文件下载程序中发现的文件名过长的问题
居然发现文件名编码后长度超过155就会不能正确显示和下载,最后只好找了这样一个折中的方法,截短了
下面是那里的代码。后来查看了RFC 2183 中的说明,有一句这样的NOTE ON PARAMETER VALUE LENGHTS: A short (length <= 78 characters),这个应该是官方的解释吧,不过我用155在IE中没有问题,不过可能是IE另外放宽了限制吧。
今天发现下面的那个155也是不可靠的,今天有个过长的文件中间有个“.”就出问题了,下载时能常显示文件名,下载文件也没有问题,但下载下来后一看文件名居然变成了那些编码的字符串,后来把155改成154或做个检测如果遇到“.”就减少这个数字就不会有问题。
下面是那里的代码。后来查看了RFC 2183 中的说明,有一句这样的NOTE ON PARAMETER VALUE LENGHTS: A short (length <= 78 characters),这个应该是官方的解释吧,不过我用155在IE中没有问题,不过可能是IE另外放宽了限制吧。
今天发现下面的那个155也是不可靠的,今天有个过长的文件中间有个“.”就出问题了,下载时能常显示文件名,下载文件也没有问题,但下载下来后一看文件名居然变成了那些编码的字符串,后来把155改成154或做个检测如果遇到“.”就减少这个数字就不会有问题。
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/// <summary>
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/// 下载附件。
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/// </summary>
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/// <param name="fileName">文件名</param>
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/// <param name="path">文件路径</param>
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public static void DownLoadFileAttachment(string fileName , string path)
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{
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if (System.IO.File.Exists(path))
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{
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try
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{
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fileName = fileName.Trim();
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for (int i = 0 ; i < System.IO.Path.InvalidPathChars.Length ; i ++)
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{
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fileName = fileName.Trim().Replace(System.IO.Path.InvalidPathChars[i].ToString() , string.Empty);
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}
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fileName = fileName.Replace(System.IO.Path.PathSeparator.ToString() , string.Empty);
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int maxLength = 155;
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int length = HttpUtility.UrlEncode(fileName).Length;
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while (length > maxLength)
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{
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int index = fileName.LastIndexOf(".");
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if (index > 0)
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{
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fileName = fileName.Substring(0 , index - 1) + fileName.Substring(index);
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}
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else
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{
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fileName = fileName.Substring(0 , fileName.Length - 1);
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}
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length = HttpUtility.UrlEncode(fileName).Length;
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}
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System.IO.FileInfo file = new System.IO.FileInfo(path);
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HttpContext.Current.Response.Clear();
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HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));
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HttpContext.Current.Response.AppendHeader("Content-Length", file.Length.ToString());
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HttpContext.Current.Response.ContentType = "application/octet-stream";
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HttpContext.Current.Response.WriteFile(file.FullName);
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HttpContext.Current.Response.End();
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}
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catch
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{
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}
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}
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else
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{
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HttpContext.Current.Response.Clear();
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DisplayNoFileMessage();
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HttpContext.Current.Response.End();
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}
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}
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