/// <summary> /// 驗證碼生成 /// </summary> public class VerificationCodeHelper { //定義顏色 private static Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple }; //定義字體 private static string font = "宋體"; //定義驗證碼字符及出現頻次 ,避免出現0 o j i l 1 x; private static String charCollection = "ASDFGHZCVBNMKQWERTYUP"; //字體大小 private static int fontSize = 23; //旋轉角度 private static int angle = 30; /// <summary> /// 驗證碼生成 /// </summary> /// <param name="guid">緩存標識</param> /// <param name="length">字符個數</param> /// <param name="width">寬度</param> /// <param name="height">高度</param> /// <returns></returns> public static byte[] GetBitmapCode(string guid, int width, int height, int length = 4) { //lk:這裏高寬需要寫死 或限制最大高寬 避免被攻擊者寫的太大導致內存佔用過高 height = height > 500 ? 500 : height; width = width > 500 ? 500 : width; string codes = ""; string code; int codeX = width / (length + 1); Random random = new Random(); using (Bitmap image = new Bitmap(width, height)) { using (Graphics g = Graphics.FromImage(image)) { //清空圖片背景色 g.Clear(Color.FromArgb(247, 247, 247)); g.FillRectangle(new SolidBrush(Color.FromArgb(247, 247, 247)), 0, 0, image.Width, image.Height); //畫圖片的背景噪音線 for (int i = 0; i < 5; i++) { g.DrawLine(new Pen(colors[random.Next(colors.Length)]), random.Next(image.Width), random.Next(image.Height), random.Next(image.Width), random.Next(image.Height)); } //文字距中 StringFormat format = new StringFormat(StringFormatFlags.NoClip); format.Alignment = StringAlignment.Center; format.LineAlignment = StringAlignment.Near; using (Font f = new Font(font, fontSize, FontStyle.Regular)) { using (Brush b = new SolidBrush(colors[random.Next(colors.Length)])) { for (int i = 0; i < length; i++) { code = charCollection[random.Next(0, charCollection.Length)].ToString(); SizeF sizeF = g.MeasureString(code, f); PointF dot = new PointF(codeX, random.Next(image.Height / 3)); g.TranslateTransform(dot.X, dot.Y);//移動光標到指定位置 int rAngel = random.Next(-angle, angle); g.RotateTransform(rAngel); g.DrawString(code, f, b, 1, 1, format); g.RotateTransform(-rAngel);//轉回去 g.TranslateTransform(2, -dot.Y);//移動光標到指定位置 codes += code; } } } //返回圖片數據 using (System.IO.MemoryStream ms = new System.IO.MemoryStream()) { image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); SaveToChache(guid, codes); return ms.ToArray(); } } } } /// <summary> /// 保存驗證碼到內存中 /// </summary> /// <param name="cacheFlag"></param> /// <param name="code"></param> public static void SaveToChache(string cacheFlag, string code) { string cacheName = RedisHelper.GetCacheName(RedisCacheType.VerificationCode, cacheFlag); CacheManager.SetCache(cacheName, code, TimeSpan.FromMinutes(5), ExpirType.Absolute); } /// <summary> /// 驗證驗證碼是否正確 /// </summary> /// <param name="cacheFlag"></param> /// <param name="code"></param> /// <returns></returns> public static string CheckCode(string cacheFlag, string code) { string cacheName = RedisHelper.GetCacheName(RedisCacheType.VerificationCode, cacheFlag); string cacheCode = CacheManager.GetCache(cacheName); if (string.IsNullOrEmpty(cacheCode)) { return "驗證碼已過期,請重新輸入!"; } else { CacheManager.RemoveCache(cacheName); if (cacheCode.Equals(code, StringComparison.OrdinalIgnoreCase) == false) { return "驗證碼錯誤,請重新輸入!"; } return null; } } }