Files
resolutionflow/backend/app/core/security_headers.py
2026-03-18 02:38:42 +00:00

81 lines
2.6 KiB
Python

"""
Security headers middleware.
Adds standard security headers to every HTTP response:
- HSTS (production only)
- X-Content-Type-Options
- X-Frame-Options
- Referrer-Policy
- Permissions-Policy
- Content-Security-Policy (report-only by default)
"""
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request
from starlette.responses import Response
from typing import Callable
from app.core.config import settings
def _build_csp_directive() -> str:
"""Build the CSP directive string from config."""
script_sources = "'self' https://us.i.posthog.com https://*.sentry.io"
if settings.CSP_EXTRA_SCRIPT_SOURCES:
script_sources += " " + " ".join(settings.CSP_EXTRA_SCRIPT_SOURCES)
connect_sources = (
"'self' https://us.posthog.com https://us.i.posthog.com "
"https://*.sentry.io https://api.resolutionflow.com"
)
if settings.CSP_EXTRA_CONNECT_SOURCES:
connect_sources += " " + " ".join(settings.CSP_EXTRA_CONNECT_SOURCES)
return "; ".join([
"default-src 'self'",
f"script-src {script_sources}",
"style-src 'self' 'unsafe-inline' https://fonts.googleapis.com",
"font-src 'self' https://fonts.gstatic.com",
"img-src 'self' data: blob:",
f"connect-src {connect_sources}",
"frame-ancestors 'none'",
"base-uri 'self'",
"form-action 'self'",
])
class SecurityHeadersMiddleware(BaseHTTPMiddleware):
"""Add security headers to every response."""
def __init__(self, app):
super().__init__(app)
# Pre-build CSP at startup so we don't rebuild per-request
self._csp = _build_csp_directive()
async def dispatch(self, request: Request, call_next: Callable) -> Response:
response = await call_next(request)
# Always set these headers
response.headers["X-Content-Type-Options"] = "nosniff"
response.headers["X-Frame-Options"] = "DENY"
response.headers["Referrer-Policy"] = "strict-origin-when-cross-origin"
response.headers["Permissions-Policy"] = (
"camera=(), microphone=(), geolocation=()"
)
# HSTS only in production (avoid locking localhost into HTTPS)
if not settings.DEBUG:
response.headers["Strict-Transport-Security"] = (
"max-age=31536000; includeSubDomains"
)
# CSP — report-only or enforcing based on config
csp_header = (
"Content-Security-Policy-Report-Only"
if settings.CSP_REPORT_ONLY
else "Content-Security-Policy"
)
response.headers[csp_header] = self._csp
return response