From aebd192f2551c12c5c88f9371ad2912382d04b6a Mon Sep 17 00:00:00 2001
From: Akbar Rahman <hi@alv.cx>
Date: Sat, 9 May 2026 23:00:15 +0100
Subject: [PATCH] make shortlinks case insensitive

---
 readme.md   | 23 ++++++++++++++++++++++-
 src/main.rs |  5 +++--
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/readme.md b/readme.md
index ef15034..a4c7b0a 100644
--- a/readme.md
+++ b/readme.md
@@ -33,6 +33,27 @@ a _really_ simple url shortener: less than 200 lines of Rust and one dependency
 
 a working [dockerfile](./Dockerfile) and [compose file](./compose.yaml) are provided.
 
+## a note on case insensitivity
+
+all shortlinks are case insenitive,
+due to the lack of [urlencoding/decoding](#a-note-on-urlencoded-characters).
+
+## a note on urlencoded characters
+
+this program does not decode urlencoded strings before checking if strings match.
+this is a deliberate choice to keep things as simple as possible.
+
+avoid using links that may be encoded.
+
+for links that will necessarily get encoded (still discouraged) (such as emojis),
+put the urlencoded string.
+for example, for the link <http://pls.cx/🤬> the following line is in my urls.txt:
+
+```
+/🤬 https://en.wikipedia.org/wiki/Controversies_of_Nestl%C3%A9 you may want the non-encoded version in case a client does not encode it? idk
+/%f0%9f%a4%ac https://en.wikipedia.org/wiki/Controversies_of_Nestl%C3%A9
+```
+
 ## why?
 
 all url shorteners i've come across are too complicated:
@@ -47,7 +68,7 @@ updating it.
 
 good question.
 i'm not sure, but i think i want to separate my concerns?
-you might just want to configure your reverse proxy instead.
+you might just want to configure your reverse proxy instead:
 
 #### caddy
 
diff --git a/src/main.rs b/src/main.rs
index 8d3c91f..b9e88e8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -46,6 +46,7 @@ async fn process_socket(mut socket: BufStream<TcpStream>, urlmap: Arc<HashMap<St
         simple_response(socket, ResponseCode::BadRequest).await;
         return;
     };
+    let path = path.to_lowercase();
 
     if http_method != "GET" {
         println!("process_request: forbidden method");
@@ -53,7 +54,7 @@ async fn process_socket(mut socket: BufStream<TcpStream>, urlmap: Arc<HashMap<St
         return;
     }
 
-    let Some(location) = urlmap.get(path) else {
+    let Some(location) = urlmap.get(&path) else {
         println!("process_request: not found");
         simple_response(socket, ResponseCode::NotFound).await;
         return;
@@ -114,7 +115,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             Err(format!("Unable to parse line: '{}'", url_pair))?
         };
 
-        urlmap.insert(slug.to_string(), redirect.to_string());
+        urlmap.insert(slug.to_lowercase(), redirect.to_string());
     }
 
     let urlmap = Arc::new(urlmap);