fix Host and :authority header not being updated on changes to host or port (#5908)

* fix map remote addon not setting `Host` header correctly

* fix failing tests

* fix coverage

* fix host and authority headers

* raise error when port is not of type int

* fix nits

* [autofix.ci] apply automated fixes

* coverage++

---------

Co-authored-by: Maximilian Hils <git@maximilianhils.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -11,6 +11,9 @@
   ([#5851](https://github.com/mitmproxy/mitmproxy/pull/5851), @italankin)
 * Removed string escaping in raw view.
   ([#5470](https://github.com/mitmproxy/mitmproxy/issues/5470), @stephenspol)
+* Updating `Request.port` now also updates the Host header if present.
+  This aligns with `Request.host`, which already does this.
+  ([#5908](https://github.com/mitmproxy/mitmproxy/pull/5908), @sujaldev)
 
 ### Breaking Changes
 

mitmproxy/http.py

@@ -749,13 +749,7 @@ class Request(Message):
     @host.setter
     def host(self, val: Union[str, bytes]) -> None:
         self.data.host = always_str(val, "idna", "strict")
-
-        # Update host header
-        if "Host" in self.data.headers:
-            self.data.headers["Host"] = val
-        # Update authority
-        if self.data.authority:
-            self.authority = url.hostport(self.scheme, self.host, self.port)
+        self._update_host_and_authority()
 
     @property
     def host_header(self) -> Optional[str]:
@@ -794,7 +788,21 @@ class Request(Message):
 
     @port.setter
     def port(self, port: int) -> None:
+        if not isinstance(port, int):
+            raise ValueError(f"Port must be an integer, not {port!r}.")
+
         self.data.port = port
+        self._update_host_and_authority()
+
+    def _update_host_and_authority(self) -> None:
+        val = url.hostport(self.scheme, self.host, self.port)
+
+        # Update host header
+        if "Host" in self.data.headers:
+            self.data.headers["Host"] = val
+        # Update authority
+        if self.data.authority:
+            self.authority = val
 
     @property
     def path(self) -> str:

test/mitmproxy/addons/test_mapremote.py

@@ -27,6 +27,16 @@ class TestMapRemote:
             mr.request(f)
             assert f.request.url == "https://mitmproxy.org/img/test.jpg"
 
+    def test_host_header(self):
+        mr = mapremote.MapRemote()
+        with taddons.context(mr) as tctx:
+            tctx.configure(mr, map_remote=["|http://[^/]+|http://example.com:4444"])
+            f = tflow.tflow()
+            f.request.url = b"http://example.org/example"
+            f.request.headers["Host"] = "example.org"
+            mr.request(f)
+            assert f.request.headers.get("Host", "") == "example.com:4444"
+
     def test_is_killed(self):
         mr = mapremote.MapRemote()
         with taddons.context(mr) as tctx:

test/mitmproxy/test_http.py

@@ -2,6 +2,7 @@ import asyncio
 import email
 import json
 import time
+from typing import Any
 from unittest import mock
 
 import pytest
@@ -10,6 +11,7 @@ from mitmproxy import flow
 from mitmproxy import flowfilter
 from mitmproxy.http import Headers
 from mitmproxy.http import HTTPFlow
+from mitmproxy.http import Message
 from mitmproxy.http import Request
 from mitmproxy.http import Response
 from mitmproxy.net.http.cookies import CookieAttrs
@@ -158,7 +160,9 @@ class TestRequestCore:
         _test_decoded_attr(treq(), "scheme")
 
     def test_port(self):
-        _test_passthrough_attr(treq(), "port")
+        _test_passthrough_attr(treq(), "port", 1234)
+        with pytest.raises(ValueError):
+            treq().port = "foo"
 
     def test_path(self):
         _test_decoded_attr(treq(), "path")
@@ -199,8 +203,7 @@ class TestRequestCore:
         request.headers["Host"] = "foo"
         request.authority = "foo"
         request.host = "example.org"
-        assert request.headers["Host"] == "example.org"
-        assert request.authority == "example.org:22"
+        assert request.headers["Host"] == request.authority == "example.org:22"
 
     def test_get_host_header(self):
         no_hdr = treq()
@@ -864,10 +867,10 @@ class TestHeaders:
         ]
 
 
-def _test_passthrough_attr(message, attr):
+def _test_passthrough_attr(message: Message, attr: str, value: Any = b"foo") -> None:
     assert getattr(message, attr) == getattr(message.data, attr)
-    setattr(message, attr, b"foo")
-    assert getattr(message.data, attr) == b"foo"
+    setattr(message, attr, value)
+    assert getattr(message.data, attr) == value
 
 
 def _test_decoded_attr(message, attr):