package main

import (
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"log"
)

// content of the CSR otherName field
// openssl asn1parse -in csr -strparse 381
//     0:d=0  hl=2 l=  63 cons: SEQUENCE
//     2:d=1  hl=2 l=  13 prim: cont [ 2 ]
//    17:d=1  hl=2 l=  14 prim: cont [ 2 ]
//    33:d=1  hl=2 l=  12 prim: cont [ 2 ]
//    47:d=1  hl=2 l=  16 cons: cont [ 0 ]
//    49:d=2  hl=2 l=   6 prim: OBJECT            :1.3.6.1.4.1.1
//    57:d=2  hl=2 l=   6 cons: cont [ 0 ]
//    59:d=3  hl=2 l=   4 prim: UTF8STRING        :test

var csrPEM = []byte(`-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----`)

func main() {
	block, _ := pem.Decode(csrPEM)
	csr, err := x509.ParseCertificateRequest(block.Bytes)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("%s", csr.Extensions[0].Id)    // prints "2.5.29.17", why?
	fmt.Printf("%s", csr.Extensions[0].Value) // prints "test", but sometimes it adds random bytes
}