Add ability to play plex media as the non-primary user (#122039)

* Adds ability to play media as the non-primary user

* Add return type for set function

homeassistant/components/plex/server.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from copy import copy
 import logging
 import ssl
 import time
@@ -664,3 +665,14 @@ class PlexServer:
     def sensor_attributes(self):
         """Return active session information for use in activity sensor."""
         return {x.sensor_user: x.sensor_title for x in self.active_sessions.values()}
+
+    def set_plex_server(self, plex_server: PlexServer) -> None:
+        """Set the PlexServer instance."""
+        self._plex_server = plex_server
+
+    def switch_user(self, username: str) -> PlexServer:
+        """Return a shallow copy of a PlexServer as the provided user."""
+        new_server = copy(self)
+        new_server.set_plex_server(self.plex_server.switchUser(username))
+
+        return new_server

homeassistant/components/plex/services.py

@@ -161,6 +161,11 @@ def process_plex_payload(
     if not plex_server:
         plex_server = get_plex_server(hass)
 
+    if isinstance(content, dict):
+        if plex_user := content.pop("username", None):
+            _LOGGER.debug("Switching to Plex user: %s", plex_user)
+            plex_server = plex_server.switch_user(plex_user)
+
     if content_type == "station":
         if not supports_playqueues:
             raise HomeAssistantError("Plex stations are not supported on this device")

tests/components/plex/test_media_search.py

@@ -57,6 +57,31 @@ async def test_media_lookups(
         )
     assert "Media for key 123 not found" in str(excinfo.value)
 
+    # Search with a different specified username
+    with (
+        patch(
+            "plexapi.library.LibrarySection.search",
+            __qualname__="search",
+        ) as search,
+        patch(
+            "plexapi.myplex.MyPlexAccount.user",
+            __qualname__="user",
+        ) as plex_account_user,
+    ):
+        plex_account_user.return_value.get_token.return_value = "token"
+        await hass.services.async_call(
+            MEDIA_PLAYER_DOMAIN,
+            SERVICE_PLAY_MEDIA,
+            {
+                ATTR_ENTITY_ID: media_player_id,
+                ATTR_MEDIA_CONTENT_TYPE: MediaType.EPISODE,
+                ATTR_MEDIA_CONTENT_ID: '{"library_name": "TV Shows", "show_name": "TV Show", "username": "Kids"}',
+            },
+            True,
+        )
+        search.assert_called_with(**{"show.title": "TV Show", "libtype": "show"})
+        plex_account_user.assert_called_with("Kids")
+
     # TV show searches
     with pytest.raises(MediaNotFound) as excinfo:
         await hass.services.async_call(