Replace noindex tag with X-Robots-Tag header

Expired files could get indexed by search engines because the 404 page
doesn't have the noindex meta tag. This puts it on the entire route so
even the 404 page tells Google to not index it.

Author: BBaoVanC

bobashare-web/Cargo.toml

@@ -37,7 +37,7 @@ thiserror = "2.0.0"
 tokio = { version = "1.23.1", features = ["full"] }
 tokio-util = { version = "0.7.4", features = ["io"] }
 tower = "0.5.0"
-tower-http = { version = "0.6.0", features = ["trace", "request-id", "fs", "util"] }
+tower-http = { version = "0.6.0", features = ["trace", "request-id", "fs", "util", "set-header"] }
 tracing = "0.1.36"
 tracing-subscriber = { version = "0.3.15", features = ["env-filter"] }
 url = "2.3.1"

bobashare-web/src/views/mod.rs

@@ -10,7 +10,9 @@ use axum::{
     Router,
 };
 use chrono::TimeDelta;
+use http::header::{HeaderName, HeaderValue};
 use hyper::StatusCode;
+use tower_http::set_header::SetResponseHeaderLayer;
 use tracing::{event, Level};
 use url::Url;
 
@@ -148,10 +150,20 @@ pub(crate) fn render_template<T: askama::Template>(tmpl: T) -> Result<Response,
 }
 
 pub fn router() -> Router<&'static AppState> {
+    let x_robots_tag_no_index = SetResponseHeaderLayer::overriding(
+        HeaderName::from_static("x-robots-tag"),
+        HeaderValue::from_static("noindex"),
+    );
     Router::new()
         .route("/", get(upload::upload))
         .route("/paste/", get(upload::paste))
         .route("/about/", get(about::about))
-        .route("/{id}", get(display::display))
-        .route("/raw/{id}", get(display::raw))
+        .route(
+            "/{id}",
+            get(display::display).layer(x_robots_tag_no_index.clone()),
+        )
+        .route(
+            "/raw/{id}",
+            get(display::raw).layer(x_robots_tag_no_index.clone()),
+        )
 }

bobashare-web/templates/display.html.jinja

@@ -13,8 +13,6 @@
     <meta name="twitter:title" content='{{ filename_truncated }} ({{ size|humansize }})'>
 {% endblock %}
 {% block head %}
-    <meta name="robots" content="noindex">
-
     {% match contents %}
         {% when DisplayType::Image %}
             <meta property="og:image" content='{{ raw_url }}'>