ASP.NET附表删除临时文件 [英] ASP.NET Schedule deletion of temporary files

问题描述

问：我有一个创建临时PDF文件（用户下载）ASP.NET应用程序。
现在，许多用户在许多天就可以创造出许多PDF文件，这需要很多的磁盘空间。

Question: I have an ASP.NET application which creates temporary PDF files (for the user to download). Now, many users over many days can create many PDFs, which take much disk space.

什么是计划删除的文件超过1天/ 8小时之前的最好方法？
在asp.net应用程序preferably itselfs ...

What's the best way to schedule deletion of files older than 1 day/ 8 hours ? Preferably in the asp.net application itselfs...

推荐答案

对于您需要创建，记下文件名的会话中的每个临时文件：

For each temporary file that you need to create, make a note of the filename in the session:

// create temporary file:
string fileName = System.IO.Path.GetTempFileName();
Session[string.Concat("temporaryFile", Guid.NewGuid().ToString("d"))] = fileName;
// TODO: write to file

接下来，添加下列清理code到Global.asax中：

Next, add the following cleanup code to global.asax:

<%@ Application Language="C#" %>
<script RunAt="server">
    void Session_End(object sender, EventArgs e) {
        // Code that runs when a session ends. 
        // Note: The Session_End event is raised only when the sessionstate mode
        // is set to InProc in the Web.config file. If session mode is set to StateServer 
        // or SQLServer, the event is not raised.

        // remove files that has been uploaded, but not actively 'saved' or 'canceled' by the user
        foreach (string key in Session.Keys) {
            if (key.StartsWith("temporaryFile", StringComparison.OrdinalIgnoreCase)) {
                try {
                    string fileName = (string)Session[key];
                    Session[key] = string.Empty;
                    if ((fileName.Length > 0) && (System.IO.File.Exists(fileName))) {
                        System.IO.File.Delete(fileName);
                    }
                } catch (Exception) { }
            }
        }

    }       
</script>

更新：我现在accually使用除上述的一种新的（改进）方法。新一涉及HttpRuntime.Cache并检查文件是否超过8小时以上。我会，如果任何人有兴趣在这里发布。这是我的新的的global.asax.cs

UPDATE: I'm now accually using a new (improved) method than the one described above. The new one involves HttpRuntime.Cache and checking that the files are older than 8 hours. I'll post it here if anyones interested. Here's my new global.asax.cs:

using System;
using System.Web;
using System.Text;
using System.IO;
using System.Xml;
using System.Web.Caching;

public partial class global : System.Web.HttpApplication {
    protected void Application_Start() {
        RemoveTemporaryFiles();
        RemoveTemporaryFilesSchedule();
    }

    public void RemoveTemporaryFiles() {
        string pathTemp = "d:\\uploads\\";
        if ((pathTemp.Length > 0) && (Directory.Exists(pathTemp))) {
            foreach (string file in Directory.GetFiles(pathTemp)) {
                try {
                    FileInfo fi = new FileInfo(file);
                    if (fi.CreationTime < DateTime.Now.AddHours(-8)) {
                        File.Delete(file);
                    }
                } catch (Exception) { }
            }
        }
    }

    public void RemoveTemporaryFilesSchedule() {
        HttpRuntime.Cache.Insert("RemoveTemporaryFiles", string.Empty, null, DateTime.Now.AddHours(1), Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable, delegate(string id, object o, CacheItemRemovedReason cirr) {
            if (id.Equals("RemoveTemporaryFiles", StringComparison.OrdinalIgnoreCase)) {
                RemoveTemporaryFiles();
                RemoveTemporaryFilesSchedule();
            }
        });
    }
}

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