Post ESO authentication, not letting the user get directly inside the app

[Peter Schober]

* uday.chandra.kumar <uday.chandra.kumar at accenture.com> [2019-03-26 19:45]:
> I am using Shibboleth as SP and MS Azure AD as IdP. I am able to get user
> authenticated but post authentication I want my user to get inside my
> application. At present, it's getting struck at login page of the app and
> user has to fill its username again on the application login page post
> successful authentication from IdP.

You can't post a SAML implementation in front of any application and
expect to magically have that application take its data (e.g. the
authenticated subject, or data derived from that) from the SAML
implementation.
So there's always integration work involved.

You fail to mention any technical details (such as the application
involved, the steps you have taken, etc.) so that's about as specific
as one can be.

> Also please enlighten me what does POST request to
> https://<app_url>/Shibboleth.sso/SAML2/POST does in this process.

Implement the HTTP-POST Protocol Binding as defined in SAML 2.0.

Slighly less tautologically: The SAML response from the IDP (Identity
Provider) is transmitted to the SP (Service Provider) by having the
HTTP User Agent (your web browser) HTTP-POST it to the SP. I.e., the
browser mediates that part of the exchange of SAML protocol messages
between the IDP and SP, without a direct connectoon needing to exist
between the IDP and the SP.

-peter