Adds --keep-host-header option (#2039)

mitmproxy/options.py

@@ -72,6 +72,7 @@ class Options(optmanager.OptManager):
         upstream_bind_address: str = "",
         mode: str = "regular",
         no_upstream_cert: bool = False,
+        keep_host_header: bool = False,
 
         http2: bool = True,
         http2_priority: bool = False,
@@ -162,6 +163,7 @@ class Options(optmanager.OptManager):
         self.upstream_bind_address = upstream_bind_address
         self.mode = mode
         self.no_upstream_cert = no_upstream_cert
+        self.keep_host_header = keep_host_header
 
         self.http2 = http2
         self.http2_priority = http2_priority

mitmproxy/proxy/protocol/http.py

@@ -290,7 +290,7 @@ class HttpLayer(base.Layer):
             request.first_line_format = "relative"
 
         # update host header in reverse proxy mode
-        if self.config.options.mode == "reverse":
+        if self.config.options.mode == "reverse" and not self.config.options.keep_host_header:
             f.request.host_header = self.config.upstream_server.address.host
 
         # Determine .scheme, .host and .port attributes for inline scripts. For

mitmproxy/tools/cmdline.py

@@ -112,6 +112,7 @@ def get_common_options(args):
         replacements=args.replacements,
         replacement_files=args.replacement_files,
         setheaders=args.setheaders,
+        keep_host_header=args.keep_host_header,
         server_replay=args.server_replay,
         scripts=args.scripts,
         stickycookie=stickycookie,
@@ -387,6 +388,11 @@ def proxy_options(parser):
         action="store", type=str, dest="upstream_bind_address",
         help="Address to bind upstream requests to (defaults to none)"
     )
+    group.add_argument(
+        "--keep-host-header",
+        action="store_true", dest="keep_host_header",
+        help="Keep the host header as proxy addres"
+    )
 
 
 def proxy_ssl_options(parser):