Integrate OpenGraph and TwitterCard with Sitefinity

Global.Application_Start.cs

protected void Application_Start(object sender, EventArgs e)
{
    Bootstrapper.Initialized += this.BootstrapperInitializedHook;
}

Global.asax.cs

using System;
using Telerik.Sitefinity.Abstractions;
using Telerik.Sitefinity.Data;
using Telerik.Sitefinity.Services;
using Telerik.Sitefinity.Web;
using Telerik.Sitefinity.Web.Events;

public class Global : System.Web.HttpApplication
{
    protected void Application_Start(object sender, EventArgs e)
    {
        Bootstrapper.Initialized += this.BootstrapperInitializedHook;
    }

    private void BootstrapperInitializedHook(object sender, ExecutedEventArgs e)
    {
        if (e.CommandName == "Bootstrapped")
        {
            EventHub.Subscribe<IPagePreRenderCompleteEvent>(evt =>
            {
                var page = evt.Page;
                var siteNode = evt.PageSiteNode;

                page.Header.Controls.Add(new OpenGraphMeta("og:title", page.Title));
                page.Header.Controls.Add(new OpenGraphMeta("og:url", UrlPath.ResolveAbsoluteUrl(siteNode.Url)));
                page.Header.Controls.Add(new TwitterMeta("twitter:title", page.Title));

                // Include additional tags ... 
            });
        }
    }
}

Global.BootstrapperInitializedHook.cs

private void BootstrapperInitializedHook(object sender, ExecutedEventArgs e)
{
    if (e.CommandName == "Bootstrapped")
    {
        EventHub.Subscribe<IPagePreRenderCompleteEvent>(evt => 
        {
            var page = evt.Page;
            var siteNode = evt.PageSiteNode;

            page.Header.Controls.Add(new OpenGraphMeta("og:title", page.Title));
            page.Header.Controls.Add(new OpenGraphMeta("og:url",  UrlPath.ResolveAbsoluteUrl(siteNode.Url)));
            page.Header.Controls.Add(new TwitterMeta("twitter:title", page.Title));
            // ... 
        });
    }
}

meta-tags.html

<meta property="og:title" content="Integrate Open Graph and Twitter Card with Sitefinity">
<meta property="og:type" content="article">
<meta name="twitter:card" content="summary_large_image">

OpenGraphMeta.cs

using System.Web.UI.HtmlControls;

public class OpenGraphMeta : HtmlMeta
{
    public OpenGraphMeta(string propertyName, string content) : base()
    {
        this.Attributes.Add("property", propertyName);
        this.Content = content;
    }
}

TwitterCardMeta.cs

using System.Web.UI.HtmlControls;

public class TwitterMeta : HtmlMeta
{
    public TwitterMeta(string propertyName, string content) : base()
    {
        this.Attributes.Add("name", propertyName);
        this.Content = content;
    }
}