如何在 Asp.net core 6 Program.cs 文件中使用 appsettings.json

Question

我正在尝试访问我的 Asp.net 核心 v6 应用程序 Program.cs 文件中的 appsettings.json，但在这个版本的 .Net 中，Startup 类和 Program 类合并在一起，并且简化了 using 和另一个语句，并且从 Program.cs 中删除。在这种情况下，如何访问 IConfiguration 或如何使用依赖注入？

已编辑： 这是 Asp.net 6 为我创建的默认 Program.cs

var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
builder.Services.AddStackExchangeRedisCache(options =>
{
    options.Configuration = "localhost:6379";
});

builder.Services.AddSwaggerGen(c =>
{
    c.SwaggerDoc("v1", new() { Title = "BasketAPI", Version = "v1" });
});
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "BasketAPI v1"));
}
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();

例如，我想在这一行中使用 appsettings.json 而不是硬类型的连接字符串：

options.Configuration = "localhost:6379";

Answer 1

虽然上面的示例有效，但执行此操作的方法如下：

var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
builder.Services.AddStackExchangeRedisCache(options =>
{
    options.Configuration = builder.Configuration["Redis"];
});

WebApplicationBuilder 有一个配置对象作为您可以使用的属性。

Answer 2

默认包含appsettings.json，可以直接使用。 如果你想明确地包含文件，你可以像这样包含它们

builder.Configuration.AddJsonFile("errorcodes.json", false, true);

还有像这样的依赖注入

builder.Services.AddDbContext<>() // like you would in older .net core projects.

Answer 3

假设一个 appsettings.json

{
    "RedisCacheOptions" : {
        "Configuration": "localhost:6379"
    }
}

没有什么能阻止您构建配置对象以提取所需的设置。

IConfiguration configuration = new ConfigurationBuilder()
                            .AddJsonFile("appsettings.json")
                            .Build();

var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
builder.Services.AddStackExchangeRedisCache(options => {
    options.Configuration = configuration["RedisCacheOptions:Configuration"];
});

//...

Answer 4

创建一个类：

public class RedisCacheOptions
{
    public string Configuration { get; set; }
}

然后，在您的 program.cs 中，执行以下操作：

var redisCacheOptions = new RedisCacheOptions();
builder.Configuration.GetSection(nameof(RedisCacheOptions)).Bind(redisCacheOptions);

您现在可以通过简单的说来访问配置信息：

redisCacheOptions.Configuration

现在假设您在 appSettings.json 中有一个 嵌套 结构，如下所示：

"AuthenticationConfiguration": {
  "JwtBearerConfiguration": {
    "Authority": "https://securetoken.google.com/somevalue",
    "TokenValidationConfiguration": {
      "Issuer": "https://securetoken.google.com/somevalue",
      "Audience": "somevalue"
    }
  }
}

那么，你的类结构会是这样的：

public class AuthenticationConfiguration
{
    public JwtBearerConfiguration JwtBearerConfiguration { get; set; } = new JwtBearerConfiguration();
}

public class JwtBearerConfiguration
{
    public string Authority { get; set; }

    public TokenValidationConfiguration TokenValidationConfiguration { get; set; } =
        new TokenValidationConfiguration();
}

public class TokenValidationConfiguration
{
    public string Issuer { get; set; }
    public string Audience { get; set; }
}

如果你这样做的话：

var authConf = new AuthenticationConfiguration();
builder.Configuration.GetSection(nameof(AuthenticationConfiguration)).Bind(authConf);

然后在您的程序中，您可以通过以下方式访问值：

AuthenticationConfiguration.JwtBearerConfiguration.Authority

这种方法可以让您不再使用魔术字符串，而且还可以获得 IntelliSense，所以这是双赢的。

Answer 5

如果我们在 appsettings 中有

"settings": {
    "url": "myurl",
    "username": "guest",
    "password": "guest"
  }

我们有课

public class Settings
    {
        public string Url { get; set; }
        public string Username { get; set; }
        public string Password { get; set; }
    }

我们也可以使用

var settings = builder.Configuration.GetSection("Settings").Get<Settings>();

var url = settings.Url; 等等......

Answer 6

在 Program.cs 中，试试这个代码：

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

ConfigurationManager configuration = builder.Configuration;

var rabbitMQSection = Configuration.GetSection("RabbitMQ");
var rabbitMQConnectionUrl = rabbitMQSection["ConnectionUrl"];

appsettings.json 文件在哪里：

"AllowedHosts": "*",
"RabbitMQ": {
    "ConnectionUrl": "amqp://guest:guest@localhost:5672/"
}

Answer 7

在 .NET 6 中

appSettings.json

{
  "Authentication": {
    "CookieAuthentication": {
      "LoginPath": "/Security/Login"
    }
  },
  "TestValue" :  "Testing data"
}

程序.cs

var builder = WebApplication.CreateBuilder(args);

var testValue = builder.Configuration.GetValue<string>("TestValue");

var cookieAuthenticationLoginPath = builder.Configuration.GetValue<string>("Authentication:CookieAuthentication:LoginPath");

Answer 8

已解决：在dotnet6的program.css中获取appsetting值

appsettings.json

  "AllowedHosts": "*",
  "ServiceUrls": {
  "EmployeeAPI": "https://localhost:44377/" },

程序.cs

var builder = WebApplication.CreateBuilder(args);    
var provider = builder.Services.BuildServiceProvider();
var configuration = provider.GetService<IConfiguration>();
SD.EmployeeAPIBase = configuration.GetValue<string>("ServiceUrls:EmployeeAPI");

类静态变量：

public static class SD //Static Details
{
    public static string EmployeeAPIBase { get; set; }     
}

最后，使用完整的网址

URL = SD.EmployeeAPIBase + "api/EmpContact/GetGovernates"

Answer 9

您可以像这样在Program.cs 中从appsettings.json 文件中读取设置值：

var dbConnectionString = builder.Configuration.GetSection("ConnectionStrings:TestDbConnection").Value;

考虑到您的appsettings.json 文件中的设置如下所示：

  "ConnectionStrings": {
    "TestDbConnection": ""
  }

Answer 10

除了@dimmits 和@Sarwarul Rizvi 回答之外，如果你想读取一个普通的键值对而不是映射到一个复杂的对象，你可以使用：

appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Information",
      "Microsoft.AspNetCore.SpaProxy": "Information",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedOrigins": "https://localhost:444/YourApplicationUri;https://localhost:7211",
  "ConnectionStrings": {
    "Default": "Connection String details"
  }
}

程序.cs

ConfigurationManager configuration = builder.Configuration;
var allowedOrigins = configuration.GetValue<string>("AllowedOrigins");

这可以用于例如配置 Cors

if (!String.IsNullOrEmpty(allowedOrigins))
{
    builder.Services.AddCors(options =>
    {
        var origins = allowedOrigins.Split(";");

        options.AddPolicy("CorsPolicy", policy =>
        {
            policy.AllowAnyMethod()
                .AllowAnyHeader()
                .AllowCredentials()
                .WithOrigins(origins);
        });
    });
}

以后及以下 app.UseRouting();

app.UseCors("CorsPolicy");