使用 Blazor 读取服务器端文件 [英] Reading server-side files using Blazor

问题描述

我有一个基于 Blazor 示例的项目，其中包含 .Client、.Server 和 .Shared 项目.我在服务器上有一个文本文件 data.txt，我希望能够使用标准的 StreamReader/System.IO.File 读/写方法.由于 Blazor 在沙箱中运行，我想我无法像在普通 Windows 应用程序中那样访问整个文件系统?我已将该文件放在 wwwroot 目录中，如果在浏览器中输入 url/data.txt 以便文件获取，我什至可以从客户端访问该文件服务，我不想让，但试图读取该文件:

I have a project based on the Blazor sample with a .Client, .Server and .Shared projects. I have a textfile data.txt on the server that I want to be able to read/write using standard StreamReader / System.IO.File methods. Since Blazor runs in a sandbox I guess I can't access the entire filesystem as I would in a normal windows app? I've placed the file in the wwwroot directory, and I can even access the file from the client if a enter url/data.txt in the browser so the file gets served, which I don't want to alow, but trying to read that file as such:

var file = File.ReadAllText("data.txt");

导致错误:

WASM: [System.IO.FileNotFoundException] Could not find file "/data.txt"

如何读取服务器端文件并对客户端隐藏它们?

How can I read server-side files and keep them hidden from the client?

推荐答案

事实证明这比我想象的要容易.我从错误的角度接近它.要访问服务器端文件，请创建一个控制器:

Turns out this was easier than I thought. I was approaching it from the wrong angle. To access server side files, create a controller as such:

using Microsoft.AspNetCore.Mvc;

namespace Favlist.Server.Controllers
{
    [Route("api/[controller]")]
    public class DataFetcher : Controller
    {
        [HttpGet("[action]")]
        public MyDataClass GetData(string action, string id)
        {
            var str = File.ReadAllText("data.txt");
            return new MyDataClass(str);
        }
    }
}

并在您的页面中调用它，如下所示:

And call it within your page like so:

@using System.IO;
@page "/dataview"
@inject HttpClient Http

@if (data == null)
{
    <p><em>Loading...</em></p>
}
else
{
    <p>@data.Name</p>
}

@functions {
    MyDataClass data;

    protected override async Task OnInitAsync()
    {
        data = await Http.GetJsonAsync<MyDataClass>("api/DataFetcher/GetData");
    }
}

MyDataClass 是您的自定义类，包含您需要读/写的任何内容.

MyDataClass is your custom class containing whatever you need to read/write.

然后您就可以像往常一样访问服务器上的任何位置的文件.当前目录是您的 Project.Server 根文件夹.

You can then access files exactly as you normally would, wherever you want on the server. The current directory is your Project.Server root folder.

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