Get peer certificate

cert.clj

(ns cert 
    (import 
      (javax.net.ssl HttpsURLConnection SSLSession SSLSocket SSLSocketFactory)))

(defn- get-sever-certs [host port]
  (let [factory (HttpsURLConnection/getDefaultSSLSocketFactory)]
    (with-open [socket (doto
                         (.createSocket factory host port)
                         (.startHandshake))]
      (-> 
        (.getSession socket)
        (.getPeerCertificates)))))

(defn get-certs [host port]
  (doseq [[i c] (map-indexed vector (get-server-certs host port))]
    (do
      (println (format "i=%d" i)) 
      (println (.getIssuerX500Principal c)) 
      (println (.getNotBefore c))
      (println (.getNotAfter c))
      (println (.getSubjectX500Principal c)))))

(get-certs "github.com" 443)