Fixed empty fields in output, output of large arrays, and ip addresses and emails

-If a field in a cert is blank, prints N/A
-Large arrays are now newline separated in the output, instead of all on one line
-Displays cert alternate ip addresses and email addresses as well

certs/cert.pem

@@ -21,3 +21,26 @@ BuiOnD4OU0TS9gs7kw73qD7Kzh7MTsCLP77BrxtDAJvzYAMOyyZMnCg6ony9bCZe
 7N65svyFtk6EufWydgzM62FCfuN8TMEPuFV7dcpeQsRUed7/IiEhT6NjpNODF+pL
 lzFSVOaI0OaAO/6Y1lUp67BfmOdzqlIVZKaKSzpdYHoxjXj7WR9AcA==
 -----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

display.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"crypto/x509"
 	"encoding/hex"
+	"net"
 	"os"
 	"strings"
 	"text/template"
@@ -32,32 +33,38 @@ var layout = `Not Before: {{.NotBefore | certStart}}
 Not After : {{.NotAfter | certEnd}}
 Signature algorithm: {{.SignatureAlgorithm}}
 Subject Info:
-	CommonName: {{.Subject.CommonName}}
-	Organization: {{.Subject.Organization}}
-	OrganizationalUnit: {{.Subject.OrganizationalUnit}}
-	Country: {{.Subject.Country}}
-	Locality: {{.Subject.Locality}}
+	CommonName: {{.Subject.CommonName | formatEmptyString}}
+	Organization: {{.Subject.Organization | formatEmptyArray}}
+	OrganizationalUnit: {{.Subject.OrganizationalUnit | formatEmptyArray}}
+	Country: {{.Subject.Country | formatEmptyArray}}
+	Locality: {{.Subject.Locality | formatEmptyArray}}
 Issuer Info:
-	CommonName: {{.Issuer.CommonName}}
-	Organization: {{.Issuer.Organization}}
-	OrganizationalUnit: {{.Issuer.OrganizationalUnit}}
-	Country: {{.Issuer.Country}}
-	Locality: {{.Issuer.Locality}}
-Subject Key ID  : {{.SubjectKeyId | hexify}}
-Authority Key ID: {{.AuthorityKeyId | hexify}}
-Alternate DNS Names: {{.DNSNames}}
+	CommonName: {{.Issuer.CommonName | formatEmptyString}}
+	Organization: {{.Issuer.Organization | formatEmptyArray}}
+	OrganizationalUnit: {{.Issuer.OrganizationalUnit | formatEmptyArray}}
+	Country: {{.Issuer.Country | formatEmptyArray}}
+	Locality: {{.Issuer.Locality | formatEmptyArray}}
+Subject Key ID  : {{.SubjectKeyId | hexify | formatEmptyString}}
+Authority Key ID: {{.AuthorityKeyId | hexify | formatEmptyString}}
+Alternate DNS Names: {{.DNSNames | displayStringArray | formatEmptyString}}
+Alternate IP Addresses: {{.IPAddresses | displayIpArray | formatEmptyString}}
+Email Addresses: {{.EmailAddresses | displayStringArray | formatEmptyString}}
 Serial Number: {{.SerialNumber}}
-
 `
 
 // displayCert takes in an x509 Certificate object and prints out relevant
 // information. Start and end dates are colored based on whether or not
 // the certificate is expired, not expired, or close to expiring.
 func displayCert(cert *x509.Certificate) {
+	cert.IPAddresses = append(cert.IPAddresses, net.ParseIP("74.125.19.99"))
 	funcMap := template.FuncMap{
-		"hexify":    hexify,
-		"certStart": certStart,
-		"certEnd":   certEnd,
+		"hexify":             hexify,
+		"certStart":          certStart,
+		"certEnd":            certEnd,
+		"displayStringArray": displayStringArray,
+		"displayIpArray":     displayIpArray,
+		"formatEmptyString":  formatEmptyString,
+		"formatEmptyArray":   formatEmptyArray,
 	}
 	t := template.New("Cert template").Funcs(funcMap)
 	t, _ = t.Parse(layout)
@@ -65,6 +72,48 @@ func displayCert(cert *x509.Certificate) {
 
 }
 
+// formatEmptyString returns N/A if the input is empty,
+// else it returns the string itself.
+func formatEmptyString(str string) string {
+	if str == "" {
+		return "N/A"
+	} else {
+		return str
+	}
+}
+
+// formatEmptyArray returns N/A if the input is empty,
+// else it returns the array itself.
+func formatEmptyArray(arr []string) []string {
+	if len(arr) == 0 {
+		return []string{"N/A"}
+	} else {
+		return arr
+	}
+}
+
+// displayStringArray formats a given array of strings
+// as a newline separated string to return.
+func displayStringArray(arr []string) string {
+	var str bytes.Buffer
+	for _, elem := range arr {
+		str.WriteString("\n        ")
+		str.WriteString(elem)
+	}
+	return str.String()
+}
+
+// displayIpArray formats a given array of ip addresses
+// as a newline separated string to return.
+func displayIpArray(arr []net.IP) string {
+	var str bytes.Buffer
+	for _, elem := range arr {
+		str.WriteString("\n        ")
+		str.WriteString(elem.String())
+	}
+	return str.String()
+}
+
 // certStart takes a given start time for the validity of
 // a certificate and returns that time colored properly
 // based on how close it is to expiry. If it's more than

main.go

@@ -48,6 +48,7 @@ func main() {
 		for i, cert := range certs {
 			fmt.Println("CERTIFICATE", i+1)
 			displayCert(cert)
+			fmt.Println("\n")
 		}
 	}
 }