Spaces:
Sleeping
Sleeping
File size: 3,397 Bytes
42f628f | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 | """
Lightweight Vercel Serverless Function - API Gateway Pattern
This proxies requests to an external ML backend (deployed elsewhere)
"""
from http.server import BaseHTTPRequestHandler
import json
import os
import urllib.request
import urllib.error
# External ML backend URL (set in Vercel environment variables)
ML_BACKEND_URL = os.getenv("ML_BACKEND_URL", "")
class handler(BaseHTTPRequestHandler):
"""Lightweight proxy handler for Vercel."""
def do_POST(self):
"""Proxy POST requests to ML backend."""
if not ML_BACKEND_URL:
self.send_error_response(503, "ML backend not configured")
return
try:
# Read request body
content_length = int(self.headers.get('Content-Length', 0))
body = self.rfile.read(content_length)
# Forward to ML backend
req = urllib.request.Request(
f"{ML_BACKEND_URL}/ask",
data=body,
headers={'Content-Type': 'application/json'},
method='POST'
)
with urllib.request.urlopen(req, timeout=30) as response:
response_data = response.read()
# Send response
self.send_response(200)
self.send_header('Content-Type', 'application/json')
self.send_header('Access-Control-Allow-Origin', '*')
self.send_header('Access-Control-Allow-Methods', 'POST, OPTIONS')
self.send_header('Access-Control-Allow-Headers', 'Content-Type')
self.end_headers()
self.wfile.write(response_data)
except urllib.error.HTTPError as e:
self.send_error_response(e.code, f"Backend error: {e.reason}")
except urllib.error.URLError as e:
self.send_error_response(503, "ML backend unavailable")
except Exception as e:
print(f"Proxy error: {str(e)}")
self.send_error_response(500, "Proxy error")
def do_OPTIONS(self):
"""Handle CORS preflight."""
self.send_response(200)
self.send_header('Access-Control-Allow-Origin', '*')
self.send_header('Access-Control-Allow-Methods', 'POST, OPTIONS')
self.send_header('Access-Control-Allow-Headers', 'Content-Type')
self.end_headers()
def do_GET(self):
"""Health check."""
self.send_response(200)
self.send_header('Content-Type', 'application/json')
self.send_header('Access-Control-Allow-Origin', '*')
self.end_headers()
response = {
"status": "healthy",
"backend_configured": bool(ML_BACKEND_URL)
}
self.wfile.write(json.dumps(response).encode('utf-8'))
def send_error_response(self, status_code, message):
"""Send error response."""
self.send_response(status_code)
self.send_header('Content-Type', 'application/json')
self.send_header('Access-Control-Allow-Origin', '*')
self.end_headers()
response = {
"response_type": "error",
"message": message,
"confidence_explanation": "Service error",
"sources": None
}
self.wfile.write(json.dumps(response).encode('utf-8'))
|