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release-server/src/jcloud_deployment_server/integrations/gitea/middlewares/signature.py
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# Copyright 2026 jCloud
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import hmac
import hashlib
import logging
from typing import Optional
from fastapi import Request
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.responses import JSONResponse
__all__ = [
'GiteaSignatureMiddleware'
]
def _get_client_host(request: Request, proxy: bool = False, proxy_host_header: Optional[str] = 'X-Forwarded-For') -> str:
'''
Returns the client host.
If ``proxy`` is ``True``, the header that is specified in
``proxy_host_header`` is used to get the client host. Otherwise, the
real client host is returned.
:param request: The request object.
:type request: Request
:param proxy: Whether a proxy is used.
:type proxy: bool
:param proxy_host_header: The header set by the proxy containing the
original client host.
:type proxy_host_header: Optional[str]
:raises ValueError: If ``proxy`` is ``True`` and
``proxy_host_header`` is ``None``.
:return: The client host.
:rtype: str
'''
if proxy:
if not proxy_host_header:
raise ValueError('Passing a proxy host header is necessary if proxy is True')
return request.headers.get(proxy_host_header)
else:
return request.client.host
class GiteaSignatureMiddleware(BaseHTTPMiddleware):
'''
A middleware to verify the Gitea signature.
:param app: The (FastAPI) app.
:param secret: The secret.
:type secret: bytes
:param logger: The logger.
:type logger: Optional[logging.Logger]
'''
def __init__(self, app, secret: bytes, logger: Optional[logging.Logger] = None) -> None:
super().__init__(app)
self.secret = secret
self.logger = logger
async def dispatch(self, request: Request, call_next):
'''
Dispatch.
:param request: The request.
:type request: Request
'''
if request.url.path.startswith('/gitea/webhook'):
signature = request.headers.get('X-Gitea-Signature')
if not signature:
if self.logger is not None:
self.logger.error(f'Permission denied: no signature (client: {_get_client_host(request)})')
return JSONResponse(
status_code = 401,
content = {'detail': 'Invalid signature'}
)
body = await request.body()
if not hmac.compare_digest(
f'sha256={hmac.new(
self.secret,
body,
hashlib.sha256
).hexdigest()}',
signature
):
if self.logger is not None:
self.logger.error(f'Permission denied: invalid signature (client: {_get_client_host(request)})')
return JSONResponse(
status_code = 401,
content = {'detail': 'Invalid signature'}
)
return await call_next(request)