Accessing Akka HTTP client certificate for the current connection

Question

I am current Apache Tomcat user designing an Akka HTTP based replacement for a HTTPS web service that uses client certificates for authentication and authorization. Using Tomcat I am accustomed to retrieving the client X509Certificate with a servlet request attribute

request.getAttribute("javax.servlet.request.X509Certificate")

I need the certificate for some additional authorization checks inside the handler for select routes. How would retrieve the client certificate in this way with Akka HTTP 10.0.x?

Answer 1

You need to enable decorating requests with TLS session info through the config settings for the server:

akka.http.server.parsing.tls-session-info-header = on

And then extract the info for a specific request using the synthetic header akka.http.scaladsl.model.headers.Tls-Session-Info like so:

headerValueByType[`Tls-Session-Info`]() { sessionInfo =>
  val sslSession = sessionInfo.getSession()
  sslSession.getPeerCertificates
  ... etc ...