According to section 5.1.2 in https://www.oasis-open.org/committees/download.php/27819/sstc-saml-tech-overview-2.0-cd-02.pdf, the request takes places as an HTTP redirect and the target URL will contain a variable named "SAMLRequest". The webapp container could detect this scenario and let it through.
According to section 5.1.2 in https:/ /www.oasis- open.org/ committees/ download. php/27819/ sstc-saml- tech-overview- 2.0-cd- 02.pdf, the request takes places as an HTTP redirect and the target URL will contain a variable named "SAMLRequest".
The webapp container could detect this scenario and let it through.