feat(server): add URL redirect for uppercase paths

* Introduce Lua-based redirect to handle requests for uppercase
  `GpgFrontend` URLs, ensuring they are rewritten to lowercase
  equivalents for consistency.
* Enable the `mod_magnet` module in the server config, applying the
  Lua redirect logic before other rewrites.
* Improve user experience by preventing duplicate route handling and
  enforcing a unified URL structure.

1 files changed, 31 insertions, 0 deletions

diff --git a/lua/redirect_lower_url.lua b/lua/redirect_lower_url.lua
new file mode 100644
index 0000000..74ffc30
--- /dev/null
+++ b/lua/redirect_lower_url.lua
@@ -0,0 +1,31 @@
+-- /usr/lib/cgit/lua/debug_gpgfrontend.lua
+local r = lighty.r
+local a = r.req_attr
+
+-- Get the "original" path to avoid being affected by rewrites
+local raw = a["uri.path-raw"] or a["uri.path"] or "/"
+local orig = a["request.orig-uri"] or raw
+
+-- Match two entry points:
+--   1) /GpgFrontend/...
+--   2) /cgit.cgi/GpgFrontend/...   (when the user accessed cgit.cgi directly)
+local new_path
+
+if orig:match("^/GpgFrontend") then
+  new_path = orig:gsub("^/GpgFrontend", "/gpgfrontend")
+elseif orig:match("^/cgit%.cgi/GpgFrontend") then
+  -- Convert /cgit.cgi/GpgFrontend/... to /gpgfrontend/... so rewrite adds /cgit.cgi only once
+  new_path = orig:gsub("^/cgit%.cgi/GpgFrontend", "/gpgfrontend")
+end
+
+if new_path then
+  local q = a["uri.query"]
+  if q and #q > 0 and not new_path:find("%?") then
+    new_path = new_path .. "?" .. q
+  end
+  r.resp_header["Location"] = new_path
+  return 301
+end
+
+r.resp_header["X-Magnet-Probed"] = "1"
+return 0
\ No newline at end of file