Use xml marshaling to create the rss feed

lib/rss.go

@@ -0,0 +1,158 @@
+package trantor
+
+import (
+	"encoding/xml"
+	"errors"
+	"net/http"
+	"strings"
+
+	"gitlab.com/trantor/trantor/lib/database"
+)
+
+type rss struct {
+	XMLName xml.Name `xml:"rss"`
+	Version string   `xml:"version,attr"`
+	Channel channel  `xml:"channel"`
+}
+
+type channel struct {
+	Title          string `xml:"title"`
+	Description    string `xml:"description"`
+	Link           string `xml:"link"`
+	ManagingEditor string `xml:"managingEditor,omitempty"`
+	Item           []item `xml:"item"`
+}
+
+type item struct {
+	Title       string     `xml:"title"`
+	Description string     `xml:"description"`
+	Link        string     `xml:"link"`
+	GUID        *guid      `xml:"guid,omitempty"`
+	Enclosure   *enclosure `xml:"enclosure,omitempty"`
+	Category    []string   `xml:"category"`
+}
+
+type guid struct {
+	IsPermaLink bool   `xml:"isPermaLink,attr"`
+	Chardata    string `xml:",chardata"`
+}
+
+type enclosure struct {
+	URL    string `xml:"url,attr"`
+	Length int    `xml:"length,attr"`
+	Type   string `xml:"type,attr"`
+}
+
+func loadRss(w http.ResponseWriter, tmpl string, data interface{}) error {
+	var err error
+	var res rss
+	switch tmpl {
+	case "news":
+		res, err = newsRss(data)
+	case "search":
+		res, err = searchRss(data)
+	case "list":
+		res, err = listRss(data)
+	}
+	if err != nil {
+		return err
+	}
+	w.Write([]byte(xml.Header))
+	enc := xml.NewEncoder(w)
+	enc.Indent("", "    ")
+	return enc.Encode(res)
+}
+
+func newsRss(data interface{}) (rss, error) {
+	news, ok := data.(newsData)
+	if !ok {
+		return rss{}, errors.New("Data is not valid")
+	}
+
+	feed := rss{
+		Version: "2.0",
+		Channel: channel{
+			Title:       news.S.Title,
+			Description: "News of the library",
+			Link:        news.S.BaseURL + "/news/",
+			Item:        make([]item, len(news.News)),
+		},
+	}
+	for i, n := range news.News {
+		feed.Channel.Item[i] = item{
+			Title:       n.Date,
+			Description: n.Text,
+			Link:        news.S.BaseURL + "/news/",
+		}
+	}
+
+	return feed, nil
+}
+
+func searchRss(data interface{}) (rss, error) {
+	search, ok := data.(searchData)
+	if !ok {
+		return rss{}, errors.New("Data is not valid")
+	}
+
+	description := "Last books added"
+	link := search.S.BaseURL
+	if search.S.Search != "" {
+		description = "Book search: " + search.S.Search
+		link += "/search/?q=" + search.S.Search
+	}
+
+	feed := rss{
+		Version: "2.0",
+		Channel: channel{
+			Title:       search.S.Title,
+			Description: description,
+			Link:        link,
+			Item:        bookListRss(search.Books, search.S.BaseURL),
+		},
+	}
+	return feed, nil
+}
+
+func listRss(data interface{}) (rss, error) {
+	lb, ok := data.(listData)
+	if !ok {
+		return rss{}, errors.New("Data is not valid")
+	}
+
+	feed := rss{
+		Version: "2.0",
+		Channel: channel{
+			Title:          lb.S.Title,
+			Description:    strings.Join(lb.List.Description, "\n"),
+			Link:           lb.S.BaseURL + "/list/" + lb.List.ListID,
+			ManagingEditor: lb.List.User.Username,
+			Item:           bookListRss(lb.List.Books, lb.S.BaseURL),
+		},
+	}
+	return feed, nil
+}
+
+func bookListRss(books []database.Book, baseURL string) []item {
+	items := make([]item, len(books))
+	for i, b := range books {
+		items[i] = item{
+			Title:       b.Title,
+			Description: b.Description,
+			Link:        baseURL + "/download/" + b.ID,
+			Category:    b.Tags,
+			Enclosure: &enclosure{
+				URL:    baseURL + "/download/" + b.ID + "/" + b.Title + ".epub",
+				Length: b.FileSize,
+				Type:   "application/epub+zip",
+			},
+		}
+		if b.Isbn != "" {
+			items[i].GUID = &guid{
+				IsPermaLink: false,
+				Chardata:    "ISBN: " + b.Isbn,
+			}
+		}
+	}
+	return items
+}