/
seo_tag.go
244 lines (210 loc) · 7.16 KB
/
seo_tag.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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
package plugins
import (
"bytes"
"fmt"
"text/template"
"github.com/osteele/gojekyll/utils"
"github.com/osteele/liquid"
"github.com/osteele/liquid/render"
"github.com/osteele/liquid/tags"
"github.com/tdewolff/minify"
"github.com/tdewolff/minify/html"
)
type jekyllSEOTagPlugin struct {
plugin
site Site
tpl *liquid.Template
}
func init() {
register("jekyll-seo-tag", &jekyllSEOTagPlugin{})
}
func (p *jekyllSEOTagPlugin) AfterInitSite(s Site) error {
p.site = s
return nil
}
func (p *jekyllSEOTagPlugin) ConfigureTemplateEngine(e *liquid.Engine) error {
e.RegisterTag("seo", p.seoTag)
tpl, err := e.ParseTemplate([]byte(seoTagTemplateSource))
if err != nil {
panic(err)
}
p.tpl = tpl
return nil
}
func (p *jekyllSEOTagPlugin) seoTag(ctx render.Context) (string, error) {
buf := new(bytes.Buffer)
e := seoTagTemplate.Execute(buf, seoTag{p.tpl, ctx})
return buf.String(), e
}
type seoTag struct {
tpl *liquid.Template
ctx render.Context
}
var seoSiteFields = []string{"url", "twitter", "facebook", "logo", "social", "google_site_verification", "lang"}
var seoPageOrSiteFields = []string{"author", "description", "image", "author", "lang"}
func (p seoTag) TagBody() (string, error) {
var (
ctx = p.ctx
site = liquid.FromDrop(ctx.Get("site")).(tags.IterationKeyedMap)
page = liquid.FromDrop(ctx.Get("page")).(tags.IterationKeyedMap)
pageTitle = page["title"]
siteTitle = site["title"]
canonicalURL = fmt.Sprintf("%s%s", site["url"], page["url"])
)
if siteTitle == nil {
siteTitle = site["name"]
}
seoTag := map[string]interface{}{
"title?": true,
"title": siteTitle,
// the following are not doc'ed, but evident from inspection:
// FIXME canonical w|w/out site.url and site.prefix
"canonical_url": canonicalURL,
"page_lang": "en_US",
"page_title": pageTitle,
"site_title": siteTitle,
}
copyFields(seoTag, site, append(seoSiteFields, seoPageOrSiteFields...))
copyFields(seoTag, page, seoPageOrSiteFields)
// seoTag["description"] = page["excerpt"] FIXME appears to behave something like following, but excerpt should not be processed
if pageTitle != nil && siteTitle != nil && pageTitle != siteTitle {
seoTag["title"] = fmt.Sprintf("%s | %s", pageTitle, siteTitle)
}
if author, ok := seoTag["author"].(string); ok {
if data, _ := utils.FollowDots(site, []string{"data", "authors", author}); data != nil {
seoTag["author"] = data
}
}
seoTag["json_ld"] = makeJSONLD(seoTag)
bindings := map[string]interface{}{
"page": page,
"site": site,
"seo_tag": seoTag,
}
b, err := p.tpl.Render(bindings)
if err != nil {
return "", err
}
m := minify.New()
m.AddFunc("text/html", html.Minify)
min := bytes.NewBuffer(make([]byte, 0, len(b)))
if err := m.Minify("text/html", min, bytes.NewBuffer(b)); err != nil {
return "", err
}
return min.String(), nil
}
func copyFields(to, from map[string]interface{}, fields []string) {
for _, name := range fields {
if value := from[name]; value != nil {
to[name] = value
}
}
}
func makeJSONLD(seoTag map[string]interface{}) interface{} {
jsonLD := map[string]interface{}{
// TODO dateModified, datePublished, publisher, mainEntityOfPage
"@context": "http://schema.org",
"@type": "WebPage", // FIXME this is BlogPosting for a blog page
"headline": seoTag["page_title"],
"description": seoTag["description"],
"url": seoTag["canonical_url"],
}
if author := seoTag["author"]; author != nil {
if m, ok := author.(map[string]interface{}); ok {
author = m["name"]
}
jsonLD["author"] = map[string]interface{}{
"@type": "Person",
"name": author,
}
}
return jsonLD
}
// This is a separate template so it isn't minimized away.
var seoTagTemplate = template.Must(template.New("SEO tag").Parse(
`<!-- Begin Jekyll SEO tag -->
{{.TagBody}}
<!-- End Jekyll SEO tag -->`))
// Taken verbatim from https://github.com/jekyll/jekyll-seo-tag/
// Adapted from github.com/jekyll/jekyll-seo-tag. Used according to the MIT License.
const seoTagTemplateSource = `{% if seo_tag.title? %}
<title>{{ seo_tag.title }}</title>
{% endif %}
{% if seo_tag.page_title %}
<meta property="og:title" content="{{ seo_tag.page_title }}" />
{% endif %}
{% if seo_tag.author.name %}
<meta name="author" content="{{ seo_tag.author.name }}" />
{% endif %}
<meta property="og:locale" content="{{ seo_tag.page_lang | replace:'-','_' }}" />
{% if seo_tag.description %}
<meta name="description" content="{{ seo_tag.description }}" />
<meta property="og:description" content="{{ seo_tag.description }}" />
{% endif %}
{% if site.url %}
<link rel="canonical" href="{{ seo_tag.canonical_url }}" />
<meta property="og:url" content="{{ seo_tag.canonical_url }}" />
{% endif %}
{% if seo_tag.site_title %}
<meta property="og:site_name" content="{{ seo_tag.site_title }}" />
{% endif %}
{% if seo_tag.image %}
<meta property="og:image" content="{{ seo_tag.image.path }}" />
{% if seo_tag.image.height %}
<meta property="og:image:height" content="{{ seo_tag.image.height }}" />
{% endif %}
{% if seo_tag.image.width %}
<meta property="og:image:width" content="{{ seo_tag.image.width }}" />
{% endif %}
{% endif %}
{% if page.date %}
<meta property="og:type" content="article" />
<meta property="article:published_time" content="{{ page.date | date_to_xmlschema }}" />
{% endif %}
{% if paginator.previous_page %}
<link rel="prev" href="{{ paginator.previous_page_path | absolute_url }}">
{% endif %}
{% if paginator.next_page %}
<link rel="next" href="{{ paginator.next_page_path | absolute_url }}">
{% endif %}
{% if site.twitter %}
{% if seo_tag.image %}
<meta name="twitter:card" content="summary_large_image" />
{% else %}
<meta name="twitter:card" content="summary" />
{% endif %}
<meta name="twitter:site" content="@{{ site.twitter.username | replace:"@","" }}" />
{% if seo_tag.author.twitter %}
<meta name="twitter:creator" content="@{{ seo_tag.author.twitter }}" />
{% endif %}
{% endif %}
{% if site.facebook %}
{% if site.facebook.admins %}
<meta property="fb:admins" content="{{ site.facebook.admins }}" />
{% endif %}
{% if site.facebook.publisher %}
<meta property="article:publisher" content="{{ site.facebook.publisher }}" />
{% endif %}
{% if site.facebook.app_id %}
<meta property="fb:app_id" content="{{ site.facebook.app_id }}" />
{% endif %}
{% endif %}
{% if site.webmaster_verifications %}
{% if site.webmaster_verifications.google %}
<meta name="google-site-verification" content="{{ site.webmaster_verifications.google }}">
{% endif %}
{% if site.webmaster_verifications.bing %}
<meta name="msvalidate.01" content="{{ site.webmaster_verifications.bing }}">
{% endif %}
{% if site.webmaster_verifications.alexa %}
<meta name="alexaVerifyID" content="{{ site.webmaster_verifications.alexa }}">
{% endif %}
{% if site.webmaster_verifications.yandex %}
<meta name="yandex-verification" content="{{ site.webmaster_verifications.yandex }}">
{% endif %}
{% elsif site.google_site_verification %}
<meta name="google-site-verification" content="{{ site.google_site_verification }}" />
{% endif %}
<script type="application/ld+json">
{{ seo_tag.json_ld | jsonify }}
</script>`