C＃MongoDB复杂类序列化

Question

我正在使用C＃MongoDB驱动程序，并且要保存以下相当复杂的JSON结构：

{
    "name" : "value",
    "age": 1,
    "isFemale": true,
    "Hobbies" : {
        //All data within the "Hobbies" node is dynamic
        //and may change from one item to another.
        "stringItem" : "value",
        "intItem" : 0.0,
        "listOfItems" : [
            { "field" : 1696.0 }
        ],
        "intArray" : [ 566.0,  1200.0 ]
    },
    "Collection" : [ 
        //All data within the "Collection" node is dynamic
        //and may change from one item to another.
        {
            "field" : "string",
            "FieldTypeId" : 2.0,
            "array" : [ 
                { "value" : "1024x1000" }
            ]
        }
    ]
}

我有代表上述对象的此类：

public class MyClass
{
    public string Name;
    public int Age;
    public bool IsFemale;
    public Dictionary<string, object> Hobbies;
    public List<Dictionary<string, object>> Collection;
}

这是我为“爱好”部分保存的内容：

"Hobbies": {
    "stringItem": "value",
    "intItem": 1,
    "listOfItems": {
        "_t": "Newtonsoft.Json.Linq.JArray, Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed",
        "_v": [{
            "_t": "JObject",
            "_v": [{
                "_t": "JProperty",
                "_v": [{
                    "_t": "JValue",
                    "_v": []
                }]
            },
            {
                "_t": "JProperty",
                "_v": [{
                    "_t": "JValue",
                    "_v": []
                }]
            }]
        }]
    }
}

我的猜测是我应该为该类编写一个自定义序列化程序，但在MONGODB .NET DRIVER手册中找不到任何有用的示例

我试图开始并实现这样的事情：

public class MyClassSerializer : SerializerBase<MyClass>, IBsonDocumentSerializer
{
    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, MyClass value)
    {
        //What to do here???
        base.Serialize(context, args, value);
    }

    public override MyClass Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        //What to do here???
        return base.Deserialize(context, args);
    }

    public bool TryGetMemberSerializationInfo(string memberName, out BsonSerializationInfo serializationInfo)
    {
        switch (memberName)
        {
            case "Name":
                serializationInfo = new BsonSerializationInfo(memberName, new StringSerializer(), typeof(string));
                return true;
            case "Age":
                serializationInfo = new BsonSerializationInfo(memberName, new Int16Serializer(), typeof(string));
                return true;
            case "IsFemale":
                serializationInfo = new BsonSerializationInfo(memberName, new BooleanSerializer(), typeof(string));
                return true;
            case "Hobbies":
                serializationInfo = new BsonSerializationInfo(memberName, new TupleSerializer<string, object>(), typeof(string));
                return true;
            case "Collection":
                serializationInfo = new BsonSerializationInfo(memberName, new ArraySerializer<Dictionary<string, object>>(), typeof(string));
                return true;
            default:
                serializationInfo = null;
                return false;
        }
    }
}

但是我找不到与此有关的任何东西。它没有完全实现，我读到我需要在某个地方注册串行器，但是在哪里...？

Answer 1

在此处找到了如何将数据保存到MongoDB的方法：字典到BsonDocument的转换省略了_t字段并对其进行了扩展，因此我想共享完整的解决方案。

步骤1：

在课堂上，我为每个值声明了2个成员：

// For the Hobbies object type:
[BsonIgnore] //ignore this value in MongoDB
public Dictionary<string, object> Hobbies { get; set; }

[JsonIgnore] //ignore this value in the response on Get requests
[BsonElement(elementName: "Hobbies")]
public BsonDocument HobbiesBson { get; set; }

/*********************************************************************/

// For the Collection object type:
[BsonIgnore] //ignore this value in MongoDB
public List<Dictionary<string, object>> Collection { get; set; }

[JsonIgnore] //ignore this value in the response on Get requests
[BsonElement(elementName: "Collection")]
public BsonArray CollectionBson { get; set; }

第2步

在我的WebAPI控制器方法中 Post

[HttpPost]
public override async Task<IActionResult> Post([FromBody] Person person)
{
    var jsonDoc = JsonConvert.SerializeObject(person.Hobbies);
    person.HobbiesBson = BsonSerializer.Deserialize<BsonDocument>(jsonDoc);

    jsonDoc = JsonConvert.SerializeObject(person.Collection);
    person.CollectionBson = BsonSerializer.Deserialize<BsonArray>(jsonDoc);

    //save
}

步骤三

在我的Get请求中，我将其反序列化为：

[HttpGet("{id?}")]
public override async Task<IActionResult> Get(string id = null)
{
    var people = //get data from mongoDB
    foreach (var person in people)
    {
        var bsonDoc = BsonExtensionMethods.ToJson(person.HobbiesBson);
        person.Hobbies = JsonConvert.DeserializeObject<Dictionary<string, object>>(bsonDoc);

        bsonDoc = BsonExtensionMethods.ToJson(person.CollectionBson);
        person.Collection = JsonConvert.DeserializeObject<List<Dictionary<string, object>>>(bsonDoc);bsonDoc);
    }
    return Ok(people);
}

这解决了我的问题，希望也能对其他人有所帮助：-)

Answer 2

处理此问题且不必创建其他属性的一种简单方法是注册自定义序列化程序。

ComplexTypeSerializer.cs

namespace MyNamespace.MongoDB.Serializers
{
    public class ComplexTypeSerializer : SerializerBase<object>
    {
        public override object Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
        {
            var serializer = BsonSerializer.LookupSerializer(typeof(BsonDocument));
            var document = serializer.Deserialize(context, args);

            var bsonDocument = document.ToBsonDocument();

            var result = BsonExtensionMethods.ToJson(bsonDocument);
            return JsonConvert.DeserializeObject<IDictionary<string, object>>(result);
        }

        public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, object value)
        {
            var jsonDocument = JsonConvert.SerializeObject(value);
            var bsonDocument = BsonSerializer.Deserialize<BsonDocument>(jsonDocument);

            var serializer = BsonSerializer.LookupSerializer(typeof(BsonDocument));
            serializer.Serialize(context, bsonDocument.AsBsonValue);
        }
    }
}

并按照http://mongodb.github.io/mongo-csharp-driver/2.3/reference/bson/serialization/ 进行注册

BsonSerializer.RegisterSerializer(typeof(IDictionary<string, object>), new ComplexTypeSerializer());

或者

BsonSerializer.RegisterSerializer(typeof(IList<IDictionary<string, object>>), new ComplexTypeSerializer());

下面的代码用一个简单的 进行了测试IDictionary<string, object>，不确定它是否适用于IList<IDictionary<string, object>>，但是如果它不受支持，您可以创建另一个自定义序列化程序来支持它。