HttpRequestCachePolicy Class

Definition

Namespace:

System.Net.Cache

Assembly:

System.Net.Requests.dll

Source:

HttpRequestCachePolicy.cs

Defines an application's caching requirements for resources obtained by using HttpWebRequest objects.

public ref class HttpRequestCachePolicy : System::Net::Cache::RequestCachePolicy

public class HttpRequestCachePolicy : System.Net.Cache.RequestCachePolicy

type HttpRequestCachePolicy = class
    inherit RequestCachePolicy

Public Class HttpRequestCachePolicy
Inherits RequestCachePolicy

Inheritance

Object

RequestCachePolicy

HttpRequestCachePolicy

Examples

The following code example creates a default cache policy for the application domain, and overrides it for a request.

// The following method demonstrates overriding the
// caching policy for a request.
static WebResponse^ GetResponseNoCache( Uri^ uri )
{
   // Set a default policy level for the "http:" and "https" schemes.
   HttpRequestCachePolicy^ policy = gcnew HttpRequestCachePolicy( HttpRequestCacheLevel::Default );
   HttpWebRequest::DefaultCachePolicy = policy;

   // Create the request.
   WebRequest^ request = WebRequest::Create( uri );

   // Define a cache policy for this request only. 
   HttpRequestCachePolicy^ noCachePolicy = gcnew HttpRequestCachePolicy( HttpRequestCacheLevel::NoCacheNoStore );
   request->CachePolicy = noCachePolicy;
   WebResponse^ response = request->GetResponse();
   Console::WriteLine( L"IsFromCache? {0}", response->IsFromCache );
   
   return response;
}

// The following method demonstrates overriding the
// caching policy for a request.
public static WebResponse GetResponseNoCache(Uri uri)
{
    // Set a default policy level for the "http:" and "https" schemes.
    HttpRequestCachePolicy policy = new HttpRequestCachePolicy(HttpRequestCacheLevel.Default);
    HttpWebRequest.DefaultCachePolicy = policy;
    // Create the request.
    WebRequest request = WebRequest.Create(uri);
    // Define a cache policy for this request only.
    HttpRequestCachePolicy noCachePolicy = new HttpRequestCachePolicy(HttpRequestCacheLevel.NoCacheNoStore);
    request.CachePolicy = noCachePolicy;
    WebResponse response = request.GetResponse();
    Console.WriteLine("IsFromCache? {0}", response.IsFromCache);
    return response;
}

Remarks

You can specify a default cache policy for your application by using the DefaultCachePolicy property or the application or machine configuration files. For more information, see <requestCaching> Element (Network Settings).

You can specify the cache policy for an individual request by using the CachePolicy property.

Caching for Web services is not supported.

Constructors

HttpRequestCachePolicy()	Initializes a new instance of the HttpRequestCachePolicy class.
HttpRequestCachePolicy(DateTime)	Initializes a new instance of the HttpRequestCachePolicy class using the specified cache synchronization date.
HttpRequestCachePolicy(HttpCacheAgeControl, TimeSpan)	Initializes a new instance of the HttpRequestCachePolicy class using the specified age control and time values.
HttpRequestCachePolicy(HttpCacheAgeControl, TimeSpan, TimeSpan)	Initializes a new instance of the HttpRequestCachePolicy class using the specified maximum age, age control value, and time value.
HttpRequestCachePolicy(HttpCacheAgeControl, TimeSpan, TimeSpan, DateTime)	Initializes a new instance of the HttpRequestCachePolicy class using the specified maximum age, age control value, time value, and cache synchronization date.
HttpRequestCachePolicy(HttpRequestCacheLevel)	Initializes a new instance of the HttpRequestCachePolicy class using the specified cache policy.

Properties

CacheSyncDate	Gets the cache synchronization date for this instance.
Level	Gets the HttpRequestCacheLevel value that was specified when this instance was created.
MaxAge	Gets the maximum age permitted for a resource returned from the cache.
MaxStale	Gets the maximum staleness value that is permitted for a resource returned from the cache.
MinFresh	Gets the minimum freshness that is permitted for a resource returned from the cache.

Methods

Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string representation of this instance.

See also

• Cache Management for Network Applications