验证码,就是将一串随机产生的数字或符号,生成一幅图片,图片里加上一些干扰象素(防止OCR),由用户肉眼识别其中的验证码信息,输入表单提交网站验证,验证成功后才能使用某项功能。
网站为了防止用户利用机器人自动注册、登录、灌水,都采用了验证码技术。
我做的这个验证码是在Google扭曲验证码的基础上做的修改
包含下列文件:
1.App_Code/VerifyCode.cs
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;
/**////<summary>
/// VerifyCode 的摘要说明
///</summary>public class VerifyCode
{
验证码长度(默认6个验证码的长度)#region 验证码长度(默认6个验证码的长度)
int length = 6;
public int Length
{
get { return length; }
set { length = value; }
}
#endregion
验证码字体大小默认40像素#region 验证码字体大小默认40像素
int fontSize = 30;
public int FontSize
{
get { return fontSize; }
set { fontSize = value; }
}
#endregion
边框补#region 边框补
int padding = 2;
public int Padding
{
get { return padding; }
set { padding = value; }
}
#endregion
是否输出燥点(默认不输出)#region 是否输出燥点(默认不输出)
bool chaos = true;
public bool Chaos
{
get { return chaos; }
set { chaos = value; }
}
#endregion
输出燥点的颜色(默认灰色)#region 输出燥点的颜色(默认灰色)
Color chaosColor = Color.LightGray;
public Color ChaosColor
{
get { return chaosColor; }
set { chaosColor = value; }
}
#endregion
自定义背景色(默认白色)#region 自定义背景色(默认白色)
Color backgroundColor = Color.White;
public Color BackgroundColor
{
get { return backgroundColor; }
set { backgroundColor = value; }
}
#endregion
自定义随机颜色数组#region 自定义随机颜色数组
Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
public Color[] Colors
{
get { return colors; }
set { colors = value; }
}
#endregion
自定义字体数组#region 自定义字体数组
string[] fonts = { "Gautami" };//{"宋体"};//设置字体
public string[] Fonts
{
get { return fonts; }
set { fonts = value; }
}
#endregion
自定义随机码字符串序列(使用逗号分隔)#region 自定义随机码字符串序列(使用逗号分隔)
string codeSerial = "0,1,2,3,4,5,6,7,8,9";//"中文";//,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z
public string CodeSerial
{
get { return codeSerial; }
set { codeSerial = value; }
}
#endregion
产生波形滤镜效果#region 产生波形滤镜效果
private const double PI = 0; //3.1415926535897932384626433832795;
private const double PI2 = 0;//6.283185307179586476925286766559;
/**////<summary>
///正弦曲线Wave扭曲图片
///</summary>
///<param name="srcBmp">图片路径</param>
///<param name="bXDir">如果扭曲则选择为True</param>
///<param name="nMultValue">波形的幅度倍数,越大扭曲的程度越高,一般为3</param>
///<param name="dPhase">波形的起始相位,取值区间[0-2*PI)</param>
///<returns></returns>
public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
// 将位图背景填充为白色
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);
graph.Dispose();
double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;
for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
// 取得当前点的颜色
int nOldX = 0, nOldY = 0;
nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
nOldY = bXDir ? j : j + (int)(dy * dMultValue);
System.Drawing.Color color = srcBmp.GetPixel(i, j);
if (nOldX >= 0 && nOldX < destBmp.Width
&& nOldY >= 0 && nOldY < destBmp.Height)
{
destBmp.SetPixel(nOldX, nOldY, color);
}
}
}
return destBmp;
}
#endregion
生成校验码图片#region 生成校验码图片
public Bitmap CreateImageCode(string code)
{
int fSize = FontSize;
int fWidth = fSize + Padding;
int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 1;
int imageHeight = fSize * 2 + Padding;
System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);
Graphics g = Graphics.FromImage(image);
g.Clear(BackgroundColor);
Random rand = new Random();
//给背景添加随机生成的燥点
if (this.Chaos)
{
Pen pen = new Pen(ChaosColor, 0);
int c = Length * 10;
for (int i = 0; i < c; i++)
{
int x = rand.Next(image.Width);
int y = rand.Next(image.Height);
g.DrawRectangle(pen, x, y, 1, 1);
}
}
int left = 0, top = 0, top1 = 1, top2 = 1;
int n1 = (imageHeight - FontSize - Padding * 2);
int n2 = n1 / 4;
top1 = n2;
top2 = n2 * 2;
Font f;
Brush b;
int cindex, findex;
//随机字体和颜色的验证码字符
for (int i = 0; i < code.Length; i++)
{
cindex = rand.Next(Colors.Length - 1);
findex = rand.Next(Fonts.Length - 1);
f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
b = new System.Drawing.SolidBrush(Colors[cindex]);
if (i % 2 == 1)
{
top = top2;
}
else
{
top = top1;
}
left = i * fWidth;
g.DrawString(code.Substring(i, 1), f, b, left, top);
}
//画一个边框边框颜色为Color.Gainsboro
g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
g.Dispose();
//产生波形(Add By 51aspx.com)
image = TwistImage(image, true, 8, 4);
return image;
}
#endregion
将创建好的图片输出到页面#region 将创建好的图片输出到页面
public void CreateImageOnPage(string code, HttpContext context)
{
System.IO.MemoryStream ms = new System.IO.MemoryStream();
Bitmap image = this.CreateImageCode(code);
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
context.Response.ClearContent();
context.Response.ContentType = "image/Jpeg";
context.Response.BinaryWrite(ms.GetBuffer());
ms.Close();
ms = null;
image.Dispose();
image = null;
}
#endregion
生成随机字符码#region 生成随机字符码
public string CreateVerifyCode(int codeLen)
{
if (codeLen == 0)
{
codeLen = Length;
}
string[] arr = CodeSerial.Split(',');
string code = "";
int randValue = -1;
Random rand = new Random(unchecked((int)DateTime.Now.Ticks));
for (int i = 0; i < codeLen; i++)
{
randValue = rand.Next(0, arr.Length - 1);
code += arr[randValue];
}
return code;
}
public string CreateVerifyCode()
{
return CreateVerifyCode(0);
}
#endregion
}
2.VerifyCodes.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
VerifyCode v = new VerifyCode();
string code = v.CreateVerifyCode(4);//验证码长度
v.CreateImageOnPage(code, this.Context);
Session["ver"] = code;
}
3.Verify.aspx
<div>
<img id="imgVerify" alt="看不清?点击更换" onclick="this.src=this.src+'?'" src="VerifyCodes.aspx?" style="width: 95px; height: 34px"/><br/>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button"/></div>
4.Verify.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class Verify : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
if (TextBox1.Text == Session["ver"].ToString())
{
this.Label1.Text = "OK";
}
else
{
this.Label1.Text = "Error";
}
}
}