1 files changed, 73 insertions, 0 deletions
diff --git a/litedb/router.ml b/litedb/router.ml
new file mode 100644
index 0000000..ef9d5c5
--- /dev/null
+++ b/litedb/router.ml
@@ -0,0 +1,73 @@
+(* Import the StdLabels module which provides labeled versions of standard library functions *)
+open StdLabels
+(* Import the Routes library for type-safe HTTP routing *)
+open Routes
+(* Import Piaf for HTTP types like Method.t *)
+open Piaf
+
+(* Create a custom Map module keyed by HTTP methods (GET, POST, etc.) *)
+(* This allows us to organize routes by their HTTP verb *)
+module R = Map.Make (struct
+    (* The key type is Piaf's Method.t (represents HTTP methods) *)
+    type t = Method.t
+
+    (* Define how to compare two HTTP methods for ordering in the map *)
+    let compare a b =
+      (* Convert methods to strings (e.g., "GET", "POST") *)
+      let a_str = Method.to_string a in
+      let b_str = Method.to_string b in
+      (* Use standard string comparison *)
+      String.compare a_str b_str
+    ;;
+  end)
+
+(* Define all routes in the application *)
+let routes =
+  (* Use fold_left to build up a map of routes *)
+  List.fold_left
+    (* For each (verb, route) pair, add the route to the map under that verb *)
+    ~f:(fun acc (v, r) -> R.add_to_list v r acc)
+    (* Start with an empty map *)
+    ~init:R.empty
+    (* List of (HTTP method, route pattern -> handler) tuples *)
+    [ `GET, (s "posts" /? nil) @--> Handler.get_posts
+      (* `GET - HTTP GET method *)
+      (* s "posts" - matches the literal string "posts" *)
+      (* /? - path concatenation operator *)
+      (* nil - end of path (no more segments) *)
+      (* @--> - binds the route pattern to the handler function *)
+      (* Handler.get_posts - the function that handles this route *)
+    ; `GET, (s "posts" / int /? nil) @--> Handler.get_post
+      (* / int - captures an integer parameter (post ID) *)
+    ; `GET, (s "comments" / int /? nil) @--> Handler.get_comment
+      (* Get a single comment by ID *)
+    ; `GET, (s "users" / str / s "comments" /? nil) @--> Handler.get_user_comments  
+      (* / str - captures a string parameter (username) *)
+    ; `GET, (s "posts" / int / s "comments" /? nil) @--> Handler.get_post_comments
+      (* Get all comments for a specific post *)
+    ; `GET, (s "comments" / int / s "children" /? nil) @--> Handler.get_comment_children
+      (* Get child comments (replies) for a comment *)
+    ]
+;;
+
+(* Transform the routes map by applying 'one_of' to each list of routes *)
+(* 'one_of' combines multiple routes into a single router that tries each in order *)
+let router = R.map one_of routes
+
+(* Function to match an incoming request against our routes *)
+let match_route verb path =
+  (* Try to find routes for the given HTTP verb in our map *)
+  match R.find_opt verb router with
+  (* If we have routes for this verb, try to match the path *)
+  | Some router ->
+    (* Use the Routes library's match' function to find a matching route *)
+    (match match' router ~target:path with
+     (* Exact match - the path matches completely *)
+     | FullMatch r -> Some r
+     (* Match with trailing slash - e.g., "/posts" matches "/posts/" *)
+     | MatchWithTrailingSlash r -> Some r
+     (* No routes matched the path *)
+     | NoMatch -> None)
+  (* We don't have any routes for this HTTP verb *)
+  | None -> None
+;;