Merge pull request #4217 from crobibero/json-nullable-struct-converter

Properly handle null structs in json
pull/4260/head
Bond-009 4 years ago committed by GitHub
commit c3655e0e2e
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@ -8,37 +8,38 @@ namespace MediaBrowser.Common.Json.Converters
/// Converts a nullable struct or value to/from JSON.
/// Required - some clients send an empty string.
/// </summary>
/// <typeparam name="T">The struct type.</typeparam>
public class JsonNullableStructConverter<T> : JsonConverter<T?>
where T : struct
/// <typeparam name="TStruct">The struct type.</typeparam>
public class JsonNullableStructConverter<TStruct> : JsonConverter<TStruct?>
where TStruct : struct
{
private readonly JsonConverter<T?> _baseJsonConverter;
/// <summary>
/// Initializes a new instance of the <see cref="JsonNullableStructConverter{T}"/> class.
/// </summary>
/// <param name="baseJsonConverter">The base json converter.</param>
public JsonNullableStructConverter(JsonConverter<T?> baseJsonConverter)
/// <inheritdoc />
public override TStruct? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
if (reader.TokenType == JsonTokenType.Null)
{
_baseJsonConverter = baseJsonConverter;
return null;
}
/// <inheritdoc />
public override T? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
// Handle empty string.
// Token is empty string.
if (reader.TokenType == JsonTokenType.String && ((reader.HasValueSequence && reader.ValueSequence.IsEmpty) || reader.ValueSpan.IsEmpty))
{
return null;
}
return _baseJsonConverter.Read(ref reader, typeToConvert, options);
return JsonSerializer.Deserialize<TStruct>(ref reader, options);
}
/// <inheritdoc />
public override void Write(Utf8JsonWriter writer, T? value, JsonSerializerOptions options)
public override void Write(Utf8JsonWriter writer, TStruct? value, JsonSerializerOptions options)
{
if (value.HasValue)
{
_baseJsonConverter.Write(writer, value, options);
JsonSerializer.Serialize(writer, value.Value, options);
}
else
{
writer.WriteNullValue();
}
}
}
}

@ -0,0 +1,27 @@
using System;
using System.Text.Json;
using System.Text.Json.Serialization;
namespace MediaBrowser.Common.Json.Converters
{
/// <summary>
/// Json nullable struct converter factory.
/// </summary>
public class JsonNullableStructConverterFactory : JsonConverterFactory
{
/// <inheritdoc />
public override bool CanConvert(Type typeToConvert)
{
return typeToConvert.IsGenericType
&& typeToConvert.GetGenericTypeDefinition() == typeof(Nullable<>)
&& typeToConvert.GenericTypeArguments[0].IsValueType;
}
/// <inheritdoc />
public override JsonConverter CreateConverter(Type typeToConvert, JsonSerializerOptions options)
{
var structType = typeToConvert.GenericTypeArguments[0];
return (JsonConverter)Activator.CreateInstance(typeof(JsonNullableStructConverter<>).MakeGenericType(structType));
}
}
}

@ -39,14 +39,9 @@ namespace MediaBrowser.Common.Json
NumberHandling = JsonNumberHandling.AllowReadingFromString
};
// Get built-in converters for fallback converting.
var baseNullableInt32Converter = (JsonConverter<int?>)options.GetConverter(typeof(int?));
var baseNullableInt64Converter = (JsonConverter<long?>)options.GetConverter(typeof(long?));
options.Converters.Add(new JsonGuidConverter());
options.Converters.Add(new JsonStringEnumConverter());
options.Converters.Add(new JsonNullableStructConverter<int>(baseNullableInt32Converter));
options.Converters.Add(new JsonNullableStructConverter<long>(baseNullableInt64Converter));
options.Converters.Add(new JsonNullableStructConverterFactory());
return options;
}

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