c# - 如何在blazor Webassembly中访问appsettings

Question

我目前正在尝试将api网址保存在appsettings中。
但是，configuration.Propertiers似乎是空的。我不确定如何获取设置。
在program.cs中:

public static async Task Main(string[] args)
{
   var builder = WebAssemblyHostBuilder.CreateDefault(args);
   //string url = builder.Configuration.Properties["APIURL"].ToString();
   foreach (var prop in builder.Configuration.Properties)
      Console.WriteLine($"{prop.Key} : {prop.Value}" );
   //builder.Services.AddSingleton<Service>(new Service(url));
   builder.RootComponents.Add<App>("app");
   await builder.Build().RunAsync();
}

Answer 1

我通过使用应用程序wwwroot文件夹中的settings.json文件存储来解决此问题，并注册一个任务来获取设置:

Settings.cs

public class Settings
{
    public string ApiUrl { get; set; }
}

wwwroot/settings.json

{
   "ApiUrl": "https://localhost:51443/api"
}

Progam.cs

public static async Task Main(string[] args)
{
    var builder = WebAssemblyHostBuilder.CreateDefault(args);

    builder.Services.AddSingleton(async p =>
    {
        var httpClient = p.GetRequiredService<HttpClient>();
        return await httpClient.GetJsonAsync<Settings>("settings.json")
            .ConfigureAwait(false);
    });

SampleComponent.razor

@inject Task<Settings> getsettingsTask
@inject HttpClient client
...
@code {
    private async Task CallApi()
    {
        var settings = await getsettingsTask();
        var response = await client.GetJsonAsync<SomeResult>(settings.ApiUrl);
    }
}

这具有以下优点:

不共享服务器的appsettings.json文件，这可能是一个安全漏洞

每个环境可配置