Switch to atom feed

cmd/backend/atom.go

@@ -0,0 +1,103 @@
+package backend
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"git.streifling.com/jason/atom"
+)
+
+type Feed struct{ *atom.Feed }
+
+func GenerateAtomFeed(c *Config, db *DB) (*string, error) {
+	feed := atom.NewFeed(c.Title)
+	feed.ID = atom.NewID("urn:feed:1")
+	feed.Subtitle = atom.NewText("text", c.Description)
+	feed.AddLink(atom.NewLink(c.Link))
+
+	feed.Generator = atom.NewGenerator("cpolis")
+	feed.Generator.URI = "https://git.streifling.com/jason/cpolis"
+	feed.Generator.Version = "0.13"
+
+	articles, err := db.GetCertainArticles("published", true)
+	if err != nil {
+		return nil, fmt.Errorf("error getting published articles for RSS feed: %v", err)
+	}
+
+	for _, article := range articles {
+		articleTitle, err := ConvertToPlain(article.Title)
+		if err != nil {
+			return nil, fmt.Errorf("error converting title to plain text for RSS feed: %v", err)
+		}
+		entry := atom.NewEntry(articleTitle)
+		entry.ID = atom.NewID(fmt.Sprint("urn:entry:", article.ID))
+		entry.Content = atom.NewContent(atom.OutOfLine, "text/hmtl", article.ContentLink)
+		entry.Published = atom.NewDate(article.Created)
+
+		linkID := entry.AddLink(atom.NewLink(article.BannerLink))
+		entry.Links[linkID].Rel = "enclosure"
+		entry.Links[linkID].Type = "image/webp"
+
+		user, err := db.GetUser(article.AuthorID)
+		if err != nil {
+			return nil, fmt.Errorf("error getting user user info for RSS feed: %v", err)
+		}
+		entry.AddAuthor(atom.NewPerson(user.FirstName + " " + user.LastName))
+
+		articleSummary, err := ConvertToPlain(article.Summary)
+		if err != nil {
+			return nil, fmt.Errorf("error converting description to plain text for RSS feed: %v", err)
+		}
+		if article.AutoGenerated {
+			articleSummary = "auto generated"
+		}
+		entry.Summary = atom.NewText("text", articleSummary)
+
+		tags, err := db.GetArticleTags(article.ID)
+		if err != nil {
+			return nil, fmt.Errorf("error getting tags for articles for RSS feed: %v", err)
+		}
+		for _, tag := range tags {
+			entry.AddCategory(atom.NewCategory(tag.Name))
+		}
+
+		if article.IsInIssue || article.AutoGenerated {
+			entry.AddCategory(atom.NewCategory(fmt.Sprint("Orient Express ", article.IssueID)))
+		}
+		if article.AutoGenerated {
+			entry.AddCategory(atom.NewCategory("autogenerated"))
+		}
+
+		entry.Updated = atom.NewDate(article.Created)
+		feed.AddEntry(entry)
+	}
+
+	if err = feed.Check(); err != nil {
+		return nil, fmt.Errorf("error checking Atom feed: %v", err)
+	}
+
+	atom, err := feed.ToXML("UTF-8")
+	if err != nil {
+		return nil, fmt.Errorf("error converting RSS feed to XML: %v", err)
+	}
+
+	return &atom, nil
+}
+
+func SaveAtomFeed(filename string, feed *string) error {
+	file, err := os.Create(filename)
+	if err != nil {
+		return fmt.Errorf("error creating file for Atom feed: %v", err)
+	}
+	defer file.Close()
+	if err = file.Chmod(0644); err != nil {
+		return fmt.Errorf("error setting permissions for Atom file: %v", err)
+	}
+
+	if _, err = io.WriteString(file, *feed); err != nil {
+		return fmt.Errorf("error writing to Atom file: %v", err)
+	}
+
+	return nil
+}