给静态博客实现rss

手痒了，想给博客添加 feed.xml 以实现 rss 功能。

实现原理和 tera 的 html 模板渲染大差不差，大概思路就是遍历一边文章。

模板文件：

<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
    <channel>
        <title>Candlest's Blog</title>
        <link>http://candlest.github.io/</link>
        <description>Candlest 的博客</description>
        <language>zh-cn</language>

        {% for post in post_index | sort(attribute="datetime") |reverse%}
        <item>
            <title>{{post.title}}</title>
            <link>https://candlest.github.io/Post/{{post.url_name}}</link>
        </item>
        {% endfor %}
    </channel>
</rss>

代码：

impl Builder
{
    /* ... */
    pub fn build_feed(&self) {
        let tera = match Tera::new(
            format!(
                "{}/{}/{}/*.html",
                self.project_root_path, self.config.template_dir, self.config.theme
            )
            .as_str(),
        ) {
            Ok(t) => t,
            Err(e) => {
                println!("Parsing error(s): {}", e);
                ::std::process::exit(1);
            }
        };
        let mut context = tera::Context::new();
        context.insert("post_index", &self.posts_index);
        context.insert("tags", &self.tags);
        context.insert("categories", &self.categroies);
        //render
        let rendered = tera.render("feed.html", &context).unwrap();
        //let folder = std::path::Path::new(html_output_path.as_str());
        //let _ = std::fs::create_dir_all(folder);
        let html_output_path = format!("{}/feed.xml", self.config.public_dir);
        std::fs::write(html_output_path, rendered).unwrap();
    }
}
/* ... */
pub fn build() {
    let pro_path = String::from("./");
    let builder = Builder::new(pro_path);
    let mut builder_o = builder.clone();
    utils::info(utils::Info::GENERATE, "now generate", utils::PUBLIC_DIR);
    let handle_static = std::thread::spawn(move || {
        builder.build_static_dir();
    });
    builder_o.pre_create_posts_index();
    builder_o.build_all();
    builder_o.build_feed();
    handle_static.join().unwrap();
}