将hal + json反序列化为复杂模型

时间:2019-01-10 13:07:29

标签: c# json json.net deserialization json-deserialization

我有以下HAL+JSON示例:

{
    "id": "4a17d6fe-a617-4cf8-a850-0fb6bc8576fd",
    "country": "DE",
    "_embedded": {
      "company": {
        "name": "Apple",
        "industrySector": "IT",
      "owner": "Klaus Kleber",
      "_embedded": {
        "emailAddresses": [
          {
            "id": "4a17d6fe-a617-4cf8-a850-0fb6bc8576fd",
            "value": "test2@consoto.com",
            "type": "Business",
            "_links": {
              "self": {
                "href": "https://any-host.com/api/v1/customers/1234"
              }
            }
          }
        ],
        "phoneNumbers": [
          {
            "id": "4a17d6fe-a617-4cf8-a850-0fb6bc8576fd",
            "value": "01670000000",
            "type": "Business",
            "_links": {
              "self": {
                "href": "https://any-host.com/api/v1/customers/1234"
              }
            }
          }
        ],
      },
      "_links": {
        "self": {
          "href": "https://any-host.com/api/v1/customers/1234"
        },
        "phoneNumbers": {
          "href": "https://any-host.com/api/v1/customers/1234"
        },
        "addresses": {
          "href": "https://any-host.com/api/v1/customers/1234"
        },
      }
    },
  },
  "_links": {
    "self": {
      "href": "https://any-host.com/api/v1/customers/1234"
    },
    "legalPerson": {
      "href": "https://any-host.com/api/v1/customers/1234"
    },
    "naturalPerson": {
      "href": "https://any-host.com/api/v1/customers/1234"
    }
  }
}

以及以下型号:

public class Customer
{
    public Guid Id { get; set; }
    public string Country { get; set; }
    public LegalPerson Company { get; set; }
}
public class LegalPerson
{
    public string Name { get; set; }
    public string IndustrySector { get; set; }
    public string Owner { get; set; }
    public ContactInfo[] EmailAddresses { get; set; }
    public ContactInfo[] PhoneNumbers { get; set; }
}
public class ContactInfo
{
    public Guid Id { get; set; }
    public string Type { get; set; }
    public string Value { get; set; }
}

现在,由于_embbeded,我无法使用Newtonsoft.Json进行现成的序列化,因为这样Company将是null

我希望看到Json.NET的native hal+json support,但它只建议使用自定义JsonConverter

我开始自己创建一个自定义商品,但感觉就像是在“重新发明轮子”。

那么,有谁知道解决这个问题的聪明方法?

更新:

  • 重要的是不要更改模型/类。我可以添加属性,但不能更改其结构。

3 个答案:

答案 0 :(得分:5)

最可能的解决方案是建议您创建一个自定义转换器以解析所需的模型。

在这种情况下,自定义转换器将需要能够读取嵌套路径。

这应该提供一个简单的解决方法。

public class NestedJsonPathConverter : JsonConverter {

    public override object ReadJson(JsonReader reader, Type objectType,
                                    object existingValue, JsonSerializer serializer) {
        JObject jo = JObject.Load(reader);
        var properties = jo.Properties();
        object targetObj = existingValue ?? Activator.CreateInstance(objectType);
        var resolver = serializer.ContractResolver as DefaultContractResolver;

        foreach (PropertyInfo propertyInfo in objectType.GetProperties()
                                                .Where(p => p.CanRead && p.CanWrite)) {

            var attributes = propertyInfo.GetCustomAttributes(true).ToArray();

            if (attributes.OfType<JsonIgnoreAttribute>().Any())
                continue;

            var jsonProperty = attributes.OfType<JsonPropertyAttribute>().FirstOrDefault();

            var jsonPath = (jsonProperty != null ? jsonProperty.PropertyName : propertyInfo.Name);

            if (resolver != null) {
                jsonPath = resolver.GetResolvedPropertyName(jsonPath);
            }

            JToken token = jo.SelectToken(jsonPath) ?? GetTokenCaseInsensitive(properties, jsonPath);

            if (token != null && token.Type != JTokenType.Null) {
                object value = token.ToObject(propertyInfo.PropertyType, serializer);
                propertyInfo.SetValue(targetObj, value, null);
            }
        }
        return targetObj;
    }

    JToken GetTokenCaseInsensitive(IEnumerable<JProperty> properties, string jsonPath) {
        var parts = jsonPath.Split('.');

        var property = properties.FirstOrDefault(p =>
            string.Equals(p.Name, parts[0], StringComparison.OrdinalIgnoreCase)
        );

        for (var i = 1; i < parts.Length && property != null && property.Value is JObject; i++) {
            var jo = property.Value as JObject;
            property = jo.Properties().FirstOrDefault(p =>
                string.Equals(p.Name, parts[i], StringComparison.OrdinalIgnoreCase)
            );
        }

        if (property != null && property.Type != JTokenType.Null) {
            return property.Value;
        }

        return null;
    }

    public override bool CanConvert(Type objectType) {
         //Check if any JsonPropertyAttribute has a nested property name {name}.{sub}
        return objectType
            .GetProperties()
            .Any(p =>
                p.CanRead
                && p.CanWrite
                && p.GetCustomAttributes(true)
                    .OfType<JsonPropertyAttribute>()
                    .Any(jp => (jp.PropertyName ?? p.Name).Contains('.'))
            );
    }

    public override bool CanWrite {
        get { return false; }
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
        throw new NotImplementedException();
    }
}

现在不需要更改原始类的结构,只需将需要自定义路径的属性用JsonPropertyAttribute修饰即可,即可指示填充该属性的路径。

在此示例中

public class Customer {
    public Guid Id { get; set; }
    public string Country { get; set; }
    [JsonProperty("_embedded.company")]
    public LegalPerson Company { get; set; }
}
public class LegalPerson {
    public string Name { get; set; }
    public string IndustrySector { get; set; }
    public string Owner { get; set; }
    [JsonProperty("_embedded.emailAddresses")]
    public ContactInfo[] EmailAddresses { get; set; }
    [JsonProperty("_embedded.phoneNumbers")]
    public ContactInfo[] PhoneNumbers { get; set; }
}

只需根据需要包含转换器。

var settings = new JsonSerializerSettings {
    ContractResolver = new DefaultContractResolver {
        NamingStrategy = new CamelCaseNamingStrategy()
    }
};
settings.Converters.Add(new NestedJsonPathConverter());

var customer = JsonConvert.DeserializeObject<Customer>(json, settings);

代码的两个重要部分是GetTokenCaseInsensitive方法,该方法搜索请求的令牌并允许嵌套路径不区分大小写。

JToken GetTokenCaseInsensitive(IEnumerable<JProperty> properties, string jsonPath) {
    var parts = jsonPath.Split('.');

    var property = properties.FirstOrDefault(p =>
        string.Equals(p.Name, parts[0], StringComparison.OrdinalIgnoreCase)
    );

    for (var i = 1; i < parts.Length && property != null && property.Value is JObject; i++) {
        var jo = property.Value as JObject;
        property = jo.Properties().FirstOrDefault(p =>
            string.Equals(p.Name, parts[i], StringComparison.OrdinalIgnoreCase)
        );
    }

    if (property != null && property.Type != JTokenType.Null) {
        return property.Value;
    }

    return null;
}

和覆盖的CanConvert(将检查所有属性是否具有嵌套路径)

public override bool CanConvert(Type objectType) {
     //Check if any JsonPropertyAttribute has a nested property name {name}.{sub}
    return objectType
        .GetProperties()
        .Any(p => 
            p.CanRead 
            && p.CanWrite
            && p.GetCustomAttributes(true)
                .OfType<JsonPropertyAttribute>()
                .Any(jp => (jp.PropertyName ?? p.Name).Contains('.'))
        );
}

答案 1 :(得分:4)

可能的解决方案是使用自定义JsonConverter,而不是从头开始实现所有转换逻辑。

前一段时间,我发现并更新了JsonPathConverter,该属性允许将属性路径用于JsonProperty属性。例如您的情况

 [JsonProperty("_embedded.company")]
 public LegalPerson Company { get; set; }

因此具有属性的模型将如下所示:

[JsonConverter(typeof(JsonPathConverter))]
public class Customer
{
    [JsonProperty("id")]
    public Guid Id { get; set; }

    [JsonProperty("country")]
    public string Country { get; set; }

    [JsonProperty("_embedded.company")]
    public LegalPerson Company { get; set; }
}

[JsonConverter(typeof(JsonPathConverter))]
public class LegalPerson
{
    [JsonProperty("name")]
    public string Name { get; set; }

    [JsonProperty("industrySector")]
    public string IndustrySector { get; set; }

    [JsonProperty("owner")]
    public string Owner { get; set; }

    [JsonProperty("_embedded.emailAddresses")]
    public ContactInfo[] EmailAddresses { get; set; }

    [JsonProperty("_embedded.phoneNumbers")]
    public ContactInfo[] PhoneNumbers { get; set; }
}

public class ContactInfo
{
    [JsonProperty("id")]
    public Guid Id { get; set; }

    [JsonProperty("value")]
    public string Type { get; set; }

    [JsonProperty("type")]
    public string Value { get; set; }
}

JsonPathConverter的代码是这个。但我相信您可以改善它。

  public class JsonPathConverter : JsonConverter
{
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var properties = value.GetType().GetRuntimeProperties().Where(p => p.CanRead && p.CanWrite);
        JObject main = new JObject();

        foreach (PropertyInfo prop in properties)
        {
            JsonPropertyAttribute att = prop.GetCustomAttributes(true)
                .OfType<JsonPropertyAttribute>()
                .FirstOrDefault();

            string jsonPath = att != null ? att.PropertyName : prop.Name;

            if (serializer.ContractResolver is DefaultContractResolver resolver)
                jsonPath = resolver.GetResolvedPropertyName(jsonPath);

            var nesting = jsonPath.Split('.');
            JObject lastLevel = main;

            for (int i = 0; i < nesting.Length; ++i)
            {
                if (i == (nesting.Length - 1))
                {
                    lastLevel[nesting[i]] = new JValue(prop.GetValue(value));
                }
                else
                {
                    if (lastLevel[nesting[i]] == null)
                        lastLevel[nesting[i]] = new JObject();

                    lastLevel = (JObject) lastLevel[nesting[i]];
                }
            }
        }

        serializer.Serialize(writer, main);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue,
        JsonSerializer serializer)
    {
        var jo = JToken.Load(reader);
        object targetObj = Activator.CreateInstance(objectType);

        foreach (PropertyInfo prop in objectType.GetRuntimeProperties().Where(p => p.CanRead && p.CanWrite))
        {
            var attributes = prop.GetCustomAttributes(true).ToArray();

            JsonIgnoreAttribute ignoreAttribute = attributes.OfType<JsonIgnoreAttribute>().FirstOrDefault();

            if (ignoreAttribute != null)
                continue;

            JsonPropertyAttribute att = attributes.OfType<JsonPropertyAttribute>().FirstOrDefault();

            string jsonPath = att != null ? att.PropertyName : prop.Name;

            if (serializer.ContractResolver is DefaultContractResolver resolver)
                jsonPath = resolver.GetResolvedPropertyName(jsonPath);

            if (!Regex.IsMatch(jsonPath, @"^[a-zA-Z0-9_.-]+$"))
                throw new InvalidOperationException(
                    $"JProperties of JsonPathConverter can have only letters, numbers, underscores, hyphens and dots but name was ${jsonPath}."); // Array operations not permitted

            JToken token = jo.SelectToken(jsonPath);

            if (token != null && token.Type != JTokenType.Null)
            {
                object value;
                var jsonConverterAttr = attributes.OfType<JsonConverterAttribute>().FirstOrDefault();
                if (jsonConverterAttr == null)
                {
                    value = token.ToObject(prop.PropertyType, serializer);
                }
                else
                {
                    var converter = (JsonConverter) Activator.CreateInstance(jsonConverterAttr.ConverterType,
                        jsonConverterAttr.ConverterParameters);

                    var r = token.CreateReader();
                    r.Read();
                    value = converter.ReadJson(r, prop.PropertyType, prop.GetValue(targetObj),
                        new JsonSerializer());
                }

                prop.SetValue(targetObj, value, null);
            }
        }

        return targetObj;
    }

    public override bool CanConvert(Type objectType)
    {
        // CanConvert is not called when [JsonConverter] attribute is used
        return false;
    }
}

最后,您可以像这样使用它:

var json = "*your json string here*";
var customer = JsonConvert.DeserializeObject<Customer>(json);

答案 2 :(得分:1)

company对象将在Embedded _embedded对象下。

喜欢

    class Program
    {
        static void Main(string[] args)
        {
            string json = "{\"id\": \"4a17d6fe-a617-4cf8-a850-0fb6bc8576fd\",\"country\": \"DE\",\"_embedded\": {\"company\": {\"name\": \"Apple\",\"industrySector\": \"IT\",\"owner\": \"Klaus Kleber\",\"_embedded\": {\"emailAddresses\": [{\"id\": \"4a17d6fe-a617-4cf8-a850-0fb6bc8576fd\",\"value\": \"test2@consoto.com\",\"type\": \"Business\",\"_links\": {\"self\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"}}}],\"phoneNumbers\": [{\"id\": \"4a17d6fe-a617-4cf8-a850-0fb6bc8576fd\",\"value\": \"01670000000\",\"type\": \"Business\",\"_links\": {\"self\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"}}}],},\"_links\": {\"self\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"},\"phoneNumbers\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"},\"addresses\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"},}},},\"_links\": {\"self\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"},\"legalPerson\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"},\"naturalPerson\": {\"href\": \"https://any-host.com/api/v1/customers/1234\"}}}";

            CustomerJson results = JsonConvert.DeserializeObject<CustomerJson>(json);
            Customer customer = new Customer()
            {
                Id = results.id,
                Country = results.country,
                Company = new LegalPerson()
                {
                    EmailAddresses = results._embedded.company._embedded.emailAddresses,
                    PhoneNumbers = results._embedded.company._embedded.phoneNumbers,
                    IndustrySector = results._embedded.company.industrySector,
                    Name = results._embedded.company.name,
                    Owner = results._embedded.company.owner
                }
            };

        }

    }

    public class EmbeddedContactInfoJson
    {
        public ContactInfo[] emailAddresses { get; set; }
        public ContactInfo[] phoneNumbers { get; set; }
    }
    public class CompanyJson
    {
        public string name { get; set; }
        public string industrySector { get; set; }
        public string owner { get; set; }
        public EmbeddedContactInfoJson _embedded { get; set; }
        public EmbeddedLinksJson _links { get; set; }
    }

    public class EmbeddedJson
    {
        public CompanyJson company { get; set; }
    }
    public class HrefJson
    {
        public string href { get; set; }
    }

    public class EmbeddedLinksJson
    {
        public HrefJson self { get; set; }
        public HrefJson phoneNumbers { get; set; }
        public HrefJson addresses { get; set; }
    }
    public class LinksJson
    {
        public HrefJson self { get; set; }
        public HrefJson legalPerson { get; set; }
        public HrefJson naturalPerson { get; set; }
    }
    public class CustomerJson
    {
        public Guid id { get; set; }
        public string country { get; set; }
        public EmbeddedJson _embedded { get; set; }
        public LinksJson _links { get; set; }
    }

    public class Customer
    {
        public Guid Id { get; set; }
        public string Country { get; set; }
        public LegalPerson Company { get; set; }
    }
    public class LegalPerson
    {
        public string Name { get; set; }
        public string IndustrySector { get; set; }
        public string Owner { get; set; }
        public ContactInfo[] EmailAddresses { get; set; }
        public ContactInfo[] PhoneNumbers { get; set; }
    }
    public class ContactInfo
    {
        public Guid Id { get; set; }
        public string Type { get; set; }
        public string Value { get; set; }
    }