原理：使用go提供的模块 crypto/tls，可以获取域名证书的信息，通过到期时间可以判断证书是否过期
package main
import (
"crypto/tls"
"fmt"
)
func main() {
conn, _ := tls.Dial("tcp", "www.baidu.com:443", nil)
cert := conn.ConnectionState().PeerCertificates[0]
// 时间信息
fmt.Printf("NotBefore: %v\n", cert.NotBefore)
// NotBefore: 2022-07-05 05:16:02 +0000 UTC
fmt.Printf("NotAfter: %v\n", cert.NotAfter)
// NotAfter: 2023-08-06 05:16:01 +0000 UTC
// 其他信息
fmt.Printf("IPAddresses: %v\n", cert.IPAddresses)
fmt.Printf("Version: %v\n", cert.Version)
fmt.Printf("SerialNumber: %v\n", cert.SerialNumber)
fmt.Printf("Issuer: %v\n", cert.Issuer)
fmt.Printf("Subject: %v\n", cert.Subject)
}Python实现的可视化工具
