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Upgrading JsonApiSerializer from 1.3.1 to 1.74 Issues with custom converter

I'm using this git repository JsonApiSerializer with a project and tying to update to the latest version 1.74. Everything works fine in version 1.3.1 but after upgrading to version 1.74 the custom converter cant get the Json to deserialize properly. I set a breakpoint on the converter put it never hits the ReadJson Method, instead it jumps out on the line
public override bool CanConvert(Type objectType) => false;
Is anyone familiar with JsonApiSerializer or customer converters able to see what the issue might be.
I receive this error.
JsonSerializationException: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.String' because the type requires a JSON primitive value (e.g. string, number, boolean, null) to deserialize correctly. To fix this error either change the JSON to a JSON primitive value (e.g. string, number, boolean, null) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List<T>) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'data[0].relationships.matches.data[0].type'.
Object I'm trying to deserialize to
public class PubgPlayer : PubgShardedEntity
{
[JsonProperty("Name")]
public string Name { get; set; }
[JsonProperty]
public DateTime CreatedAt { get; set; }
[JsonProperty]
public string PatchVersion { get; set; }
[JsonProperty]
public string TitleId { get; set; }
[JsonProperty("matches")]
[JsonConverter(typeof(RelationshipIdConverter))]
public IEnumerable<string> MatchIds { get; set; }
}
This is the custom converter
public class RelationshipIdConverter : JsonConverter
{
public override bool CanConvert(Type objectType) => false;
public override bool CanWrite => false;
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
//if the reader is not reading a relationship object just deserialize as normal.
//This allows us to serialize and deserialize multiple times after converting from the Json-API format
if (reader.TokenType != JsonToken.StartObject)
return serializer.Deserialize(reader, objectType);
JToken jt = JToken.Load(reader);
var dataToken = jt.SelectToken("data");
if (objectType == typeof(string))
return dataToken["id"].ToString();
return dataToken.Select(x => (string)x["id"]).ToList();
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) { }
}
Example Json
{
"data":[
{
"type":"player",
"id":"account.f96f1d482a5d4a21a4135f598f5a5c6a",
"attributes":{
"name":"Nomad_o7",
"stats":null,
"titleId":"pubg",
"shardId":"steam",
"patchVersion":""
},
"relationships":{
"assets":{
"data":[
]
},
"matches":{
"data":[
{
"type":"match",
"id":"e14ca749-3c19-49dd-9486-03de90669fa3"
},
{
"type":"match",
"id":"73dbca3e-eeee-44eb-9c43-3f71df0e02ae"
},
{
"type":"match",
"id":"e9f80ed0-1e78-4500-950f-174028fb73cc"
}
]
}
},
"links":{
"self":"https://api.pubg.com/shards/steam/players/account.f96f1d482a5d4a21a4135f598f5a5c6a",
"schema":""
}
},
{
"type":"player",
"id":"account.82bad0072f31455d8d9f8d834da2f2f3",
"attributes":{
"name":"TGLTN",
"stats":null,
"titleId":"pubg",
"shardId":"steam",
"patchVersion":""
},
"relationships":{
"assets":{
"data":[
]
},
"matches":{
"data":[
{
"type":"match",
"id":"4a6f064e-c292-4e9b-a3a6-bbaed891ce27"
},
{
"type":"match",
"id":"efd9434c-4116-4b56-815d-e30903b37c23"
},
{
"type":"match",
"id":"c1e56bff-db4c-470b-bb44-3c2068e33245"
},
{
"type":"match",
"id":"44d27efc-3cc6-4935-8bbe-702e4da44744"
},
{
"type":"match",
"id":"be3ebed3-9183-47f1-b4b0-40a2229dd5ff"
}
]
}
},
"links":{
"self":"https://api.pubg.com/shards/steam/players/account.82bad0072f31455d8d9f8d834da2f2f3",
"schema":""
}
}
],
"links":{
"self":"https://api.pubg.com/shards/steam/players?filter[playerNames]=Nomad_o7,TGLTN"
},
"meta":{
}
}

I don't know how it could work before since you have a bug in your class
[JsonProperty("matches")]
[JsonConverter(typeof(RelationshipIdConverter))]
public IEnumerable<string> MatchIds { get; set; }
but if you look at your json , you will see, that mathes is not a collection of strings, matches is a collection of objects
public partial class Relationships
{
[JsonProperty("assets")]
public Assets Assets { get; set; }
[JsonProperty("matches")]
public Matches MatchIds { get; set; }
}
public partial class Matches
{
[JsonProperty("data")]
public List<MatchesDatum> Data { get; set; }
}
public partial class MatchesDatum
{
[JsonProperty("type")]
public string Type { get; set; }
[JsonProperty("id")]
public Guid Id { get; set; }
}
and IMHO you don't need any custom converter

Deserialize JSON with dynamic keys using C# Json.NET

From an external API I am receiving the below JSON response for the bank details of a customer.
{
"bankDetails":[
{
"ABC Bank":[
{
"sNo":1,
"acNo":"1235465",
"acBalance":"100.25"
},
{
"sNo":2,
"acNo":"1235467",
"acBalance":"50.25"
}
],
"bankName":"ABC Bank",
"totalAmount":"150.50"
},
{
"XYZ Bank":[
{
"sNo":1,
"acNo":"1248565",
"acBalance":"75.25"
}
],
"bankName":"XYZ Bank",
"totalAmount":"75.25"
},
{
"BCD Bank":[
{
"sNo":1,
"acNo":"145665",
"acBalance":"10.25"
},
{
"sNo":2,
"acNo":"195267",
"acBalance":"5.25"
}
],
"bankName":"BCD Bank",
"totalAmount":"15.50"
}
]
}
I need to deserialize this to a C# class using JSON.Net. What should be structure of the C# class as the first key is dynamic?. The first key with bank name returned will be different for each customer

The typical solution to dealing with dynamic keys is to use a Dictionary<string, T> in place of a regular class. See How can I deserialize a child object with dynamic (numeric) key names? for an example of this. However, that solution doesn't really work for your case, because there are other properties in the same object which do not have dynamic keys (the bankName and totalAmount), and the values of those properties are primitives whereas the value of dynamic property is an array of bank accounts. A better solution here is to use a JsonConverter.
Before we get to that, we need to set up a class structure to deserialize into. This is pretty straightforward:
class RootObject
{
public List<Bank> BankDetails { get; set; }
}
[JsonConverter(typeof(BankConverter))]
class Bank
{
public string BankName { get; set; }
public decimal TotalAmount { get; set; }
public List<Account> Accounts { get; set; }
}
class Account
{
[JsonProperty("sNo")]
public int SequenceNumber { get; set; }
[JsonProperty("acNo")]
public string AccountNumber { get; set; }
[JsonProperty("acBalance")]
public decimal Balance { get; set; }
}
You'll notice that I've added a few [JsonProperty] attributes in the Account class to map the shorthand property names in the JSON to friendlier property names in that class. And the [JsonConverter] attribute on the Bank class tells the serializer that we will be using a custom BankConverter to handle that class.
Here is the code for the BankConverter. It uses a JObject internally to make it easier to read and work with the JSON.
class BankConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return objectType == typeof(Bank);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
JObject obj = JObject.Load(reader);
Bank bank = new Bank();
// populate the known properties (bankName and totalAmount)
serializer.Populate(obj.CreateReader(), bank);
// now handle the dynamic key
bank.Accounts = obj[bank.BankName].ToObject<List<Account>>(serializer);
return bank;
}
public override bool CanWrite
{
get { return false; }
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
With these classes in place, you can deserialize the JSON like this:
var root = JsonConvert.DeserializeObject<RootObject>(json);
Here is a working demo: https://dotnetfiddle.net/knsRLv

Deserializing JSON response which differ in each response

I have complicated JSON respone which containt about 100 attributes/objects/arrays and have difrrent responses in terms of object/array.
Firstly I have structure like that (when object exists)
{
'att1': 'desc',
'att2': '83482',
'att3': null,
'test': {
'object_array1': [
100
],
'object_array2': [
'desc'
]
}
}
public class Root
{
//fields here
public Test test { get; set; }
}
public class Test
{
public List<int> object_array1 { get; set; }
public List<string> object_array2 { get; set; }
}
The issue I have is when this objects is empty.
After that resposne is changing and returning empty array.
So it is chaning to this:
{
'att1': 'desc',
'att2': '83482',
'att3': null,
'test': [
]
}
And beacause of that I have standard error:
Additional information: Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'Test' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
I was trying to write customconverter with something like that:
private bool IsArray(string fieldName, JObject jObject)
{
return jObject[fieldName].Type == JTokenType.Array;
}
I'm using JSON.NET
But I failed miserably. Any help would be much appreciated

Use custom converter which would check token type that has been read in the ReadJson method and substitute some default value for test when the token is of type JArray (assuming it can only be an array when the test object is "empty"):
public class Root
{
[JsonConverter(typeof(TestIgnoreEmptyListConverter))]
public Test test { get; set; }
}
// .................
public class TestIgnoreEmptyListConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return typeof(Test).IsAssignableFrom(objectType) || objectType.IsArray;
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var token = JToken.Load(reader);
if (token is JArray)
return default(Test);
else
return token.ToObject<Test>();
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
Demo: https://dotnetfiddle.net/Q3S5hX

Your JSON propert name does not match object's name. Serializer tries to serialize/deserialize using property name or attributes.
Change this to the right name
public Test test { get; set; }
Or use attribute to set json name for a property.
[JsonProperty("test")]
public Test objects { get; set; }
Or even better, refactor your code to respect C# conventions. (I suggest to rename fields to be more descriptive)
public class Root
{
[JsonProperty("test")]
public Test Test { get; set; }
}
public class Test
{
[JsonProperty("object_array1")]
public List<int> IntArray { get; set; }
[JsonProperty("object_array2")]
public List<string> StringArray { get; set; }
}

Why is Json Dot Net not even trying to evaluate my interface properties?

I have an object where I'm trying to intercept the deserialization process for two properties which are interfaces. I'm using Json Dot Net.
The issue that I'm facing is that Json Dot Net doesn't even try to convert the two IDataStore properties. In other words, 'CanConvert' is never even run for those types.
I've tried adding JsonProperty and JsonConverter attributes and still no dice.
Any insight would be appreciated.
Edit (and Answer) After being asked by Ron Beyer to post the JSON, it became clear that Json Dot Net doesn't even consider operating on a property if the source JSON doesn't have it. When adding '"SourceDataStore":{}' it tries to convert that property. I was thinking it would look at the current object type and iterate over that but there's obviously a matching process beforehand
JSON
{
"Name":"My First Definition",
"SourceDataStoreType":"SqlDataStore",
"DestinationDataStoreType":"MongoDataStore"
}
Class
internal class Definition
{
public string Name { get; set; }
public DataStoreTypes SourceDataStoreType { get; set; }
public DataStoreTypes DestinationDataStoreType { get; set; }
public IDataStore SourceDataStore { get; set; }
public IDataStore DestinationDataStore { get; set; }
public Definition()
{
}
}
Converter
public class DataStoreConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
var b = objectType == typeof(IDataStore);
return b;
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
return new SqlDataStore();
}
public override bool CanWrite
{
get { return false; }
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
Code
var definition = JsonConvert.DeserializeObject<Definition>(definitionsJson, new JsonSerializerSettings
{
Converters = new[] { new DataStoreConverter() }
});
return definition;

(Comments to an answer)
I asked for the JSON example to verify that 1) the JSON was well formatted and 2) included the properties in question.
The issue, it turns out that you figured out, is that the JSON deserializer will not attempt to run the conversion on any properties it does not find in the JSON. This is because the deserializer parses the JSON and looks for appropriate properties in the object to fill in. If the property doesn't exist in the JSON, it won't attempt to build that property from nothing.
There are two solutions to this, either you can add a null (blank) property for those in the JSON, or you can edit your object to create them when you run the constructor, something like:
internal class Definition
{
public string Name { get; set; }
public DataStoreTypes SourceDataStoreType { get; set; }
public DataStoreTypes DestinationDataStoreType { get; set; }
public IDataStore SourceDataStore { get; set; }
public IDataStore DestinationDataStore { get; set; }
public Definition()
{
var container = YourIOCContainerHere.Instance;
SourceDataStore = container.Resolve<IDataStore>();
DestinationDataStore = container.Resolve<IDataStore>();
//Or, without using IOC/DI
SourceDataStore = new SqlDataStore();
DestinationDataStore = new SqlDataStore();
}
}

JSON deserialization fails only when array is empty

On some occasions when I receive JSON whose one of the array property is empty the deserialization fails, throwing the following exception :
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'SonicApi.ClickMark[]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.
Path auftakt_result.click_marks, line 1, position 121.
Trying to ignore null values with the following code didn't help:
var jsonSerializerSettings = new JsonSerializerSettings();
jsonSerializerSettings.NullValueHandling = NullValueHandling.Ignore;
Here is an example of JSON that produces the error :
{
"status": {
"code": 200
},
"auftakt_result": {
"clicks_per_bar": 0,
"overall_tempo": 0,
"overall_tempo_straight": 0,
"click_marks": {}
}
}
Here is an example of JSON whose array is not empty and does not produce any error:
{
"status": {
"code": 200
},
"auftakt_result": {
"clicks_per_bar": 8,
"overall_tempo": 144.886978,
"overall_tempo_straight": 144.90889,
"click_marks": [
{
"index": 0,
"bpm": 144.226624,
"probability": 0.828170717,
"time": 0.0787981859,
"downbeat": "false"
},
{
"index": 1,
"bpm": 144.226517,
"probability": 0.831781149,
"time": 0.286802721,
"downbeat": "false"
},
etc ...
Here are the C# types representing above objects:
public sealed class AnalyzeTempoResponse
{
[JsonProperty("auftakt_result")]
public AuftaktResult AuftaktResult { get; set; }
[JsonProperty("status")]
public Status Status { get; set; }
}
public sealed class Status
{
[JsonProperty("code")]
public int Code { get; set; }
}
public sealed class AuftaktResult
{
[JsonProperty("clicks_per_bar")]
public int ClicksPerBar { get; set; }
[JsonProperty("overall_tempo")]
public double OverallTempo { get; set; }
[JsonProperty("overall_tempo_straight")]
public double OverallTempoStraight { get; set; }
[JsonProperty("click_marks")]
public ClickMark[] ClickMarks { get; set; }
}
public sealed class ClickMark
{
[JsonProperty("index")]
public int Index { get; set; }
[JsonProperty("bpm")]
public double Bpm { get; set; }
[JsonProperty("probability")]
public double Probability { get; set; }
[JsonProperty("time")]
public double Time { get; set; }
[JsonProperty("downbeat")]
public string Downbeat { get; set; }
}
How can I deserialize responses whose click_marks content is null ?
If that matters, I am using the latest version of Newtonsoft.Json : v6.0
EDIT
Here is the adopted solution according #khellang's answer :
public class ClickMarkArrayConverter : CustomCreationConverter<ClickMark[]>
{
public override ClickMark[] Create(Type objectType)
{
return new ClickMark[] {};
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue,
JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.StartArray)
{
return serializer.Deserialize(reader, objectType);
}
if (reader.TokenType == JsonToken.StartObject)
{
serializer.Deserialize(reader); // NOTE : value must be consumed otherwise an exception will be thrown
return null;
}
throw new NotSupportedException("Should not occur, check JSON for a new type of malformed syntax");
}
}

It has nothing to do with null values (none of your JSON examples have null values for any property). You're trying to deserialize a JSON object into a ClickMark[]:
"click_marks": {} // <-- This is an object, not null, not an array.
The reason it works for example number two is that the click_marks property actually is an array of ClickMark objects:
"click_marks": [{...}, {...}, {...}] // <-- This is an array with three objects.
Where does the data come from? You need to make sure that the click_marks property is either an array or an object, not both, and that your typed C# object ClickMarks matches the "type" of the JSON property.
If you have no control over the data, e.g. if it comes from a 3rd party, I'd suggest you write a custom JsonConverter that you can apply to that single property:
public class ObjectToArrayConverter<T> : CustomCreationConverter<T[]>
{
public override T[] Create(Type objectType)
{
return new T[0];
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.StartArray)
{
return serializer.Deserialize(reader, objectType);
}
else
{
return new T[] { serializer.Deserialize<T>(reader) };
}
}
}
And apply it like this:
public sealed class AuftaktResult
{
// ...
[JsonProperty("click_marks")]
[JsonConverter(typeof(ObjectToArrayConverter<ClickMark>))]
public ClickMark[] ClickMarks { get; set; }
}
This will check if the value is a single object and wrap it in an array so it will match your C# POCO property :)