blob: 8828e59b04585761f28bfafb62a0ed1f9c19965e (
plain)
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
|
package ogtags
import (
"strings"
"golang.org/x/net/html"
)
// extractOGTags traverses the HTML document and extracts approved Open Graph tags
func (c *OGTagCache) extractOGTags(doc *html.Node) map[string]string {
ogTags := make(map[string]string)
var traverseNodes func(*html.Node)
traverseNodes = func(n *html.Node) {
// isOGMetaTag only checks if it's a <meta> tag.
// The actual filtering happens in extractMetaTagInfo now.
if isOGMetaTag(n) {
property, content := c.extractMetaTagInfo(n)
if property != "" {
ogTags[property] = content
}
}
for child := n.FirstChild; child != nil; child = child.NextSibling {
traverseNodes(child)
}
}
traverseNodes(doc)
return ogTags
}
// isOGMetaTag checks if a node is *any* meta tag
func isOGMetaTag(n *html.Node) bool {
if n == nil {
return false
}
return n.Type == html.ElementNode && n.Data == "meta"
}
// extractMetaTagInfo extracts property and content from a meta tag
// *and* checks if the property is approved.
// Returns empty property string if the tag is not approved.
func (c *OGTagCache) extractMetaTagInfo(n *html.Node) (property, content string) {
var rawProperty string // Store the property found before approval check
for _, attr := range n.Attr {
if attr.Key == "property" || attr.Key == "name" {
rawProperty = attr.Val
}
if attr.Key == "content" {
content = attr.Val
}
}
// Check if the rawProperty is approved
isApproved := false
for _, prefix := range c.approvedPrefixes {
if strings.HasPrefix(rawProperty, prefix) {
isApproved = true
break
}
}
// Check exact approved tags if not already approved by prefix
if !isApproved {
for _, tag := range c.approvedTags {
if rawProperty == tag {
isApproved = true
break
}
}
}
// Only return the property if it's approved
if isApproved {
property = rawProperty
}
// Content is returned regardless, but property will be "" if not approved
return property, content
}
|
