Issue 5329 - Added standard social media meta data to website-defaults

includes/meta/social.tmpl

+{# open graph #}
+
+{% if host and page %}
+  <meta property="og:url" content="{{ host }}/{{ page }}">
+{% endif %}
+{% if og_type %}
+  <meta property="og:type" content="{{ og_type }}">
+{% endif %}
+{% if og_site_name %}
+  <meta property="og:site_name" content="{{ og_site_name }}">
+{% endif %}
+{% if og_title %}
+  <meta property="og:title" content="{{ og_title }}">

[juliandoucette, 2017/07/11 12:10:45]

I think I should add a fallback here for social networks that may not fall back
to title.

[ire, 2017/07/12 07:55:19]

I agree.

I may be confused with your term "fallback" here, but isn't this tag supposed to
be the fallback, and the proprietary tags the "enhancement"?

[juliandoucette, 2017/07/12 15:52:38]

I'm suggesting:

if og_title
  og:title = og_title
else if title
  og:title = title

both title and og_title may be set in the frontmatter of pages.

[ire, 2017/07/13 09:39:46]

Ah right. I read your initial statement in the wrong way. What you are
suggesting looks good. 

A thought: are there ever cases where `og_title` would be different from
`title`? If not we may only actually need title. At the same time it could be
useful to have the option to set something different. What do you think?

[juliandoucette, 2017/07/14 11:27:31]

RE: Will title be different than og:title (and alike)

Probably not. But they should be.

Optimizing for search engines is different than optimizing for social media.

Search title
:   `PRIMARY_KEYWORD SECONDARY_KEYWORD | BRAND_NAME` 60 chars
(https://moz.com/learn/seo/title-tag)

Social title
:   `PAGE_HEADING` 40 chars, "A clear title without branding or mentioning the
domain itself." (https://developers.facebook.com/docs/sharing/best-practices)

[juliandoucette, 2017/07/14 11:27:31]

Done.

[ire, 2017/07/17 07:18:22]

Okay makes sense. Thanks.

+{% endif %}
+{% if og_description %}
+  <meta property="og:description" content="{{ og_description }}">

[juliandoucette, 2017/07/11 12:10:45]

I think I should add a fallback here for social networks that may not fall back
to description.

[juliandoucette, 2017/07/14 11:27:31]

Done.

+{% endif %}
+{% if og_image %}
+  <meta property="og:image" content="{{ og_image }}">
+{% else if og_site_image %}
+  <meta property="og:image" content="{{ og_site_image }}">
+{% endif %}
+<meta property="og:locale" content="{{ locale }}">
+{% for alternate_locale in locales %}
+  {% if alternate_locale != locale %}
+    <meta property="og:locale:alternate" content="{{ alternate_locale }}">
+  {% endif %}
+{% endfor %}
+
+{# facebook #}
+
+{% if facebook_id %}
+  <meta property="fb:app_id" content="{{ facebook_id }}">
+{% endif %}
+
+{# twitter #}
+
+{% if twitter_site %}
+  <meta name="twitter:site" content="@{{ twitter_site }}">
+{% endif %}
+{% if twitter_card %}
+  <meta name="twitter:card" content="{{ twitter_card }}">
+{% else if og_image or og_site_image %}
+  <meta name="twitter:card" content="summary_large_image">
+{% else %}
+  <meta name="twitter:card" content="summary">
+{% endif %}
+{% if twitter_image_alt %}
+  <meta name="twitter:image:alt" content="{{ twitter_image_alt }}">
+{% endif %}
+
+{# pinterest #}
+
+{% if pinterest_id %}
+  <meta name="p:domain_verify" content="{{ pinterest_id }}">
+{% endif %}