我们上一节建了数据库的表,但我发现很多东西还未完善起来,比如验证码,我们先做好验证码吧,验证码我们再熟悉不过了,为了防止恶意的登录,我们必须在登录页面加入验证码,下面我将分享一个验证码,这个是用C#画的,原理是,生成一个随机4位数,将其保存为session或者是cookie形式,将用户输入的验证码进行对比,
验证码可以是一个视图cshtml,或者是一个aspx页面,也可以是一个ashx一般处理程序,我们这里用ashx来显示
在App.Admin下的Core文件夹下新建一个一般处理文件verify_code.ashx,复制以下代码(此验证码适用aspx程序的)
using System;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web;
using System.Web.SessionState;
namespace App.Admin
{
/// <summary>
/// 验证码生成类
/// </summary>
public class verify_code : IHttpHandler, IRequiresSessionState
{
public void ProcessRequest(HttpContext context)
{
int codeW = 80;
int codeH = 22;
int fontSize = 16;
string chkCode = string.Empty;
//颜色列表,用于验证码、噪线、噪点
Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };
//字体列表,用于验证码
string[] font = { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" };
//验证码的字符集,去掉了一些容易混淆的字符
char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
Random rnd = new Random();
//生成验证码字符串
for (int i = 0; i < 4; i++)
{
chkCode += character[rnd.Next(character.Length)];
}
//写入Session
context.Session["Code"] = chkCode;
//创建画布
Bitmap bmp = new Bitmap(codeW, codeH);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.White);
//画噪线
for (int i = 0; i < 1; i++)
{
int x1 = rnd.Next(codeW);
int y1 = rnd.Next(codeH);
int x2 = rnd.Next(codeW);
int y2 = rnd.Next(codeH);
Color clr = color[rnd.Next(color.Length)];
g.DrawLine(new Pen(clr), x1, y1, x2, y2);
}
//画验证码字符串
for (int i = 0; i < chkCode.Length; i++)
{
string fnt = font[rnd.Next(font.Length)];
Font ft = new Font(fnt, fontSize);
Color clr = color[rnd.Next(color.Length)];
g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 18 + 2, (float)0);
}
//画噪点
for (int i = 0; i < 100; i++)
{
int x = rnd.Next(bmp.Width);
int y = rnd.Next(bmp.Height);
Color clr = color[rnd.Next(color.Length)];
bmp.SetPixel(x, y, clr);
}
//清除该页输出缓存,设置该页无缓存
context.Response.Buffer = true;
context.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
context.Response.Expires = 0;
context.Response.CacheControl = "no-cache";
context.Response.AppendHeader("Pragma", "No-Cache");
//将验证码图片写入内存流,并将其以 "image/Png" 格式输出
MemoryStream ms = new MemoryStream();
try
{
bmp.Save(ms, ImageFormat.Png);
context.Response.ClearContent();
context.Response.ContentType = "image/Png";
context.Response.BinaryWrite(ms.ToArray());
}
finally
{
//显式释放资源
bmp.Dispose();
g.Dispose();
}
}
public bool IsReusable
{
get
{
return false;
}
}
}
}
注意
//写入Session context.Session["Code"] = chkCode; 调用这个页面将生成一个session,我们将与用户输入的代码进行对比,OK回到Account的index视图
在验证码的位置嵌入这个页面
<tr>
<td style="width: 80px; text-align: right">验证码:
</td>
<td>
<input style="width: 50px" type="text" name="ValidateCode" id="ValidateCode" />
<img id="codeImg" alt="刷新验证码!" style="margin-bottom: -8px; cursor: pointer;" src="/Core/verify_code.ashx" onclick="this.src=this.src+'?'" />
<a href="javascript:$('#codeImg').trigger('click')">看不清?</a>
</td>
</tr>
编译后预览一下