Serving and Verifying.network 在 Asp.Net Core 3.1 中共享图像 Web 应用程序 (Razor Pages)

Question

I have a.network file share which contains images that are served from various applications. In an older application we simply created a Virtual Directory in IIS and used Server.MapPath(...) to get the correct path. This no longer exists in Asp.Net Core 3.1.

So I added a /Data folder to my project and then added an additional app.UseStaticFiles instance to map the /Data folder to the.network share path.

Here is the code from the Configure(...) function in Startup.cs :

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            . . .

            // serves static js/css/whatever files from /wwwroot
            app.UseStaticFiles();

            // serves static image files from /Data
            app.UseStaticFiles(new StaticFileOptions
            {
                FileProvider = new PhysicalFileProvider(Path.Combine(env.ContentRootPath, "Data")),
                RequestPath = "//networkdriveshare/pathToImages"
            });

            app.UseCookiePolicy();
            app.UseRouting();            
            app.UseAuthorization();            
            app.UseSession();
            
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapRazorPages();
            });
        }

Issue

I need to be able to determine if a physical image exists on the.network share prior to displaying it.

What Works

I can display an image using the tag within the Razor page markup just fine and confirmed it is from the.network share as follows:

    <img src="~/Data/PathInNetworkDrive/placeholder.jpg" alt="placholder test" class="card-img" />

What does NOT Work

I need to be able to determine if an image file physically exists on the.network share within the C# code behind in the main page.

Everything I have tried gives me an error or just does not find a file when I know there are thousands of files out there.

This is not a security issue at least I don't think it is since I am able to get to the images from the Razor page markup described above.

What I have tried

I have tried using the environment: var storagePhoto = _env.ContentRootPath combined with '/Data' folder with simple code:

        // finds nothing of course, ever
        var storagePhoto = Path.Combine(_env.ContentRootPath, "Data");
        if (System.IO.File.Exists(storagePhoto))
            // found
        else
            // not found

Tried adding a File Provider in Startup.cs and then injecting in razor page:

    // Startup.cs
    var imagesProvider = new PhysicalFileProvider(Path.Combine(_env.ContentRootPath, "Data"));
    var compositeProvider = new CompositeFileProvider(imagesProvider);

    services.AddSingleton<IFileProvider>(compositeProvider);

    // Index.cshtml.cs
    public class IndexModel : PageModel
    {
        private readonly IFileProvider _fileProvider;
        private readonly ILogger<IndexModel> _logger;
        private IWebHostEnvironment _env;
        ...


        public IndexModel(ILogger<IndexModel> logger,
            IFileProvider fileProvider,
            IWebHostEnvironment env)
        {
            _logger = logger;
            _env = env;
            _fileProvider = fileProvider;
        }

        // blows up on 'GetDirectoryContents' just displays the path to /Data in the error message
        public IActionResult OnGet()
        {
            try
            {
                var contents = _fileProvider.GetDirectoryContents(string.Empty);
                //var filePath = Path.Combine("wwwroot", "js", "site.js");
                //var fileInfo = provider.GetFileInfo(filePath);
            }
            catch (Exception ext)
            {
                Console.WriteLine($"{ext.Message}");
            }        
        }
        ...
    }

Any help would be welcome

Answer 1

Answer

Once I corrected the path to the.network share that fixed the issue of finding out whether a photo existed or not - turns out I made a mistake by modifying the config on the server which worked but was wrong. It was \\server\folder when it should have been \\\\server\\folder - dumb mistake.

Second, I had the additional app.UseStaticFiles function configured incorrectly, my fault for misreading an example (yep another mistake), this is how it should be:

            app.UseStaticFiles(new StaticFileOptions
            {
                FileProvider = new PhysicalFileProvider("\\\\server\\folder"),
                RequestPath = "/Data"
            });

The path in my initial Question was on entered as the RequestPath and not passed into the PhysicalFileProvider(...) function.

Third, I had to remove the IIS Virtual Directory from the IIS app setup as it was blocking the new static file path.

Security was correct already but we double checked it.

So, turns out that the path I was on was correct but I made a couple of mistakes.