forked from nkanaev/yarr
/
feed.go
170 lines (149 loc) · 3.85 KB
/
feed.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
package parser
import (
"bytes"
"encoding/xml"
"errors"
"fmt"
"io"
"net/url"
"strings"
"time"
"github.com/mzfr/yarr/src/content/htmlutil"
"golang.org/x/net/html/charset"
)
var UnknownFormat = errors.New("unknown feed format")
type feedProbe struct {
feedType string
callback func(r io.Reader) (*Feed, error)
encoding string
}
func sniff(lookup string) (out feedProbe) {
lookup = strings.TrimSpace(lookup)
lookup = strings.TrimLeft(lookup, "\x00\xEF\xBB\xBF\xFE\xFF")
if len(lookup) == 0 {
return
}
switch lookup[0] {
case '<':
decoder := xmlDecoder(strings.NewReader(lookup))
for {
token, _ := decoder.Token()
if token == nil {
break
}
// check <?xml encoding="ENCODING" ?>
if el, ok := token.(xml.ProcInst); ok && el.Target == "xml" {
out.encoding = strings.ToLower(procInst("encoding", string(el.Inst)))
}
if el, ok := token.(xml.StartElement); ok {
switch el.Name.Local {
case "rss":
out.feedType = "rss"
out.callback = ParseRSS
return
case "RDF":
out.feedType = "rdf"
out.callback = ParseRDF
return
case "feed":
out.feedType = "atom"
out.callback = ParseAtom
return
}
}
}
case '{':
out.feedType = "json"
out.callback = ParseJSON
return
}
return
}
func Parse(r io.Reader) (*Feed, error) {
return ParseWithEncoding(r, "")
}
func ParseWithEncoding(r io.Reader, fallbackEncoding string) (*Feed, error) {
lookup := make([]byte, 2048)
n, err := io.ReadFull(r, lookup)
switch {
case err == io.ErrUnexpectedEOF:
lookup = lookup[:n]
r = bytes.NewReader(lookup)
case err != nil:
return nil, err
default:
r = io.MultiReader(bytes.NewReader(lookup), r)
}
out := sniff(string(lookup))
if out.feedType == "" {
return nil, UnknownFormat
}
if out.encoding == "" && fallbackEncoding != "" {
r, err = charset.NewReaderLabel(fallbackEncoding, r)
if err != nil {
return nil, err
}
}
if (out.feedType != "json") && (out.encoding == "" || out.encoding == "utf-8") {
// XML decoder will not rely on custom CharsetReader (see `xmlDecoder`)
// to handle invalid xml characters.
// Assume input is already UTF-8 and do the cleanup here.
r = NewSafeXMLReader(r)
}
feed, err := out.callback(r)
if feed != nil {
feed.cleanup()
}
return feed, err
}
func ParseAndFix(r io.Reader, baseURL, fallbackEncoding string) (*Feed, error) {
feed, err := ParseWithEncoding(r, fallbackEncoding)
if err != nil {
return nil, err
}
feed.TranslateURLs(baseURL)
feed.SetMissingDatesTo(time.Now())
return feed, nil
}
func (feed *Feed) cleanup() {
feed.Title = strings.TrimSpace(feed.Title)
feed.SiteURL = strings.TrimSpace(feed.SiteURL)
for i, item := range feed.Items {
feed.Items[i].GUID = strings.TrimSpace(item.GUID)
feed.Items[i].URL = strings.TrimSpace(item.URL)
feed.Items[i].Title = strings.TrimSpace(htmlutil.ExtractText(item.Title))
feed.Items[i].Content = strings.TrimSpace(item.Content)
if item.ImageURL != "" && strings.Contains(item.Content, item.ImageURL) {
feed.Items[i].ImageURL = ""
}
if item.AudioURL != "" && strings.Contains(item.Content, item.AudioURL) {
feed.Items[i].AudioURL = ""
}
}
}
func (feed *Feed) SetMissingDatesTo(newdate time.Time) {
for i, item := range feed.Items {
if item.Date.IsZero() {
feed.Items[i].Date = newdate
}
}
}
func (feed *Feed) TranslateURLs(base string) error {
baseUrl, err := url.Parse(base)
if err != nil {
return fmt.Errorf("failed to parse base url: %#v", base)
}
siteUrl, err := url.Parse(feed.SiteURL)
if err != nil {
return fmt.Errorf("failed to parse feed url: %#v", feed.SiteURL)
}
feed.SiteURL = baseUrl.ResolveReference(siteUrl).String()
for _, item := range feed.Items {
itemUrl, err := url.Parse(item.URL)
if err != nil {
return fmt.Errorf("failed to parse item url: %#v", item.URL)
}
item.URL = siteUrl.ResolveReference(itemUrl).String()
}
return nil
}