无法在Flask中获得传入请求的SSL证书

Question

我需要获取传入请求的SSL证书，并检查此客户端是否可以访问此特定端点。发送请求的服务很好，我可以看到带有以下代码的证书：

from requests.packages.urllib3.contrib import pyopenssl as reqs

def https_cert_subject_alt_names(host, port):
    """Read subject domains in https cert from remote server"""

    x509 = reqs.OpenSSL.crypto.load_certificate(
        reqs.OpenSSL.crypto.FILETYPE_PEM,
        reqs.ssl.get_server_certificate((host, port))
    )
    return x509.get_subject()

if __name__ == '__main__':
    domains = https_cert_subject_alt_names(domain_name, 443)
    print(domains)

我收到请求的烧瓶应用程序非常简单：

# -*- coding: utf-8 -*-
import logging
from flask import Flask, request

logger = logging.getLogger(__name__)
app = Flask(__name__)


@app.before_request
def before_request():
    logger.debug(request.environ)


@app.route("/")
def hello():
    return "Hello World!"


if __name__ == "__main__":
    app.run(host='0.0.0.0', port=5001)

Nginx的配置是这样的，因此我应该在request.environ中接收证书：

# Make the following two variables accessible to the application:
uwsgi_param SSL_CLIENT_VERIFY $ssl_client_verify;
uwsgi_param SSL_CLIENT_RAW_CERT $ssl_client_raw_cert;

但是我在request.environ中真正拥有的是：

{
    'wsgi.version': (1, 0),
    'wsgi.url_scheme': 'http',
    'wsgi.input': < _io.BufferedReader name = 5 > ,
    'wsgi.errors': < _io.TextIOWrapper name = '<stderr>'
    mode = 'w'
    encoding = 'UTF-8' > ,
    'wsgi.multithread': False,
    'wsgi.multiprocess': False,
    'wsgi.run_once': False,
    'werkzeug.server.shutdown': < function WSGIRequestHandler.make_environ. < locals > .shutdown_server at 0x7f84fc631400 > ,
    'SERVER_SOFTWARE': 'Werkzeug/0.14.1',
    'REQUEST_METHOD': 'GET',
    'SCRIPT_NAME': '',
    'PATH_INFO': '/',
    'QUERY_STRING': '',
    'REMOTE_ADDR': '172.19.0.5',
    'REMOTE_PORT': 50612,
    'SERVER_NAME': '0.0.0.0',
    'SERVER_PORT': '5001',
    'SERVER_PROTOCOL': 'HTTP/1.1',
    'HTTP_HOST': '192.168.0.10:5001',
    'HTTP_USER_AGENT': 'python-requests/2.19.1',
    'HTTP_ACCEPT_ENCODING': 'gzip, deflate',
    'HTTP_ACCEPT': '*/*',
    'HTTP_CONNECTION': 'keep-alive',
    'CONTENT_TYPE': 'application/json',
    'werkzeug.request': < Request 'http://192.168.0.10:5001/' [GET] >
}

如您所见，那里没有证书信息。我这样在客户端应用中发出请求：

import requests

url = 'http://192.168.0.10:5001/'
headers = {'Content-Type': 'application/json'}

requests.get(url, headers=headers)

那么如何从Flask应用程序中获取SSL证书？