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TwoLevelCacheExtensions.Get<TItem> method (1 of 2)

namespace: Serenity   assembly: Serenity.Net.Core

Tries to read a value from local cache. If it is not found there, tries the distributed cache. If neither contains the specified key, produces value by calling a loader function and adds the value to local and distributed cache for a given expiration time. By using a group key, all items on both cache types that are members of this group can be expired at once.

public static TItem Get<TItem>(this ITwoLevelCache cache, string cacheKey, TimeSpan expiration, 
    string groupKey, Func<TItem> loader)
    where TItem : class
parameter description
TItem Data type
cache Two level cache
cacheKey The item key for local and distributed cache
expiration Local and remote expiration
groupKey Group key that will hold generation (version). Can be used to expire all items that depend on it. This can be a table name. When a table changes, you change its version, and all cached data that depends on that table is expired.
loader The delegate that will be called to generate value, if not found in local cache, or distributed cache, or all found items are expired.

Remarks

To not check group generation every time an item is requested, generation number itself is also cached in local cache. Thus, when a generation number changes, local cached items might expire after about 5 seconds. This means that, if you use this strategy in a web farm setup, when a change occurs in one server, other servers might continue to use old local cached data for 5 seconds more. If this is a problem for your configuration, use DistributedCache directly.

See Also

TwoLevelCacheExtensions.Get<TItem> method (2 of 2)

namespace: Serenity   assembly: Serenity.Net.Core

Tries to read a value from local cache. If it is not found there, tries the distributed cache. If neither contains the specified key, produces value by calling a loader function and adds the value to local and distributed cache for a given expiration time. By using a group key, all items on both cache types that are members of this group can be expired at once.

public static TItem Get<TItem>(this ITwoLevelCache cache, string cacheKey, 
    TimeSpan localExpiration, TimeSpan remoteExpiration, string groupKey, Func<TItem> loader)
    where TItem : class
parameter description
TItem Data type
cache Two level cache
cacheKey The item key for local and distributed cache
localExpiration Local expiration
remoteExpiration Distributed cache expiration (is usually same with local expiration)
groupKey Group key that will hold generation (version). Can be used to expire all items that depend on it. This can be a table name. When a table changes, you change its version, and all cached data that depends on that table is expired.
loader The delegate that will be called to generate value, if not found in local cache, or distributed cache, or all found items are expired.

Remarks

To not check group generation every time an item is requested, generation number itself is also cached in local cache. Thus, when a generation number changes, local cached items might expire after about 5 seconds. This means that, if you use this strategy in a web farm setup, when a change occurs in one server, other servers might continue to use old local cached data for 5 seconds more. If this is a problem for your configuration, use DistributedCache directly.

See Also