首先，nginx必定会设置一个Header传送过来真实的IP
nginx.conf
server {
proxy_set_header X-Real-IP $remote_addr;
location / {
proxy_pass http://192.168.7.206:8888/;
}
}
然后，tornado的Handler里面进行如下处理：
class Handler(BaseRequestHandler):
def post(self):
self.get()
def get(self):
remote_ip = self.request.headers.get("X-Real-Ip", "")
此处，下面两行其实是没有任何区别的，ng的header到了tornado会做一次统一整理（具体可以参考class HTTPHeaders）。
ip = self.request.headers.get("X-Real-Ip", "")
ip = self.request.headers.get("X-Real-IP", "")
然后，就可以了。
但是，这里为啥还有但是呢？这段日志还有奇怪的地方，它记录的还不对，这个是tornado的默认日志。
[I 150806 14:54:21 web:1811] 200 POST / (192.168.7.62) 2.74ms
看tornado==v4.2.0的代码web.py文件某处一定有如下类似的部分：
def log_request(self, handler):
"""Writes a completed HTTP request to the logs. By default writes to the python root logger. To change
this behavior either subclass Application and override this method,
or pass a function in the application settings dictionary as
``log_function``.
"""
if "log_function" in self.settings:
self.settings["log_function"](handler)
return
if handler.get_status() < 400:
log_method = access_log.info
elif handler.get_status() < 500:
log_method = access_log.warning
else:
log_method = access_log.error
request_time = 1000.0 * handler.request.request_time()
log_method("%d %s %.2fms", handler.get_status(),
handler._request_summary(), request_time)
这块其实就是日志的实现，_request_summary 又是啥？
def _request_summary(self):
return "%s %s (%s)" % (self.request.method, self.request.uri,
self.request.remote_ip)
后续继续看，发现，self.request.remote_ip这个其实就是tornado针对客户端IP做的快捷访问，这里为啥不对呢？
原来要在初始化listen的时候设置一个参数：
def main():
app = Application()
app.listen(options.port, xheaders = True)
产生的效果就是
[I 150806 13:52:53 web:1908] 200 POST / (192.168.7.214) 1.86ms
真实IP反映到Tornado的基础日志里了。
具体实现追踪可以查看 tornado\httpserver.py 中的相关代码。
class _ServerRequestAdapter(httputil.HTTPMessageDelegate):
def headers_received(self, start_line, headers):
if self.server.xheaders:
self.connection.context._apply_xheaders(headers)
class _HTTPRequestContext(object):
def _apply_xheaders(self, headers):
"""Rewrite the ``remote_ip`` and ``protocol`` fields."""
# Squid uses X-Forwarded-For, others use X-Real-Ip
ip = headers.get("X-Forwarded-For", self.remote_ip)
ip = ip.split(',')[-1].strip()
ip = headers.get("X-Real-Ip", ip)
if netutil.is_valid_ip(ip):
self.remote_ip = ip
# AWS uses X-Forwarded-Proto
proto_header = headers.get(
"X-Scheme", headers.get("X-Forwarded-Proto",
self.protocol))
if proto_header in ("http", "https"):
self.protocol = proto_header
def _unapply_xheaders(self):
"""Undo changes from `_apply_xheaders`.
Xheaders are per-request so they should not leak to the next
request on the same connection.
"""
self.remote_ip = self._orig_remote_ip
self.protocol = self._orig_protocol