using System.Security.Cryptography;
using System.Text;

namespace Infrastructure
{
 public static class StringExtensions
 {
 public static string MaxSubstring(this string origin, int maxLength)
 {
 return origin.Length >= maxLength ? origin.Substring(0, maxLength) : origin;
 }

 public static string ToMd5(this string origin)
 {
 if (string.IsNullOrWhiteSpace(origin))
 {
 return string.Empty;
 }

 var md5Algorithm = MD5.Create();
 var utf8Bytes = Encoding.UTF8.GetBytes(origin);
 var md5Hash = md5Algorithm.ComputeHash(utf8Bytes);
 var hexString = new StringBuilder();
 foreach (var hexByte in md5Hash)
 {
 hexString.Append(hexByte.ToString("x2"));
 }
 return hexString.ToString();
 }
 }
}