網關介紹
網關其實就是將我們寫好的API全部放在一個統一的地址暴露在公網，提供訪問的一個入口，在 .NET Core下可以使用Ocelot來幫助我們很方便的接入API 網關，與之類似的庫還有ProxyKit，微軟也發布了一個反向代理的庫YARP，
關于網關的介紹不多說了，網上文章也挺多的，這些都是不錯的選擇，聽說后期Ocelot將會使用YARP來重寫，本篇主要實踐一下在.NET Core環境下使用Ocelot，
- Ocelot官網：https://threemammals.com/ocelot
- Ocelot檔案：https://ocelot.readthedocs.io
- GitHub：https://github.com/ThreeMammals/Ocelot
- Ocelot資源匯總：https://www.cnblogs.com/shanyou/p/10363360.html
接入使用
介面示例
先創建幾個專案用于測驗，創建兩個默認的API專案，Api_A和Api_B，在創建一個網關專案Api_Gateway，網關專案可以選擇空的模板，
現在分別在Api_A和Api_B中寫幾個api，將默認的WeatherForecastController中回傳模型WeatherForecast添加一個欄位Source，用于區分是哪個API回傳的資料，
using System;
namespace Api_A
{
public class WeatherForecast
{
public string Source { get; set; } = "Api_A";
public DateTime Date { get; set; }
public int TemperatureC { get; set; }
public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
public string Summary { get; set; }
}
}
using System;
namespace Api_B
{
public class WeatherForecast
{
public string Source { get; set; } = "Api_B";
public DateTime Date { get; set; }
public int TemperatureC { get; set; }
public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
public string Summary { get; set; }
}
}
直接使用WeatherForecastController默認方法，在路由中添加api前綴，
using Microsoft.AspNetCore.Mvc;
using System;
using System.Collections.Generic;
using System.Linq;
namespace Api_A.Controllers
{
[ApiController]
[Route("api/[controller]")]
public class WeatherForecastController : ControllerBase
{
private static readonly string[] Summaries = new[]
{
"Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
};
[HttpGet]
public IEnumerable<WeatherForecast> Get()
{
var rng = new Random();
return Enumerable.Range(1, 5).Select(index => new WeatherForecast
{
Date = DateTime.Now.AddDays(index),
TemperatureC = rng.Next(-20, 55),
Summary = Summaries[rng.Next(Summaries.Length)]
}).ToArray();
}
}
}
using Microsoft.AspNetCore.Mvc;
using System;
using System.Collections.Generic;
using System.Linq;
namespace Api_B.Controllers
{
[ApiController]
[Route("api/[controller]")]
public class WeatherForecastController : ControllerBase
{
private static readonly string[] Summaries = new[]
{
"Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
};
[HttpGet]
public IEnumerable<WeatherForecast> Get()
{
var rng = new Random();
return Enumerable.Range(1, 5).Select(index => new WeatherForecast
{
Date = DateTime.Now.AddDays(index),
TemperatureC = rng.Next(-20, 55),
Summary = Summaries[rng.Next(Summaries.Length)]
}).ToArray();
}
}
}
再分別在Api_A和Api_B中添加兩個控制器：ApiAController、ApiBController，然后加上幾個簡單的restful api，
using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;
namespace Api_A.Controllers
{
[Route("api/[controller]")]
[ApiController]
public class ApiAController : ControllerBase
{
[HttpGet]
public IEnumerable<string> Get()
{
return new string[] { "value1", "value2" };
}
[HttpGet("{id}")]
public string Get(int id)
{
return $"Get：{id}";
}
[HttpPost]
public string Post([FromForm] string value)
{
return $"Post:{value}";
}
[HttpPut("{id}")]
public string Put(int id, [FromForm] string value)
{
return $"Put:{id}:{value}";
}
[HttpDelete("{id}")]
public string Delete(int id)
{
return $"Delete:{id}";
}
}
}
using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;
namespace Api_B.Controllers
{
[Route("api/[controller]")]
[ApiController]
public class ApiBController : ControllerBase
{
[HttpGet]
public IEnumerable<string> Get()
{
return new string[] { "value1", "value2" };
}
[HttpGet("{id}")]
public string Get(int id)
{
return $"Get：{id}";
}
[HttpPost]
public string Post([FromForm] string value)
{
return $"Post:{value}";
}
[HttpPut("{id}")]
public string Put(int id, [FromForm] string value)
{
return $"Put:{id}:{value}";
}
[HttpDelete("{id}")]
public string Delete(int id)
{
return $"Delete:{id}";
}
}
}
方便查看介面，這里添加一下swagger組件，這樣我們Api_A和Api_B專案分別就有了6個介面，
接著打包docker鏡像，放在docker中運行這兩個api專案，這一步可以用任何你熟悉的方式，run起來即可，
docker build -t api_a:dev -f ./Api_A/Dockerfile .
docker build -t api_b:dev -f ./Api_B/Dockerfile .
build成功后，指定兩個埠運行api專案，
docker run -d -p 5050:80 --name api_a api_a:dev
docker run -d -p 5051:80 --name api_b api_b:dev
Api_A指定了5050埠，通過 http://localhost:5050/swagger打開可以看到swagger檔案界面，Api_B指定了5051埠，通過 http://localhost:5051/swagger打開可以看到swagger檔案界面，這樣就大功告成了，接下來才是重點將兩個api專案配置到Api_Gateway網關專案中，
配置網關
在網關專案Api_Gateway中都添加Ocelot組件包，
Install-Package Ocelot
Ocelot中最關鍵的就是配置路由資訊，新建一個ocelot.json組態檔，將我們的兩個API介面匹配規則放進去，
{
"Routes": [
//ApiA
{
"DownstreamPathTemplate": "/api/WeatherForecast",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "localhost",
"Port": 5050
}
],
"UpstreamPathTemplate": "/ApiA/WeatherForecast",
"UpstreamHttpMethod": [ "Get" ]
},
{
"DownstreamPathTemplate": "/api/ApiA",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "localhost",
"Port": 5050
}
],
"UpstreamPathTemplate": "/ApiA",
"UpstreamHttpMethod": [ "Get", "POST" ]
},
{
"DownstreamPathTemplate": "/api/ApiA/{id}",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "localhost",
"Port": 5050
}
],
"UpstreamPathTemplate": "/ApiA/{id}",
"UpstreamHttpMethod": [ "Get", "Put", "Delete" ]
},
//ApiB
{
"DownstreamPathTemplate": "/api/WeatherForecast",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "localhost",
"Port": 5051
}
],
"UpstreamPathTemplate": "/ApiB/WeatherForecast",
"UpstreamHttpMethod": [ "Get" ]
},
{
"DownstreamPathTemplate": "/api/ApiB",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "localhost",
"Port": 5051
}
],
"UpstreamPathTemplate": "/ApiB",
"UpstreamHttpMethod": [ "Get", "POST" ]
},
{
"DownstreamPathTemplate": "/api/ApiB/{id}",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "localhost",
"Port": 5051
}
],
"UpstreamPathTemplate": "/ApiB/{id}",
"UpstreamHttpMethod": [ "Get", "Put", "Delete" ]
}
],
"GlobalConfiguration": {
"BaseUrl": "https://localhost:44335"
}
}
關于組態檔中的各項具體含義，可以參考官方檔案中的介紹，主要就是將DownstreamPathTemplate模板內容轉換為UpstreamPathTemplate模板內容進行介面的訪問，同時可以指定HTTP請求的方式等等，GlobalConfiguration中的BaseUrl為我們暴漏出去的網關地址，
設定好ocelot.json后，需要在代碼中使用它，在Program.cs中添加組態檔，
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
namespace Api_Gateway
{
public class Program
{
public static void Main(string[] args)
{
CreateHostBuilder(args).Build().Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureAppConfiguration((context, config) =>
{
config.AddJsonFile("ocelot.json", optional: false, reloadOnChange: true);
})
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup<Startup>();
});
}
}
在Startup.cs中使用Ocelot，
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Ocelot.DependencyInjection;
using Ocelot.Middleware;
namespace Api_Gateway
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddOcelot();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapGet("/", async context =>
{
await context.Response.WriteAsync("Hello World!");
});
});
app.UseOcelot().Wait();
}
}
}
完成以上操作后，我們試著去呼叫介面看看能否正確獲取預期資料，
curl -X GET "https://localhost:44335/ApiA"
curl -X GET "https://localhost:44335/ApiB"
curl -X POST "https://localhost:44335/ApiA" -H "Content-Type: multipart/form-data" -F "value=https://www.cnblogs.com/meowv/archive/2020/09/28/ApiA"
curl -X POST "https://localhost:44335/ApiB" -H "Content-Type: multipart/form-data" -F "value=https://www.cnblogs.com/meowv/archive/2020/09/28/ApiB"
curl -X GET "https://localhost:44335/ApiA/12345"
curl -X GET "https://localhost:44335/ApiB/12345"
curl -X PUT "https://localhost:44335/ApiA/12345" -H "Content-Type: multipart/form-data" -F "value=https://www.cnblogs.com/meowv/archive/2020/09/28/ApiA"
curl -X PUT "https://localhost:44335/ApiB/12345" -H "Content-Type: multipart/form-data" -F "value=https://www.cnblogs.com/meowv/archive/2020/09/28/ApiB"
curl -X DELETE "https://localhost:44335/ApiA/12345"
curl -X DELETE "https://localhost:44335/ApiB/12345"
curl -X GET "https://localhost:44335/ApiA/WeatherForecast"
curl -X GET "https://localhost:44335/ApiB/WeatherForecast"
可以看到，兩個專案中的介面全部可以通過網關專案暴露的地址進行中轉，是不是很方便？
本篇只是簡單的應用，對于Ocelot的功能遠不止于此，它非常強大，還可以實作請求聚合、服務發現、認證、鑒權、限流熔斷、并內置了負載均衡器，而且這些功能都是只需要簡單的配置即可完成，就不一一描述了，如有實際開發需求和問題，可以查看官方檔案和示例，
轉載請註明出處，本文鏈接：https://www.uj5u.com/net/134794.html
標籤：.NET技术