Add RSS feed (#1229)

Cargo.toml

@@ -39,6 +39,7 @@ miniscript = "9.0.0"
 ord-bitcoincore-rpc = { git = "https://github.com/casey/rust-bitcoincore-rpc", branch = "ord" }
 redb = "0.11.0"
 regex = "1.6.0"
+rss = "2.0.1"
 rust-embed = "6.4.0"
 rustls = "0.20.6"
 rustls-acme = { version = "0.5.0", features = ["axum"] }

src/index.rs

@@ -668,6 +668,20 @@ impl Index {
     )
   }
 
+  pub(crate) fn get_feed_inscriptions(&self, n: usize) -> Result<Vec<(u64, InscriptionId)>> {
+    Ok(
+      self
+        .database
+        .begin_read()?
+        .open_table(INSCRIPTION_NUMBER_TO_INSCRIPTION_ID)?
+        .iter()?
+        .rev()
+        .take(n)
+        .map(|(number, id)| (number.value(), Entry::load(*id.value())))
+        .collect(),
+    )
+  }
+
   pub(crate) fn get_inscription_entry(
     &self,
     inscription_id: InscriptionId,

src/subcommand/server.rs

@@ -138,6 +138,7 @@ impl Server {
         .route("/faq", get(Self::faq))
         .route("/favicon.ico", get(Self::favicon_ico))
         .route("/favicon.svg", get(Self::favicon_svg))
+        .route("/feed.xml", get(Self::feed))
         .route("/input/:block/:transaction/:input", get(Self::input))
         .route("/inscription/:inscription_id", get(Self::inscription))
         .route("/inscriptions", get(Self::inscriptions))
@@ -568,6 +569,47 @@ impl Server {
     )
   }
 
+  async fn feed(
+    Extension(chain): Extension<Chain>,
+    Extension(index): Extension<Arc<Index>>,
+  ) -> ServerResult<Response> {
+    let mut builder = rss::ChannelBuilder::default();
+
+    match chain {
+      Chain::Mainnet => builder.title("Inscriptions"),
+      _ => builder.title(format!("Inscriptions – {chain:?}")),
+    };
+
+    builder.generator(Some("ord".to_string()));
+
+    for (number, id) in index.get_feed_inscriptions(100)? {
+      builder.item(
+        rss::ItemBuilder::default()
+          .title(format!("Inscription {number}"))
+          .link(format!("/inscription/{id}"))
+          .guid(Some(rss::Guid {
+            value: format!("/inscription/{id}"),
+            permalink: true,
+          }))
+          .build(),
+      );
+    }
+
+    Ok(
+      (
+        [
+          (header::CONTENT_TYPE, "application/rss+xml"),
+          (
+            header::CONTENT_SECURITY_POLICY,
+            "default-src 'unsafe-inline'",
+          ),
+        ],
+        builder.build().to_string(),
+      )
+        .into_response(),
+    )
+  }
+
   async fn static_asset(Path(path): Path<String>) -> ServerResult<Response> {
     let content = StaticAssets::get(if let Some(stripped) = path.strip_prefix('/') {
       stripped
@@ -1990,4 +2032,24 @@ mod tests {
       "max-age=31536000; includeSubDomains; preload",
     );
   }
+
+  #[test]
+  fn feed() {
+    let server = TestServer::new_with_sat_index();
+    server.mine_blocks(1);
+
+    server.bitcoin_rpc_server.broadcast_tx(TransactionTemplate {
+      inputs: &[(1, 0, 0)],
+      witness: inscription("text/foo", "hello").to_witness(),
+      ..Default::default()
+    });
+
+    server.mine_blocks(1);
+
+    server.assert_response_regex(
+      "/feed.xml",
+      StatusCode::OK,
+      ".*<title>Inscription 0</title>.*",
+    );
+  }
 }

src/templates.rs

@@ -94,6 +94,7 @@ mod tests {
     <meta name=format-detection content='telephone=no'>
     <meta name=viewport content='width=device-width,initial-scale=1.0'>
     <title>Foo</title>
+    <link rel=alternate href=/feed.xml type=application/rss\+xml title='Inscription RSS Feed'>
     <link rel=icon type=image/svg\+xml href=/favicon.svg>
     <link rel=icon type=image/png href=/favicon.ico>
     <link rel=stylesheet href=/static/index.css>

templates/page.html

@@ -8,6 +8,7 @@
     <meta property=og:image content='{{ url }}'>
 %% }
     <title>{{ self.content.title() }}</title>
+    <link rel=alternate href=/feed.xml type=application/rss+xml title='Inscription RSS Feed'>
     <link rel=icon type=image/svg+xml href=/favicon.svg>
     <link rel=icon type=image/png href=/favicon.ico>
     <link rel=stylesheet href=/static/index.css>