How SharePoint add-ins can identify the Host Site URL?

Question

How my add-ins(Provider hosted) can know Host site URL where it is running?

Actually, In my case there are external and internal farm with different site URL (see below 2 URLs). Now, in my app, How to get the host site URL? There is single code which runs for both add-ins (external and internal).

e.g

External site: https://external.mycompany.com/sites/0028

Internal site: https://internal.mycompany.com/sites/0029

Answer 1

I am assuming that you have the code so you should have client id for both the apps. To check the host URL you can simply append "/_layouts/15/AppInv.aspx" to the site URL. For Example in your case it should be :

External site: https://external.mycompany.com/sites/0028/_layouts/15/AppInv.aspx

Internal site: https://internal.mycompany.com/sites/0029/_layouts/15/AppInv.aspx

On the page you can enter the client id and search, it will show you all the details related to app.

Answer 2

Finally, I got it with HttpContext.Current.Request.Url.AbsoluteUri;