/// <summary>
/// 启动分片（默认启用）。
/// </summary>
/// <param name="sharded">给定的 <see cref="ShardedDescriptor"/>。</param>
/// <param name="value">输出 <typeparamref name="TValue"/>。</param>
/// <returns>返回布尔值。</returns>
protected virtual bool Enabling(ShardedDescriptor sharded, [MaybeNullWhen(false)] out TValue value)
{
// 如果引用对象是值对象
if (sharded.ReferenceValue is TValue referenceValue)
{
value = referenceValue;
return(true);
}
// 如果引用对象是属性值对象
if (sharded.ReferenceValue is not null && sharded.Entity is not null &&
sharded.Entity.EntityType == (sharded.ReferenceType ?? sharded.ReferenceValue.GetType()))
{
var property = GetEntityProperty(sharded.Entity);
if (property is not null)
{
var propertyValue = property.GetValue(sharded.ReferenceValue);
ArgumentNullException.ThrowIfNull(propertyValue);
value = (TValue)propertyValue !;
return(true);
}
}
value = default;
return(false);
}
/// <summary>
/// 对存取器的数据库分片。
/// </summary>
/// <param name="shardingManager">给定的 <see cref="IShardingManager"/>。</param>
/// <param name="accessor">给定的 <see cref="IAccessor"/>。</param>
/// <param name="descriptor">输出 <see cref="ShardedDescriptor"/>。</param>
/// <returns>返回 <see cref="IAccessor"/>。</returns>
public static IAccessor ShardDatabase(this IShardingManager shardingManager, IAccessor accessor,
[MaybeNullWhen(false)] out ShardedDescriptor descriptor)
{
var attribute = accessor.AccessorDescriptor?.Sharded;
if (attribute is null)
{
descriptor = null;
return(accessor);
}
descriptor = shardingManager.CreateDescriptor(attribute);
descriptor.DefaultStrategy?.FormatSuffix(descriptor);
var shardedName = descriptor.ToString();
if (!shardedName.Equals(descriptor.BaseName, StringComparison.Ordinal))
{
var newConnectionString = accessor.CurrentConnectionString !
.Replace(attribute.BaseName !, shardedName);
accessor.ChangeConnection(newConnectionString);
}
return(accessor);
}
/// <summary>
/// 格式化分片后缀。
/// </summary>
/// <param name="sharded">给定的 <see cref="ShardedDescriptor"/>。</param>
/// <returns>返回字符串。</returns>
public virtual string FormatSuffix(ShardedDescriptor sharded)
{
var suffix = sharded.Suffix;
if (Enabling(sharded, out TValue? value))
{
foreach (var p in _parameters)
{
suffix = suffix.Replace(p.Key, p.Value(value), ParameterComparison);
}
}
return(sharded.Suffix = suffix);
}
private static ShardedDescriptor CreateDescriptor(this IShardingManager manager,
ShardedAttribute attribute)
{
if (string.IsNullOrEmpty(attribute.BaseName))
{
throw new ArgumentException($"The {nameof(attribute)}.{nameof(attribute.BaseName)} is null or empty.");
}
var descriptor = new ShardedDescriptor(attribute.BaseName, attribute.Suffix);
if (attribute.DefaultStrategyType is not null)
{
descriptor.DefaultStrategy = manager.GetStrategy(attribute.DefaultStrategyType);
}
return(descriptor);
}
public void AllTest()
{
var now = DateTime.Now;
var sharding = new ShardedDescriptor("Shard", now.Year.ToString());
var expected = $"{sharding.BaseName}{sharding.SuffixConnector}{now.Year}";
Assert.Equal(expected, sharding);
var copyShard = ShardedDescriptor.Parse(expected);
Assert.Equal(expected, copyShard);
var newSharding = sharding.WithSuffix(now.Month.ToString());
expected = $"{sharding.BaseName}{sharding.SuffixConnector}{now.Month}";
Assert.Equal(expected, newSharding);
}
