hugo-theme-bootstrap4-blog/layouts/partials/opengraph.html

<meta property="og:title" content="{{ .Title }}" />
<meta property="og:description" content="{{ with .Description }}{{ . }}{{ else }}{{if .IsPage}}{{ .Summary }}{{ else }}{{ with .Site.Params.description }}{{ . }}{{ end }}{{ end }}{{ end }}" />
<meta property="og:type" content="{{ if .IsPage }}article{{ else }}website{{ end }}" />
<meta property="og:url" content="{{ .Permalink }}" />
{{ with .Params.images }}{{ range first 6 . }}
  <meta property="og:image" content="{{ . | absURL }}" />
{{ end }}{{ end }}

{{ if .IsPage }}
{{ if not .Date.IsZero }}<meta property="article:published_time" content="{{ .Date.Format "2006-01-02T15:04:05-07:00" | safeHTML }}"/>{{ end }}
{{ if not .Lastmod.IsZero }}<meta property="article:modified_time" content="{{ .Lastmod.Format "2006-01-02T15:04:05-07:00" | safeHTML }}"/>{{ end }}
{{ else }}
{{ if not .Site.LastChange.IsZero }}<meta property="og:updated_time" content="{{ .Date.Format "2006-01-02T15:04:05-07:00" | safeHTML }}"/>{{ end }}
{{ end }}{{ with .Params.audio }}
<meta property="og:audio" content="{{ . }}" />{{ end }}{{ with .Params.locale }}
<meta property="og:locale" content="{{ . }}" />{{ end }}{{ with .Site.Params.title }}
<meta property="og:site_name" content="{{ . }}" />{{ end }}{{ with .Params.videos }}
{{ range .Params.videos }}
  <meta property="og:video" content="{{ . | absURL }}" />
{{ end }}{{ end }}

<!-- If it is part of a series, link to related articles -->
{{ $permalink := .Permalink }}
{{ $siteSeries := .Site.Taxonomies.series }}{{ with .Params.series }}
{{ range $name := . }}
  {{ $series := index $siteSeries $name }}
  {{ range $page := first 6 $series.Pages }}
    {{ if ne $page.Permalink $permalink }}<meta property="og:see_also" content="{{ $page.Permalink }}" />{{ end }}
  {{ end }}
{{ end }}{{ end }}

{{ if .IsPage }}
{{ range .Site.Authors }}{{ with .Social.facebook }}
<meta property="article:author" content="https://www.facebook.com/{{ . }}" />{{ end }}{{ with .Site.Social.facebook }}
<meta property="article:publisher" content="https://www.facebook.com/{{ . }}" />{{ end }}
<meta property="article:published_time" content="{{ .PublishDate }}" />
<meta property="article:modified_time" content="{{ .Date }}" />
<meta property="article:section" content="{{ .Section }}" />
{{ with .Params.tags }}{{ range first 6 . }}
  <meta property="article:tag" content="{{ . }}" />{{ end }}{{ end }}
{{ end }}{{ end }}

<!-- Facebook Page Admin ID for Domain Insights -->
{{ with .Site.Social.facebook_admin }}<meta property="fb:admins" content="{{ . }}" />{{ end }}