Add SEO improvements: canonical, hreflang, schema fixes, robots.txt

- Fix breadcrumb schema position bug (3 → 2) for Google Rich Results
- Override article/post schemas to use post image instead of site logo
- Fix og:type to emit "article" on post pages with published/modified times
- Add canonical link and hreflang alternate tags (incl. x-default) for bilingual site
- Add organizationName/organizationLogo params for valid Organization schema
- Add robots.txt with sitemap pointer
- Add preconnect hint for analytics host

layouts/partials/head_custom.html

@@ -1,3 +1,11 @@
+    <link rel="canonical" href="{{ .Permalink }}" />
+    {{ if .IsTranslated }}
+    {{ range .AllTranslations }}
+    <link rel="alternate" hreflang="{{ .Lang }}" href="{{ .Permalink }}" />
+    {{ end }}
+    {{ range .AllTranslations }}{{ if eq .Lang "en" }}<link rel="alternate" hreflang="x-default" href="{{ .Permalink }}" />{{ end }}{{ end }}
+    {{ end }}
+    <link rel="preconnect" href="https://pythagore.p0m.fr" />
     <script async defer data-website-id="714f2f10-3a65-4c5b-971f-7cea9eac1ecd" src="https://pythagore.p0m.fr/pythagore.js"></script>
     <link rel="stylesheet" href="{{ "css/custom.css" | absURL }}" />
     <style>

layouts/partials/header.html

@@ -90,14 +90,15 @@
 
     {{ if $thumbs }}
     <div class="container">
-      {{range $i, $thumb := $thumbs}}
-      <a href="{{ $thumb.link | absURL }}" target="_blank">
-        <div class="thumbApp" style="background-image:url('{{ $thumb.src | absURL }}')">
-          {{ if $thumb.desc }}<p><span>{{ $thumb.desc }}</span></p>{{end}}
-        </div>
-      </a>
-      {{ end }}
-      <span style="clear:both; display: block"></span>
+      <div class="thumbApps">
+        {{range $i, $thumb := $thumbs}}
+        <a href="{{ $thumb.link | absURL }}" target="_blank">
+          <div class="thumbApp" style="background-image:url('{{ $thumb.src | absURL }}')">
+            {{ if $thumb.desc }}<p><span>{{ $thumb.desc }}</span></p>{{end}}
+          </div>
+        </a>
+        {{ end }}
+      </div>
       <hr class="small">
     </div>
     {{ end }}

layouts/partials/seo/opengraph.html

@@ -0,0 +1,21 @@
+{{- with .Title | default .Site.Title }}
+<meta property="og:title" content="{{ . }}" />
+{{- end }}
+{{- with .Description | default .Params.subtitle | default .Summary }}
+<meta property="og:description" content="{{ . }}">
+{{- end }}
+{{- with .Params.share_img | default .Params.image | default .Site.Params.logo }}
+<meta property="og:image" content="{{ . | absURL }}" />
+{{- end }}
+{{- with .Site.Params.fb_app_id }}
+<meta property="fb:app_id" content="{{ . }}" />
+{{- end }}
+<meta property="og:url" content="{{ .Permalink | absLangURL }}" />
+{{- if .IsPage }}
+<meta property="og:type" content="article" />
+{{- with .PublishDate }}<meta property="article:published_time" content="{{ .Format "2006-01-02T15:04:05Z07:00" }}" />{{- end }}
+{{- with .Lastmod }}<meta property="article:modified_time" content="{{ .Format "2006-01-02T15:04:05Z07:00" }}" />{{- end }}
+{{- else }}
+<meta property="og:type" content="website" />
+{{- end }}
+<meta property="og:site_name" content="{{ .Site.Title }}" />

layouts/partials/seo/structured/article.html

@@ -0,0 +1,28 @@
+<script type="application/ld+json">
+{
+  "@context": "http://schema.org",
+  "@type": "Article",
+  "author": {
+    "name" : "{{ if .Params.author -}}{{ .Params.author }}{{- else if .Site.Params.author.name -}}{{ .Site.Params.author.name }}{{- end }}"
+  },
+  "headline": "{{ .Title }}",
+  "description" : "{{ if .Description }}{{ .Description | plainify }}{{ else }}{{if .IsPage}}{{ .Summary | plainify  }}{{ end }}{{ end }}",
+  "inLanguage" : "{{ .Lang }}",
+  "wordCount": {{ .WordCount }},
+  "datePublished" : "{{ .PublishDate.Format "2006-01-02T15:04:05-07:00" }}",
+  "dateModified" : "{{ .Lastmod.Format "2006-01-02T15:04:05-07:00"  }}",
+  "image" : "{{ .Params.share_img | default .Params.image | default .Site.Params.logo | absURL }}",
+  "keywords" : [ "{{ range $i, $e := .Params.tags }}{{ if $i }}, {{ end }}{{ $e }}{{ end }}" ],
+  "mainEntityOfPage" : "{{ .Permalink }}",
+  "publisher" : {
+    "@type": "Organization",
+    "name" : "{{ .Site.BaseURL }}",
+    "logo" : {
+        "@type" : "ImageObject",
+        "url" : "{{ .Site.Params.logo | absURL }}",
+        "height" :  60 ,
+        "width" :  60
+    }
+  }
+}
+</script>

layouts/partials/seo/structured/breadcrumb.html

@@ -0,0 +1,21 @@
+<script type="application/ld+json">
+{
+  "@context": "http://schema.org",
+  "@type": "BreadcrumbList",
+  "itemListElement": [{
+        "@type": "ListItem",
+        "position": 1,
+        "item": {
+          "@id": "{{ .Site.BaseURL }}",
+          "name": "home"
+        }
+    },{
+        "@type": "ListItem",
+        "position": 2,
+        "item": {
+          "@id": "{{ .Permalink }}",
+          "name": "{{ .Title | humanize }}"
+        }
+    }]
+}
+</script>

layouts/partials/seo/structured/post.html

@@ -0,0 +1,47 @@
+<script type="application/ld+json"> {
+  "@context" : "http://schema.org",
+  "@type" : "BlogPosting",
+  {{ if .Params.categories }}{{ range .Params.categories }}"articleSection" : "{{ . }}",{{ end }}{{ end }}
+  "name" : "{{ .Title | safeJS }}",
+  "headline" : "{{ .Title | safeJS }}",
+  "mainEntityOfPage": {
+    "@type": "WebPage",
+    "@id": "{{ .Permalink }}"
+  },
+  "description" : "{{ if .Description }}{{ .Description | plainify }}{{ else }}{{if .IsPage}}{{ .Summary | plainify  }}{{ end }}{{ end }}",
+  "inLanguage" : "{{ .Lang }}",
+  {{ if .Params.author -}}
+    "author": {
+      "@type": "Person",
+      "name": "{{ .Params.author }}"
+  },
+  {{- else if .Site.Params.author.name -}}
+    "author": {
+      "@type": "Person",
+      "name": "{{ .Site.Params.author.name }}"
+  },
+  {{- end }}
+  "copyrightYear" : "{{ .Site.Params.since }} - {{ .Site.Lastmod.Format "2006" }}",
+  {{ if not .PublishDate.IsZero -}}
+    "datePublished": "{{ .PublishDate.Format "2006-01-02T15:04:05-07:00" | safeHTML }}",
+  {{- else if not .Date.IsZero -}}
+    "datePublished": "{{ .Date.Format "2006-01-02T15:04:05-07:00" | safeHTML }}",
+  {{- end }}
+  {{ with .Lastmod -}}
+    "dateModified": "{{ .Format "2006-01-02T15:04:05-07:00" | safeHTML }}",
+  {{- end }}
+  "url" : "{{ .Permalink }}",
+  "wordCount" : "{{ .WordCount }}",
+  "image" : "{{ .Params.share_img | default .Params.image | default .Site.Params.logo | absURL }}",
+  "keywords" : [ "{{ range $i, $e := .Params.tags }}{{ if $i }}, {{ end }}{{ $e }}{{ end }}" ],
+  "publisher" : {
+    "@type": "Organization",
+    "name" : "{{ .Site.BaseURL }}",
+    "logo" : {
+        "@type" : "ImageObject",
+        "url" : "{{ .Site.Params.logo | absURL }}",
+        "height" :  60 ,
+        "width" :  60
+    }
+  }
+} </script>