+
+
+@pytest.mark.asyncio
+async def test_json_error_body_is_passed_through_unchanged(
+    provider: BaseUpstreamProvider,
+) -> None:
+    json_body = json.dumps(
+        {"error": {"message": "Invalid model", "type": "invalid_request_error"}}
+    ).encode()
+    upstream = _make_upstream_response(
+        body=json_body, status_code=400, content_type="application/json"
+    )
+
+    response = await provider.forward_upstream_error_response(
+        _make_request(), "v1/messages", upstream
+    )
+
+    assert response.status_code == 400
+    assert bytes(response.body) == json_body
+    assert response.media_type == "application/json"

tests/unit/test_upstream_routstr.py

@@ -74,3 +74,39 @@ async def test_get_balance_returns_none_on_connect_timeout(
     balance = await provider.get_balance()
 
     assert balance is None
+
+
+def test_normalize_request_path_keeps_v1_prefix() -> None:
+    """Routstr upstream stores ``base_url`` without ``/v1``; the prefix
+    must stay on the path so ``build_request_url`` produces ``/v1/<endpoint>``
+    instead of ``/<endpoint>`` (which the upstream Routstr 404s with HTML)."""
+    provider = RoutstrUpstreamProvider(
+        base_url="https://privateprovider.xyz", api_key="key"
+    )
+
+    assert provider.normalize_request_path("v1/messages") == "v1/messages"
+    assert provider.normalize_request_path("/v1/messages") == "v1/messages"
+    assert (
+        provider.normalize_request_path("v1/chat/completions")
+        == "v1/chat/completions"
+    )
+
+
+def test_build_request_url_for_v1_messages() -> None:
+    """Forwarding ``/v1/messages`` must hit the upstream's ``/v1/messages``."""
+    provider = RoutstrUpstreamProvider(
+        base_url="https://privateprovider.xyz", api_key="key"
+    )
+
+    normalized = provider.normalize_request_path("v1/messages")
+
+    assert (
+        provider.build_request_url(normalized)
+        == "https://privateprovider.xyz/v1/messages"
+    )
+
+
+def test_supports_anthropic_messages_natively() -> None:
+    """Routstr nodes serve ``/v1/messages`` directly, so the proxy must
+    forward as-is instead of round-tripping through litellm."""
+    assert RoutstrUpstreamProvider.supports_anthropic_messages is True