125 lines
4.2 KiB
C#
125 lines
4.2 KiB
C#
using Microsoft.AspNetCore.Http;
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using Microsoft.AspNetCore.Http.Features;
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using Microsoft.Extensions.Caching.Distributed;
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using System;
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using System.Collections.Concurrent;
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using System.IO;
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using System.Text;
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using System.Threading.Tasks;
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namespace CloudGaming.Code.MiddlewareExtend
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{
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/// <summary>
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/// Redis 缓存中间件
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/// </summary>
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public class RedisCacheMiddleware
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{
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private readonly RequestDelegate _next;
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private static readonly ConcurrentDictionary<Endpoint, RedisCacheAttribute> _attributeCache = new();
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public RedisCacheMiddleware(RequestDelegate next)
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{
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_next = next;
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}
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public async Task InvokeAsync(HttpContext context,
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IServiceProvider _serviceProvider,
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AppConfig appConfig
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)
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{
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// 检查当前请求是否需要缓存
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var cacheAttribute = GetCacheAttribute(context);
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if (cacheAttribute == null)
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{
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await _next(context);
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return;
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}
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var _cache = appConfig.GetRedisDataBase();
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// 生成缓存键（基于请求路径和查询字符串）
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var cacheKey = GenerateCacheKey(context.Request, appConfig);
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// 尝试从 Redis 缓存中获取数据
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var cachedResponse = await _cache.StringGetAsync(cacheKey);
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if (!cachedResponse.IsNullOrEmpty)
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{
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context.Response.StatusCode = StatusCodes.Status200OK;
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context.Response.ContentType = "application/json";
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await context.Response.WriteAsync(cachedResponse);
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return;
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}
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// 捕获原始响应流
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var originalResponseStream = context.Response.Body;
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try
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{
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using (var memoryStream = new MemoryStream())
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{
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context.Response.Body = memoryStream;
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// 调用下一个中间件
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await _next(context);
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// 将响应流重新定位到起始位置
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memoryStream.Position = 0;
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// 读取响应内容
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var responseBody = await new StreamReader(memoryStream).ReadToEndAsync();
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await _cache.StringSetAsync(cacheKey, responseBody, cacheAttribute.TimeSpan);
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// 将内容写回原始响应流
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memoryStream.Position = 0;
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await memoryStream.CopyToAsync(originalResponseStream);
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}
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}
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finally
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{
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context.Response.Body = originalResponseStream;
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}
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}
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private RedisCacheAttribute GetCacheAttribute(HttpContext context)
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{
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var endpoint = context.Features.Get<IEndpointFeature>()?.Endpoint;
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if (endpoint == null) return null;
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if (_attributeCache.TryGetValue(endpoint, out var cachedAttribute))
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{
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return cachedAttribute;
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}
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var attribute = endpoint.Metadata.GetMetadata<RedisCacheAttribute>();
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if (attribute != null)
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{
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_attributeCache.TryAdd(endpoint, attribute);
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}
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return attribute;
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}
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private string GenerateCacheKey(HttpRequest request, AppConfig appConfig)
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{
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var appRequestInfo = new AppRequestConfig(request);
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var cacheKey = $"cache:api:{request.Path.Value.Replace('/', '.').TrimStart('.')}:{appRequestInfo.Key}:{(string.IsNullOrEmpty(request.QueryString.Value) ? "default" : request.QueryString)}";
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return cacheKey;
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}
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}
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/// <summary>
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/// Redis 缓存特性类
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/// </summary>
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[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
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public class RedisCacheAttribute : Attribute
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{
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public TimeSpan TimeSpan { get; }
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public RedisCacheAttribute(int durationInSeconds) => TimeSpan = TimeSpan.FromSeconds(durationInSeconds);
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public RedisCacheAttribute(int hours, int minutes, int seconds) => TimeSpan = new TimeSpan(hours, minutes, seconds);
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public RedisCacheAttribute(int minutes, int seconds) => TimeSpan = new TimeSpan(0, minutes, seconds);
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}
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}
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