如何實(shí)現(xiàn) ASP.NET Core WebApi 的版本化
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Web API 的版本化可以盡量保證在相同url情況下保留一個(gè) api 的多個(gè)版本，通常一個(gè) webapi 會(huì)有多個(gè)client，這些client包括：app，web，html5，crawl 等等同構(gòu)或者異構(gòu)的平臺(tái)，當(dāng) api 升級(jí)之后，往往升級(jí)前的 api 也得保留，當(dāng)維護(hù)兩個(gè)api的時(shí)候就是一個(gè)不小的挑戰(zhàn)，畢竟還是存在一些 client 用戶(hù)需要訪(fǎng)問(wèn)老的api，這時(shí)候就需要將 webapi 版本化。
安裝 Versioning 包
要想使用 webapi 的版本化功能，需要用 nuget 引用 Microsoft.AspNetCore.Mvc.Versioning 包，還可以通過(guò) Visual Studio 2019 的 NuGet package manager 可視化界面安裝 或者 通過(guò) NuGet package manager 命令行工具輸入以下命令：
- dotnet add package Microsoft.AspNetCore.Mvc.Versioning
啟動(dòng) API 版本化
當(dāng)包成功添加到項(xiàng)目之后，接下來(lái)就可以在 Startup.ConfigureServices 中將 ApiVersioning 注入到容器中，如下代碼所示：
- public class Startup
- {
- public void ConfigureServices(IServiceCollection services)
- {
- services.AddControllers();
- services.AddApiVersioning();
- }
- }
在調(diào)用 AddApiVersioning() 的時(shí)候記得 using Microsoft.AspNetCore.Mvc.Versioning，除了這個(gè)默認(rèn)方法，還可以做一些全局配置，如下代碼所示：
- public class Startup
- {
- public void ConfigureServices(IServiceCollection services)
- {
- services.AddControllers();
- services.AddApiVersioning(v =>
- {
- v.ReportApiVersions = true;
- v.AssumeDefaultVersionWhenUnspecified = true;
- v.DefaultApiVersion = new ApiVersion(1, 0);
- });
- }
- }
使用 QueryString 指定版本號(hào)
先來(lái)看一下代碼，考慮如下的 api。
- [ApiController]
- [ApiVersion("2.0")]
- [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();
- }
- }
從代碼中可以看到，我在 WeatherForecastController 上標(biāo)記了該 Controller 是 v2.0 版本，接下來(lái)如何訪(fǎng)問(wèn)呢?可以通過(guò)如下鏈接: http://localhost:61582/api/weatherforecast?api-version=2.0
看到這里，有些朋友就有疑問(wèn)了，v2.0 的 Get 是有了，那 v1.0 的 Get 怎么訪(fǎng)問(wèn)呢?實(shí)際開(kāi)發(fā)中的做法是這樣的，會(huì)用兩個(gè)命名空間來(lái)表示相應(yīng)的版本號(hào)，可以看如下代碼：
- namespace WebApplication6.Controllers.v1
- {
- [ApiController]
- [ApiVersion("1.0")]
- [Route("api/[controller]")]
- public class WeatherForecastController : ControllerBase
- {
- private static readonly string[] Summaries = new[]
- {
- "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
- };
- private readonly ILogger<WeatherForecastController> _logger;
- public WeatherForecastController(ILogger<WeatherForecastController> logger)
- {
- _logger = logger;
- }
- [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();
- }
- }
- }
- namespace WebApplication6.Controllers.v2
- {
- [ApiController]
- [ApiVersion("2.0")]
- [Route("api/[controller]")]
- public class WeatherForecastController : ControllerBase
- {
- private static readonly string[] Summaries = new[]
- {
- "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
- };
- private readonly ILogger<WeatherForecastController> _logger;
- public WeatherForecastController(ILogger<WeatherForecastController> logger)
- {
- _logger = logger;
- }
- [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();
- }
- }
- }
從上面代碼可以看到 WebApplication6.Controllers.v1 表示版本 v1.0 ， WebApplication6.Controllers.v2 表示版本 v2.0，接下來(lái)依次瀏覽這兩個(gè)url。
使用 routes 指定版本號(hào)
很顯然使用 QueryString 的方式不是很優(yōu)雅也不符合 Restful 規(guī)范，接下來(lái)看一下如何通過(guò) Route 改造，考慮下面的類(lèi)，請(qǐng)注意我是如何在 route 中進(jìn)行版本化的。
- [ApiController]
- [ApiVersion("1.0")]
- [Route("api/v{version:apiVersion}/[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();
- }
- }
在這里，我將 [Route("api/[controller]")] 替換成了 [Route("api/v{version:apiVersion}/[controller]")]，接下來(lái)將項(xiàng)目跑起來(lái)，如下圖所示：
忽略 API 版本
在 API 版本化時(shí)，有些 API 可能只有一個(gè)版本的需求，這時(shí)候可以使用 ApiVersionNeutral 特性來(lái)忽視版本化，如下代碼所示：
- [ApiVersionNeutral]
- [Route("api/[controller]")]
- [ApiController]
- 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();
- }
- }
譯文鏈接：https://www.infoworld.com/article/3433156/advanced-versioning-in-aspnet-core-web-api.html
