Retrieve browser headers in Python

Question

I'm currently drawing a blank as how to get the current browser header information for a user in Python Tornado? For example, in PHP you'd simple view the $_SERVER data. What is Tornado's alternative?

Note: How do I get the client IP of a Tornado request? and the "request" does not work for me.

Answer 1

Here's a snippet based off of a server I have where we retrieve some header data from the request:

class api(tornado.web.RequestHandler):
 def initialize(self, *args, **kwargs):
 self.remote_ip = self.request.headers.get('X-Forwarded-For', self.request.headers.get('X-Real-Ip', self.request.remote_ip))
 self.using_ssl = (self.request.headers.get('X-Scheme', 'http') == 'https')
 def get(self):
 self.write("Hello " + ("s" if self.using_ssl else "") + " " + self.remote_ip)

• mikemaccana: It's worth noting some background here. The reason @James might find self.request.protocol to be inaccurate is that some server setups (eg Amazon ELBs which handle SSL, other types of server-side proxies) change the protocol and IP before passing things onto your server. Using X-Forwarded-For and other headers provided by these proxies allows you to work out what the browser actually requested.
• johndodo: Also, you should know that the client can set "X-Forwarded-For" by himself, leading you to accept this value as his IP. So you should only use this if there is a setup that sets this header, not in general.

Answer 2

You can use logic similar to tornado/httpserver.py or just create tornado.httpserver.HTTPServer() with xheaders=True.

# Squid uses X-Forwarded-For, others use X-Real-Ip
ip = self.headers.get("X-Forwarded-For", self.remote_ip)
ip = ip.split(',')[-1].strip()
ip = self.headers.get(
 "X-Real-Ip", ip)
if netutil.is_valid_ip(ip):
 self.remote_ip = ip
# AWS uses X-Forwarded-Proto
proto = self.headers.get(
 "X-Scheme", self.headers.get("X-Forwarded-Proto", self.protocol))
if proto in ("http", "https"):
 self.protocol = proto