C#•13mo ago

❔ Prevent accepting numeric values as enum

Hello, I have an API that exposes an enum field Vehicle (Car, Bike, Truck) in the POST. The problem is that when I POST a request with a body {"vehicle" :"1" }, it gets accepted and gets automatically converted to Vehicle.Bike.. But something like {"vehicle" :"bar" } results in a bad request, which is what I need ! Any idea on how to stop parsing integer like enum values?

17 Replies

RubyNovaDev•13mo ago

You would require a custom mapping for that As enums are, at their core, integers So by default they're gonna end up as numbers Depending on how you are mapping your model, newtownoft Vs STJ, the requirements for this will probably differ I am unsure how you would explicitly make it a bad request to pass it as a number but you can probably bake it into the custom mapping somehow

LazyGuard•13mo ago

What do you mean by a custom mapping ?

RubyNovaDev•13mo ago

By default when you're using a model it will do it's best based on the reflection data to build a JSON object If you want behaviour that is different you have to specify it yourself

LazyGuard•13mo ago

Okay I see ! Do you have some code examples on how to do this things ?

RubyNovaDev•13mo ago

^ But even if I knew this it's been too long for me to remember exactly Your best bet is the documentation for whatever it is you're using for this

LazyGuard•13mo ago

I've found something like this https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/converters-how-to?pivots=dotnet-7-0

How to write custom converters for JSON serialization - .NET

Learn how to create custom converters for the JSON serialization classes that are provided in the System.Text.Json namespace.

LazyGuard•13mo ago

Is that what you mean ? ovveriding the Read and Wrtie function of the jsonConverter of the enum

RubyNovaDev•13mo ago

If you are using STJ That will probably do it

LazyGuard•13mo ago

Yu I am using STJ

RubyNovaDev•13mo ago

Well all I can say is give it a whirl and see what explodes 🙂

LazyGuard•13mo ago

Yup, but still thinking about how to say "is not an integer value" 😆 Oh maybe there is some int.TryParse by default

RubyNovaDev•13mo ago

I'm sure you'll figure it iut Out* MSDocs are some of the best around after all

LazyGuard•13mo ago

yup yup, thanks dude 🙏

Shirasho•13mo ago

STJ also has a string enum converter that accepts a bool setting whether integers are valid.

LazyGuard•13mo ago

yeah but when putting it to false, it will not accept 1,2,3 etc. but still accepts "1","2","3" etc.

Angius•13mo ago

https://stackoverflow.com/a/59096114/6042255

services
    .AddMvc()
    // Or .AddControllers(...)
    .AddJsonOptions(opts =>
    {
        var enumConverter = new JsonStringEnumConverter();
        opts.JsonSerializerOptions.Converters.Add(enumConverter);
    })

services
    .AddMvc()
    // Or .AddControllers(...)
    .AddJsonOptions(opts =>
    {
        var enumConverter = new JsonStringEnumConverter();
        opts.JsonSerializerOptions.Converters.Add(enumConverter);
    })

Won't this do?

Accord•13mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Prevent accepting numeric values as enum