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