dotnet 运行 OR dotnet watch with development environment from 命令行？

Question

我正在对运行 asp.net 核心项目使用 dotnet watch 命令。但是，默认情况下，它选择 Production 作为环境。

我已经尝试了两种选择：

1) > dotnet watch ASPNETCORE_ENVIRONMENT=Development

2) > dotnet run ASPNETCORE_ENVIRONMENT=Development

但它仍然将生产环境作为环境。

注意：在 visual studio 中，环境变量在项目属性中默认设置为 Development 并且运行ning from visual studio 选择该变量。

问题是：如何使用任一命令行运行开发中的 dotnet 核心项目？：

1) dotnet run
2) dotnet watch

Answer 1

ASPNETCORE_ENVIRONMENT 是一个环境变量（和 AFAIK）而不是切换到 dotnet cli。

所以你要做的是在使用该工具之前设置它：

rem Windows
C:\> set ASPNETCORE_ENVIRONMENT=Development
C:\> dotnet ...

rem Unix
$ export ASPNETCORE_ENVIRONMENT=Development
$ dotnet ...

Answer 2

你也可以在调用时设置变量内联dotnet:

ASPNETCORE_ENVIRONMENT=Development dotnet run

我发现这非常适合 NPM 脚本，但必须始终在 dotnet 之前调用，例如：

{
  ...
  "scripts": {
    "start": "cd MyApp && ASPNETCORE_ENVIRONMENT=Development dotnet run",
    "watch": "cd MyApp && ASPNETCORE_ENVIRONMENT=Development dotnet watch"
  },
}

注意：这只适用于OSX或Linux；对于跨平台解决方案，您可以使用 cross-env:

npm install cross-env -D

然后将脚本更改为：

{
  ...
  "scripts": {
    "start": "cd MyApp && cross-env ASPNETCORE_ENVIRONMENT=Development dotnet run",
    "watch": "cd MyApp && cross-env ASPNETCORE_ENVIRONMENT=Development dotnet watch"
  },
}

Answer 3

如果您调整 WebHostBuilder 处理其配置的方式，您不必使用环境变量。这只是 dotnet new -t web 的默认值。例如，如果您希望能够将默认环境设置为 "development" instead of production 并便于在命令行中覆盖环境，您可以通过修改正常的 Program.cs 代码来实现这个...

    public static void Main(string[] args) {
        var host = new WebHostBuilder()
            .UseKestrel()
            .UseUrls("http://0.0.0.0:5000")
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseIISIntegration()
            .UseStartup<Startup>()
            .Build();

        host.Run();
    }

...变成这样...

    private static readonly Dictionary<string, string> defaults =
        new Dictionary<string, string> {
            { WebHostDefaults.EnvironmentKey, "development" }
        };

    public static void Main(string[] args) {
        var configuration =
            new ConfigurationBuilder()
                .AddInMemoryCollection(defaults)
                .AddEnvironmentVariables("ASPNETCORE_")
                .AddCommandLine(args)
                .Build();

        var host =
            new WebHostBuilder()
                .UseConfiguration(configuration)
                .UseKestrel()
                .UseUrls("http://0.0.0.0:5000")
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseIISIntegration()
                .UseStartup<Startup>()
                .Build();

        host.Run();
    }

这样做，环境变量仍然有效，但您可以在命令行上覆盖它而无需任何第三方依赖项，如下所示：

dotnet run environment=development
dotnet run environment=staging

这其实就是the yeoman generators do.

Answer 4

来自 Building Single Page Applications on ASP.NET Core with JavaScriptServices（已添加样式）：

If you’re using PowerShell in Windows, execute $Env:ASPNETCORE_ENVIRONMENT = "Development"

If you’re using cmd.exe in Windows, execute setx ASPNETCORE_ENVIRONMENT "Development", and then restart your command prompt to make the change take effect

If you’re using Mac/Linux, execute export ASPNETCORE_ENVIRONMENT=Development

Answer 5

感谢@Technetium 的回答，这是 dotnetcore 2.0 的更新，对我来说非常有效：

public class Program
    {
        private static readonly Dictionary<string, string> defaults = new Dictionary<string, string> {{ WebHostDefaults.EnvironmentKey, "Development" }};
        private static IConfiguration config;
        public static void Main(string[] args)
        {
            config = new ConfigurationBuilder()
                .AddInMemoryCollection(defaults)
                .AddEnvironmentVariables("ASPNETCORE_")
                .AddCommandLine(args)
                .Build();
            BuildWebHost(args).Run();
        }
public static IWebHost BuildWebHost(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseConfiguration(config)
                /* Following setting already accounted for in CreateDefaultBuilder() : https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.webhost.createdefaultbuilder?view=aspnetcore-2.0 */
                // .UseContentRoot(Directory.GetCurrentDirectory())
                .UseStartup<Startup>()
                .Build();
    }

再次感谢@Technetium

Answer 6

检查文档

https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-run?tabs=netcore21

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/environments?view=aspnetcore-2.1

dotnet run --launch-profile EnvironmentsSample

launchSettings.json

{ 
  "profiles": {    
    "EnvironmentsSample": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Staging"
      },
      "applicationUrl": "http://localhost:54340/"
    },   
  }
}

dotnet 运行 OR dotnet watch with development environment from 命令行？

dotnet run OR dotnet watch with development environment from command line?

.net-core

asp.net-core

dotnet-cli

.net-core-rc2