Get number of new emails from Microsoft Exchange server in SharePoint

Question

We need to create widget that displays number of new/unread emails of current logged SharePoint user. Preferably using JSOM/Rest API for Javascript

We've done the following:

• Link SharePoint to sync profiles from Active Directory (AD)
• Configure SharePoint/Exchange server Single Sign-On (SSO)

Answer 1

I somehow figured to have a workaround

• download EWS (Exchange Web Services Managed API)
• create and configure impersonate application account
  http://www.techieshelp.com/exchange-2013-configuring-impersonation-applications/
• install .NET EWS client library (https://www.nuget.org/packages/Microsoft.Exchange.WebServices/)

here is my web part C# code behind

using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.DirectoryServices;
using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Threading.Tasks;
using Microsoft.Exchange.WebServices;
using Microsoft.Exchange.WebServices.Data;
using Microsoft.SharePoint;

namespace Messagerie.WidgetVisualWebPart
{
    public partial class WidgetVisualWebPartUserControl : UserControl
    {

        protected void Page_Load(object sender, EventArgs e)
        {
            ServicePointManager.ServerCertificateValidationCallback = delegate(Object obj, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
            {

                if (errors == System.Net.Security.SslPolicyErrors.None)
                {
                    return true;
                }

                if ((errors & System.Net.Security.SslPolicyErrors.RemoteCertificateChainErrors) != 0)
                {
                    if (chain != null && chain.ChainStatus != null)
                    {
                        foreach (System.Security.Cryptography.X509Certificates.X509ChainStatus status in chain.ChainStatus)
                        {
                            if ((certificate.Subject == certificate.Issuer) &&
                               (status.Status == System.Security.Cryptography.X509Certificates.X509ChainStatusFlags.UntrustedRoot))
                            {

                                continue;
                            }
                            else
                            {
                                if (status.Status != System.Security.Cryptography.X509Certificates.X509ChainStatusFlags.NoError)
                                {

                                    return false;
                                }
                            }
                        }
                    }

                    return true;
                }
                else
                {

                    return false;
                }
            };

            ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);
            service.EnableScpLookup = true;
            try
            {
                service.Credentials = new WebCredentials("impersonateAccount@example.com", "impersonateAccountPassword", System.Net.NetworkInformation.IPGlobalProperties.GetIPGlobalProperties().DomainName);
                service.Url = new Uri("https://mail.domain.com/EWS/Exchange.asmx");
                service.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SID, SPContext.Current.Web.CurrentUser.UserId.NameId);

                Folder inbox = Folder.Bind(service, WellKnownFolderName.Inbox);
                // ...
            }
            catch (Exception exception)
            {
                ErrorMessage = exception.Message;
            }
        }
    }
}