PowerJSON is a fork of the smallest, fastest polymorphic JSON serializer--fastJSON.

Please read the article about fastJSON here.

The following features and changes are added to version 3:

• Streaming serialization API.
• Type alias system for polymorphic deserialization.
• Changes of default settings for serialization.
• Deprecation of obsolete APIs.

1. Change the assembly reference from fastJSON.dll to PowerJson.dll.
2. Replace all fastJSON namespace to PowerJson.
3. Change JSON to Json in all API types and methods. Typically the JSON class and its ToJSON method overloads.
4. The JSONParameters class has been merged into SerializationManager class.
5. Default values in the previous JSONParameters class has changed. SerializeStaticMembers, UseFastGuid and UseEscapedUnicode will have the default value of false instead of true in previous versions.
6. Some settings in the previous JSONParameters class has been renamed. ShowReadOnlyProperties, ShowReadOnlyFields shall be changed to SerializeReadOnlyProperties and SerializeReadOnlyFields respectively.
7. UsingGlobalTypes in the previous JSONParameters are no longer used. No global types will be written to the serialized JSON string.
8. The $type extension will show the alias (settable by calling the OverrideTypeAlias< T> (String) method, or applying to the type with the JsonTypeAliasAttribute) or FullName instead of the AssemblyQualifiedName of the type.
9. All obsolete features in previous versions shall be removed or changed to corresponding API.

The following features are added to the original fastJSON.

• Rename serialized members.
• Rename serialized Enum values.
• Deserializing non-public types.
• Serializing and deserializing non-public members.
• Polymorphic serialization without JSON extensions.
• Write out additional key-value pairs in the serialized JSON.
• Conditional serialization.
• Noninvasive control over serialization.
• Easiest implemetation of customized serialization and deserialization.
• A comprehensive documentation.

The newly introduced classes and interfaces have brought more control onto each aspect in serialization.

• SerializationManager: Caches the reflection result and controls the serialization. Supports non-invasive control over serialization.
• IReflectionController: Controls every possible aspect in reflection for serialization.
• IJsonInterceptor: Intercepts JSON serialization and enables conditional serialization.
• IJsonConverter: Converts between various value types.
• JsonConverter<TOriginal,TSerialized>: A base class which implements IJsonConverter and simplifies the data conversion.

This fork has empowered fastJSON to serialize and deserialize objects with additional attribute types. The attributes are listed below:

• JsonInterceptorAttribute: 1) controls the procedure of serialization. 2) allows conditional serialization. 3) allows writing out extra key-value pairs in the serialized object.
• JsonFieldAttribute: 1) controls the name of the serialized field or property. 2) allows serializing interface or abstract types with the Type and Name conbination in the attribute.
• JsonIncludeAttribute: 1) explicitly controls whether a field or property is serialized or not. 2) allows serializing readonly property even when the ShowReadOnlyProperties setting is turned off.
• JsonConverterAttribute: allows transforming data before serialization.
• JsonEnumValueAttribute: controls the serialized literal name of an Enum value.
• JsonSerializableAttribute: enables serializing and deserializing non-public types or members.
• JsonNonSerializedValueAttribute: prevents specified member value from serializing.
• JsonContainerAttribute: puts enumerable items into a field named by this attribute to fully serialize types implementing IEnumerable.
• JsonTypeAliasAttribute: sets the alias of a type for polymorphic deserialization. +

+ new in version 3

Some .NET built-in attributes are also supported.

• DefaultValueAttribute: values equal to DefaultValueAttribute.Value are not serialized.
• ReadOnlyAttribute: values are not deserialized when ReadOnlyAttribute.IsReadOnly is set to true.
• DataContractAttribute
• DataMemberAttribute: Currently only the Name setting is supported, other settings such as Order, IsRequired are not supported.
• EnumMemberAttribute
• IgnoreDataMemberAttribute

XML serialization attributes are optionally supported (listed below). By default, the support is disabled and can be accessed by creating a new SerializationManager with a JsonReflectionController which has that option turned on.

• XmlElementAttribute
• XmlAttributeAttribute
• XmlArrayAttribute
• XmlEnumAttribute
• XmlIgnoreAttribute

This fork introduced the following settings in JsonParameters:

• NamingConvention: control the naming convention of serialized fields and properties. It has added support for camel-case, uppercase names.
• SerializeStaticMembers: control whether static fields or properties should be serialized. (2015-4-2)
• ShowReadOnlyFields: control whether readonly fields should be serialized. (2015-4-7)
• SerializeEmptyCollections: control whether zero length collections, arrays, lists, dictionaries, etc. are serialized. (2015-4-25)

This fork also fixed some issues in the original fastJSON project:

• The serialized Enum value could be incorrect when the underlying type is Int64 or UInt64.
• Null values were ignored in deserialization (when the constructor initialize the value of the member, in deserialization, the null value should not be ignored and set the member to null).
• Multi-value items in NameValueCollection were not serialized correctly.
• Serializing TimeSpan type could cause application stack overflow. (2015-4-2)
• Read-only static fields were serialized regardless ShowReadOnlyProperties was turned off. (2015-4-7)
• ShowReadOnlyProperties was not in effect for the same type after change. (2015-4-7)
• Deserialization on Dictionary<N, List<V>> type could fail. (2015-4-9)
• "Release" compiled edition did not support dynamic types.
• Multi-demensional arrays could not be deserialized. (2015-4-25)
• List<T[]> list could not be deserialized. (2015-4-27)
• HashSet<T> could not be serialized. (2015-5-13)
• Types implementing IEnumerable could not be fully serialized. (2015-8-25)

• Performance has been more thoroughly optimized. It is faster than the fastest :)
• The Beautify method of JSON has introduced a new parameter: decodeUnicode, which allows decode "\uXXXX" encoded Unicode characters into human readable ones.