asp.net core blazor：网络共享上的图像/文件工作 1 分钟，然后停止工作

Posted 2023-03-22

【中文标题】asp.net core blazor：网络共享上的图像/文件工作 1 分钟，然后停止工作

【英文标题】：asp.net core blazor: Images / files on network share work for 1 minute, then stop working

【发布时间】：2021-12-25 08:13:51

【问题描述】：

我的应用程序从网络共享存储和检索照片图像。我的开发机器是在 VMWare 上运行 Visual Studio 2019 的 Windows 2018。

应用首次打开时，图片效果很好。然后大约 1 分钟（左右）后，图像 404。

基本上，我正在尝试在 IIS 中实现一些经典的 asp.net 虚拟目录。这允许通过网络共享读取/写入文件。我的理解是 asp.net core 打破了老派的虚拟目录......

我尝试了很多方法，例如更改图像在网络上的位置（不同的物理机器）。没有运气。我还尝试了 NetworkConnection 的各种实现（参见下面的代码）。纳达。

我也尝试过使用 UseStaticFiles 而不是 UseFileServer：

app.UseStaticFiles(new StaticFileOptions
                
                    FileProvider = new PhysicalFileProvider(
                    Path.Combine("\\\\DESKTOP-QRDNRCJ\\Images\\Photos2")),
                    RequestPath = new PathString("/Photos2")
                );

最后，我尝试了 IP 地址而不是机器网络名称。

---

为了简化 *** 的调试，我制作了一个全新的 Blazor 解决方案，其中包含一个仅显示 3 张图像的页面。大约 1 分钟后它也会失败。

有趣：有时三分之二的图像会渲染一段时间。但最终所有 3 个都是 404。

此外，有时当我通过网络保存文件（使用不在下方的完整应用程序）时，它会保存文件的名称，但文件大小 = 0 k。

这很令人沮丧，因为该应用的运行时间很短。所以我没有犯错字或其他错误（据我所知）。

以下是一些帮助我入门的参考资料：

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/static-files?view=aspnetcore-5.0&tabs=aspnetcore2x#serve-files-outside-of-web-root

https://thecodeblogger.com/2021/05/17/network-path-for-static-files-in-asp-net-core-web-applications/

https://www.c-sharpcorner.com/article/virtual-directory-inside-of-asp-net-core-app-in-iis/

这是我的代码：

带有 3 张图片的简单页面：

@page "/index"
@page "/"
<img src="Photos2/birthday.gif" /><img src="Photos2/bo.jpg" /><img src="Photos2/dotnet.png" />

Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using WebApplication2.Data;
using System.Net;
using Microsoft.Extensions.FileProviders;
using System.IO;
using Microsoft.AspNetCore.Http;

namespace WebApplication2

    public class Startup
    
        public Startup(IConfiguration configuration)
        
            Configuration = configuration;
        

        public IConfiguration Configuration  get; 

        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        
            services.AddRazorPages();
            services.AddServerSideBlazor();
            services.AddSingleton<WeatherForecastService>();
        

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        
            if (env.IsDevelopment())
            
                app.UseDeveloperExceptionPage();
            
            else
            
                app.UseExceptionHandler("/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            

            app.UseHttpsRedirection();
            app.UseStaticFiles();

            var sourceCredentials = new NetworkCredential  Domain = "192.168.1.162", UserName = "ImageManager", Password = "qwer1234)" ;

            using (new NetworkConnection("\\\\192.168.1.162\\Images\\Photos2", sourceCredentials))
            
                app.UseFileServer(new FileServerOptions()
                
                    FileProvider = new PhysicalFileProvider(
                        Path.Combine("\\\\192.168.1.162\\Images\\Photos2")),
                    RequestPath = new PathString("/Photos2"),
                    EnableDirectoryBrowsing = true
                );

            

            app.UseRouting();

            app.UseEndpoints(endpoints =>
            
                endpoints.MapBlazorHub();
                endpoints.MapFallbackToPage("/_Host");
            );
        
    

NetworkConnection 的类。

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Net;

public class NetworkConnection : IDisposable

    readonly string _networkName;

    public NetworkConnection(string networkName, NetworkCredential credentials)
    
        _networkName = networkName;

        var netResource = new NetResource
        
            Scope = ResourceScope.GlobalNetwork,
            ResourceType = ResourceType.Disk,
            DisplayType = ResourceDisplaytype.Share,
            RemoteName = networkName
        ;

        var userName = string.IsNullOrEmpty(credentials.Domain)
            ? credentials.UserName
            : string.Format(@"0\1", credentials.Domain, credentials.UserName);

        var result = WNetAddConnection2(
            netResource,
            credentials.Password,
            userName,
            0);

        if (result != 0)
        
            throw new Win32Exception(result, "Error connecting to remote share");
        
    

    ~NetworkConnection()
    
        Dispose(false);
    

    public void Dispose()
    
        Dispose(true);
        GC.SuppressFinalize(this);
    

    protected virtual void Dispose(bool disposing)
    
        WNetCancelConnection2(_networkName, 0, true);
    

    [DllImport("mpr.dll")]
    private static extern int WNetAddConnection2(NetResource netResource,
        string password, string username, int flags);

    [DllImport("mpr.dll")]
    private static extern int WNetCancelConnection2(string name, int flags,
        bool force);

    [StructLayout(LayoutKind.Sequential)]
    public class NetResource
    
        public ResourceScope Scope;
        public ResourceType ResourceType;
        public ResourceDisplaytype DisplayType;
        public int Usage;
        public string LocalName;
        public string RemoteName;
        public string Comment;
        public string Provider;
    

    public enum ResourceScope : int
    
        Connected = 1,
        GlobalNetwork,
        Remembered,
        Recent,
        Context
    ;

    public enum ResourceType : int
    
        Any = 0,
        Disk = 1,
        Print = 2,
        Reserved = 8,
    

    public enum ResourceDisplaytype : int
    
        Generic = 0x0,
        Domain = 0x01,
        Server = 0x02,
        Share = 0x03,
        File = 0x04,
        Group = 0x05,
        Network = 0x06,
        Root = 0x07,
        Shareadmin = 0x08,
        Directory = 0x09,
        Tree = 0x0a,
        Ndscontainer = 0x0b
    

【问题讨论】：

将单个路径传递给 Path.Combine 是没有意义的

是的，大声笑，点了。现在，关于我的实际问题/问题...

【参考方案1】：

我想我解决了。发帖以防有人绊倒类似的东西......

我需要删除“使用”。所以这...

    using (new NetworkConnection("\\\\192.168.1.162\\Images\\Photos2",sourceCredentials))
            
                app.UseFileServer(new FileServerOptions()
                
                    FileProvider = new PhysicalFileProvider(
                        Path.Combine("\\\\192.168.1.162\\Images\\Photos2")),
                    RequestPath = new PathString("/Photos2"),
                    EnableDirectoryBrowsing = true
                );

            

变成了这样：

    new NetworkConnection("\\\\192.168.1.162\\Images\\Photos2", sourceCredentials);

   app.UseFileServer(new FileServerOptions()
   
       FileProvider = new PhysicalFileProvider(
                Path.Combine("\\\\192.168.1.162\\Images\\Photos2")),
                RequestPath = new PathString("/Photos2"),
                EnableDirectoryBrowsing = true
   );

唯一的区别是“使用”和括号被删除了。

为什么会这样？我猜 NetworkConnection 对象需要被持久化。如果我使用“使用”，则不是。那是我的问题，30-60 秒后，我的网络连接不起作用。

真希望我能更快地实现这个简单的修复！