From 637f0b47dddcdda9ae278f3f67f48d137a89c468 Mon Sep 17 00:00:00 2001
From: "Wyatt J. Miller" <wyatt@wyattjmiller.com>
Date: Tue, 10 Dec 2024 14:06:22 -0500
Subject: [PATCH] added rss generator

---
 backend/public/Cargo.lock          | 55 ++++++++++++++++++
 backend/public/Cargo.toml          |  3 +-
 backend/public/src/main.rs         |  1 +
 backend/public/src/routes/posts.rs | 43 +++++++++++++-
 backend/public/src/utils/mod.rs    |  1 +
 backend/public/src/utils/rss.rs    | 90 ++++++++++++++++++++++++++++++
 6 files changed, 190 insertions(+), 3 deletions(-)
 create mode 100644 backend/public/src/utils/mod.rs
 create mode 100644 backend/public/src/utils/rss.rs

diff --git a/backend/public/Cargo.lock b/backend/public/Cargo.lock
index f29299d..a313c98 100644
--- a/backend/public/Cargo.lock
+++ b/backend/public/Cargo.lock
@@ -79,6 +79,12 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "atomic-waker"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
+
 [[package]]
 name = "autocfg"
 version = "1.3.0"
@@ -586,6 +592,25 @@ dependencies = [
  "spinning_top",
 ]
 
+[[package]]
+name = "h2"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "524e8ac6999421f49a846c2d4411f337e53497d8ec55d67753beffa43c5d9205"
+dependencies = [
+ "atomic-waker",
+ "bytes",
+ "fnv",
+ "futures-core",
+ "futures-sink",
+ "http",
+ "indexmap",
+ "slab",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.5"
@@ -705,6 +730,7 @@ dependencies = [
  "bytes",
  "futures-channel",
  "futures-util",
+ "h2",
  "http",
  "http-body",
  "httparse",
@@ -1162,6 +1188,7 @@ dependencies = [
  "tower_governor",
  "tracing",
  "tracing-subscriber",
+ "xml",
 ]
 
 [[package]]
@@ -1908,6 +1935,19 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "tokio-util"
+version = "0.7.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61e7c3654c13bcd040d4a03abee2c75b1d14a37b423cf5a813ceae1cc903ec6a"
+dependencies = [
+ "bytes",
+ "futures-core",
+ "futures-sink",
+ "pin-project-lite",
+ "tokio",
+]
+
 [[package]]
 name = "tower"
 version = "0.4.13"
@@ -2395,6 +2435,21 @@ version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
 
+[[package]]
+name = "xml"
+version = "0.8.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ede1c99c55b4b3ad0349018ef0eccbe954ce9c342334410707ee87177fcf2ab4"
+dependencies = [
+ "xml-rs",
+]
+
+[[package]]
+name = "xml-rs"
+version = "0.8.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea8b391c9a790b496184c29f7f93b9ed5b16abb306c05415b68bcc16e4d06432"
+
 [[package]]
 name = "zerocopy"
 version = "0.7.35"
diff --git a/backend/public/Cargo.toml b/backend/public/Cargo.toml
index e094372..f4f7b7c 100644
--- a/backend/public/Cargo.toml
+++ b/backend/public/Cargo.toml
@@ -7,7 +7,7 @@ authors = ["Wyatt J. Miller <wyatt@wyattjmiller.com"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-axum = "0.7.6"
+axum = { version = "0.7.6", features = ["http2", "tokio"] }
 tower-http = { version = "0.6.1", features = ["trace", "cors"] }
 tower_governor = "0.4.2"
 tokio = { version = "1.40.0", features = ["full"] }
@@ -23,3 +23,4 @@ dotenvy = "0.15.7"
 serde = "1.0.210"
 serde_json = "1.0.128"
 chrono = "0.4.38"
+xml = "0.8.20"
diff --git a/backend/public/src/main.rs b/backend/public/src/main.rs
index 4e496bf..9f62690 100644
--- a/backend/public/src/main.rs
+++ b/backend/public/src/main.rs
@@ -16,6 +16,7 @@ use tracing_subscriber::{filter, layer::SubscriberExt, prelude::*, util::Subscri
 mod config;
 mod datasources;
 mod routes;
+mod utils;
 
 pub struct AppState {
     db: PgPool,
diff --git a/backend/public/src/routes/posts.rs b/backend/public/src/routes/posts.rs
index 8aa7d3d..f5678d6 100644
--- a/backend/public/src/routes/posts.rs
+++ b/backend/public/src/routes/posts.rs
@@ -1,7 +1,11 @@
+use std::collections::HashMap;
+
+use crate::utils::rss;
 use crate::{datasources::posts::PostsDatasource, AppState};
+use axum::http::{HeaderMap, HeaderValue};
 use axum::{
     extract::{Path, State},
-    http::StatusCode,
+    http::{header, StatusCode},
     response::IntoResponse,
     routing::get,
     Json, Router,
@@ -10,7 +14,7 @@ use chrono::Utc;
 use serde::{Deserialize, Serialize, Serializer};
 use sqlx::{Pool, Postgres};
 
-#[derive(sqlx::FromRow, Serialize, Debug)]
+#[derive(sqlx::FromRow, Serialize, Debug, Clone)]
 pub struct Post {
     pub post_id: i32,
     pub author_id: Option<i32>,
@@ -51,6 +55,7 @@ impl PostsRoute {
             .route("/popular", get(PostsRoute::get_popular_posts))
             .route("/hot", get(PostsRoute::get_hot_posts))
             .route("/featured", get(PostsRoute::get_featured_posts))
+            .route("/rss", get(PostsRoute::get_rss_posts))
             .with_state(app_state.db.clone())
     }
 
@@ -104,6 +109,40 @@ impl PostsRoute {
             Err(e) => Err((StatusCode::INTERNAL_SERVER_ERROR, e.to_string())),
         }
     }
+
+    // get rss posts
+    async fn get_rss_posts(State(pool): State<Pool<Postgres>>) -> impl IntoResponse {
+        match PostsDatasource::get_all(&pool).await {
+            Ok(posts) => {
+                let web_url = std::env::var("BASE_URI_WEB").expect("No environment variable found");
+                let mapped_posts: HashMap<String, Post> = posts
+                    .into_iter()
+                    .map(|post| (post.post_id.to_string(), post))
+                    .collect();
+                let xml: String = rss::generate_rss(
+                    "Wyatt's blog",
+                    "Wyatt and friends",
+                    web_url.as_str(),
+                    &mapped_posts,
+                );
+                let mut headers = HeaderMap::new();
+                headers.insert(
+                    header::CONTENT_DISPOSITION,
+                    HeaderValue::from_str(r#"attachment; filename="posts.xml""#).unwrap(),
+                );
+                headers.insert(
+                    header::CONTENT_TYPE,
+                    HeaderValue::from_static("application/xml"),
+                );
+                (headers, xml)
+            }
+            Err(e) => {
+                let mut headers = HeaderMap::new();
+                headers.insert("Content-Type", HeaderValue::from_static("text/plain"));
+                (headers, e.to_string())
+            }
+        }
+    }
 }
 
 pub fn serialize_datetime<S>(
diff --git a/backend/public/src/utils/mod.rs b/backend/public/src/utils/mod.rs
new file mode 100644
index 0000000..aaa67c0
--- /dev/null
+++ b/backend/public/src/utils/mod.rs
@@ -0,0 +1 @@
+pub mod rss;
diff --git a/backend/public/src/utils/rss.rs b/backend/public/src/utils/rss.rs
new file mode 100644
index 0000000..6d09d32
--- /dev/null
+++ b/backend/public/src/utils/rss.rs
@@ -0,0 +1,90 @@
+use crate::routes::posts;
+use std::collections::HashMap;
+use xml::escape::escape_str_pcdata;
+
+pub struct RssEntry {
+    pub title: String,
+    pub link: String,
+    pub description: Option<String>,
+    pub created_at: String,
+    pub author: String,
+    pub guid: String,
+}
+
+impl From<posts::Post> for RssEntry {
+    fn from(post: posts::Post) -> Self {
+        let web_url = std::env::var("BASE_URI_WEB").expect("Environment variable not found");
+        let post_url = format!("{}{}{}", web_url, "/posts/", post.post_id.to_string());
+        let author_full_name = format!("{} {}", post.first_name.unwrap(), post.last_name.unwrap());
+
+        Self {
+            title: post.title.clone(),
+            link: post_url.clone(),
+            description: Some(post.body.clone()),
+            created_at: post
+                .created_at
+                .expect("No timestamp was available")
+                .to_rfc2822(),
+            author: author_full_name,
+            guid: post_url.clone(),
+        }
+    }
+}
+
+impl RssEntry {
+    pub fn to_item(&self) -> String {
+        format!(
+            r#"
+            <item>
+                <title><![CDATA[{}]]></title>
+                <description><![CDATA[{}]]></description>
+                <pubDate>{}</pubDate>
+                <link>{}</link>
+                <guid isPermaLink="true">{}</guid>
+            </item>
+            "#,
+            self.title,
+            self.description.clone().unwrap_or_default(),
+            self.created_at,
+            self.guid,
+            self.guid
+        )
+    }
+}
+
+pub fn generate_rss(
+    title: &str,
+    description: &str,
+    link: &str,
+    posts: &HashMap<String, posts::Post>,
+) -> String {
+    println!("{:?}", posts);
+    let values = posts.clone().into_values();
+    println!("{:?}", values);
+
+    let rss_entries = values
+        .map(|p| p.into())
+        .map(|r: RssEntry| r.to_item())
+        .collect::<String>();
+
+    let safe_title = escape_str_pcdata(title);
+    let safe_description = escape_str_pcdata(description);
+    println!("{:?}", rss_entries);
+
+    format!(
+        r#"<?xml version="1.0" encoding="UTF-8"?>
+            <rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
+                <channel>
+                  <title>{safe_title}</title>
+                    <description>{safe_description}</description>
+                    <link>{link}</link>
+                    <language>en-us</language>
+                    <ttl>60</ttl>
+                    <generator>Kyouma 1.0.0-SE</generator>
+                    <atom:link href="https://wyattjmiller.com/posts.xml" rel="self" type="application/rss+xml" />
+                    {}
+                </channel>
+            </rss>"#,
+        rss_entries
+    )
+}