Add HTML5 import preflight check

services/api-server/src/api_server/main.py

@@ -40,6 +40,7 @@ from api_server.html5 import (
     render_html5_index,
     render_html5_project_setup,
     render_html5_project_rows,
+    render_html5_import_check,
     render_html5_setup_summary,
     render_html5_source,
     render_html5_status,
@@ -1692,6 +1693,17 @@ async def html5_project_setup_source(project_id: str, request: Request) -> Respo
     )
 
 
+@app.post("/html5/projects/{project_id}/setup/check")
+async def html5_project_setup_check(project_id: str, request: Request) -> Response:
+    form = await _html5_form_data(request)
+    source = ImportSourceKind(_form_value(form, "source") or _current_import_source(project_id).value)
+    check = _import_check_response(project_id, source, ImportRequest(source=source))
+    return Response(
+        render_html5_import_check(project_id, check),
+        media_type="text/html; charset=utf-8",
+    )
+
+
 @app.post("/html5/projects/{project_id}/setup/import")
 async def html5_project_setup_import(project_id: str, request: Request) -> Response:
     form = await _html5_form_data(request)