first commit

internal/feed/feed.go

@@ -0,0 +1,82 @@
+// Package feed generates RSS 2.0 / Atom feeds from blog posts.
+package feed
+
+import (
+	"encoding/xml"
+	"time"
+
+	"ridgwaysystems.org/website/internal/blog"
+)
+
+// --- RSS 2.0 ---
+
+type rssChannel struct {
+	XMLName       xml.Name  `xml:"channel"`
+	Title         string    `xml:"title"`
+	Link          string    `xml:"link"`
+	Description   string    `xml:"description"`
+	Language      string    `xml:"language"`
+	LastBuildDate string    `xml:"lastBuildDate"`
+	AtomLink      atomLink  `xml:"atom:link"`
+	Items         []rssItem `xml:"item"`
+}
+
+type atomLink struct {
+	Href string `xml:"href,attr"`
+	Rel  string `xml:"rel,attr"`
+	Type string `xml:"type,attr"`
+}
+
+type rssItem struct {
+	Title       string `xml:"title"`
+	Link        string `xml:"link"`
+	Description string `xml:"description"`
+	PubDate     string `xml:"pubDate"`
+	GUID        string `xml:"guid"`
+}
+
+type rssFeed struct {
+	XMLName xml.Name   `xml:"rss"`
+	Version string     `xml:"version,attr"`
+	Atom    string     `xml:"xmlns:atom,attr"`
+	Channel rssChannel `xml:"channel"`
+}
+
+// RSS generates RSS 2.0 XML for the given posts.
+func RSS(siteURL, siteTitle, siteDesc string, posts []*blog.Post) ([]byte, error) {
+	var items []rssItem
+	for _, p := range posts {
+		postURL := siteURL + "/blog/" + p.Slug
+		items = append(items, rssItem{
+			Title:       p.Title,
+			Link:        postURL,
+			Description: p.Description,
+			PubDate:     p.ParsedDate.Format(time.RFC1123Z),
+			GUID:        postURL,
+		})
+	}
+
+	feed := rssFeed{
+		Version: "2.0",
+		Atom:    "http://www.w3.org/2005/Atom",
+		Channel: rssChannel{
+			Title:         siteTitle,
+			Link:          siteURL,
+			Description:   siteDesc,
+			Language:      "en-us",
+			LastBuildDate: time.Now().Format(time.RFC1123Z),
+			AtomLink: atomLink{
+				Href: siteURL + "/blog/feed.xml",
+				Rel:  "self",
+				Type: "application/rss+xml",
+			},
+			Items: items,
+		},
+	}
+
+	out, err := xml.MarshalIndent(feed, "", "  ")
+	if err != nil {
+		return nil, err
+	}
+	return append([]byte(xml.Header), out...), nil
+}