From 2d548e83bafb90ff4a05aef79d1d5d0a01af2a6c Mon Sep 17 00:00:00 2001
From: Michal Vanko <mklakakilli@gmail.com>
Date: Tue, 30 Jan 2024 22:19:36 +0100
Subject: [PATCH] RSS feed

---
 axum_server/Cargo.toml    |  1 +
 axum_server/src/feed.rs   | 50 +++++++++++++++++++++++++++++++++++++++
 axum_server/src/main.rs   |  1 +
 axum_server/src/router.rs |  6 ++++-
 4 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 axum_server/src/feed.rs

diff --git a/axum_server/Cargo.toml b/axum_server/Cargo.toml
index 6280dab..8e85b38 100644
--- a/axum_server/Cargo.toml
+++ b/axum_server/Cargo.toml
@@ -12,6 +12,7 @@ axum = "0.7.3"
 chrono = { version = "0.4.31", features = ["serde"] }
 gray_matter = "0.2.6"
 markdown = "1.0.0-alpha.16"
+rss = "2.0.7"
 serde = "1.0.195"
 serde_json = "1.0.111"
 tokio = { version = "1.35.1", features = ["full"] }
diff --git a/axum_server/src/feed.rs b/axum_server/src/feed.rs
new file mode 100644
index 0000000..9a81575
--- /dev/null
+++ b/axum_server/src/feed.rs
@@ -0,0 +1,50 @@
+use axum::http::{header, StatusCode};
+use axum::response::IntoResponse;
+use chrono::Utc;
+use rss::{ChannelBuilder, GuidBuilder, Item, ItemBuilder};
+
+use crate::{pages::post::PostMetadata, post_list::get_post_list};
+
+pub async fn render_rss_feed() -> Result<impl IntoResponse, StatusCode> {
+    let mut post_list = get_post_list::<PostMetadata>().await.unwrap_or(vec![]);
+    post_list.sort_by_key(|post| post.metadata.date);
+    post_list.reverse();
+
+    let last_build_date = Utc::now().to_rfc2822();
+    let publish_date = post_list.last().map_or_else(
+        || last_build_date.clone(),
+        |post| post.metadata.date.to_rfc2822(),
+    );
+
+    let post_items = post_list
+        .into_iter()
+        .map(|post| {
+            ItemBuilder::default()
+                .title(Some(post.metadata.title))
+                .link(Some(format!("https://michalvanko.dev/blog/{}", post.slug)))
+                // TODO Description should be just a preview
+                .description(None)
+                .guid(Some(
+                    GuidBuilder::default()
+                        .value(format!("https://michalvanko.dev/blog/{}", post.slug))
+                        .build(),
+                ))
+                .pub_date(Some(post.metadata.date.to_rfc2822()))
+                .build()
+        })
+        .collect::<Vec<Item>>();
+
+    let feed_builder = ChannelBuilder::default()
+        .title("michalvanko.dev latest posts".to_string())
+        .link("https://michalvanko.dev".to_string())
+        .description("Latest posts published on michalvanko.dev blog site".to_string())
+        .language(Some("en".to_string()))
+        .webmaster(Some("michalvankosk@gmail.com".to_string()))
+        .pub_date(Some(publish_date))
+        .last_build_date(Some(last_build_date))
+        .items(post_items)
+        .build();
+
+    let response = feed_builder.to_string();
+    return Ok(([(header::CONTENT_TYPE, "application/xml")], response));
+}
diff --git a/axum_server/src/main.rs b/axum_server/src/main.rs
index e1c8d5d..b30e175 100644
--- a/axum_server/src/main.rs
+++ b/axum_server/src/main.rs
@@ -2,6 +2,7 @@ use axum;
 use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
 
 mod components;
+mod feed;
 mod pages;
 mod post_list;
 mod post_parser;
diff --git a/axum_server/src/router.rs b/axum_server/src/router.rs
index cf87917..77c7f68 100644
--- a/axum_server/src/router.rs
+++ b/axum_server/src/router.rs
@@ -1,4 +1,7 @@
-use crate::pages::{index::render_index, post::render_post, post_list::render_post_list};
+use crate::{
+    feed::render_rss_feed,
+    pages::{index::render_index, post::render_post, post_list::render_post_list},
+};
 use axum::{extract::MatchedPath, http::Request, routing::get, Router};
 use tower_http::trace::TraceLayer;
 use tracing::info_span;
@@ -9,6 +12,7 @@ pub fn get_router() -> Router {
         .route("/blog", get(render_post_list))
         .route("/blog/tags/:tag", get(render_post_list))
         .route("/blog/:post_id", get(render_post))
+        .route("/feed.xml", get(render_rss_feed))
         .layer(
             TraceLayer::new_for_http().make_span_with(|request: &Request<_>| {
                 // Log the matched route's path (with placeholders not filled in).