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package feeds
import (
"encoding/json"
"encoding/xml"
"io"
"sort"
"time"
)
type Link struct {
Href, Rel, Type, Length string
}
type Author struct {
Name, Email string
}
type Image struct {
Url, Title, Link string
Width, Height int
}
type Enclosure struct {
Url, Length, Type string
}
type Item struct {
Title string
Link *Link
Source *Link
Author *Author
Description string // used as description in rss, summary in atom
Id string // used as guid in rss, id in atom
IsPermaLink string // an optional parameter for guid in rss
Updated time.Time
Created time.Time
Enclosure *Enclosure
Content string
}
type Feed struct {
Title string
Link *Link
Description string
Author *Author
Updated time.Time
Created time.Time
Id string
Subtitle string
Items []*Item
Copyright string
Image *Image
}
// add a new Item to a Feed
func (f *Feed) Add(item *Item) {
f.Items = append(f.Items, item)
}
// returns the first non-zero time formatted as a string or ""
func anyTimeFormat(format string, times ...time.Time) string {
for _, t := range times {
if !t.IsZero() {
return t.Format(format)
}
}
return ""
}
// interface used by ToXML to get a object suitable for exporting XML.
type XmlFeed interface {
FeedXml() interface{}
}
// turn a feed object (either a Feed, AtomFeed, or RssFeed) into xml
// returns an error if xml marshaling fails
func ToXML(feed XmlFeed) (string, error) {
x := feed.FeedXml()
data, err := xml.MarshalIndent(x, "", " ")
if err != nil {
return "", err
}
// strip empty line from default xml header
s := xml.Header[:len(xml.Header)-1] + string(data)
return s, nil
}
// WriteXML writes a feed object (either a Feed, AtomFeed, or RssFeed) as XML into
// the writer. Returns an error if XML marshaling fails.
func WriteXML(feed XmlFeed, w io.Writer) error {
x := feed.FeedXml()
// write default xml header, without the newline
if _, err := w.Write([]byte(xml.Header[:len(xml.Header)-1])); err != nil {
return err
}
e := xml.NewEncoder(w)
e.Indent("", " ")
return e.Encode(x)
}
// creates an Atom representation of this feed
func (f *Feed) ToAtom() (string, error) {
a := &Atom{f}
return ToXML(a)
}
// WriteAtom writes an Atom representation of this feed to the writer.
func (f *Feed) WriteAtom(w io.Writer) error {
return WriteXML(&Atom{f}, w)
}
// creates an Rss representation of this feed
func (f *Feed) ToRss() (string, error) {
r := &Rss{f}
return ToXML(r)
}
// WriteRss writes an RSS representation of this feed to the writer.
func (f *Feed) WriteRss(w io.Writer) error {
return WriteXML(&Rss{f}, w)
}
// ToJSON creates a JSON Feed representation of this feed
func (f *Feed) ToJSON() (string, error) {
j := &JSON{f}
return j.ToJSON()
}
// WriteJSON writes an JSON representation of this feed to the writer.
func (f *Feed) WriteJSON(w io.Writer) error {
j := &JSON{f}
feed := j.JSONFeed()
e := json.NewEncoder(w)
e.SetIndent("", " ")
return e.Encode(feed)
}
// Sort sorts the Items in the feed with the given less function.
func (f *Feed) Sort(less func(a, b *Item) bool) {
lessFunc := func(i, j int) bool {
return less(f.Items[i], f.Items[j])
}
sort.SliceStable(f.Items, lessFunc)
}
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