1. Nuget installs the relevant dll
Web API 2 : Install-Package Strathweb.CacheOutput.WebApi2
Web API 1 : Install-Package Strathweb.CacheOutput
Two. Create a new ActionFilterAttribute and override the related methods
public class WebApiOutputCacheAttribute : ActionFilterAttribute
{
Cache time/sec
private int _timespan;
Client cache time/sec
private int _clientTimeSpan;
Whether it is cached by anonymous users
private bool _anonymousOnly;
Cache the index key
private string _cachekey;
Cache warehouses
private static readonly ObjectCache WebApiCache = MemoryCache.Default;
public WebApiOutputCacheAttribute(int timespan, int clientTimeSpan, bool anonymousOnly)
{
_timespan = timespan;
_clientTimeSpan = clientTimeSpan;
_anonymousOnly = anonymousOnly;
}
//是否缓存
private bool _isCacheable(HttpActionContext ac)
{
if (_timespan > 0 && _clientTimeSpan > 0)
{
if (_anonymousOnly)
if (Thread.CurrentPrincipal.Identity.IsAuthenticated)
return false;
if (ac. Request.Method == HttpMethod.Get) return true;
}
else
{
throw new InvalidOperationException("Wrong Arguments");
}
return false;
}
private CacheControlHeaderValue setClientCache()
{
var cachecontrol = new CacheControlHeaderValue();
cachecontrol. MaxAge = TimeSpan.FromSeconds(_clientTimeSpan);
cachecontrol. MustRevalidate = true;
return cachecontrol;
}
//Action调用前执行的方法
public override void OnActionExecuting(HttpActionContext ac)
{
if (ac != null)
{
if (_isCacheable(ac))
{
_cachekey = string. Join(":", new string[] { ac. Request.RequestUri.AbsolutePath, ac. Request.Headers.Accept.FirstOrDefault(). ToString() });
if (WebApiCache.Contains(_cachekey))
{
var val = (string)WebApiCache.Get(_cachekey);
if (val != null)
{
ac. Response = ac. Request.CreateResponse();
ac. Response.Content = new StringContent(val);
var contenttype = (MediaTypeHeaderValue)WebApiCache.Get(_cachekey + ":response-ct");
if (contenttype == null)
contenttype = new MediaTypeHeaderValue(_cachekey. Split(':')[1]);
ac. Response.Content.Headers.ContentType = contenttype;
ac. Response.Headers.CacheControl = setClientCache();
return;
}
}
}
}
else
{
throw new ArgumentNullException("actionContext");
}
}
//Action调用后执行方法
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
{
if (!( WebApiCache.Contains(_cachekey)))
{
var body = actionExecutedContext.Response.Content.ReadAsStringAsync(). Result;
WebApiCache.Add(_cachekey, body, DateTime.Now.AddSeconds(_timespan));
WebApiCache.Add(_cachekey + ":response-ct", actionExecutedContext.Response.Content.Headers.ContentType, DateTime.Now.AddSeconds(_timespan));
}
if (_isCacheable(actionExecutedContext.ActionContext))
actionExecutedContext.ActionContext.Response.Headers.CacheControl = setClientCache();
}
}
3. The controller needs to add the cache to the Get method to add the filter
[WebApiOutputCache(120,60,false)]
public string GetShoppingCart()
{
return "Hello World";
}
start, observe the breakpoint, and observe the effect. The whole process is: initialize the cache filter at startup, and then call the Get method with the filter added, enter the OnActionExecuting method, determine whether there is a relevant cache, if there is, return the result directly, if not, call the controller's Action, and then call the OnActionExecuted method to add the relevant cache key-value pair and set the cache expiration time to return the result. |
Posted on 1/17/2019 4:40:51 PM
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Posted on 1/19/2019 9:09:45 AM