From 4209b6ceac4e93f3fe414b2aa30ba064524e9f71 Mon Sep 17 00:00:00 2001
From: Carlton Gibson <carlton.gibson@noumenal.es>
Date: Thu, 14 Mar 2024 15:09:39 +0100
Subject: [PATCH] Correct WSGI adapter handling of root path.

Fixes #442
---
 asgiref/wsgi.py    |  8 ++++++--
 setup.cfg          |  2 +-
 tests/test_wsgi.py | 24 +++++++++++++++++++++++-
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/asgiref/wsgi.py b/asgiref/wsgi.py
index bf1be604..65af4279 100644
--- a/asgiref/wsgi.py
+++ b/asgiref/wsgi.py
@@ -54,10 +54,14 @@ def build_environ(self, scope, body):
         """
         Builds a scope and request body into a WSGI environ object.
         """
+        script_name = scope.get("root_path", "").encode("utf8").decode("latin1")
+        path_info = scope["path"].encode("utf8").decode("latin1")
+        if path_info.startswith(script_name):
+            path_info = path_info[len(script_name) :]
         environ = {
             "REQUEST_METHOD": scope["method"],
-            "SCRIPT_NAME": scope.get("root_path", "").encode("utf8").decode("latin1"),
-            "PATH_INFO": scope["path"].encode("utf8").decode("latin1"),
+            "SCRIPT_NAME": script_name,
+            "PATH_INFO": path_info,
             "QUERY_STRING": scope["query_string"].decode("ascii"),
             "SERVER_PROTOCOL": "HTTP/%s" % scope["http_version"],
             "wsgi.version": (1, 0),
diff --git a/setup.cfg b/setup.cfg
index e98a079e..ab3364d6 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -47,7 +47,7 @@ asyncio_mode = strict
 
 [flake8]
 exclude = venv/*,tox/*,specs/*
-ignore = E123,E128,E266,E402,W503,E731,W601
+ignore = E123,E128,E266,E402,W503,E731,W601,E203
 max-line-length = 119
 
 [isort]
diff --git a/tests/test_wsgi.py b/tests/test_wsgi.py
index aabea4df..5f50ce66 100644
--- a/tests/test_wsgi.py
+++ b/tests/test_wsgi.py
@@ -3,7 +3,7 @@
 import pytest
 
 from asgiref.testing import ApplicationCommunicator
-from asgiref.wsgi import WsgiToAsgi
+from asgiref.wsgi import WsgiToAsgi, WsgiToAsgiInstance
 
 
 @pytest.mark.asyncio
@@ -11,6 +11,7 @@ async def test_basic_wsgi():
     """
     Makes sure the WSGI wrapper has basic functionality.
     """
+
     # Define WSGI app
     def wsgi_application(environ, start_response):
         assert environ["HTTP_TEST_HEADER"] == "test value 1,test value 2"
@@ -55,11 +56,32 @@ def wsgi_application(environ, start_response):
     assert (await instance.receive_output(1)) == {"type": "http.response.body"}
 
 
+def test_script_name():
+    scope = {
+        "type": "http",
+        "http_version": "1.0",
+        "method": "GET",
+        "root_path": "/base",
+        "path": "/base/foo/",
+        "query_string": b"bar=baz",
+        "headers": [
+            [b"test-header", b"test value 1"],
+            [b"test-header", b"test value 2"],
+        ],
+    }
+    adapter = WsgiToAsgiInstance(None)
+    adapter.scope = scope
+    environ = adapter.build_environ(scope, None)
+    assert environ["SCRIPT_NAME"] == "/base"
+    assert environ["PATH_INFO"] == "/foo/"
+
+
 @pytest.mark.asyncio
 async def test_wsgi_path_encoding():
     """
     Makes sure the WSGI wrapper has basic functionality.
     """
+
     # Define WSGI app
     def wsgi_application(environ, start_response):
         assert environ["SCRIPT_NAME"] == "/中国".encode().decode("latin-1")