new: Made the Cache-Control headers fully configurable

README.md

@@ -133,9 +133,11 @@ the `slug_length` variable. It defaults to 8, and a minimum of 4 is supported.
 To enable public mode, set `public_mode` to `Enable`. With this, anyone will be able to add 
 links. Listing existing links or deleting links will need admin access using the password.
 
-By default, the server sends `no-cache` and `private` Cache-Control headers. To disable those,
-set `cache_control_header` to `Disable`. It might help boost performance if served through a 
-proxy.
+By default, the server sends no Cache-Control headers. You can set custom `cache_control_header` 
+to send your desired headers. It must be a comma separated list of valid 
+[RFC 7234 §5.2](https://datatracker.ietf.org/doc/html/rfc7234#section-5.2) headers. For example,
+you can set it to `no-cache, private` to disable caching. It might help during testing if
+served through a proxy.
 
 ## Instructions for CLI usage
 The application can be used from the terminal using something like `curl`. In all the examples
@@ -179,6 +181,6 @@ pointing to illegal content. Since there are no logs, it's impossible to prove
 that those links aren't created by you.
 
 ## Notes
-- It started as a fork of [this project](https://gitlab.com/draganczukp/simply-shorten).
+- It started as a fork of [`simply-shorten`](https://gitlab.com/draganczukp/simply-shorten).
 - The list of adjectives and names used for random short url generation is a modified
   version of [this list used by docker](https://github.com/moby/moby/blob/master/pkg/namesgenerator/names-generator.go).

actix/src/main.rs

@@ -36,8 +36,7 @@ async fn main() -> Result<()> {
 
     let cache_control_header = env::var("cache_control_header")
         .ok()
-        .filter(|s| !s.trim().is_empty())
-        .unwrap_or(String::from("Enable"));
+        .filter(|s| !s.trim().is_empty());
 
     // Actually start the server
     HttpServer::new(move || {
@@ -54,10 +53,10 @@ async fn main() -> Result<()> {
             .app_data(web::Data::new(AppState {
                 db: database::open_db(db_location.clone()),
             }))
-            .wrap(if cache_control_header == "Disable" {
-                middleware::DefaultHeaders::new()
+            .wrap(if let Some(header) = &cache_control_header {
+                middleware::DefaultHeaders::new().add(("Cache-Control", header.to_owned()))
             } else {
-                middleware::DefaultHeaders::new().add(("Cache-Control", "no-cache, private"))
+                middleware::DefaultHeaders::new()
             })
             .service(services::link_handler)
             .service(services::getall)

compose.yaml

@@ -36,9 +36,10 @@ services:
             # delete, or listing), change the following option to Enable.
             # - public_mode=Disable
             
-            # By default, the server sends `no-cache` and `private` Cache-Control
-            # headers. To disable those, change the following option to Disable.
-            # - cache_control_header=Enable
+            # By default, the server sends no Cache-Control headers. You can supply a 
+            # comma separated list of valid header as per RFC 7234 §5.2 to send those
+            # headers instead.
+            # - cache_control_header=no-cache, private
         volumes:
             - db:/urls.sqlite
         networks: