Making sure Host request header is the first one

Signed-off-by: Lucas Kanashiro <kanashiro.duarte@gmail.com>
Signed-off-by: Sergio Oliveira <seocam@seocam.com>

revproxy/connection.py

@@ -0,0 +1,24 @@
+
+from urllib3.connection import HTTPConnection, HTTPSConnection
+from urllib3.connectionpool import HTTPConnectionPool, HTTPSConnectionPool
+
+
+def _output(self, s):
+    """Host header should always be first"""
+
+    if s.lower().startswith('host: '):
+        self._buffer.insert(1, s)
+    else:
+        self._buffer.append(s)
+
+HTTPConnectionPool.ConnectionCls = type(
+    'RevProxyHTTPConnection',
+    (HTTPConnection,),
+    {'_output': _output},
+)
+
+HTTPSConnectionPool.ConnectionCls = type(
+    'RevProxyHTTPSConnection',
+    (HTTPSConnection,),
+    {'_output': _output}
+)

revproxy/pool.py

@@ -0,0 +1,27 @@
+
+from urllib3.poolmanager import PoolManager as PoolManager_, SSL_KEYWORDS
+
+from .connection import HTTPConnectionPool, HTTPSConnectionPool
+
+pool_classes_by_scheme = {
+    'http': HTTPConnectionPool,
+    'https': HTTPSConnectionPool,
+}
+
+
+class PoolManager(PoolManager_):
+    def _new_pool(self, scheme, host, port):
+        """
+        Create a new :class:`ConnectionPool` based on host, port and scheme.
+        This method is used to actually create the connection pools handed out
+        by :meth:`connection_from_url` and companion methods. It is intended
+        to be overridden for customization.
+        """
+        pool_cls = pool_classes_by_scheme[scheme]
+        kwargs = self.connection_pool_kw
+        if scheme == 'http':
+            kwargs = self.connection_pool_kw.copy()
+            for kw in SSL_KEYWORDS:
+                kwargs.pop(kw, None)
+
+        return pool_cls(host, port, **kwargs)

revproxy/views.py

@@ -16,9 +16,10 @@
 from django.views.generic.base import ContextMixin
 
 from .exceptions import InvalidUpstream
+from .pool import PoolManager
 from .response import get_django_response
-from .utils import normalize_request_headers, encode_items
 from .transformer import DiazoTransformer
+from .utils import normalize_request_headers, encode_items
 
 # Chars that don't need to be quoted. We use same than nginx:
 #   https://github.com/nginx/nginx/blob/nginx-1.9/src/core/ngx_string.c
@@ -31,7 +32,7 @@
                            "'http' or 'https' (%s).")
 }
 
-HTTP_POOLS = urllib3.PoolManager()
+HTTP_POOLS = PoolManager()
 
 
 class ProxyView(View):