IIS中托管时目录中的文件未列出

Question

I have used the below code to list the folders and files in a directory. In the web.config file, I have added:

<add key="DetailUrlFileExtensions" value=".html,.pdf,.htm" />

fileExtensions = ConfigurationManager.AppSettings["DetailUrlFileExtensions"];
if (fileExtensions != string.Empty)
{
    extentions = fileExtensions.Split(',');
}

var items = Directory.GetFileSystemEntries(dirName);
foreach (var item in items)
{
    if (extentions != null)
    {
        string ext = item.Substring(item.LastIndexOf('.'));
        FileAttributes attr = System.IO.File.GetAttributes(item);
        if ((attr & FileAttributes.Directory) == FileAttributes.Directory)
        {
            list.Add(new Node(Path.GetFileName(item), item, Directory.Exists(item), true));
        }
        else if (extentions.Contains(ext))
        {
            list.Add(new Node(Path.GetFileName(item), item, Directory.Exists(item)));
        }
    }
    else
    {
        list.Add(new Node(Path.GetFileName(item), item, Directory.Exists(item)));
    }
}

But, when running in IIS, it is not working. The folder contains folders and files, and when running in IIS the files are not adding to list. When running in debug mode from application with 5 folders and 11 files, the foreach block execute 14 times (not 16), but when running from IIS with same folders and files, foreach block execute only 8 times, and no values are added to list.

It will list all files when extentions is null .

How can I resolve this issue?

Answer 1

Most likely you problem is in IIS_USRS user permission for the folder and its content. Possible solutions:

• try to give IIS_USRS user Full permissions about the folder (reduce then to READ if it work)
• run you application pool under your windows user
• if security concept does not let you use two solutions mentioned above, develop an internally visible service that could be running on your server under a power user and then in your code get all information you need but over the internally visible service

Answer 2

The following line will fail if the item does not contain a . character.

string ext = item.Substring(item.LastIndexOf('.'));

Since you are processing directories as well as files, I suspect that directories will likely not contain . characters.

You can safely manipulate file system paths using the System.IO.Path class. Specifically, the above code can be replaced with:

string ext = Path.GetExtension(item);

The GetExtension method will return string.Empty if there is no extension, rather than throwing an exception.

Alternatively, you can move the retrieval of the file extension to the else block and not perform it for directories:

FileAttributes attr = System.IO.File.GetAttributes(item);
if ((attr & FileAttributes.Directory) == FileAttributes.Directory)
{
    list.Add(new Node(Path.GetFileName(item), item, Directory.Exists(item), true));
}
else
{
    string ext = item.Substring(item.LastIndexOf('.'));
    if (extentions.Contains(ext)){
        list.Add(new Node(Path.GetFileName(item), item, Directory.Exists(item)));
    }
}

However, even in this case I recommend using System.IO.Path since there is no guarantee that file names will have . characters.