// IApiMediator.cs
using Microsoft.AspNetCore.Mvc;
using System.Threading.Tasks;
namespace DotNet8ApiVersionExample;
public interface IApiMediator
{
void RegisterHandler(IRequestHandler handler);
Task<IActionResult> ProcessRequestAsync(string version, string action, object? data);
Task<object?> ForwardRequestAsync(string targetVersion, string action, object? data);
}
// IRequestHandler.cs
namespace DotNet8ApiVersionExample;
public interface IRequestHandler
{
string SupportedVersion { get; }
void SetMediator(IApiMediator mediator);
Task<IActionResult> HandleRequestAsync(string action, object? data);
}

// ApiMediator.cs
using Microsoft.AspNetCore.Mvc;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
namespace DotNet8ApiVersionExample;
public class ApiMediator : IApiMediator
{
private readonly Dictionary<string, IRequestHandler> _handlers = new();
public void RegisterHandler(IRequestHandler handler)
{
if (handler == null)
throw new ArgumentNullException(nameof(handler));
var version = handler.SupportedVersion;
if (!_handlers.ContainsKey(version))
{
_handlers.Add(version, handler);
handler.SetMediator(this);
}
}
public async Task<IActionResult> ProcessRequestAsync(string version, string action, object? data)
{
if (_handlers.TryGetValue(version, out var handler))
{
return await handler.HandleRequestAsync(action, data);
}
return new NotFoundObjectResult($"不支持的API版本: {version}");
}
public async Task<object?> ForwardRequestAsync(string targetVersion, string action, object? data)
{
if (_handlers.TryGetValue(targetVersion, out var handler))
{
// 這里簡化處理，實際可能需要轉換數據格式
var result = await handler.HandleRequestAsync(action, data);
if (result is ObjectResult objectResult)
{
return objectResult.Value;
}
}
return null;
}
}

// V1RequestHandler.cs
using Microsoft.AspNetCore.Mvc;
using System.Threading.Tasks;
namespace DotNet8ApiVersionExample;
public class V1RequestHandler : IRequestHandler
{
public string SupportedVersion => "v1";
public IApiMediator? Mediator { get; private set; }
public void SetMediator(IApiMediator mediator)
{
Mediator = mediator;
}
public async Task<IActionResult> HandleRequestAsync(string action, object? data)
{
switch (action)
{
case "getUser":
return await GetUser((int?)data);
case "getOrders":
return await GetOrders((int?)data);
default:
return new NotFoundObjectResult($"V1 API不支持的操作: {action}");
}
}
private Task<IActionResult> GetUser(int? id)
{
if (!id.HasValue)
return Task.FromResult<IActionResult>(new BadRequestObjectResult("用戶ID不能為空"));
// 模擬數據庫查詢
var user = new V1User { Id = id.Value, Name = "張三", Age = 30 };
return Task.FromResult<IActionResult>(new OkObjectResult(user));
}
private Task<IActionResult> GetOrders(int? userId)
{
// 實現(xiàn)V1版本的訂單查詢邏輯
return Task.FromResult<IActionResult>(new OkObjectResult(new[] {
new V1Order { Id = 1, Product = "商品A", Amount = 99.9m }
}));
}
}
// V2RequestHandler.cs
using Microsoft.AspNetCore.Mvc;
using System.Threading.Tasks;
namespace DotNet8ApiVersionExample;
public class V2RequestHandler : IRequestHandler
{
public string SupportedVersion => "v2";
public IApiMediator? Mediator { get; private set; }
public void SetMediator(IApiMediator mediator)
{
Mediator = mediator;
}
public async Task<IActionResult> HandleRequestAsync(string action, object? data)
{
switch (action)
{
case "getUser":
return await GetUser((int?)data);
case "getOrders":
return await GetOrders((int?)data);
case "getUserWithAddress":
return await GetUserWithAddress((int?)data);
case "getLegacyReport":
// 調用V1版本處理遺留報表
if (Mediator != null)
{
var legacyData = await Mediator.ForwardRequestAsync("v1", "getOrders", data);
return new OkObjectResult(new V2Report {
Data = legacyData,
GeneratedAt = DateTime.Now,
FormatVersion = "2.0"
});
}
return new BadRequestObjectResult("無法生成報表");
default:
return new NotFoundObjectResult($"V2 API不支持的操作: {action}");
}
}
private Task<IActionResult> GetUser(int? id)
{
// 實現(xiàn)V2版本的用戶查詢邏輯，返回更豐富的信息
var user = new V2User {
Id = id.Value,
FullName = "張三",
Age = 30,
MemberSince = new DateTime(2020, 1, 1)
};
return Task.FromResult<IActionResult>(new OkObjectResult(user));
}
// 其他方法實現(xiàn)...
}

// ApiController.cs
using Microsoft.AspNetCore.Mvc;
namespace DotNet8ApiVersionExample.Controllers;
[ApiController]
[Route("api/{version}/[controller]")]
public class ApiController : ControllerBase
{
private readonly IApiMediator _mediator;
public ApiController(IApiMediator mediator)
{
_mediator = mediator;
}
[HttpGet("user")]
public async Task<IActionResult> GetUser(string version, [FromQuery] int? id)
{
return await _mediator.ProcessRequestAsync(version, "getUser", id);
}
[HttpGet("orders")]
public async Task<IActionResult> GetOrders(string version, [FromQuery] int? userId)
{
return await _mediator.ProcessRequestAsync(version, "getOrders", userId);
}
[HttpGet("user-with-address")]
public async Task<IActionResult> GetUserWithAddress(string version, [FromQuery] int? id)
{
return await _mediator.ProcessRequestAsync(version, "getUserWithAddress", id);
}
[HttpGet("legacy-report")]
public async Task<IActionResult> GetLegacyReport(string version, [FromQuery] int? userId)
{
return await _mediator.ProcessRequestAsync(version, "getLegacyReport", userId);
}
}

var builder = WebApplication.CreateBuilder(args);
// 添加控制器
builder.Services.AddControllers();
// 注冊中介者和處理器
builder.Services.AddSingleton<IApiMediator, ApiMediator>();
builder.Services.AddTransient<IRequestHandler, V1RequestHandler>();
builder.Services.AddTransient<IRequestHandler, V2RequestHandler>();
var app = builder.Build();
// 配置中間件
app.UseHttpsRedirection();
app.UseRouting();
app.UseAuthorization();
app.MapControllers();
app.Run();