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Class SingleServerCacheVersionService

A simple cache version service that assumes the cache is always in sync. This is useful in scenarios where you have a single server setup and do not need to manage cache synchronization across multiple servers.

Inheritance

object

Namespace: Umbraco.Cms.Core.Cache

Assembly: Umbraco.Core.dll

Syntax

public class SingleServerCacheVersionService : IRepositoryCacheVersionService

Constructors

SingleServerCacheVersionService()

Declaration

public SingleServerCacheVersionService()

Methods

FlushCacheUpdatesAsync()

Publishes the cache updates registered by SetCacheUpdatedAsync<TEntity>() whose publication was deferred.

Declaration

public Task FlushCacheUpdatesAsync()

Returns

Type	Description
Task

Remarks

Called once the cache instructions for the current unit of work have been written. Implementations that publish updates immediately have nothing to do here.

GetCacheVersionsAsync()

Gets the cache versions currently published for all entity types.

Declaration

public Task<IReadOnlyCollection<RepositoryCacheVersion>> GetCacheVersionsAsync()

Returns

Type	Description
Task<IReadOnlyCollection<RepositoryCacheVersion>>	The published cache versions; a version whose value is null has never been published.

Remarks

The synchronization reads this snapshot before processing the cache instructions and adopts it afterwards through SetCachesSyncedAsync(IEnumerable<RepositoryCacheVersion>), so the two must be implemented together. No snapshot can be derived from the other members, so the default implementation throws.

Exceptions

Type	Condition
NotImplementedException	Thrown when the implementation does not provide the snapshot.

IsCacheSyncedAsync<TEntity>()

Validates if the cache is synced with the database.

Declaration

public Task<bool> IsCacheSyncedAsync<TEntity>() where TEntity : class

Returns

Type	Description
Task<bool>	True if cache is synced, false if cache needs fast-forwarding.

Type Parameters

Name	Description
TEntity	The type of the cached entity.

SetCacheUpdatedAsync<TEntity>()

Registers a cache update for the specified entity type.

Declaration

public Task SetCacheUpdatedAsync<TEntity>() where TEntity : class

Returns

Type	Description
Task

Type Parameters

Name	Description
TEntity	The type of the cached entity.

Remarks

Other servers detect the update through the published cache version. An implementation may defer publishing it until FlushCacheUpdatesAsync() is called, so that the version never becomes visible before the cache instructions that describe the change.

SetCachesSyncedAsync()

Registers that the cache has been synced with the database.

Declaration

public Task SetCachesSyncedAsync()

Returns

Type	Description
Task

Remarks

Adopts the versions currently published. Prefer SetCachesSyncedAsync(IEnumerable<RepositoryCacheVersion>) with versions read before the cache instructions were processed.

SetCachesSyncedAsync(IEnumerable<RepositoryCacheVersion>)

Registers that the local caches have been synced up to the given cache versions.

Declaration

public Task SetCachesSyncedAsync(IEnumerable<RepositoryCacheVersion> cacheVersions)

Parameters

Type	Name	Description
IEnumerable<RepositoryCacheVersion>	cacheVersions	The versions read before the cache instructions were processed, typically from GetCacheVersionsAsync().

Returns

Type	Description
Task

Remarks

Adopting the versions read before processing, rather than the versions published afterwards, means a version published while instructions were being processed is still seen as out of date and triggers another sync. Concurrent syncs may adopt an older set last; that costs one redundant sync and nothing more. Delegating to SetCachesSyncedAsync() would discard the snapshot and reintroduce that race, so the default implementation throws instead.

Exceptions

Type	Condition
NotImplementedException	Thrown when the implementation does not adopt the given snapshot.