向现有WebAPI添加版本控制

https://api.example.com/v1/users
https://api.example.com/v2/users

// ASP.NET Core 示例
[RoutePrefix("api/v{version:int}")]
public class UsersController : ControllerBase
{
    [HttpGet]
    [Route("users")]
    public IActionResult GetUsers(int version)
    {
        if (version == 1)
        {
            // 处理版本1的逻辑
        }
        else if (version == 2)
        {
            // 处理版本2的逻辑
        }
        return Ok();
    }
}

GET /api/users HTTP/1.1
Host: api.example.com
X-API-Version: 1

// ASP.NET Core 示例
public class ApiVersionMiddleware
{
    private readonly RequestDelegate _next;

    public ApiVersionMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        var version = context.Request.Headers["X-API-Version"].FirstOrDefault();
        if (version != null)
        {
            // 设置版本信息到HttpContext.Items中
            context.Items["ApiVersion"] = version;
        }
        await _next(context);
    }
}

https://api.example.com/users?version=1
https://api.example.com/users?version=2

// ASP.NET Core 示例
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
    [HttpGet]
    public IActionResult GetUsers([FromQuery] int version = 1)
    {
        if (version == 1)
        {
            // 处理版本1的逻辑
        }
        else if (version == 2)
        {
            // 处理版本2的逻辑
        }
        return Ok();
    }
}

GET /api/users HTTP/1.1
Host: api.example.com
Accept: application/vnd.example.v1+json

// ASP.NET Core 示例
[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
    [HttpGet]
    [Produces("application/vnd.example.v1+json")]
    public IActionResult GetUsersV1()
    {
        // 处理版本1的逻辑
        return Ok();
    }

    [HttpGet]
    [Produces("application/vnd.example.v2+json")]
    public IActionResult GetUsersV2()
    {
        // 处理版本2的逻辑
        return Ok();
    }
}