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fix: add browser User-Agent to fix CF 403s on openai_compat backends #13

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fix: add browser User-Agent to fix CF 403s on openai_compat backends #13

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22 changes: 20 additions & 2 deletions proxy.py
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,10 @@
UC_MODEL_MAP optional JSON, e.g. {"claude-opus-4-8":"my-model"}
UC_LOG optional log file path (default stderr)
UC_VERBOSE default 0
UC_BROWSER_UA User-Agent for openai_compat upstreams (default: modern
Chrome UA). Fixes CF 403 "browser_signature_banned" on
providers like crof.ai (same keys work in droid/factory).
Override with env or per-route "headers".

ROUTE SHAPE (config.json "routes" object)
-----------------------------------------
Expand Down Expand Up @@ -146,6 +150,15 @@
DIRECTIVES = {"planner": None, "strip": True} # filled from config in main()
_ROUTE_ALIASES = {} # normalized token -> concrete route id

# BROWSER_UA: browser UA for openai_compat (and classifier) calls.
# CF-protected providers (e.g. crof.ai) ban Python-urllib (error 1010
# "browser_signature_banned"). Matches droid/factory clients.
# Override: UC_BROWSER_UA=... or route "headers".
BROWSER_UA = os.environ.get(
"UC_BROWSER_UA",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36"
)

try:
UC_MODEL_MAP = json.loads(os.environ.get("UC_MODEL_MAP", "") or "{}")
if not isinstance(UC_MODEL_MAP, dict):
Expand Down Expand Up @@ -1694,7 +1707,8 @@ def _classifier_complete(slot, system_prompt, user_content, timeout):
payload[bk] = _expand_env(bv) if isinstance(bv, str) else bv
data = json.dumps(payload).encode("utf-8")
headers = {"Content-Type": "application/json", "Accept": "application/json",
"Content-Length": str(len(data))}
"Content-Length": str(len(data)), "User-Agent": BROWSER_UA,
"Accept-Language": "en-US,en;q=0.9"}
auth = slot.get("auth")
if auth and auth != "passthrough":
Handler._apply_auth_header(headers, auth)
Expand All @@ -1715,7 +1729,7 @@ def _classifier_complete(slot, system_prompt, user_content, timeout):
"messages": [{"role": "user", "content": user_content}]}
data = json.dumps(payload).encode("utf-8")
headers = {"Content-Type": "application/json", "Content-Length": str(len(data)),
"anthropic-version": "2023-06-01"}
"anthropic-version": "2023-06-01", "User-Agent": BROWSER_UA}
auth = slot.get("auth")
if auth and auth != "passthrough":
Handler._apply_auth_header(headers, auth)
Expand Down Expand Up @@ -1999,6 +2013,7 @@ def _handle_models(self) -> bool:
fwd_headers = {k: v for k, v in self.headers.items()
if k.lower() not in _HOP_BY_HOP}
fwd_headers["Accept-Encoding"] = "identity"
fwd_headers.setdefault("User-Agent", BROWSER_UA)
url = UPSTREAM + self.path
base = {"data": [], "has_more": False, "first_id": None, "last_id": None}
try:
Expand Down Expand Up @@ -2083,6 +2098,7 @@ def _proxy(self, method: str):
for hk, hv in (route.get("headers") or {}).items():
fwd_headers[hk] = hv
fwd_headers["Accept-Encoding"] = "identity"
fwd_headers.setdefault("User-Agent", BROWSER_UA)
if body:
fwd_headers["Content-Length"] = str(len(body))
req = urllib.request.Request(url, data=body or None,
Expand Down Expand Up @@ -2140,6 +2156,8 @@ def _handle_openai_compat(self, body: bytes, route: dict):
"Content-Type": "application/json",
"Accept": "text/event-stream" if want_stream else "application/json",
"Content-Length": str(len(payload)),
"User-Agent": BROWSER_UA,
"Accept-Language": "en-US,en;q=0.9",
}
auth_override = route.get("auth")
if auth_override and auth_override != "passthrough":
Expand Down