Meta tags creation: rules and default values

Property Default value Overridable
og:site_name site name from Joomla! global configuration
og:url the url is generated by the component router
og:locale the page language
og:type article overridable by video (website wil be soon available for multi-items views) yes
og:title will use the 68 first characters of the article title yes
og:description will use the 200 first characters of the article text yes
og:image will use the article images. full + html, intro + html, or html (plugin conf.) yes
og:image:width automatic from og:image -
og:image:height automatic from og:image -
og:image:type automatic from og:image -
og:video only available manually yes
og:video:url automatic from og:video -
og:video:secure_url automatic from og:video -
og:video:type semi-automatic from og:video with fetch button yes
og:video:width semi-automatic from og:video with fetch button yes
og:video:height semi-automatic from og:video with fetch button yes
og:see_also only available manually (article selector to link related items) yes
og:updated_time automatic from object table modified in ISO8601
article:author socialmeta configuration (fig.2-4) overridable in contact view
article:expiration_time automatic from object table publish_down in ISO8601
article:modified_time automatic from object table modified in ISO8601
article:published_time automatic from object table publish_up in ISO8601
article:publisher socialmeta configuration (fig.2-5)
article:section automatic from object table catid
article:tag automatic from object table getItemTags(**id**)
fb:app_id socialmeta configuration (fig.2-2)
fb:admins socialmeta configuration (fig.2-3)
twitter:card idem og:type (article == summary_large_image) (video == player)
twitter:site socialmeta configuration (fig.2-6) overridable in contact view
twitter:player idem og:video yes
twitter:player:width idem og:video:width yes
twitter:player:height idem og:video:height yes