C#•3y 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" }

{"vehicle" :"1" }

{"vehicle" :"1" }

{"vehicle" :"1" }, it gets accepted and gets automatically converted to Vehicle.Bike.. But something like

{"vehicle" :"bar" }

{"vehicle" :"bar" }

{"vehicle" :"bar" }

{"vehicle" :"bar" } results in a bad request, which is what I need !
Any idea on how to stop parsing integer like enum values?

RubyNovaDev•6/22/23, 12:53 AM

You would require a custom mapping for that

RubyNovaDev•6/22/23, 12:53 AM

As enums are, at their core, integers

RubyNovaDev•6/22/23, 12:54 AM

So by default they're gonna end up as numbers

RubyNovaDev•6/22/23, 12:54 AM

Depending on how you are mapping your model, newtownoft Vs STJ, the requirements for this will probably differ

RubyNovaDev•6/22/23, 12:55 AM

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

LazyGuardOP•6/22/23, 12:56 AM

What do you mean by a custom mapping ?

RubyNovaDev•6/22/23, 12:57 AM

By default when you're using a model it will do it's best based on the reflection data to build a JSON object

RubyNovaDev•6/22/23, 12:57 AM

If you want behaviour that is different you have to specify it yourself

LazyGuardOP•6/22/23, 12:57 AM

Okay I see !

LazyGuardOP•6/22/23, 12:58 AM

Do you have some code examples on how to do this things ?

RRubyNovaDev Depending on how you are mapping your model, newtownoft Vs STJ, the requirements...

RubyNovaDev•6/22/23, 12:58 AM

But even if I knew this it's been too long for me to remember exactly

RubyNovaDev•6/22/23, 12:58 AM

Your best bet is the documentation for whatever it is you're using for this

LazyGuardOP•6/22/23, 12:59 AM

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.

LazyGuardOP•6/22/23, 12:59 AM

Is that what you mean ?

LazyGuardOP•6/22/23, 1:00 AM

ovveriding the ReadRead and WrtieWrtie function of the jsonConverter of the enum

LLazyGuard ovveriding the `Read` and `Wrtie` function of the jsonConverter of the enum

RubyNovaDev•6/22/23, 1:01 AM

If you are using STJ

RubyNovaDev•6/22/23, 1:01 AM

That will probably do it

LazyGuardOP•6/22/23, 1:01 AM

Yu I am using STJ

RubyNovaDev•6/22/23, 1:01 AM

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

LazyGuardOP•6/22/23, 1:02 AM

Yup, but still thinking about how to say "is not an integer value"

LazyGuardOP•6/22/23, 1:03 AM

Oh maybe there is some int.TryParseint.TryParse by default

RubyNovaDev•6/22/23, 1:04 AM

I'm sure you'll figure it iut

RubyNovaDev•6/22/23, 1:04 AM

Out*

RubyNovaDev•6/22/23, 1:04 AM

MSDocs are some of the best around after all

LazyGuardOP•6/22/23, 1:04 AM

yup yup, thanks dude

Shirasho•6/22/23, 5:32 PM

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

LazyGuardOP•6/22/23, 6:51 PM

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

Angius•6/22/23, 11:31 PM

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•6/23/23, 11:47 PM

Was this issue resolved? If so, run

/close

/close

otherwise I will mark this as stale and this post will be archived until there is new activity.

❔ Prevent accepting numeric values as enum

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