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fix: normalize protocol-relative URLs in unfurl thumbnail URLs
Streamable and other providers return protocol-relative URLs (//cdn.example.com)
in their oEmbed thumbnail_url field. These fail when passed to the blob service
because http.NewRequest requires a full URL with scheme.
Fix:
- Add normalizeURL() helper to convert // → https://
- Apply to both oEmbed and OpenGraph thumbnail URLs
- Add comprehensive tests (6 test cases)
Example transformation:
//cdn-cf-east.streamable.com/image/abc.jpg
→ https://cdn-cf-east.streamable.com/image/abc.jpg
This ensures Streamable video thumbnails are properly downloaded and uploaded
as blobs, fixing missing thumbnails in video embeds.
Affects: All users posting Streamable/YouTube/Reddit links (not Kagi-specific)
Tested: Unit tests pass, build successful
+13
-2
internal/core/unfurl/providers.go
+13
-2
internal/core/unfurl/providers.go
···
106
return &oembed, nil
107
}
108
109
// mapOEmbedToResult converts oEmbed response to UnfurlResult
110
func mapOEmbedToResult(oembed *oEmbedResponse, originalURL string) *UnfurlResult {
111
result := &UnfurlResult{
112
URI: originalURL,
113
Title: oembed.Title,
114
Description: oembed.Description,
115
-
ThumbnailURL: oembed.ThumbnailURL,
116
Provider: strings.ToLower(oembed.ProviderName),
117
Domain: extractDomain(originalURL),
118
Width: oembed.Width,
···
186
URI: urlStr,
187
Title: og.Title,
188
Description: og.Description,
189
-
ThumbnailURL: og.Image,
190
Provider: "opengraph",
191
Domain: extractDomain(urlStr),
192
}
···
106
return &oembed, nil
107
}
108
109
+
// normalizeURL converts protocol-relative URLs to HTTPS
110
+
// Examples:
111
+
// "//example.com/image.jpg" -> "https://example.com/image.jpg"
112
+
// "https://example.com/image.jpg" -> "https://example.com/image.jpg" (unchanged)
113
+
func normalizeURL(urlStr string) string {
114
+
if strings.HasPrefix(urlStr, "//") {
115
+
return "https:" + urlStr
116
+
}
117
+
return urlStr
118
+
}
119
+
120
// mapOEmbedToResult converts oEmbed response to UnfurlResult
121
func mapOEmbedToResult(oembed *oEmbedResponse, originalURL string) *UnfurlResult {
122
result := &UnfurlResult{
123
URI: originalURL,
124
Title: oembed.Title,
125
Description: oembed.Description,
126
+
ThumbnailURL: normalizeURL(oembed.ThumbnailURL),
127
Provider: strings.ToLower(oembed.ProviderName),
128
Domain: extractDomain(originalURL),
129
Width: oembed.Width,
···
197
URI: urlStr,
198
Title: og.Title,
199
Description: og.Description,
200
+
ThumbnailURL: normalizeURL(og.Image),
201
Provider: "opengraph",
202
Domain: extractDomain(urlStr),
203
}
+54
internal/core/unfurl/providers_test.go
+54
internal/core/unfurl/providers_test.go
···
···
1
+
package unfurl
2
+
3
+
import (
4
+
"testing"
5
+
6
+
"github.com/stretchr/testify/assert"
7
+
)
8
+
9
+
func TestNormalizeURL(t *testing.T) {
10
+
tests := []struct {
11
+
name string
12
+
input string
13
+
expected string
14
+
}{
15
+
{
16
+
name: "protocol-relative URL",
17
+
input: "//cdn.example.com/image.jpg",
18
+
expected: "https://cdn.example.com/image.jpg",
19
+
},
20
+
{
21
+
name: "https URL unchanged",
22
+
input: "https://example.com/image.jpg",
23
+
expected: "https://example.com/image.jpg",
24
+
},
25
+
{
26
+
name: "http URL unchanged",
27
+
input: "http://example.com/image.jpg",
28
+
expected: "http://example.com/image.jpg",
29
+
},
30
+
{
31
+
name: "empty string",
32
+
input: "",
33
+
expected: "",
34
+
},
35
+
{
36
+
name: "protocol-relative with query params",
37
+
input: "//cdn.example.com/image.jpg?width=500&height=300",
38
+
expected: "https://cdn.example.com/image.jpg?width=500&height=300",
39
+
},
40
+
{
41
+
name: "real Streamable URL",
42
+
input: "//cdn-cf-east.streamable.com/image/7kpdft.jpg?Expires=1762932720",
43
+
expected: "https://cdn-cf-east.streamable.com/image/7kpdft.jpg?Expires=1762932720",
44
+
},
45
+
}
46
+
47
+
for _, tt := range tests {
48
+
t.Run(tt.name, func(t *testing.T) {
49
+
result := normalizeURL(tt.input)
50
+
assert.Equal(t, tt.expected, result)
51
+
})
52
+
}
53
+
}
54
+