feat: Redirect root to prefix

When `CME_ROUTE_PREFIX` is set, redirect root to the prefix.

capella_model_explorer/app.py

@@ -6,6 +6,7 @@
 import contextlib
 import logging
 import pathlib
+import sys
 import tempfile
 import time
 import traceback
@@ -34,6 +35,15 @@
 logger.info("\tCapella model: '%s'", c.MODEL)
 logger.info("\tTemplates directory: '%s'", c.TEMPLATES_DIR)
 
+if any(
+    (
+        c.ROUTE_PREFIX and not c.ROUTE_PREFIX.startswith("/"),
+        "/" in c.ROUTE_PREFIX and not c.ROUTE_PREFIX.replace("/", ""),
+    )
+):
+    logger.error("Route prefix is invalid.")
+    sys.exit(1)
+
 
 @contextlib.asynccontextmanager
 async def lifespan(_):
@@ -89,6 +99,13 @@ def metrics() -> t.Any:
     )
 
 
+@app.get("/")
+def prefix_redirect() -> t.Any:
+    if c.ROUTE_PREFIX:
+        return fh.RedirectResponse(url=app.url_path_for("main_home"))
+    return home()
+
+
 @ar.get("/", name="main_home")
 def home() -> t.Any:
     """Show home/ landing page with all reports in categories."""