Navigation between sites using same lang cookie

Question

I'm trying to navigate between sites but current language is not consistent between sites under the same tenant, how to unify lang cookie?

Answer 1

Are the sites on different domains? If so, I suspect it's a cookie issue. By default, Sitecore (and ASP.NET) will use a very specific domain for its cookies to limit the cookies to only that domain. Since cookies cannot be shared across domains, when you switch domains, Sitecore can't see the language cookie anymore.

To resolve this, I would recommend creating an httpRequestEnd pipeline processor that looks for your site's cookie (sitename#lang) in the Response.Cookies collection and updates the Domain on it to be less specific.

Disclaimer: this code has not been tested in this exact form.

The pipeline processor

namespace Custom.Pipelines.HttpRequestEnd
{
    public class UpdateLanguageCookieDomain : HttpRequestProcessor
    {
        public override void Process(HttpRequestArgs args)
        {
            // For performance and cleanliness reasons, only run this on requests for your site
            SiteContext currentSite = Context.Site;
            if (currentSite == null || !currentSite.Name.Equals("yoursitename"))
                return;

            if (string.IsNullOrEmpty(args.Context.Request.Url?.DnsSafeHost))
                return;

            string[] domainChunks = _HttpContext.Request.Url.DnsSafeHost.Split(new[] { '.' }, StringSplitOptions.RemoveEmptyEntries);
            // If it's only 2 or fewer chunks, then it's safe to leave the cookie domain as the full domain
            if (domainChunks.Length > 2)
            {
                // If it's more than 2 chunks, we should set the cookie domain to the least-restrictive domain possible
                // e.g. subdomain.domain.com -> [subdomain, domain, com] -> ".domain.com"
                var domain = $".{domainChunks[domainChunks.Length - 2]}.{domainChunks[domainChunks.Length - 1]}";

                foreach (string key in args.Context.Request.Cookies.AllKeys.Where(key => key == "yoursitename#lang))
                {
                    args.Context.Response.Cookies[key].Domain = domain;
                }
            }
        }
    }
}

The config patch

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:set="http://www.sitecore.net/xmlconfig/set/">
    <sitecore>
        <pipelines>
            <httpRequestEnd>
                <processor patch:after="processor[@type='Sitecore.Pipelines.HttpRequest.EndDiagnostics, Sitecore.Kernel']" type="Custom.Pipelines.HttpRequestEnd.UpdateLanguageCookieDomain,Custom" />
            </httpRequestEnd>
        </pipelines>
    </sitecore>
</configuration>