.NET Core development actual combat (Lesson 9: command line configuration provider) - Study Notes

09 | Command Line Configuration Provider: The easiest and quickest to configure injection method

This section explains how to use the command-line parameters to configure the data source as

Command line configuration (provider) supports three formats of command

1, no prefix mode key = value

2, dual-mode --key = value hyphens or --key value

3, n-bar pattern / key = value or / key value

NOTE: The equal sign separators and separator spaces can not be mixed

Replace Mode command: command parameters aliasing

1, must begin with a single dash (- -) or a double bar ()

2, Key mapping dictionary can not contain duplicate

Source link:
https://github.com/witskeeper/geektime/tree/master/samples/ConfigurationCommandLineDemo

First introduced three packages

• Microsoft.Extensions.Configuration.Abstractions
• Microsoft.Extensions.Configuration
• Microsoft.Extensions.Configuration.CommandLine

The main program

namespace ConfigurationCommandLineDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder();

            // 把入参传递给命令行参提供程序
            builder.AddCommandLine(args);

            var configurationRoot = builder.Build();

            Console.WriteLine($"CommandLineKey1:{configurationRoot["CommandLineKey1"]}");
            Console.WriteLine($"CommandLineKey2:{configurationRoot["CommandLineKey2"]}");
            Console.ReadKey();
        }
    }
}

Right-property project, command set debug mode startup parameters

CommandLineKey1=value1 --CommandLineKey2=value2 /CommandLineKey3=value3 --k1=k3

You can also edit files, launchSettings.json

{
  "profiles": {
    "ConfigurationCommandLineDemo": {
      "commandName": "Project",
      "commandLineArgs": "CommandLineKey1=value1 --CommandLineKey2=value2 /CommandLineKey3=value3 --k1=k3"
    }
  }
}

Start the program, the output is as follows:

CommandLineKey1:value1
CommandLineKey2:value2

Followed by command substitution

namespace ConfigurationCommandLineDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder();

            //// 把入参传递给命令行参提供程序
            //builder.AddCommandLine(args);

            #region 命令替换
            var mapper = new Dictionary<string, string> { { "-k1", "CommandLineKey1" } };
            builder.AddCommandLine(args, mapper);
            #endregion

            var configurationRoot = builder.Build();

            Console.WriteLine($"CommandLineKey1:{configurationRoot["CommandLineKey1"]}");
            Console.WriteLine($"CommandLineKey2:{configurationRoot["CommandLineKey2"]}");
            Console.ReadKey();
        }
    }
}

The double bar --k1 = k3 to single bar -k1 = k3

{
  "profiles": {
    "ConfigurationCommandLineDemo": {
      "commandName": "Project",
      "commandLineArgs": "CommandLineKey1=value1 --CommandLineKey2=value2 /CommandLineKey3=value3 -k1=k3"
    }
  }
}

Start the program, the output is as follows:

CommandLineKey1:k3
CommandLineKey2:value2

As can be seen, -k1 replacement value inside CommandLineKey1

This scene is what to do?

.NET can actually look at their command-line tool

Open the console, enter dotnet --help

sdk-options:
  -d|--diagnostics  启用诊断输出。
  -h|--help         显示命令行帮助。
  --info            显示 .NET Core 信息。
  --list-runtimes   显示安装的运行时。
  --list-sdks       显示安装的 SDK。
  --version         显示使用中的 .NET Core SDK 版本。

Here you can see options to support dual bars long name and short name of the single bars

In fact most typical scenario is to use the command-line parameters provide a way of naming quick short name, for example, you can replace -h --help

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