gtsocial-umbx

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feed.go (3235B)

      1 package feeds
      2 
      3 import (
      4 	"encoding/json"
      5 	"encoding/xml"
      6 	"io"
      7 	"sort"
      8 	"time"
      9 )
     10 
     11 type Link struct {
     12 	Href, Rel, Type, Length string
     13 }
     14 
     15 type Author struct {
     16 	Name, Email string
     17 }
     18 
     19 type Image struct {
     20 	Url, Title, Link string
     21 	Width, Height    int
     22 }
     23 
     24 type Enclosure struct {
     25 	Url, Length, Type string
     26 }
     27 
     28 type Item struct {
     29 	Title       string
     30 	Link        *Link
     31 	Source      *Link
     32 	Author      *Author
     33 	Description string // used as description in rss, summary in atom
     34 	Id          string // used as guid in rss, id in atom
     35 	Updated     time.Time
     36 	Created     time.Time
     37 	Enclosure   *Enclosure
     38 	Content     string
     39 }
     40 
     41 type Feed struct {
     42 	Title       string
     43 	Link        *Link
     44 	Description string
     45 	Author      *Author
     46 	Updated     time.Time
     47 	Created     time.Time
     48 	Id          string
     49 	Subtitle    string
     50 	Items       []*Item
     51 	Copyright   string
     52 	Image       *Image
     53 }
     54 
     55 // add a new Item to a Feed
     56 func (f *Feed) Add(item *Item) {
     57 	f.Items = append(f.Items, item)
     58 }
     59 
     60 // returns the first non-zero time formatted as a string or ""
     61 func anyTimeFormat(format string, times ...time.Time) string {
     62 	for _, t := range times {
     63 		if !t.IsZero() {
     64 			return t.Format(format)
     65 		}
     66 	}
     67 	return ""
     68 }
     69 
     70 // interface used by ToXML to get a object suitable for exporting XML.
     71 type XmlFeed interface {
     72 	FeedXml() interface{}
     73 }
     74 
     75 // turn a feed object (either a Feed, AtomFeed, or RssFeed) into xml
     76 // returns an error if xml marshaling fails
     77 func ToXML(feed XmlFeed) (string, error) {
     78 	x := feed.FeedXml()
     79 	data, err := xml.MarshalIndent(x, "", "  ")
     80 	if err != nil {
     81 		return "", err
     82 	}
     83 	// strip empty line from default xml header
     84 	s := xml.Header[:len(xml.Header)-1] + string(data)
     85 	return s, nil
     86 }
     87 
     88 // WriteXML writes a feed object (either a Feed, AtomFeed, or RssFeed) as XML into
     89 // the writer. Returns an error if XML marshaling fails.
     90 func WriteXML(feed XmlFeed, w io.Writer) error {
     91 	x := feed.FeedXml()
     92 	// write default xml header, without the newline
     93 	if _, err := w.Write([]byte(xml.Header[:len(xml.Header)-1])); err != nil {
     94 		return err
     95 	}
     96 	e := xml.NewEncoder(w)
     97 	e.Indent("", "  ")
     98 	return e.Encode(x)
     99 }
    100 
    101 // creates an Atom representation of this feed
    102 func (f *Feed) ToAtom() (string, error) {
    103 	a := &Atom{f}
    104 	return ToXML(a)
    105 }
    106 
    107 // WriteAtom writes an Atom representation of this feed to the writer.
    108 func (f *Feed) WriteAtom(w io.Writer) error {
    109 	return WriteXML(&Atom{f}, w)
    110 }
    111 
    112 // creates an Rss representation of this feed
    113 func (f *Feed) ToRss() (string, error) {
    114 	r := &Rss{f}
    115 	return ToXML(r)
    116 }
    117 
    118 // WriteRss writes an RSS representation of this feed to the writer.
    119 func (f *Feed) WriteRss(w io.Writer) error {
    120 	return WriteXML(&Rss{f}, w)
    121 }
    122 
    123 // ToJSON creates a JSON Feed representation of this feed
    124 func (f *Feed) ToJSON() (string, error) {
    125 	j := &JSON{f}
    126 	return j.ToJSON()
    127 }
    128 
    129 // WriteJSON writes an JSON representation of this feed to the writer.
    130 func (f *Feed) WriteJSON(w io.Writer) error {
    131 	j := &JSON{f}
    132 	feed := j.JSONFeed()
    133 
    134 	e := json.NewEncoder(w)
    135 	e.SetIndent("", "  ")
    136 	return e.Encode(feed)
    137 }
    138 
    139 // Sort sorts the Items in the feed with the given less function.
    140 func (f *Feed) Sort(less func(a, b *Item) bool) {
    141 	lessFunc := func(i, j int) bool {
    142 		return less(f.Items[i], f.Items[j])
    143 	}
    144 	sort.SliceStable(f.Items, lessFunc)
    145 }