/// <summary>
/// The <see cref="Serialize(object?,DynamoSerializerOptions)"/> method serializes an object to a DynamoDB attribute value.
/// </summary>
/// <param name="value">The object to serialize.</param>
/// <param name="options">The serialization options to use.</param>
/// <returns>A DynamoDB attribute value or <c>null</c> when the object state cannot be represented in DynamoDB.</returns>
public static AttributeValue?Serialize(object?value, DynamoSerializerOptions options)
{
// check for types mapped to attribute type 'NULL'
if (value is null)
{
return(new AttributeValue {
NULL = true
});
}
// find a suiteable converter for the provided type
var typeToConvert = value.GetType();
var converter = options.GetConverters().FirstOrDefault(converter => converter.CanConvert(typeToConvert));
if (converter is null)
{
throw new DynamoSerializationException($"cannot convert value of type '{typeToConvert?.FullName ?? "<null>"}'");
}
return(converter.ToAttributeValue(value, typeToConvert, options));
}
/// <summary>
/// The <see cref="Deserialize(Dictionary{string, AttributeValue},Type,DynamoSerializerOptions)"/> method deserializes a DynamoDB document into a <paramref name="targetType"/> instance.
/// </summary>
/// <param name="document">The DynamoDB document to deserialize.</param>
/// <param name="targetType">The type to deserialize into.</param>
/// <param name="options">The deserialization options to use.</param>
/// <returns>An instance of <paramref name="targetType"/> or <c>null</c> when the DynamoDB document is <c>null</c>.</returns>
public static object?Deserialize(Dictionary <string, AttributeValue> document, Type?targetType, DynamoSerializerOptions options)
{
var usedTargetType = ((targetType is null) || (targetType == typeof(object)))
? typeof(Dictionary <string, object>)
: targetType;
var converter = options.GetConverters().FirstOrDefault(converter => converter.CanConvert(usedTargetType));
if (converter == null)
{
throw new DynamoSerializationException($"cannot convert document {nameof(AttributeValue.M)} (given: {targetType?.FullName ?? "<null>"})");
}
return(converter.FromMap(document, usedTargetType, options));
}
/// <summary>
/// The <see cref="Deserialize(AttributeValue,Type,DynamoSerializerOptions)"/> method deserializes a DynamoDB attribute value into a <paramref name="targetType"/> instance.
/// </summary>
/// <param name="attribute">The DynamoDB attribute value to deserialize.</param>
/// <param name="targetType">The type to deserialize into.</param>
/// <param name="options">The deserialization options to use.</param>
/// <returns>An instance of <paramref name="targetType"/> or <c>null</c> when the DynamoDB attribute value is <c>NULL</c>.</returns>
public static object?Deserialize(AttributeValue?attribute, Type?targetType, DynamoSerializerOptions options)
{
// handle missing value
if (attribute == null)
{
return(FindConverter(typeof(object), "<default>", (converter, usedTargetType) => converter.GetDefaultValue(usedTargetType, options)));
}
// handle boolean value
if (attribute.IsBOOLSet)
{
return(FindConverter(typeof(bool), nameof(AttributeValue.BOOL), (converter, usedTargetType) => converter.FromBool(attribute.BOOL, usedTargetType, options)));
}
// handle string value
if (!(attribute.S is null))
{
return(FindConverter(typeof(string), nameof(AttributeValue.S), (converter, usedTargetType) => converter.FromString(attribute.S, usedTargetType, options)));
}
// handle number value
if (!(attribute.N is null))
{
return(FindConverter(typeof(double), nameof(AttributeValue.N), (converter, usedTargetType) => converter.FromNumber(attribute.N, usedTargetType, options)));
}
// handle binary value
if (!(attribute.B is null))
{
return(FindConverter(typeof(byte[]), nameof(AttributeValue.B), (converter, usedTargetType) => converter.FromBinary(attribute.B, usedTargetType, options)));
}
// handle list value
if (attribute.IsLSet)
{
return(FindConverter(typeof(List <object>), nameof(AttributeValue.L), (converter, usedTargetType) => converter.FromList(attribute.L, usedTargetType, options)));
}
// handle map value
if (attribute.IsMSet)
{
return(Deserialize(attribute.M, targetType, options));
}
// handle binary set value
if (attribute.BS.Any())
{
return(FindConverter(typeof(HashSet <byte[]>), nameof(AttributeValue.BS), (converter, usedTargetType) => converter.FromBinarySet(attribute.BS, usedTargetType, options)));
}
// handle string set value
if (attribute.SS.Any())
{
return(FindConverter(typeof(HashSet <string>), nameof(AttributeValue.SS), (converter, usedTargetType) => converter.FromStringSet(attribute.SS, usedTargetType, options)));
}
// handle number set value
if (attribute.NS.Any())
{
return(FindConverter(typeof(HashSet <double>), nameof(AttributeValue.NS), (converter, usedTargetType) => converter.FromNumberSet(attribute.NS, usedTargetType, options)));
}
// handle null value
if (attribute.NULL)
{
return(FindConverter(typeof(object), nameof(AttributeValue.NULL), (converter, usedTargetType) => converter.FromNull(usedTargetType, options)));
}
throw new DynamoSerializationException($"invalid attribute value");
// local functions
object?FindConverter(Type defaultType, string attributeValueTypeName, Func <IDynamoAttributeConverter, Type, object?> convert)
{
var usedTargetType = ((targetType is null) || (targetType == typeof(object)))
? defaultType
: targetType;
var converter = options.GetConverters().FirstOrDefault(converter => converter.CanConvert(usedTargetType));
if (converter == null)
{
throw new DynamoSerializationException($"cannot convert attribute value {attributeValueTypeName} (given: {targetType?.FullName ?? "<null>"})");
}
return(convert(converter, usedTargetType));
}
}
/// <summary>
/// The <see cref="Deserialize(Dictionary{string, AttributeValue},DynamoSerializerOptions)"/> method deserializes a DynamoDB document into a <typeparamref name="TRecord"/> instance.
/// </summary>
/// <param name="document">The DynamoDB document to deserialize.</param>
/// <param name="options">The deserialization options to use.</param>
/// <typeparam name="TRecord">The type to deserialize into.</typeparam>
/// <returns>An instance of <typeparamref name="TRecord"/> or <c>null</c> when the DynamoDB document is <c>null</c>.</returns>
public static TRecord?Deserialize <TRecord>(Dictionary <string, AttributeValue> document, DynamoSerializerOptions options)
where TRecord : class
=> (TRecord?)Deserialize(document, typeof(TRecord), options);
