trampster / JsonSrcGen

Json library that uses .NET 5 Source Generators

JsonSrcGen

Json library that uses .NET 5 c# Source Generators

Note: Requires the .NET 5 to run.

Supported Types

Classes Class serializers can be generated by defining a Json attribute on the class

[Json]
public class MyType
{
    [JsonName("my_name")]
    public string MyProperty {get;set}

    [JsonIgnore]
    public string IgnoredProperty {get;set;}
}

var converter = new JsonConverter();

ReadOnlySpan<char> json = convert.ToJson(new MyType(){MyProperty = "Some value"});

var myType = new MyType();
convert.FromJson("{\"MyProperty\:\"Some value\"}", myType);

Properties with the following types are supported:

Integer Types	Others
int	float?
int?	double
uint	double?
uint?	boolean
ushort	boolean?
ushort?	string
short	DateTime
short?	DateTime?
byte	DateTimeOffset
byte?	DateTimeOffset?
long	Guid
long?	Arrays
float	List

Arrays

Arrays are generated by defining a JsonArray attribute at the assembly level.

[assembly: JsonArray(typeof(bool))]

List

Lists are generated by defining a JsonList attribute at the assembly level.

[assembly: JsonList(typeof(bool))]

Dictionary

Dictionaries are generated by defining a JsonList attribute at the assembly level. Only Dictionaries with string keys are supported currently.

[assembly: JsonDictionary(typeof(string), typeof(int))]

Values

Simple json values are generated by defining a JsonValue attribute at the assembly level.

[assembly: JsonValue(typeof(int))]

Custom Converters

You can customize the conversion for specific types by providing your own converter. You must implement ICustomConverter and put the CustomConverter attribute on your class.

[CustomConverter(typeof(int))]
public class CustomCaseStringConverter : ICustomConverter<int>
{
    public void ToJson(IJsonBuilder builder, int value)
    {
        // Write your json to the builder here
    }

    public ReadOnlySpan<char> FromJson(ReadOnlySpan<char> json, ref int value)
    {
        // Read the Json from the json span here
    }
}

Leave out null properties

You can instruct JsonSrcGen to skip serializing null property values by adding the following attribute:

[JsonIgnoreNull]
public class MyJsonType
{
    int? MyProperty {get;set;}
}

Set Property to default if missing

By default JsonSrcGen doesn't set properties to there default value if they are missing in the JSON. If you always give FromJson a new instance this isn't a problem. However if you reused objects (which is a big performance boost) then the property wont get set unless present in the Json. If you want JsonSrcGen to set missing properties to default then you can specify this using the JsonOptionalAttribute

public class MyJsonType
{
    [JsonOptional]
    string MyProperty{get;set;}
}

UTF8 Support

JsonSrcGen supports UTF8 via ReadOnlySpan.

To Json looks is the same as string ToJson byte with Utf8 at the end of the name

ReadOnlySpan<byte> json = convert.ToJsonUtf8(new MyType(){MyProperty = "Some value"});

From Json is even easier as the method name is the same as string FromJson but takes a ReadOnlySpan instead of ReadOnlySpan

ReadOnlySpan<byte> utf8Json = Encoding.Utf8.GetBytes("{\"MyProperty\:\"Some value\"}");
convert.FromJson(utf8Json, myType);

Nuget Packages

JsonSrcGen is available as a nuget package: https://www.nuget.org/packages/JsonSrcGen/