Nginx module fetch client ssl certificate

Question

I am developing an "nginx" module and want to fetch client side certificate in my c code. I am unable to figure out how to do so in my custom module. I tried searching online but the closest I could get was

ssl_verify_client optional_no_ca;
.
.
.
add-header X-Client-Cert $ssl_client_certificate

Using this I can add the header X-Client-Cert to the output but what I really want is to be able to extract the certificate in my nginx module and extract the CName from the certificate for authentication.

Answer 1

I was able to get it working with ngx_http_get_variable API

Documentation - https://www.nginx.com/resources/wiki/extending/api/variables/