Reimplement UI injection (#236)

custom_components/auth_oidc/tools/helpers.py

@@ -1,8 +1,17 @@
 """Helper functions for the integration."""
 
+from typing import TYPE_CHECKING
+
 from homeassistant.components import http
+from aiohttp import web
+
 from ..views.loader import AsyncTemplateRenderer
 
+if TYPE_CHECKING:
+    from ..provider import OpenIDAuthProvider
+
+STATE_COOKIE_NAME = "auth_oidc_state"
+
 
 def get_url(path: str, force_https: bool) -> str:
     """Returns the requested path appended to the current request base URL."""
@@ -22,3 +31,39 @@ async def get_view(template: str, parameters: dict | None = None) -> str:
 
     renderer = AsyncTemplateRenderer()
     return await renderer.render_template(f"{template}.html", **parameters)
+
+
+def get_state_id(request: web.Request) -> str | None:
+    """Return the current OIDC state cookie, if present."""
+    return request.cookies.get(STATE_COOKIE_NAME)
+
+
+async def get_valid_state_id(
+    request: web.Request, oidc_provider: "OpenIDAuthProvider"
+) -> str | None:
+    """Return state id only when cookie exists and state is still valid."""
+    state_id = get_state_id(request)
+    if not state_id:
+        return None
+
+    if not await oidc_provider.async_is_state_valid(state_id):
+        return None
+
+    return state_id
+
+
+def html_response(html: str, status: int = 200) -> web.Response:
+    """Return an HTML response with the standard content type."""
+    return web.Response(text=html, content_type="text/html", status=status)
+
+
+async def template_response(
+    template: str, parameters: dict | None = None
+) -> web.Response:
+    """Render a template and return it as an HTML response."""
+    return html_response(await get_view(template, parameters))
+
+
+async def error_response(message: str, status: int = 400) -> web.Response:
+    """Render the shared error view."""
+    return html_response(await get_view("error", {"error": message}), status=status)