SEO and author fixes (#1456)

* Fix canonical URL
* Fix next/previous page paths
* Group meta types together
* Fix twitter:creator conditional
* Allow `author` to accept an object or string
* Reduce white-space
* Add "website" as default `og:type`
* Add `article:modified_time`
* Show `article:modified_time` on `article` only

Fixes #289

_includes/author-profile.html

@@ -1,8 +1,5 @@
-{% if page.author and site.data.authors[page.author] %}
+{% assign author = page.author | default: page.authors[0] | default: site:author %}
-  {% assign author = site.data.authors[page.author] %}
+{% assign author = site.data.authors[author] | default: author %}
-{% else %}
-  {% assign author = site.author %}
-{% endif %}
 
 <div itemscope itemtype="http://schema.org/Person">
 

_includes/seo.html

@@ -1,76 +1,77 @@
-<!-- begin SEO -->
+<!-- begin _includes/seo.html -->
-{% if site.url %}
+{%- if site.url -%}
-  {% assign seo_url = site.url | append: site.baseurl %}
+  {%- assign seo_url = site.url | append: site.baseurl -%}
-{% endif %}
+{%- endif -%}
-{% assign seo_url = seo_url | default: site.github.url %}
+{%- assign seo_url = seo_url | default: site.github.url -%}
 
-{% if page.title %}
+{%- if page.title -%}
-  {% assign seo_title = page.title | append: " " | append: site.title_separator | append: " " | append: site.title %}
+  {%- assign seo_title = page.title | append: " " | append: site.title_separator | append: " " | append: site.title -%}
-{% endif %}
+{%- endif -%}
 
-{% if seo_title %}
+{%- if seo_title -%}
-  {% assign seo_title = seo_title | markdownify | strip_html | strip_newlines | escape_once %}
+  {%- assign seo_title = seo_title | markdownify | strip_html | strip_newlines | escape_once -%}
-{% endif %}
+{%- endif -%}
 
-{% if site.url %}
+{%- assign canonical_url = page.url | replace: "index.html", "" | absolute_url %}
-  {% assign canonical_url = page.url | replace: "index.html", "" | prepend: site.url %}
+
-{% endif %}
+{%- assign seo_description = page.description | default: page.excerpt | default: site.description -%}
+{%- if seo_description -%}
+  {%- assign seo_description = seo_description | markdownify | strip_html | strip_newlines | escape_once -%}
+{%- endif -%}
+
+{%- assign author = page.author | default: page.authors[0] | default: site:author -%}
+{%- assign author = site.data.authors[author] | default: author -%}
+
+{%- if author.twitter -%}
+  {%- assign author_twitter = author.twitter | replace: "@", "" -%}
+{%- endif -%}
+
+{%- assign page_large_image = page.header.og_image | default: page.header.overlay_image | default: page.header.image -%}
+{%- unless page_large_image contains '://' -%}
+  {%- assign page_large_image = page_large_image | absolute_url -%}
+{%- endunless -%}
+{%- assign page_large_image = page_large_image | escape -%}
+
+{%- assign page_teaser_image = page.header.teaser | default: site.og_image -%}
+{%- unless page_teaser_image contains '://' -%}
+  {%- assign page_teaser_image = page_teaser_image | absolute_url -%}
+{%- endunless -%}
+{%- assign page_teaser_image = page_teaser_image | escape -%}
+
+{%- assign site_og_image = site.og_image -%}
+{%- unless site_og_image contains '://' -%}
+  {%- assign site_og_image = site_og_image | absolute_url -%}
+{%- endunless -%}
+{%- assign site_og_image = site_og_image | escape -%}
+
+{%- if page.date -%}
+  {%- assign og_type = "article" -%}
+{%- else -%}
+  {%- assign og_type = "website" -%}
+{%- endif -%}
 
 <title>{{ seo_title | default: site.title }}{% if paginator %}{% unless paginator.page == 1 %} {{ site.title_separator }} {{ site.data.ui-text[site.locale].page | default: "Page" }} {{ paginator.page }}{% endunless %}{% endif %}</title>
-
-{% assign seo_description = page.description | default: page.excerpt | default: site.description %}
-{% if seo_description %}
-  {% assign seo_description = seo_description | markdownify | strip_html | strip_newlines | escape_once %}
-{% endif %}
-
 <meta name="description" content="{{ seo_description }}">
 
-{% assign seo_author = page.author | default: page.author[0] | default: site.author.name %}
+{% if author.name %}
-{% if seo_author %}
+  <meta name="author" content="{{ author.name | default: author }}">
-  {% if seo_author.twitter %}
-    {% assign seo_author_twitter = seo_author.twitter %}
-  {% else %}
-    {% if site.data.authors and site.data.authors[seo_author] %}
-      {% assign seo_author_twitter = site.data.authors[seo_author].twitter  %}
-    {% else %}
-      {% assign seo_author_twitter = seo_author  %}
-    {% endif %}
-  {% endif %}
-  {% assign seo_author_twitter = seo_author_twitter | replace: "@", "" %}
 {% endif %}
 
-<meta name="author" content="{{ seo_author }}">
+<meta property="og:type" content="{{ og_type }}">
-
 <meta property="og:locale" content="{{ site.locale | replace: "-", "_" | default: "en_US" }}">
 <meta property="og:site_name" content="{{ site.title }}">
 <meta property="og:title" content="{{ page.title | default: site.title | markdownify | strip_html | strip_newlines | escape_once }}">
-
+<meta property="og:url" content="{{ canonical_url }}">
-{% if seo_url %}
-  <link rel="canonical" href="{{ page.url | prepend: seo_url | replace: "/index.html", "/" }}">
-  <meta property="og:url" content="{{ page.url | prepend: seo_url | replace: "/index.html", "/" }}">
-{% endif %}
 
 {% if page.excerpt %}
   <meta property="og:description" content="{{ seo_description }}">
 {% endif %}
 
-{% assign page_large_image = page.header.og_image | default: page.header.overlay_image | default: page.header.image %}
+{% if page_large_image %}
-{% unless page_large_image contains '://' %}
+  <meta property="og:image" content="{{ page_large_image }}">
-  {% assign page_large_image = page_large_image | absolute_url %}
+{% elsif page_teaser_image %}
-{% endunless %}
+  <meta property="og:image" content="{{ page_teaser_image }}">
-{% assign page_large_image = page_large_image | escape %}
+{% endif %}
-
-{% assign page_teaser_image = page.header.teaser | default: site.og_image %}
-{% unless page_teaser_image contains '://' %}
-  {% assign page_teaser_image = page_teaser_image | absolute_url %}
-{% endunless %}
-{% assign page_teaser_image = page_teaser_image | escape %}
-
-{% assign site_og_image = site.og_image %}
-{% unless site_og_image contains '://' %}
-  {% assign site_og_image = site_og_image | absolute_url %}
-{% endunless %}
-{% assign site_og_image = site_og_image | escape %}
 
 {% if site.twitter.username %}
   <meta name="twitter:site" content="@{{ site.twitter.username | replace: "@", "" }}">
@@ -88,11 +89,19 @@
     {% endif %}
   {% endif %}
 
-  {% if seo_author_twitter %}
+  {% if author_twitter %}
-    <meta name="twitter:creator" content="@{{ seo_author_twitter }}">
+    <meta name="twitter:creator" content="@{{ author_twitter }}">
   {% endif %}
 {% endif %}
 
+{% if page.date %}
+  <meta property="article:published_time" content="{{ page.date | date_to_xmlschema }}">
+{% endif %}
+
+{% if og_type == "article" and page.last_modified_at %}
+  <meta property="article:modified_time" content="{{ page.last_modified_at | date_to_xmlschema }}">
+{% endif %}
+
 {% if site.facebook %}
   {% if site.facebook.publisher %}
     <meta property="article:publisher" content="{{ site.facebook.publisher }}">
@@ -103,22 +112,13 @@
   {% endif %}
 {% endif %}
 
-{% if page_large_image %}
+<link rel="canonical" href="{{ canonical_url }}">
-  <meta property="og:image" content="{{ page_large_image }}">
-{% elsif page_teaser_image %}
-  <meta property="og:image" content="{{ page_teaser_image }}">
-{% 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 | prepend: seo_url }}">
+  <link rel="prev" href="{{ paginator.previous_page_path | absolute_url }}">
 {% endif %}
 {% if paginator.next_page %}
-  <link rel="next" href="{{ paginator.next_page_path | prepend: seo_url }}">
+  <link rel="next" href="{{ paginator.next_page_path | absolute_url }}">
 {% endif %}
 
 {% if site.og_image %}
@@ -159,4 +159,4 @@
 {% if site.naver-site-verification %}
   <meta name="naver-site-verification" content="{{ site.naver-site-verification }}">
 {% endif %}
-<!-- end SEO -->
+<!-- end _includes/seo.html -->