using System; using System.Collections.Generic; using System.IO; using System.Linq; using System.Net; using System.Net.Http; using System.Net.Http.Headers; using System.Runtime.Caching; using System.Text; using System.Web; using System.Web.Http.Filters; namespace SH3H.WAP.WorkSheet.Outgoing.WebApi.Filters { /// <summary> /// 定义过滤2s内重复提交的action /// </summary> [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false)] public class FWActionSubmitFilterAttribute : ActionFilterAttribute { MemoryCacheHelper _cache = new MemoryCacheHelper(); /// <summary> /// 客户端缓存（用户代理）缓存相对过期时间 /// </summary> public int ClientCacheExpiration { set; get; } /// <summary> /// 服务端缓存过期时间 /// </summary> public int ServerCacheExpiration { set; get; } /// <summary> /// /// </summary> /// <param name="clientCacheExpiration">客户端过期时间。单位为秒，默认为600秒(10分钟)</param> /// <param name="serverCacheExpiration">服务端过期时间。单位为秒，默认为7200秒(120分钟)</param> public FWActionSubmitFilterAttribute(int clientCacheExpiration = 10, int serverCacheExpiration = 30) { this.ClientCacheExpiration = clientCacheExpiration; this.ServerCacheExpiration = serverCacheExpiration; } /// <summary> /// 判定是否用缓存中的内容，还是执行action是去取内容 /// 注：一旦给actionContext.Response赋值了，则会使用这个值来输出响应 /// </summary> /// <param name="actionContext"></param> public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext) { // **************************************** 穿透缓存 ********************************************* // 若无缓存,则直接返回 string cacheKey = getCacheKey(actionContext); if (_cache.Contains(cacheKey) == false) return; if (_cache.Contains(cacheKey + ":etag") == false) return; // **************************************** 使用缓存 ********************************************* // 获取缓存中的etag var etag = _cache.Get<string>(cacheKey + ":etag"); // 若etag没有被改变，则返回304， if (actionContext.Request.Headers.IfNoneMatch.Any(x => x.Tag == etag)) //IfNoneMatch为空时，返回的是一个集合对象 { actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.NotModified); // 响应对象还没有生成，需要先生成 // 304 not modified actionContext.Response.Headers.CacheControl = GetDefaultCacheControl(); actionContext.Response.Headers.ETag = new EntityTagHeaderValue(etag); return; } else //从缓存中返回响应 { actionContext.Response = actionContext.Request.CreateResponse(); // 响应对象还没有生成，需要先生成 // 设置协商缓存：etag actionContext.Response.Headers.ETag = new EntityTagHeaderValue(etag); //用缓存中的值（为最新的）更新它 // 设置user agent的本地缓存 actionContext.Response.Headers.CacheControl = GetDefaultCacheControl(); // 从缓存中取中响应内容 var content = _cache.Get<byte[]>(cacheKey); actionContext.Response.Content = new ByteArrayContent(content); return; } } /// <summary> /// 将输出保存在缓存中。 /// </summary> /// <param name="actionExecutedContext"></param> /// <param name="cancellationToken"></param> /// <returns></returns> public override async System.Threading.Tasks.Task OnActionExecutedAsync(HttpActionExecutedContext actionExecutedContext, System.Threading.CancellationToken cancellationToken) { // 响应对象已经生成，可以直接调用 actionExecutedContext.Response // 设置协商缓存：etag EntityTagHeaderValue etag = new EntityTagHeaderValue(""" + Guid.NewGuid().ToString() + """); // 根据http协议， ETag的值必须用引号包含起来 actionExecutedContext.Response.Headers.ETag = etag; // 设置user agent的本地缓存 actionExecutedContext.Response.Headers.CacheControl = GetDefaultCacheControl(); // actionExecutedContext.Response.Headers.Remove("Content-Length"); // 改变了值，它会发生变化。删除它的话，后续的程序会自动地再计算 // 保存到缓存 string cacheKey = getCacheKey(actionExecutedContext.ActionContext); var contentBytes = await actionExecutedContext.Response.Content.ReadAsByteArrayAsync(); _cache.Add(cacheKey + ":etag", etag.Tag, DateTimeOffset.Now.AddSeconds(this.ServerCacheExpiration)); _cache.Add(cacheKey, contentBytes, DateTimeOffset.Now.AddSeconds(this.ServerCacheExpiration)); } /// <summary> /// 默认的用户代理本地缓存配置，10分钟的相对过期时间 /// 对应响应header中的 Cache-Control /// 这里设置里面的子项max-age。如：Cache-Control: max-age=3600 /// </summary> /// <returns></returns> CacheControlHeaderValue GetDefaultCacheControl() { CacheControlHeaderValue control = new CacheControlHeaderValue(); control.MaxAge = TimeSpan.FromSeconds(this.ClientCacheExpiration); // 它对应响应头中的 cacheControl :max-age=10项 return control; } /// <summary> /// /// </summary> /// <param name="actionContext"></param> /// <returns></returns> string getCacheKey(System.Web.Http.Controllers.HttpActionContext actionContext) { string cacheKey = null; //获取POST中data var context = (HttpContextBase)actionContext.Request.Properties["MS_HttpContext"]; context.Request.InputStream.Seek(0, SeekOrigin.Begin); using (var sr = new StreamReader(context.Request.InputStream, Encoding.UTF8, true, 1024, true)) { string body = sr.ReadToEnd(); // Logging here... } cacheKey = actionContext.Request.RequestUri.PathAndQuery; // 路径和查询部分,如： /api/values/1?ee=33&oo=5 // 对路径中的参数进行重排，升序排列 string controllerName = actionContext.ControllerContext.ControllerDescriptor.ControllerName; string actionName = actionContext.ActionDescriptor.ActionName; if (actionContext.ActionArguments.ContainsKey("id") == false) { cacheKey = controllerName + "/" + actionName; } else { string id = actionContext.ActionArguments["id"].ToString(); cacheKey = controllerName + "/" + actionName + "/" + id; } return cacheKey; } } /// <summary> /// 缓存辅助类 /// </summary> public class MemoryCacheHelper { private static readonly MemoryCache _cache = MemoryCache.Default; /// <summary> /// /// </summary> /// <param name="key"></param> public void RemoveStartsWith(string key) { lock (_cache) { _cache.Remove(key); } } /// <summary> /// /// </summary> /// <typeparam name="T"></typeparam> /// <param name="key"></param> /// <returns></returns> public T Get<T>(string key) where T : class { var o = _cache.Get(key) as T; return o; } /// <summary> /// /// </summary> /// <param name="key"></param> /// <returns></returns> [Obsolete("Use Get<T> instead")] public object Get(string key) { return _cache.Get(key); } /// <summary> /// /// </summary> /// <param name="key"></param> public void Remove(string key) { lock (_cache) { _cache.Remove(key); } } /// <summary> /// /// </summary> /// <param name="key"></param> /// <returns></returns> public bool Contains(string key) { return _cache.Contains(key); } /// <summary> /// /// </summary> /// <param name="key"></param> /// <param name="o"></param> /// <param name="expiration"></param> /// <param name="dependsOnKey"></param> public void Add(string key, object o, DateTimeOffset expiration, string dependsOnKey = null) { var cachePolicy = new CacheItemPolicy { AbsoluteExpiration = expiration }; if (!string.IsNullOrWhiteSpace(dependsOnKey)) { cachePolicy.ChangeMonitors.Add( _cache.CreateCacheEntryChangeMonitor(new[] { dependsOnKey }) ); } lock (_cache) { _cache.Add(key, o, cachePolicy); } } /// <summary> /// /// </summary> public IEnumerable<string> AllKeys { get { return _cache.Select(x => x.Key); } } } }