lucky_serializer_example.cr

# src/actions/rss/show.cr
#...
xml ArticlesXmlSerializer.new(articles, {title: "Feed Name", description: "Here's the descr", path: request.path }).render
#...

# src/actions/xml_action.cr
abstract class XMLAction < Lucky::Action
    private def xml(body : String)
        Lucky::TextResponse.new(context, content_type: "text/xml; charset=utf-8", body: body, status: 200)
    end
end

# src/serializers/article_xml_serializer.cr
require "xml"
class ArticlesXmlSerializer < Lucky::Serializer

    property title : String = ""
    property description : String = ""
    property base_url : String = "https://example.dev"
    property path : String = ""

    def initialize(@articles : ArticleQuery, options = {} of String => String)
        @title = options.fetch("title", @title)
        @description = options.fetch("description", @description)
        @base_url = options.fetch("base_url", @base_url)
        @path = options.fetch("path", @path)
    end

    def render
        XML.build(indent: "  ", encoding: "UTF-8") do |xml|
            xml.element(
                "rss", 
                version: "2.0", 
                "xmlns:dc": "http://purl.org/dc/elements/1.1/",
                "xmlns:content": "http://purl.org/rss/1.0/modules/content/",
                "xmlns:atom": "http://www.w3.org/2005/Atom",
                "xmlns:media": "http://search.yahoo.com/mrss/"
                ) do
                xml.element("channel") do
                    xml.element("title") { xml.cdata title }
                    xml.element("description") { xml.cdata description }
                    xml.element("link") { xml.text base_url }
                    xml.element("generator") { xml.text "Solo" }
                    xml.element("lastBuildDate") { xml.text Time.utc_now.to_s }
                    xml.element("atom:link") { 
                        xml.attribute "href", "#{base_url}#{path}"
                        xml.attribute "rel", "self"
                        xml.attribute "type", "application/rss+xml"
                    }
                    xml.element("ttl") { xml.text "60" }
                    @articles.each do |article|
                        xml.element("item") do
                            xml.element("title") { xml.cdata article.title }
                            if article.meta_description
                                xml.element("description") { xml.cdata article.meta_description.not_nil! }
                            end
                            xml.element("link") { xml.text "#{base_url}/articles/#{article.slug}" }
                            xml.element("dc:creator") { xml.cdata "Author Name" }
                            xml.element("pubDate") { xml.text article.created_at.to_s }
                            if article.og_image
                                xml.element("media:content") do
                                    xml.attribute "url", "article.og_image"
                                    xml.attribute "medium", "image"
                                end
                            end
                            if article.content
                                content = Markdown.to_html(article.content.not_nil!)
                                xml.element("content:encoded") { xml.cdata content }
                            end
                        end
                    end
                end
            end
        end
    end
end