如何使用Swashbuckle在Swagger API文档/OpenAPI规范中包含子类
本文关键字：OpenAPI 范中包 子类 文档 Swashbuckle 何使用 Swagger API | 更新日期: 2023-09-27 18:27:46
我在c#中有一个Asp.Net web API 5.2项目，并使用Swashbuckle生成文档。
我有一个包含继承的模型，比如从Animal抽象类中获得Animal属性，以及从中派生的Dog和Cat类
Swashbuckle只显示了Animal类的模式，所以我尝试使用ISchemaFilter（他们也建议这样做），但我无法使其工作，而且我也找不到合适的示例。
有人能帮忙吗？
Swashbuckle似乎没有正确实现多态性，我理解作者关于子类作为参数的观点（如果一个操作需要一个Animal类，并且如果你用狗对象或猫对象调用它，它的行为会有所不同，那么你应该有两个不同的操作…）但作为返回类型，我认为返回Animal和对象可以是Dog或Cat类型。
因此，为了描述我的API并根据正确的指导原则生成正确的JSON模式（请注意我描述判别器的方式，如果你有自己的判别器，你可能需要特别更改该部分），我使用文档和模式过滤器如下：
SwaggerDocsConfig configuration;
.....
configuration.DocumentFilter<PolymorphismDocumentFilter<YourBaseClass>>();
configuration.SchemaFilter<PolymorphismSchemaFilter<YourBaseClass>>();
.....
public class PolymorphismSchemaFilter<T> : ISchemaFilter
{
private readonly Lazy<HashSet<Type>> derivedTypes = new Lazy<HashSet<Type>>(Init);
private static HashSet<Type> Init()
{
var abstractType = typeof(T);
var dTypes = abstractType.Assembly
.GetTypes()
.Where(x => abstractType != x && abstractType.IsAssignableFrom(x));
var result = new HashSet<Type>();
foreach (var item in dTypes)
result.Add(item);
return result;
}
public void Apply(Schema schema, SchemaRegistry schemaRegistry, Type type)
{
if (!derivedTypes.Value.Contains(type)) return;
var clonedSchema = new Schema
{
properties = schema.properties,
type = schema.type,
required = schema.required
};
//schemaRegistry.Definitions[typeof(T).Name]; does not work correctly in SwashBuckle
var parentSchema = new Schema { @ref = "#/definitions/" + typeof(T).Name };
schema.allOf = new List<Schema> { parentSchema, clonedSchema };
//reset properties for they are included in allOf, should be null but code does not handle it
schema.properties = new Dictionary<string, Schema>();
}
}
public class PolymorphismDocumentFilter<T> : IDocumentFilter
{
public void Apply(SwaggerDocument swaggerDoc, SchemaRegistry schemaRegistry, System.Web.Http.Description.IApiExplorer apiExplorer)
{
RegisterSubClasses(schemaRegistry, typeof(T));
}
private static void RegisterSubClasses(SchemaRegistry schemaRegistry, Type abstractType)
{
const string discriminatorName = "discriminator";
var parentSchema = schemaRegistry.Definitions[SchemaIdProvider.GetSchemaId(abstractType)];
//set up a discriminator property (it must be required)
parentSchema.discriminator = discriminatorName;
parentSchema.required = new List<string> { discriminatorName };
if (!parentSchema.properties.ContainsKey(discriminatorName))
parentSchema.properties.Add(discriminatorName, new Schema { type = "string" });
//register all subclasses
var derivedTypes = abstractType.Assembly
.GetTypes()
.Where(x => abstractType != x && abstractType.IsAssignableFrom(x));
foreach (var item in derivedTypes)
schemaRegistry.GetOrRegister(item);
}
}
前面的代码实现的内容在"支持多态性的模型"一节中有详细说明
{
"definitions": {
"Pet": {
"type": "object",
"discriminator": "petType",
"properties": {
"name": {
"type": "string"
},
"petType": {
"type": "string"
}
},
"required": [
"name",
"petType"
]
},
"Cat": {
"description": "A representation of a cat",
"allOf": [
{
"$ref": "#/definitions/Pet"
},
{
"type": "object",
"properties": {
"huntingSkill": {
"type": "string",
"description": "The measured skill for hunting",
"default": "lazy",
"enum": [
"clueless",
"lazy",
"adventurous",
"aggressive"
]
}
},
"required": [
"huntingSkill"
]
}
]
},
"Dog": {
"description": "A representation of a dog",
"allOf": [
{
"$ref": "#/definitions/Pet"
},
{
"type": "object",
"properties": {
"packSize": {
"type": "integer",
"format": "int32",
"description": "the size of the pack the dog is from",
"default": 0,
"minimum": 0
}
},
"required": [
"packSize"
]
}
]
}
}
}
要继续学习Paulo的好答案，如果您使用的是Swagger 2.0，您需要修改类，如图所示：
public class PolymorphismSchemaFilter<T> : ISchemaFilter
{
private readonly Lazy<HashSet<Type>> derivedTypes = new Lazy<HashSet<Type>>(Init);
private static HashSet<Type> Init()
{
var abstractType = typeof(T);
var dTypes = abstractType.Assembly
.GetTypes()
.Where(x => abstractType != x && abstractType.IsAssignableFrom(x));
var result = new HashSet<Type>();
foreach (var item in dTypes)
result.Add(item);
return result;
}
public void Apply(Schema model, SchemaFilterContext context)
{
if (!derivedTypes.Value.Contains(context.SystemType)) return;
var clonedSchema = new Schema
{
Properties = model.Properties,
Type = model.Type,
Required = model.Required
};
//schemaRegistry.Definitions[typeof(T).Name]; does not work correctly in SwashBuckle
var parentSchema = new Schema { Ref = "#/definitions/" + typeof(T).Name };
model.AllOf = new List<Schema> { parentSchema, clonedSchema };
//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 static void RegisterSubClasses(ISchemaRegistry schemaRegistry, Type abstractType)
{
const string discriminatorName = "discriminator";
var parentSchema = schemaRegistry.Definitions[abstractType.Name];
//set up a discriminator property (it must be required)
parentSchema.Discriminator = discriminatorName;
parentSchema.Required = new List<string> { discriminatorName };
if (!parentSchema.Properties.ContainsKey(discriminatorName))
parentSchema.Properties.Add(discriminatorName, new Schema { Type = "string" });
//register all subclasses
var derivedTypes = abstractType.Assembly
.GetTypes()
.Where(x => abstractType != x && abstractType.IsAssignableFrom(x));
foreach (var item in derivedTypes)
schemaRegistry.GetOrRegister(item);
}
public void Apply(SwaggerDocument swaggerDoc, DocumentFilterContext context)
{
RegisterSubClasses(context.SchemaRegistry, typeof(T));
}
}
由于合并到Swashbuckle.AspNetCore中，您可以通过使用获得对多态模式的基本支持
services.AddSwaggerGen(c =>
{
c.GeneratePolymorphicSchemas();
}
您还可以通过Annotations库中的属性来表达派生类型：
[SwaggerSubTypes(typeof(SubClass), Discriminator = "value")]
本文将进一步详细介绍如何使用Newtonsoft反序列化派生类型。
我想跟进Craig的回答。
如果您使用NSwag从Swagger API文档中生成TypeScript定义，该文档使用Paulo的回答中解释的方法生成，并在Craig的回答中进一步增强，则您可能会面临以下问题：
-
生成的TypeScript定义将具有重复的属性，即使生成的类将扩展基类。考虑以下C#类：
public abstract class BaseClass { public string BaseProperty { get; set; } } public class ChildClass : BaseClass { public string ChildProperty { get; set; } }当使用上述答案时，
IBaseClass和IChildClass接口的TypeScript定义如下所示：export interface IBaseClass { baseProperty : string | undefined; } export interface IChildClass extends IBaseClass { baseProperty : string | undefined; childProperty: string | undefined; }正如您所看到的，
baseProperty在基类和子类中都被错误地定义。为了解决这个问题，我们可以修改PolymorphismSchemaFilter<T>类的Apply方法，使其只在模式中包含所拥有的属性，即从当前类型模式中排除继承的属性。这里有一个例子：public void Apply(Schema model, SchemaFilterContext context) { ... // Prepare a dictionary of inherited properties var inheritedProperties = context.SystemType.GetProperties() .Where(x => x.DeclaringType != context.SystemType) .ToDictionary(x => x.Name, StringComparer.OrdinalIgnoreCase); var clonedSchema = new Schema { // Exclude inherited properties. If not excluded, // they would have appeared twice in nswag-generated typescript definition Properties = model.Properties.Where(x => !inheritedProperties.ContainsKey(x.Key)) .ToDictionary(x => x.Key, x => x.Value), Type = model.Type, Required = model.Required }; ... } -
生成的TypeScript定义不会引用任何现有中间抽象类的属性。考虑以下C#类：
public abstract class SuperClass { public string SuperProperty { get; set; } } public abstract class IntermediateClass : SuperClass { public string IntermediateProperty { get; set; } } public class ChildClass : BaseClass { public string ChildProperty { get; set; } }在这种情况下，生成的TypeScript定义如下所示：
export interface ISuperClass { superProperty: string | undefined; } export interface IIntermediateClass extends ISuperClass { intermediateProperty : string | undefined; } export interface IChildClass extends ISuperClass { childProperty: string | undefined; }请注意生成的
IChildClass接口是如何直接扩展ISuperClass的，而忽略了IIntermediateClass接口，从而有效地使IChildClass的任何实例都没有intermediateProperty属性。我们可以使用以下代码来解决这个问题：
public void Apply(Schema model, SchemaFilterContext context) { ... // Use the BaseType name for parentSchema instead of typeof(T), // because we could have more classes in the hierarchy var parentSchema = new Schema { Ref = "#/definitions/" + (context.SystemType.BaseType?.Name ?? typeof(T).Name) }; ... }这将确保子类正确地引用中间类。
总之，最后的代码看起来是这样的：
public void Apply(Schema model, SchemaFilterContext context)
{
if (!derivedTypes.Value.Contains(context.SystemType))
{
return;
}
// Prepare a dictionary of inherited properties
var inheritedProperties = context.SystemType.GetProperties()
.Where(x => x.DeclaringType != context.SystemType)
.ToDictionary(x => x.Name, StringComparer.OrdinalIgnoreCase);
var clonedSchema = new Schema
{
// Exclude inherited properties. If not excluded,
// they would have appeared twice in nswag-generated typescript definition
Properties =
model.Properties.Where(x => !inheritedProperties.ContainsKey(x.Key))
.ToDictionary(x => x.Key, x => x.Value),
Type = model.Type,
Required = model.Required
};
// Use the BaseType name for parentSchema instead of typeof(T),
// because we could have more abstract classes in the hierarchy
var parentSchema = new Schema
{
Ref = "#/definitions/" + (context.SystemType.BaseType?.Name ?? typeof(T).Name)
};
model.AllOf = new List<Schema> { parentSchema, clonedSchema };
// reset properties for they are included in allOf, should be null but code does not handle it
model.Properties = new Dictionary<string, Schema>();
}
我们最近升级到.NET Core 3.1和Swashbuckle.AspNetCore 5.0API也有所改变。如果有人需要这个过滤器，这里是代码的最小变化，以获得类似的行为：
public class PolymorphismDocumentFilter<T> : IDocumentFilter
{
public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
{
RegisterSubClasses(context.SchemaRepository, context.SchemaGenerator, typeof(T));
}
private static void RegisterSubClasses(SchemaRepository schemaRegistry, ISchemaGenerator schemaGenerator, Type abstractType)
{
const string discriminatorName = "$type";
OpenApiSchema parentSchema = null;
if (schemaRegistry.TryGetIdFor(abstractType, out string parentSchemaId))
parentSchema = schemaRegistry.Schemas[parentSchemaId];
else
parentSchema = schemaRegistry.GetOrAdd(abstractType, parentSchemaId, () => new OpenApiSchema());
// set up a discriminator property (it must be required)
parentSchema.Discriminator = new OpenApiDiscriminator() { PropertyName = discriminatorName };
parentSchema.Required = new HashSet<string> { discriminatorName };
if (parentSchema.Properties == null)
parentSchema.Properties = new Dictionary<string, OpenApiSchema>();
if (!parentSchema.Properties.ContainsKey(discriminatorName))
parentSchema.Properties.Add(discriminatorName, new OpenApiSchema() { Type = "string", Default = new OpenApiString(abstractType.FullName) });
// register all subclasses
var derivedTypes = abstractType.GetTypeInfo().Assembly.GetTypes()
.Where(x => abstractType != x && abstractType.IsAssignableFrom(x));
foreach (var item in derivedTypes)
schemaGenerator.GenerateSchema(item, schemaRegistry);
}
}
public class PolymorphismSchemaFilter<T> : ISchemaFilter
{
private readonly Lazy<HashSet<Type>> derivedTypes = new Lazy<HashSet<Type>>(Init);
public void Apply(OpenApiSchema schema, SchemaFilterContext context)
{
if (!derivedTypes.Value.Contains(context.Type)) return;
Type type = context.Type;
var clonedSchema = new OpenApiSchema
{
Properties = schema.Properties,
Type = schema.Type,
Required = schema.Required
};
// schemaRegistry.Definitions[typeof(T).Name]; does not work correctly in Swashbuckle.AspNetCore
var parentSchema = new OpenApiSchema
{
Reference = new OpenApiReference() { ExternalResource = "#/definitions/" + typeof(T).Name }
};
var assemblyName = Assembly.GetAssembly(type).GetName();
schema.Discriminator = new OpenApiDiscriminator() { PropertyName = "$type" };
// This is required if you use Microsoft's AutoRest client to generate the JavaScript/TypeScript models
schema.Extensions.Add("x-ms-discriminator-value", new OpenApiObject() { ["name"] = new OpenApiString($"{type.FullName}, {assemblyName.Name}") });
schema.AllOf = new List<OpenApiSchema> { parentSchema, clonedSchema };
// reset properties for they are included in allOf, should be null but code does not handle it
schema.Properties = new Dictionary<string, OpenApiSchema>();
}
private static HashSet<Type> Init()
{
var abstractType = typeof(T);
var dTypes = abstractType.GetTypeInfo().Assembly
.GetTypes()
.Where(x => abstractType != x && abstractType.IsAssignableFrom(x));
var result = new HashSet<Type>();
foreach (var item in dTypes)
result.Add(item);
return result;
}
}
我没有完全检查结果，但它似乎给出了相同的行为。
还要注意，您需要导入以下名称空间：
using Microsoft.OpenApi.Models;
using Microsoft.OpenApi.Any;
using System.Reflection;
using Swashbuckle.AspNetCore.SwaggerGen;
这适用于5.6.3:版本
services.AddSwaggerGen(options =>
{
options.UseOneOfForPolymorphism();
options.SelectDiscriminatorNameUsing(_ => "type");
});