Proxito: always add nginx internal path (#11080)

* Proxito: always add nginx internal path

Currently, this allows serving files like:
https://docs.readthedocs.io/_/static/proxito-static/javascript/readthedocs-analytics.js

We should always add the internal path to avoid serving files over
incorrect paths.

* Test

readthedocs/proxito/tests/test_full.py

@@ -1729,6 +1729,28 @@ def test_serve_static_files(self):
             resp.headers["Cache-Tag"], "project,project:rtd-staticfiles,rtd-staticfiles"
         )
 
+    @mock.patch(
+        "readthedocs.proxito.views.mixins.staticfiles_storage",
+        new=StaticFileSystemStorageTest(),
+    )
+    def test_serve_static_files_internal_nginx_redirect_always_appended(self):
+        """Test for #11080."""
+        resp = self.client.get(
+            reverse(
+                "proxito_static_files",
+                args=["proxito-static/javascript/readthedocs-doc-embed.js"],
+            ),
+            headers={"host": "project.readthedocs.io"},
+        )
+        self.assertEqual(resp.status_code, 200)
+        self.assertEqual(
+            resp.headers["x-accel-redirect"],
+            "/proxito-static/media/proxito-static/javascript/readthedocs-doc-embed.js",
+        )
+        self.assertEqual(
+            resp.headers["Cache-Tag"], "project,project:rtd-staticfiles,rtd-staticfiles"
+        )
+
     @mock.patch("readthedocs.proxito.views.mixins.staticfiles_storage")
     def test_serve_invalid_static_file(self, staticfiles_storage):
         staticfiles_storage.url.side_effect = Exception

readthedocs/proxito/views/mixins.py

@@ -1,4 +1,3 @@
-import copy
 import mimetypes
 from urllib.parse import parse_qsl, urlencode, urlparse
 
@@ -233,22 +232,17 @@ def _serve_file_from_nginx(self, path, root_path):
         :param path: The path of the file to serve.
         :param root_path: The root path of the internal redirect.
         """
-        original_path = copy.copy(path)
-        if not path.startswith(f"/{root_path}/"):
-            if path[0] == "/":
-                path = path[1:]
-            path = f"/{root_path}/{path}"
-
+        internal_path = f"/{root_path}/" + path.lstrip("/")
         log.debug(
             "Nginx serve.",
-            original_path=original_path,
-            path=path,
+            original_path=path,
+            internal_path=internal_path,
         )
 
-        content_type, encoding = mimetypes.guess_type(path)
+        content_type, encoding = mimetypes.guess_type(internal_path)
         content_type = content_type or "application/octet-stream"
         response = HttpResponse(
-            f"Serving internal path: {path}", content_type=content_type
+            f"Serving internal path: {internal_path}", content_type=content_type
         )
         if encoding:
             response["Content-Encoding"] = encoding
@@ -258,11 +252,11 @@ def _serve_file_from_nginx(self, path, root_path):
         # as the header value.
         # https://github.com/benoitc/gunicorn/issues/1448
         # https://docs.djangoproject.com/en/1.11/ref/unicode/#uri-and-iri-handling
-        x_accel_redirect = iri_to_uri(path)
+        x_accel_redirect = iri_to_uri(internal_path)
         response["X-Accel-Redirect"] = x_accel_redirect
 
         # Needed to strip any GET args, etc.
-        response.proxito_path = urlparse(path).path
+        response.proxito_path = urlparse(internal_path).path
         return response
 
     def _serve_file_from_python(self, request, path, storage):