使用.Net Core编写命令行工具(CLI)

2019/04/10 10:10
阅读数 82

命令行工具(CLI)

  命令行工具(CLI)是在图形用户界面得到普及之前使用最为广泛的用户界面,它通常不支持鼠标,用户通过键盘输入指令,计算机接收到指令后,予以执行。

  通常认为,命令行工具(CLI)没有图形用户界面(GUI)那么方便用户操作。因为,命令行工具的软件通常需要用户记忆操作的命令,但是,由于其本身的特点,命令行工具要较图形用户界面节约计算机系统的资源。在熟记命令的前提下,使用命令行工具往往要较使用图形用户界面的操作速度要快。所以,图形用户界面的操作系统中,都保留着可选的命令行工具。

  另外,命令行工具(CLI)应该是一个开箱即用的工具,不需要安装任何依赖。

  一些熟悉的CLI工具如下:

  1. dotnet cli

  2. vue cli

  3. angular cli

  4. aws cli

  5. azure cli

 

 指令设计

  本文将使用.Net Core(版本3.1.102)编写一个CLI工具,实现配置管理以及条目(item)管理(调用WebApi实现),详情如下:

  

 

框架说明 

  编写CLI使用的主要框架是CommandLineUtils,它主要有以下优势:

  1. 良好的语法设计

  2. 支持依赖注入

  3. 支持generic host

 

WebApi

  提供api让cli调用,实现条目(item)的增删改查:

[Route("api/items")]
[ApiController]
public class ItemsController : ControllerBase
{
    private readonly IMemoryCache _cache;
    private readonly string _key = "items";

    public ItemsController(IMemoryCache memoryCache)
    {
        _cache = memoryCache;
    }

    [HttpGet]
    public IActionResult List()
    {
        var items = _cache.Get<List<Item>>(_key);
        return Ok(items);
    }

    [HttpGet("{id}")]
    public IActionResult Get(string id)
    {
        var item = _cache.Get<List<Item>>(_key).FirstOrDefault(n => n.Id == id);
        return Ok(item);
    }

    [HttpPost]
    public IActionResult Create(ItemForm form)
    {
        var items = _cache.Get<List<Item>>(_key) ?? new List<Item>();

        var item = new Item
        {
            Id = Guid.NewGuid().ToString("N"),
            Name = form.Name,
            Age = form.Age
        };

        items.Add(item);

        _cache.Set(_key, items);
        
        return Ok(item);
    }

    [HttpDelete("{id}")]
    public IActionResult Delete(string id)
    {
        var items = _cache.Get<List<Item>>(_key);

        var item = items?.SingleOrDefault(n => n.Id == id);
        if (item == null)
        {
            return NotFound();
        }

        items.Remove(item);
        _cache.Set(_key, items);

        return Ok();
    }
}

 

CLI

  1. Program - 函数入口

[HelpOption(Inherited = true)] //显示指令帮助,并且让子指令也继承此设置
[Command(Description = "A tool to communicate with web api"), //指令描述
 Subcommand(typeof(ConfigCommand), typeof(ItemCommand))] //子指令
class Program
{
    public static int Main(string[] args)
    {
//配置依赖注入
var serviceCollection = new ServiceCollection(); serviceCollection.AddSingleton(PhysicalConsole.Singleton); serviceCollection.AddSingleton<IConfigService, ConfigService>(); serviceCollection.AddHttpClient<IItemClient, ItemClient>(); var services = serviceCollection.BuildServiceProvider(); var app = new CommandLineApplication<Program>(); app.Conventions .UseDefaultConventions() .UseConstructorInjection(services); var console = (IConsole)services.GetService(typeof(IConsole)); try { return app.Execute(args); } catch (UnrecognizedCommandParsingException ex) //处理未定义指令 { console.WriteLine(ex.Message); return -1; } }
//指令逻辑
private int OnExecute(CommandLineApplication app, IConsole console) { console.WriteLine("Please specify a command."); app.ShowHelp(); return 1; } }

 

  2. ConfigCommand和ItemCommand - 实现的功能比较简单,主要是指令描述以及指定对应的子指令

[Command("config", Description = "Manage config"),
 Subcommand(typeof(GetCommand), typeof(SetCommand))]
public class ConfigCommand
{
    private int OnExecute(CommandLineApplication app, IConsole console)
    {
        console.Error.WriteLine("Please submit a sub command.");
        app.ShowHelp();
        return 1;
    }
}

[Command("item", Description = "Manage item"),
 Subcommand(typeof(CreateCommand), typeof(GetCommand), typeof(ListCommand), typeof(DeleteCommand))]
public class ItemCommand
{
    private int OnExecute(CommandLineApplication app, IConsole console)
    {
        console.Error.WriteLine("Please submit a sub command.");
        app.ShowHelp();
        return 1;
    }
}

 

  3. ConfigService - 配置管理的具体实现,主要是文件读写

public interface IConfigService
{
    void Set();

    Config Get();
}

public class ConfigService: IConfigService
{
    private readonly IConsole _console;
    private readonly string _directoryName;
    private readonly string _fileName;

    public ConfigService(IConsole console)
    {
        _console = console;
        _directoryName = ".api-cli";
        _fileName = "config.json";
    }

    public void Set()
    {
        var directory = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), _directoryName);
        if (!Directory.Exists(directory))
        {
            Directory.CreateDirectory(directory);
        }

        var config = new Config
        {
//弹出交互框,让用户输入,设置默认值为http://localhost:5000/ Endpoint
= Prompt.GetString("Specify the endpoint:", "http://localhost:5000/") }; if (!config.Endpoint.EndsWith("/")) { config.Endpoint += "/"; } var filePath = Path.Combine(directory, _fileName); using (var outputFile = new StreamWriter(filePath, false, Encoding.UTF8)) { outputFile.WriteLine(JsonConvert.SerializeObject(config, Formatting.Indented)); } _console.WriteLine($"Config saved in {filePath}."); } public Config Get() { var filePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), _directoryName, _fileName); if (File.Exists(filePath)) { var content = File.ReadAllText(filePath); try { var config = JsonConvert.DeserializeObject<Config>(content); return config; } catch { _console.WriteLine("The config is invalid, please use 'config set' command to reset one."); } } else { _console.WriteLine("Config is not existed, please use 'config set' command to set one."); } return null; } }

 

  4. ItemClient - 调用Web Api的具体实现,使用HttpClientFactory的方式

public interface IItemClient
{
    Task<string> Create(ItemForm form);

    Task<string> Get(string id);

    Task<string> List();

    Task<string> Delete(string id);
}

public class ItemClient : IItemClient
{
    public HttpClient Client { get; }

    public ItemClient(HttpClient client, IConfigService configService)
    {
        var config = configService.Get();
        if (config == null)
        {
            return;
        }

        client.BaseAddress = new Uri(config.Endpoint);

        Client = client;
    }

    public async Task<string> Create(ItemForm form)
    {
        var content = new StringContent(JsonConvert.SerializeObject(form), Encoding.UTF8, "application/json");
        var result = await Client.PostAsync("/api/items", content);

        if (result.IsSuccessStatusCode)
        {
            var stream = await result.Content.ReadAsStreamAsync();
            var item = Deserialize<Item>(stream);
            return $"Item created, info:{item}";
        }

        return "Error occur, please again later.";
    }

    public async Task<string> Get(string id)
    {
        var result = await Client.GetAsync($"/api/items/{id}");

        if (result.IsSuccessStatusCode)
        {
            var stream = await result.Content.ReadAsStreamAsync();
            var item = Deserialize<Item>(stream);

            var response = new StringBuilder();
            response.AppendLine($"{"Id".PadRight(40, ' ')}{"Name".PadRight(20, ' ')}Age");
            response.AppendLine($"{item.Id.PadRight(40, ' ')}{item.Name.PadRight(20, ' ')}{item.Age}");
            return response.ToString();
        }

        return "Error occur, please again later.";
    }

    public async Task<string> List()
    {
        var result = await Client.GetAsync($"/api/items");

        if (result.IsSuccessStatusCode)
        {
            var stream = await result.Content.ReadAsStreamAsync();
            var items = Deserialize<List<Item>>(stream);

            var response = new StringBuilder();
            response.AppendLine($"{"Id".PadRight(40, ' ')}{"Name".PadRight(20, ' ')}Age");

            if (items != null && items.Count > 0)
            {
                foreach (var item in items)
                {
                    response.AppendLine($"{item.Id.PadRight(40, ' ')}{item.Name.PadRight(20, ' ')}{item.Age}");
                }
            }
            
            return response.ToString();
        }

        return "Error occur, please again later.";
    }

    public async Task<string> Delete(string id)
    {
        var result = await Client.DeleteAsync($"/api/items/{id}");

        if (result.IsSuccessStatusCode)
        {
            return $"Item {id} deleted.";
        }

        if (result.StatusCode == HttpStatusCode.NotFound)
        {
            return $"Item {id} not found.";
        }

        return "Error occur, please again later.";
    }

    private static T Deserialize<T>(Stream stream)
    {
        using var reader = new JsonTextReader(new StreamReader(stream));
        var serializer = new JsonSerializer();
        return (T)serializer.Deserialize(reader, typeof(T));
    }
}

 

如何发布

  在项目文件中设置发布程序的名称(AssemblyName):

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <AssemblyName>api-cli</AssemblyName>
  </PropertyGroup>

 

  进入控制台程序目录:

  cd src/NetCoreCLI

 

  发布Linux使用版本:

  dotnet publish -c Release -r linux-x64 /p:PublishSingleFile=true

 

  发布Windows使用版本:

  dotnet publish -c Release -r win-x64 /p:PublishSingleFile=true

 

  发布MAC使用版本:

dotnet publish -c Release -r osx-x64 /p:PublishSingleFile=true

 

使用示例

  这里使用Linux作为示例环境。

  1. 以docker的方式启动web api

  

 

  2. 虚拟机上没有安装.net core的环境

  

 

  3. 把编译好的CLI工具拷贝到虚拟机上,授权并移动到PATH中(如果不移动,可以通过./api-cli的方式调用)

sudo chmod +x api-cli #授权
    sudo mv ./api-cli /usr/local/bin/api-cli #移动到PATH

 

  4. 设置配置文件:api-cli config set

  

 

  5. 查看配置文件:api-cli config get

  

 

  6. 创建条目:api-cli item create 

  

 

  7. 条目列表:api-cli item list

  

 

  8. 获取条目:api-cli item get

  

 

  9. 删除条目:api-cli item delete

  

 

  10. 指令帮助:api-cli -h, api-cli config -h, api-cli item -h

  

  

  

 

   11. 错误指令:api-cli xxx

  

 

源码地址

  https://github.com/ErikXu/NetCoreCLI

 

参考资料

  https://docs.microsoft.com/en-us/dotnet/core/rid-catalog#using-rids](https://docs.microsoft.com/en-us/dotnet/core/rid-catalog#using-rids

  https://medium.com/swlh/build-a-command-line-interface-cli-program-with-net-core-428c4c85221

原文出处:https://www.cnblogs.com/Erik_Xu/p/12374379.html

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