JSON serialization -- int to string. -- exception

[mweel1]

My code is blowing up because JSON serialization won't happen from an integer to string during de-serialization.

If the target type is a string, shouldn't anything cast?

I dont feel like I should have build an entire convert for this, it should be built in IMOH.

Works fine in Newtonsoft.

Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
See info in area-owners.md if you want to be subscribed.

Issue Details

---

My code is blowing up because JSON serialization won't happen from an integer to string.

If the target type is a string, shouldn't anything cast?

I dont feel like I should have build an entire convert for this, it should be built in IMOH.

Works fine in Newtonsoft.

Author:	mweel1
Assignees:	-
Labels:	area-System.Text.Json
Milestone:	-

[gregsdennis]

The serializer respects the JSON content and type structure. If the JSON type of a value is a number, then you're only going to get numeric types out.

[eiriktsarpalis]

This is by design, support for other JSON types can be added easily using a custom converter

var options = new JsonSerializerOptions { Converters = { new ForgivingStringConverter() } };

MyPoco result;

result = JsonSerializer.Deserialize<MyPoco>("""{ "Value" : false }""", options);
Console.WriteLine(result.Value);

result = JsonSerializer.Deserialize<MyPoco>("""{ "Value" : true }""", options);
Console.WriteLine(result.Value);

result = JsonSerializer.Deserialize<MyPoco>("""{ "Value" : 42 }""", options);
Console.WriteLine(result.Value);

result = JsonSerializer.Deserialize<MyPoco>("""{ "Value" : 3.1415926 }""", options);
Console.WriteLine(result.Value);

public class MyPoco
{
    public string? Value { get; set; }
}

public sealed class ForgivingStringConverter : System.Text.Json.Serialization.JsonConverter<string>
{
    public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        return reader.TokenType switch
        {
            JsonTokenType.False => "false",
            JsonTokenType.True => "true",
            JsonTokenType.Number => Encoding.UTF8.GetString(reader.HasValueSequence ? reader.ValueSequence.ToArray() : reader.ValueSpan),
            _ => reader.GetString(),
        };
    }

    public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options)
    {
        writer.WriteStringValue(value);
    }
}