Authentication with SharePoint Online in Microsoft 365 and simple console application

Question

I need your help with my small application.

I need to create easy console application which will sign into SharePoint Online and download some documents from library.

When I am doing this on older SharePoint version it works fine. Unfortunately, its not working on SharePoint Online in Microsoft 365.

string userName = "[email protected]";
            string passwordPlain = "passw0rd";
            string baseUrl = "https://teams.mypage.com/sites/TESTSITE/";

            var passWord = new SecureString();

            foreach (char c in passwordPlain) 
                passWord.AppendChar(c);

            var creds = new SharePointOnlineCredentials(userName, passWord);
            
            try
            {
                var authDiguestToken = GetRequestDigest(creds, baseUrl);
               

                Console.WriteLine("Result " + authDiguestToken);
            }
            catch (Exception ex)
            {
                Console.WriteLine("\n\n Exception: \n\n " + ex.Message);
            }

So in this example I am going to get token value and display on console.

 private static string GetRequestDigest(SharePointOnlineCredentials creds, string baseUrl)
        {
            var client = new RestClient(baseUrl + "_api/");
            var digestRequest = new RestRequest("contextinfo", Method.POST);
            digestRequest.AddHeader("Accept", "application/json");

            //authentication cookie
            client.CookieContainer = new CookieContainer();
            client.CookieContainer.SetCookies(new Uri(baseUrl), creds.GetAuthenticationCookie(new Uri(baseUrl)));

            //I'm using dynamic jsut for demo, it's better to use some strongly typed class  
            return client.Execute<string>(digestRequest).Data;
        }

So in this case I am using cookie, not sure why its not working with other SharePoint Online in Microsoft 365.

Is there something special which needs to be done to get authenticated?

Answer 1

Simple answer is don't use a username and password. Instead, follow the process at Using modern authentication with CSOM for .NET Standard.

Note that this also applies to the .NET Framework; the older version of CSOM.

Answer 2

SharePointOnlineCredentials still works in my tenant. Some new tenants may disabled LegacyAuthProtocolsEnabled. Could you have a check that setting is enabled?

$TenantSettings = Get-SPOTenant 
$TenantSettings.LegacyAuthProtocolsEnabled
Set-SPOTenant -LegacyAuthProtocolsEnabled $True

More reference:

• https://www.koskila.net/how-to-fix-the-web-site-does-not-support-sharepoint-online-credentials-the-response-status-code-is-unauthorized-error/

BR

Answer 3

You can try using AuthenticationManager.GetWebLoginClientContext method of OfficeDevPnP.Core Namespace.

I have used this before with CSOM console applications and it works great with SharePoint Online. This method will also work if you have multi-factor authentication enabled on your tenant.

Check this article for more information: Using CSOM To Connect To A SharePoint Site

You can also check other authentication methods at: Authenticate SharePoint Using PnP Authentication Manager

Answer 4

Is PnP PowerShell an alternative? You could achieve your requirement with a couple of lines as you have a command to connect and another to download files

https://docs.microsoft.com/en-us/powershell/module/sharepoint-pnp/connect-pnponline

https://docs.microsoft.com/en-us/powershell/module/sharepoint-pnp/get-pnpfile?view=sharepoint-ps