From 9ef69b99b22e79b6bfcd2ddf321f9d7530131ae9 Mon Sep 17 00:00:00 2001
From: Tilmann Becker <tilmann.becker@gmail.com>
Date: Wed, 23 Aug 2017 17:01:15 +0200
Subject: [PATCH] demo: parse X-Forwarded-Proto header

---
 daphne/http_protocol.py | 10 ++++++++--
 daphne/utils.py         |  9 ++++++++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/daphne/http_protocol.py b/daphne/http_protocol.py
index 32dc276..b8c02c0 100755
--- a/daphne/http_protocol.py
+++ b/daphne/http_protocol.py
@@ -81,12 +81,18 @@ class WebRequest(http.Request):
                 self.server_addr = None
 
             if self.factory.proxy_forwarded_address_header:
-                self.client_addr = parse_x_forwarded_for(
+                client, proto = parse_x_forwarded_for(
                     self.requestHeaders,
                     self.factory.proxy_forwarded_address_header,
                     self.factory.proxy_forwarded_port_header,
-                    self.client_addr
+                    original=self.client_addr
                 )
+                self.client_addr = client
+                if proto:
+                    # If we get a proto header, force ssl on or off (affects self.isSecure)
+                    self.setHost(host=self.host.host.encode('utf-8'),
+                                 port=self.host.port,
+                                 ssl=True if proto == 'https' else False)
 
             # Check for unicodeish path (or it'll crash when trying to parse)
             try:
diff --git a/daphne/utils.py b/daphne/utils.py
index cb8043c..dac6a8d 100644
--- a/daphne/utils.py
+++ b/daphne/utils.py
@@ -11,6 +11,7 @@ def header_value(headers, header_name):
 def parse_x_forwarded_for(headers,
                           address_header_name='X-Forwarded-For',
                           port_header_name='X-Forwarded-Port',
+                          proto_header_name='X-Forwarded-Proto',
                           original=None):
     """
     Parses an X-Forwarded-For header and returns a host/port pair as a list.
@@ -18,6 +19,7 @@ def parse_x_forwarded_for(headers,
     @param headers: The twisted-style object containing a request's headers
     @param address_header_name: The name of the expected host header
     @param port_header_name: The name of the expected port header
+    @param proto_header_name: The name of the expected protocol header
     @param original: A host/port pair that should be returned if the headers are not in the request
     @return: A list containing a host (string) as the first entry and a port (int) as the second.
     """
@@ -33,6 +35,7 @@ def parse_x_forwarded_for(headers,
 
     address_header_name = address_header_name.lower().encode("utf-8")
     result = original
+    proto_value = None
     if address_header_name in headers:
         address_value = header_value(headers, address_header_name)
 
@@ -52,4 +55,8 @@ def parse_x_forwarded_for(headers,
                 except ValueError:
                     pass
 
-    return result
+            proto_header_name = proto_header_name.lower().encode("utf-8")
+            if proto_header_name in headers:
+                proto_value = header_value(headers, proto_header_name)
+
+    return result, proto_value