From 1143ec376faec4ca45fea199af72448525028c53 Mon Sep 17 00:00:00 2001
From: Artur Shiriev <lesnik512@gmail.com>
Date: Fri, 6 Nov 2026 12:22:46 +0300
Subject: [PATCH] Preserve OAuth settings in offline FastAPI Swagger docs

Refs #437
---
 lite_bootstrap/helpers/fastapi_helpers.py |  7 ++++-
 tests/test_fastapi_offline_docs.py        | 34 ++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/lite_bootstrap/helpers/fastapi_helpers.py b/lite_bootstrap/helpers/fastapi_helpers.py
index 120f4dd..6af2d9d 100644
--- a/lite_bootstrap/helpers/fastapi_helpers.py
+++ b/lite_bootstrap/helpers/fastapi_helpers.py
@@ -64,10 +64,15 @@ def enable_offline_docs(
         @app.get(docs_url, include_in_schema=False)
         async def custom_swagger_ui_html(request: Request) -> HTMLResponse:
             root_path = _safe_root_path(request.scope.get("root_path", ""))
+            oauth2_redirect_url = app.swagger_ui_oauth2_redirect_url
+            if oauth2_redirect_url:
+                oauth2_redirect_url = f"{root_path}{oauth2_redirect_url}"
             return get_swagger_ui_html(
                 openapi_url=f"{root_path}{app_openapi_url}",
                 title=f"{app.title} - Swagger UI",
-                oauth2_redirect_url=app.swagger_ui_oauth2_redirect_url,
+                oauth2_redirect_url=oauth2_redirect_url,
+                init_oauth=app.swagger_ui_init_oauth,
+                swagger_ui_parameters=app.swagger_ui_parameters,
                 swagger_js_url=f"{root_path}{static_path}/swagger-ui-bundle.js",
                 swagger_css_url=f"{root_path}{static_path}/swagger-ui.css",
             )
diff --git a/tests/test_fastapi_offline_docs.py b/tests/test_fastapi_offline_docs.py
index 4711ed2..88202f8 100644
--- a/tests/test_fastapi_offline_docs.py
+++ b/tests/test_fastapi_offline_docs.py
@@ -30,7 +30,12 @@ def test_fastapi_offline_docs() -> None:
 
 
 def test_fastapi_offline_docs_root_path() -> None:
-    app: FastAPI = FastAPI(title="Tests", root_path="/some-root-path", docs_url="/custom_docs")
+    app = FastAPI(
+        title="Tests",
+        root_path="/some-root-path",
+        docs_url="/custom_docs",
+        swagger_ui_oauth2_redirect_url=None,
+    )
     enable_offline_docs(app, static_path="/static")
 
     with TestClient(app, root_path="/some-root-path") as client:
@@ -38,6 +43,7 @@ def test_fastapi_offline_docs_root_path() -> None:
         assert response.status_code == HTTPStatus.OK
         assert "/some-root-path/static/swagger-ui.css" in response.text
         assert "/some-root-path/static/swagger-ui-bundle.js" in response.text
+        assert "oauth2RedirectUrl" not in response.text
 
         response = client.get("/some-root-path/static/swagger-ui.css")
         assert response.status_code == HTTPStatus.OK
@@ -48,6 +54,32 @@ def test_fastapi_offline_docs_root_path() -> None:
         assert "/some-root-path/openapi.json" in response.text
 
 
+@pytest.mark.parametrize(
+    "swagger_setting",
+    [
+        '"clientId": "public-demo"',
+        '"usePkceWithAuthorizationCodeGrant": true',
+        '"persistAuthorization": true',
+        "oauth2RedirectUrl: window.location.origin + '/api/docs/oauth2-redirect'",
+    ],
+)
+def test_offline_swagger_preserves_native_settings(swagger_setting: str) -> None:
+    app = FastAPI(
+        swagger_ui_init_oauth={"clientId": "public-demo", "usePkceWithAuthorizationCodeGrant": True},
+        swagger_ui_parameters={"persistAuthorization": True},
+    )
+    with TestClient(app, root_path="/api") as client:
+        native_response = client.get("/docs")
+
+    enable_offline_docs(app, static_path="/static")
+    with TestClient(app, root_path="/api") as client:
+        offline_response = client.get("/docs")
+
+    assert native_response.status_code == offline_response.status_code == HTTPStatus.OK
+    assert swagger_setting in native_response.text
+    assert swagger_setting in offline_response.text
+
+
 def test_fastapi_offline_docs_raises_without_openapi_url() -> None:
     app = FastAPI(openapi_url=None)