重定向后不显示PHP SAML后变量

Question

I'm working with a SSO Saml authentication flow which looks as follows:

1. User sends SAMLRequest
2. User is redirected to IdP login page
3. User submits login details
4. IdP authenticates and redirects to my consumer assertion processing page
5. Access token extracted and submitted for a token to interact with API

I'm stuck on step 5. In fiddler, I can see the request header being sent with the required SAMLResponse posted, but it does not show in $_POST, $_GET and I've tried file_get_contents('php://input'). The response is the result of a 301 redirect.

The incoming header request with the required SAMLResponse redirected (301) to my assertion consumer page looks as follows. I can't figure out how to extract the posted parameter SAMLResponse?

POST http://localhost/xxxxxxxxxxx Host: localhost Connection: keep-alive Content-Length: 7710 Cache-Control: max-age=0 Origin: null Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36 Content-Type: application/x-www-form-urlencoded Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8 Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.8 Cookie: optimizelyEndUserId=oeu1463724346007r0.9674156716176872; ajs_anonymous_id=%22c336991a-286a-4278-8cb2-3d00d784f376%22; optimizelySegments=%7B%225943211328%22%3A%22direct%22%2C%225934960299%22%3A%22false%22%2C%225952160221%22%3A%22gc%22%7D; optimizelyBuckets=%7B%7D; ajs_user_id=null; ajs_group_id=null; _ga=GA1.1.1336717339.1458634274; PHPSESSID=imtffdda2a6g576rtd0vpb8ro2

SAMLResponse=xxxxxxxxxxxxxxxx

I've been scanning the web for a week but have not found a solution. Thanks in advance for any help.

Answer 1

It turns out I was missing a trailing / on my consumer assertion url which of course meant the server was redirecting to index.php resulting in the loss of post vabriables.