Swashbuckle多态性支持问题 [英] Swashbuckle polymorphism support issue
问题描述
我正在使用Swashbuckle v3.0.
I am using Swashbuckle v3.0.
我不确定这是否是错误，但是多态性无法正常工作.我有以下课程:
I am not sure weather this is a bug or not, but polymorphism is not working as it should. I have the following classes:
BasePersonDocumentDto
{
Id,
Number
}
IdentityDto: BasePersonDocumentDto
{
}
PassportDto: BasePersonDocumentDto
{
VisaNumber
}
要应用继承&多态性，我创建了一个架构和文档过滤器. 我遵循了这个答案我使用的代码.
To apply Inheritance & Polymorphism, i have created a schema and document filters. I followed this answer Below are the code i used.
public class PolymorphismSchemaFilter<T> : ISchemaFilter
{
private List<Type> derivedTypes = new List<Type>() { typeof(IdentityDto), typeof(PassportDto) };
public void Apply(Schema model, SchemaFilterContext context)
{
if (!derivedTypes.Contains(context.SystemType)) return;
var baseSchema = new Schema() { Ref = "#/definitions/" + typeof(T).Name };
var clonedBaseSchema = new Schema
{
Properties = model.Properties,
Type = model.Type,
Required = model.Required
};
model.AllOf = new List<Schema> { baseSchema, clonedBaseSchema };
//Reset properties for they are included in allOf, should be null but code does not handle it
model.Properties = new Dictionary<string, Schema>();
}
}
public class PolymorphismDocumentFilter<T> : IDocumentFilter
{
private List<Type> derivedTypes = new List<Type>() { typeof(IdentityDto), typeof(PassportDto) };
public void Apply(SwaggerDocument swaggerDoc, DocumentFilterContext context)
{
const string discriminatorName = "discriminator";
var baseSchema = context.SchemaRegistry.Definitions[typeof(T).Name];
//Discriminator property
baseSchema.Discriminator = discriminatorName;
baseSchema.Required = new List<string> { discriminatorName };
if (!baseSchema.Properties.ContainsKey(discriminatorName))
baseSchema.Properties.Add(discriminatorName, new Schema { Type = "string" });
//Register dervied classes
foreach (var item in derivedTypes)
context.SchemaRegistry.GetOrRegister(item);
}
}
生成的定义是:
//This is for BasePersonDocumentDto and for IdentityDto
"BasePersonDocumentDto":{
"required":[
"discriminator"
],
"type":"object",
"properties":{
"number":{
"type":"string"
},
"id":{
"format":"int32",
"type":"integer"
},
"discriminator":{
"type":"string"
}
},
"discriminator":"discriminator"
}
"PassportDto":{
"required":[
"discriminator"
],
"type":"object",
"properties":{
"number":{
"type":"string"
},
"id":{
"format":"int32",
"type":"integer"
},
"visaNumber":{
"type":"string"
},
"discriminator":{
"type":"string"
}
},
"discriminator":"discriminator"
}
现在要测试，我创建一个具有List属性的InputDto.我尝试传递以下JSON，但是即使正确传递了鉴别符，传递的两个项目也都显示为BasePersonDocumentDto.这是我传递的JSON:
Now to test, i create an InputDto that have a List property. I tried passing the following JSON, but both passed items are shown as BasePersonDocumentDto even though the discriminator is passed correctly. Here is the JSON i passed:
{
"documentsDto":[
{
"discriminator":"IdentityDto"
},
{
"visaNumber":"RRXX323TR",
"discriminator":"PassportDto"
}
]
}
推荐答案
一段时间后，我想出了一种方法来解决我的问题.我的情况很简单.我只有一个基类和一些派生类，但是昂首阔步仅生成了基类，而不生成派生类.
After sometime i was able to figure a way to solve out my issue. My case was very simple. I just had a base and some derived classes, but swagger only generated the base but not the derived.
为解决此问题，我使用了我在问题中发布的代码，该代码应用了继承，并且还添加了一个名为"discriminator"的隐式列.该列用于区分子类型.
To solve this issue, i used the code i posted in my question, which applies inheritance and also, adds an implicit column named "discriminator". This column is used to discriminate between the subtypes.
最后一个问题是当反序列化到一个对象时，昂首阔步无法使用"discriminator"列，因此，它始终映射为基本类型.我找到了两种解决方案，第一种是实现自定义模型绑定程序，第二种是实现自定义JsonConverter.
The final issue was when deserializing to an object, swagger wasn't able to use the "discriminator" column and as a result, it always mapped to base type. I found two solutions to solve this, the first was to implement a custom model binder, and the second was to implement a custom JsonConverter.
我选择了第二个选项，因为它看起来更合乎逻辑，因为我的问题是处理反序列化Json.除了在我的基类中使用JsonConverter之外，我还将其装饰为"KnownType"属性.
I went with the second option as it seems more logical since my issue was dealing with deserializing a Json. Along with using the JsonConverter with my base class, i also decorated it "KnownType" attribute.
[KnownType(typeof(IdentityDto))]
[KnownType(typeof(PassportDto))]
[JsonConverter(typeof(InheritanceConverter))]
BasePersonDocumentDto
{
Id,
Number
}
下面是JsonConverter的代码:
Below is the code for the JsonConverter:
/// <summary>
/// Json deserialization for inheritance structure with discriminator
/// </summary>
public class InheritanceConverter : JsonConverter
{
/// <summary>
/// Default name for the discriminator property
/// </summary>
private string _discriminator { get; set; } = "discriminator";
public InheritanceConverter()
{
}
/// <summary>
/// Discriminator name to map between types
/// </summary>
/// <param name="discriminator">The discriminator property name. The defualt value is 'discriminator'</param>
public InheritanceConverter(string discriminator)
{
if (!string.IsNullOrWhiteSpace(discriminator))
_discriminator = discriminator;
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
//Check null
if (reader.TokenType == JsonToken.Null) return null;
//Parse json
var jDerivedObject = JObject.Load(reader);
//Get discriminator
var discriminator = jDerivedObject.Value<string>(_discriminator);
if (string.IsNullOrWhiteSpace(discriminator))
throw new Exception("Invalid discriminator value");
//Get the type
var derivedType = GetSubType(discriminator, objectType);
//Create a new instance of the target type
var derivedObject = Activator.CreateInstance(derivedType);
//Populate the derived object
serializer.Populate(jDerivedObject.CreateReader(), derivedObject);
return derivedObject;
}
//TODO:- validate based on the base and sub-types via the KnownTypeAttributes
public override bool CanConvert(Type objectType) => true;
//Not required
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
//Not required
public override bool CanWrite => false;
#region Methods
/// <summary>
/// Get sub-type via KnownTypeAttributes
/// </summary>
/// <param name="derivedTypeName">The target type name which corosponds to the discriminator</param>
private Type GetSubType(string derivedTypeName, Type baseType)
{
var knownTypes = baseType.GetCustomAttributes(false).Where(ca => ca.GetType().Name == "KnownTypeAttribute").ToList();
if (knownTypes == null || knownTypes.Count == 0)
throw new Exception(
string.Format("Couldn't find any KnownAttributes over the base {0}. Please define at least one KnownTypeAttribute to determine the sub-type", baseType.Name));
foreach (dynamic type in knownTypes)
{
if (type.Type != null && type.Type.Name.ToLower() == derivedTypeName.ToLower())
return type.Type;
}
throw new Exception(string.Format("Discriminator '{0}' doesn't match any of the defined sub-types via KnownTypeAttributes", derivedTypeName));
}
#endregion
}
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