add opengraph meta

7 files changed, 50 insertions, 25 deletions

diff --git a/src/HW/logscale-calc-tools/document.en.rest.txt b/src/HW/logscale-calc-tools/document.en.rest.txt
index cec42f7..095508f 100644
--- a/src/HW/logscale-calc-tools/document.en.rest.txt
+++ b/src/HW/logscale-calc-tools/document.en.rest.txt
@@ -78,7 +78,7 @@ Linear rule:
 
    .. image:: s24d4-1.jpg
       :alt: 4 on C scale matching with 24 on D scale
-      :class: twitter
+      :class: preview
 
 2) look with what, on the D scale, matches 1 on the C scale
 
diff --git a/src/HW/logscale-calc-tools/document.it.rest.txt b/src/HW/logscale-calc-tools/document.it.rest.txt
index 9c43b19..5a99b4f 100644
--- a/src/HW/logscale-calc-tools/document.it.rest.txt
+++ b/src/HW/logscale-calc-tools/document.it.rest.txt
@@ -80,7 +80,7 @@ Regolo lineare:
 
    .. image:: s24d4-1.jpg
       :alt: 4 della scala C corrispondente a 24 della scala D
-      :class: twitter
+      :class: preview
 
 2) guardiamo a cosa, sulla scala D, corrisponde 1 della scala C
 
diff --git a/src/modelli/sugihara-impossible-objects/document.en.rest.txt b/src/modelli/sugihara-impossible-objects/document.en.rest.txt
index ba4b166..6b90338 100644
--- a/src/modelli/sugihara-impossible-objects/document.en.rest.txt
+++ b/src/modelli/sugihara-impossible-objects/document.en.rest.txt
@@ -32,7 +32,7 @@ four suits of playing cards:
 
 .. image:: card-suits-plus-pointy-circles-t.jpg
    :target: card-suits-plus-pointy-circles.jpg
-   :class: twitter
+   :class: preview
 
 and this is what they look like from the side:
 
diff --git a/src/modelli/sugihara-impossible-objects/document.it.rest.txt b/src/modelli/sugihara-impossible-objects/document.it.rest.txt
index 7aa64f1..f0ccf0a 100644
--- a/src/modelli/sugihara-impossible-objects/document.it.rest.txt
+++ b/src/modelli/sugihara-impossible-objects/document.it.rest.txt
@@ -33,7 +33,7 @@ e i semi delle carte:
 
 .. image:: card-suits-plus-pointy-circles-t.jpg
    :target: card-suits-plus-pointy-circles.jpg
-   :class: twitter
+   :class: preview
 
 di lato sono così:
 
diff --git a/src/modelli/tachikoma/document.en.rest.txt b/src/modelli/tachikoma/document.en.rest.txt
index c9bdb0a..cd7406d 100644
--- a/src/modelli/tachikoma/document.en.rest.txt
+++ b/src/modelli/tachikoma/document.en.rest.txt
@@ -26,7 +26,7 @@ Was it worth it? See for yourself:
 .. image:: front-t.jpg
    :alt: LEGO Tachikoma, from ahead
    :target: front.jpg
-   :class: twitter
+   :class: preview
 
 .. image:: back-t.jpg
    :alt: LEGO Tachikoma, from behind
diff --git a/src/modelli/tachikoma/document.it.rest.txt b/src/modelli/tachikoma/document.it.rest.txt
index bedebb8..4a772bd 100644
--- a/src/modelli/tachikoma/document.it.rest.txt
+++ b/src/modelli/tachikoma/document.it.rest.txt
@@ -27,7 +27,7 @@ Ne è valsa la pena? Guardate qua:
 .. image:: front-t.jpg
    :alt: Tachikoma LEGO, da davanti
    :target: front.jpg
-   :class: twitter
+   :class: preview
 
 .. image:: back-t.jpg
    :alt: Tachikoma LEGO, da dietro
diff --git a/templates/du2html.xsl b/templates/du2html.xsl
index 6f77e4c..fccee23 100644
--- a/templates/du2html.xsl
+++ b/templates/du2html.xsl
@@ -17,6 +17,14 @@
  <x:param name="path"/>
  <x:param name="filename"/>
 
+ <x:variable name="locale">
+  <x:choose>
+   <x:when test="$language = 'it'">it_IT</x:when>
+   <x:when test="$language = 'en'">en_GB</x:when>
+   <x:otherwise><!-- uh? --><x:value-of select="$language"/></x:otherwise>
+  </x:choose>
+ </x:variable>
+
  <x:variable name="langs-rtf">
   <x:choose>
    <x:when test="$language = 'it'">
@@ -160,15 +168,37 @@
   <link rel="alternate" type="application/atom+xml" href="{$url}feed.{$language}.xml"/>
  </x:template>
 
- <x:template match="image[contains(concat(' ',normalize-space(string(@classes)),' '),' twitter ')]" mode="twitter-card">
+ <x:template match="image[contains(concat(' ',normalize-space(string(@classes)),' '),' preview ')]" mode="og-meta">
   <x:variable name="uri-with-slash" select="wc:dst-uri-for(@uri,/document/@source)" />
   <!-- dst-uri-for appends a / at the end :( -->
-  <meta name="twitter:image" content="https://www.thenautilus.net{substring($uri-with-slash,1,string-length($uri-with-slash) - 1)}" />
+  <x:variable name="uri" select="substring($uri-with-slash,1,string-length($uri-with-slash) - 1)" />
+  <meta name="twitter:image" content="https://www.thenautilus.net{$uri}" />
   <x:if test="@alt">
    <meta name="twitter:image:alt" content="{@alt}" />
   </x:if>
+  <meta name="og:image" content="https://www.thenautilus.net{$uri}" />
+  <x:if test="@alt">
+   <meta name="og:image:alt" content="{@alt}" />
+  </x:if>
+ </x:template>
+ <x:template match="image" mode="og-meta" priority="-1" />
+
+ <x:template match="/document" mode="og-description">
+  <x:choose>
+   <x:when test="subtitle">
+    <x:value-of select="normalize-space(subtitle)" />
+   </x:when>
+   <x:otherwise>
+    <x:variable name="content">
+     <x:apply-templates/>
+    </x:variable>
+    <x:value-of select="substring(normalize-space($content),0,200)"/>
+    <x:if test="string-length(normalize-space($content)) &gt; 200">
+     <x:text>…</x:text>
+    </x:if>
+   </x:otherwise>
+  </x:choose>
  </x:template>
- <x:template match="image" mode="twitter-card" priority="-1" />
 
  <x:template match="video">
   <video controls="true" playsinline="true">
@@ -193,7 +223,7 @@
 
  <x:template match="/document">
   <html xml:lang="{$language}" lang="{$language}">
-   <head>
+   <head prefix="og: https://ogp.me/ns#">
     <title><x:value-of select="normalize-space(title)"/></title>
     <x:apply-templates select="." mode="stylesheet" />
     <link rel="icon" type="image/png" href="/favicon.png" />
@@ -205,25 +235,20 @@
     <meta name="twitter:card" content="summary" />
     <meta name="twitter:site" content="@dakkar" />
     <meta name="twitter:title" content="{normalize-space(title)}" />
-    <x:apply-templates select="//image" mode="twitter-card" />
+    <meta name="og:site_name" content="the Nautilus" />
+    <meta name="og:title" content="{normalize-space(title)}" />
+    <x:apply-templates select="//image" mode="og-meta" />
     <meta name="twitter:description">
      <x:attribute name="content">
-      <x:choose>
-       <x:when test="subtitle">
-        <x:value-of select="normalize-space(subtitle)" />
-       </x:when>
-       <x:otherwise>
-        <x:variable name="content">
-         <x:apply-templates/>
-        </x:variable>
-        <x:value-of select="substring(normalize-space($content),0,200)"/>
-        <x:if test="string-length(normalize-space($content)) &gt; 200">
-         <x:text>…</x:text>
-        </x:if>
-       </x:otherwise>
-      </x:choose>
+      <x:apply-templates mode="og-description" />
+     </x:attribute>
+    </meta>
+    <meta name="og:description">
+     <x:attribute name="content">
+      <x:apply-templates mode="og-description" />
      </x:attribute>
     </meta>
+    <meta name="og:locale" content="{$locale}" />
    </head>
    <body>
     <div id="wrapper">