IMetadataSource.cs

namespace ToSic.Eav.Metadata;

/// <summary>
/// For querying metadata from the data source.
/// Mainly used in the Store, Cache-Systems and Apps.
/// </summary>
/// <remarks>
/// * Was renamed from `IMetadataGet` to `IMetadataSource` in v20 to better reflect its purpose.
/// </remarks>
[InternalApi_DoNotUse_MayChangeWithoutNotice("this is just fyi")]
[ShowApiWhenReleased(ShowApiMode.Never)]
public interface IMetadataSource
{
    /// <summary>
    /// Get any metadata from the current data source (usually an app)
    /// </summary>
    /// <remarks>
    /// It does not return metadata describing the source (app), but metadata stored in this app, describing something else.
    /// </remarks>
    /// <typeparam name="TKey">Key-Type used - string, int or guid</typeparam>
    /// <param name="targetType">The type-id of the target we're accessing, like 10=cms-object, 4=entity</param>
    /// <param name="key">The key which is used for lookup</param>
    /// <param name="contentTypeName">Optional content-type name, to only retrieve metadata of that type</param>
    /// <returns>A list (can be empty) of metadata items found for this target</returns>
    IEnumerable<IEntity> GetMetadata<TKey>(int targetType, TKey key, string? contentTypeName = null);

    /// <summary>
    /// Get any metadata from the current data source (usually an app)
    /// </summary>
    /// <remarks>
    /// It does not return metadata describing the source (app), but metadata stored in this app, describing something else.
    /// </remarks>
    /// <typeparam name="TKey">Key-Type used - string, int or guid</typeparam>
    /// <param name="targetType">The TargetTypes constant of the target we're accessing, like TargetTypes.Entity</param>
    /// <param name="key">The key which is used for lookup</param>
    /// <param name="contentTypeName">Optional content-type name, to only retrieve metadata of that type</param>
    /// <returns>A list (can be empty) of metadata items found for this target</returns>
    IEnumerable<IEntity> GetMetadata<TKey>(TargetTypes targetType, TKey key, string? contentTypeName = null);

}