Core2中使用Microsoft.AspNetCore.Mvc下的ResponseCacheAttribute特性来控制Http Get请求的缓存
原理是设置http请求 响应头的Cache-control来告诉浏览器如何进行客户端缓存
1、在Startup的ConfigureServices方法里面设置一个CacheProfiles,Duration属性定义浏览器缓存的秒数，CacheProfiles一个通用的缓存配置项
services.AddMvc(option =>
{
/*客户端缓存*/
option.CacheProfiles.Add("default", new Microsoft.AspNetCore.Mvc.CacheProfile
{
Duration = /*10分钟*/
});
});
2、在需要缓存的Action上面添加ResponseCacheAttribute特性，CacheProfileName 的值使用服务配置的名称，该Action将使用配置项进行缓存
[ResponseCache(CacheProfileName = "default")]
也可以在Action 上赋予 Duration 值，指定浏览器缓存的时间
查看ResponseCacheAttribute中的代码
public unsafe IFilterMetadata CreateInstance(IServiceProvider serviceProvider)
{
//IL_0000: Unknown result type (might be due to invalid IL)
//IL_0008: Unknown result type (might be due to invalid IL)
//IL_000e: Unknown result type (might be due to invalid IL)
//IL_0025: Unknown result type (might be due to invalid IL)
//IL_0032: Expected Ref, but got Unknown
//IL_0046: Unknown result type (might be due to invalid IL)
if (serviceProvider == (IServiceProvider))
{
throw new ArgumentNullException("serviceProvider");
}
IOptions<MvcOptions> requiredService = serviceProvider.GetRequiredService<IOptions<MvcOptions>>();
CacheProfile cacheProfile = null;
if (this.CacheProfileName != null)
{
((IDictionary)(?)requiredService.Value.CacheProfiles).TryGetValue((!)this.CacheProfileName, ref *(!*)(&cacheProfile));
if (cacheProfile == null)
{
throw new InvalidOperationException(Resources.FormatCacheProfileNotFound(this.CacheProfileName));
}
}
this._duration = (this._duration ?? ((cacheProfile != null) ? cacheProfile.Duration : null));
this._noStore = (this._noStore ?? ((cacheProfile != null) ? cacheProfile.NoStore : null));
this._location = (this._location ?? ((cacheProfile != null) ? cacheProfile.Location : null));
this.VaryByHeader = (this.VaryByHeader ?? ((cacheProfile != null) ? cacheProfile.VaryByHeader : null));
this.VaryByQueryKeys = (this.VaryByQueryKeys ?? ((cacheProfile != null) ? cacheProfile.VaryByQueryKeys : null));
return new ResponseCacheFilter(new CacheProfile
{
Duration = this._duration,
Location = this._location,
NoStore = this._noStore,
VaryByHeader = this.VaryByHeader,
VaryByQueryKeys = this.VaryByQueryKeys
});
}
可以得知Action上设置-----优先级高于--CacheProfiles里面的配置
缓存最终通过ResponseCacheFilter过滤器来实现，ResponseCacheFilter 的代码：
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Core;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.AspNetCore.ResponseCaching;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Linq; namespace Microsoft.AspNetCore.Mvc.Internal
{
/// <summary>
/// An <see cref="T:Microsoft.AspNetCore.Mvc.Filters.IActionFilter" /> which sets the appropriate headers related to response caching.
/// </summary>
public class ResponseCacheFilter : IResponseCacheFilter, IActionFilter, IFilterMetadata
{
private readonly CacheProfile _cacheProfile; private int? _cacheDuration; private ResponseCacheLocation? _cacheLocation; private bool? _cacheNoStore; private string _cacheVaryByHeader; private string[] _cacheVaryByQueryKeys; /// <summary>
/// Gets or sets the duration in seconds for which the response is cached.
/// This is a required parameter.
/// This sets "max-age" in "Cache-control" header.
/// </summary>
public int Duration
{
get
{
return (this._cacheDuration ?? this._cacheProfile.Duration) ?? ;
}
set
{
this._cacheDuration = value;
}
} /// <summary>
/// Gets or sets the location where the data from a particular URL must be cached.
/// </summary>
public ResponseCacheLocation Location
{
get
{
return (this._cacheLocation ?? this._cacheProfile.Location) ?? ResponseCacheLocation.Any;
}
set
{
this._cacheLocation = value;
}
} /// <summary>
/// Gets or sets the value which determines whether the data should be stored or not.
/// When set to <see langword="true" />, it sets "Cache-control" header to "no-store".
/// Ignores the "Location" parameter for values other than "None".
/// Ignores the "duration" parameter.
/// </summary>
public bool NoStore
{
get
{
return (this._cacheNoStore ?? this._cacheProfile.NoStore) ?? false;
}
set
{
this._cacheNoStore = value;
}
} /// <summary>
/// Gets or sets the value for the Vary response header.
/// </summary>
public string VaryByHeader
{
get
{
return this._cacheVaryByHeader ?? this._cacheProfile.VaryByHeader;
}
set
{
this._cacheVaryByHeader = value;
}
} /// <summary>
/// Gets or sets the query keys to vary by.
/// </summary>
/// <remarks>
/// <see cref="P:Microsoft.AspNetCore.Mvc.Internal.ResponseCacheFilter.VaryByQueryKeys" /> requires the response cache middleware.
/// </remarks>
public string[] VaryByQueryKeys
{
get
{
return this._cacheVaryByQueryKeys ?? this._cacheProfile.VaryByQueryKeys;
}
set
{
this._cacheVaryByQueryKeys = value;
}
} /// <summary>
/// Creates a new instance of <see cref="T:Microsoft.AspNetCore.Mvc.Internal.ResponseCacheFilter" />
/// </summary>
/// <param name="cacheProfile">The profile which contains the settings for
/// <see cref="T:Microsoft.AspNetCore.Mvc.Internal.ResponseCacheFilter" />.</param>
public ResponseCacheFilter(CacheProfile cacheProfile)
{
this._cacheProfile = cacheProfile;
} /// <inheritdoc />
public void OnActionExecuting(ActionExecutingContext context)
{
//IL_0008: Unknown result type (might be due to invalid IL)
//IL_0051: Unknown result type (might be due to invalid IL)
//IL_00d4: Unknown result type (might be due to invalid IL)
//IL_0185: Unknown result type (might be due to invalid IL)
if (context == null)
{
throw new ArgumentNullException("context");
}
if (!this.IsOverridden(context))
{
if (!this.NoStore && !this._cacheProfile.Duration.get_HasValue() && !this._cacheDuration.get_HasValue())
{
throw new InvalidOperationException(Resources.FormatResponseCache_SpecifyDuration("NoStore", "Duration"));
}
IHeaderDictionary headers = context.HttpContext.Response.Headers;
((IDictionary)(?)headers).Remove((!)"Vary");
((IDictionary)(?)headers).Remove((!)"Cache-Control");
((IDictionary)(?)headers).Remove((!)"Pragma");
if (!string.IsNullOrEmpty(this.VaryByHeader))
{
headers["Vary"] = this.VaryByHeader;
}
if (this.VaryByQueryKeys != null)
{
IResponseCachingFeature responseCachingFeature = context.HttpContext.Features.Get<IResponseCachingFeature>();
if (responseCachingFeature == null)
{
throw new InvalidOperationException(Resources.FormatVaryByQueryKeys_Requires_ResponseCachingMiddleware("VaryByQueryKeys"));
}
responseCachingFeature.VaryByQueryKeys = this.VaryByQueryKeys;
}
if (this.NoStore)
{
headers["Cache-Control"] = "no-store";
if (this.Location == ResponseCacheLocation.None)
{
headers.AppendCommaSeparatedValues("Cache-Control", "no-cache");
headers["Pragma"] = "no-cache";
}
}
else
{
string text = null;
switch (this.Location)
{
case ResponseCacheLocation.Any:
text = "public";
break;
case ResponseCacheLocation.Client:
text = "private";
break;
case ResponseCacheLocation.None:
text = "no-cache";
headers["Pragma"] = "no-cache";
break;
}
text = string.Format((IFormatProvider)CultureInfo.get_InvariantCulture(), "{0}{1}max-age={2}", (object)text, (object)((text != null) ? "," : null), (object)this.Duration);
if (text != null)
{
headers["Cache-Control"] = text;
}
}
}
} /// <inheritdoc />
public void OnActionExecuted(ActionExecutedContext context)
{
} internal bool IsOverridden(ActionExecutingContext context)
{
//IL_0008: Unknown result type (might be due to invalid IL)
if (context == null)
{
throw new ArgumentNullException("context");
}
return Enumerable.Last<IResponseCacheFilter>(Enumerable.OfType<IResponseCacheFilter>((IEnumerable)context.Filters)) != this;
}
}
}