Consider adding a JsonSerializerOptions.CultureInfo option

[ollie10]

Hi, I'm stuck on this problem
.Net Core 3.1 Web App with a page that uses Google Maps Autocomplete and I need to save the address and coordinates (Latitude / Longitude as decimals).

Creating an object in javascript and sending it to the controller via jQuery Ajax.

The problem is the following:

• I'm using the default System.Text.Json serializer / deserializer
• The decimal values returned by google Js API are in this format: 55.7539619 (for example)
• I use a route parameter to set statically the Culture like site.com/spain/ for es-ES site.com/russia/ for ru-RU

In the controller all the other properties arrive correctly except the latitude and longitude which are decimals

The problem arises when a culture is being used and the number is not in the format of that culture in the way that the separator is comma (for Spain for example) and not the point (which is standard for javascript)

So i looked for some solutions but none of them seems solving completely the problem:

• i could replace the dot with comma before sending but it won't work for US culture for example, and besides that I would lose precision

In Newtonsoft Json there was the possibility to specify the Culture as options of the serializer but System.Text.Json doesn't have a property like that.
I think that System.Text.Json should deserialize Json in the correct format more than 'interpreting' the culture

This is the code I'm using:

propertyToSave.OtherProp = 'text' // arrives correctly as all the other properties
propertyToSave.Latitude = selectedPlace.geometry.location.lat(); //val: 55.7539619
propertyToSave.Longitude = selectedPlace.geometry.location.lng();// val: 37.60819619999995

$.ajax({
	url: "/" + countryInfo.EnglishName.toLowerCase() + "/submit",
	dataType: "json",
	method: "POST",
	data: { property: propertyToSave, __RequestVerificationToken: $("input[name=__RequestVerificationToken]").val() },
	....

I specify that if i replace dots with commas the values arrive correctly to the controller, in any other case the properties are always 0

Any suggestion? Is a known problem? I suppose the Web API should suffer of this problem too

[ollie10]

Values sent by the browser:

Values received by the controller:

[Clockwork-Muse]

The decimal values returned by google Js API are in this format: 55.7539619 (for example)

JavaScript, and thus most use of JSON, doesn't do decimal (base-10 floating point), it uses double (base-2 floating point). This (probably) won't solve your problem, but it does mean that values that are transferred may not always be what you expect.

I use a route parameter to set statically the Culture like site.com/spain/ for es-ES site.com/russia/ for ru-RU

There's multiple problems with this, besides the one you're experiencing. The biggest one is that individual countries can have multiple major languages; Spain, for example, has Catalan (ca-ES), Canada has Quebec-French (fr-CA - there can be some pretty big penalties for ignoring this one, by the way), etc. It also ignores things like user preferences for display language. It's use in a route may be dubious (it's difficult to tell what else you're doing with it) - if I'm looking at houses/apartments/whatever in Russia, does that mean the page suddenly renders in Russian? That won't be helpful if I'm trying to book a vacation there...

If the user is logged in, respect whatever language they have selected in their profile. If they're not, use the Accept-Language header, if set. Otherwise, take a guess based on IP range.

---

I specify that if i replace dots with commas the values arrive correctly to the controller, in any other case the properties are always 0

Simply replacing the period with a comma would actually make it invalid JSON (since the comma is the attribute separator), so I'm suspicious that it works at all. Your client-side code isn't what we'd be interested in - we'd need to see your controller code. As it is, in a trivial example I cannot reproduce your issue.

(personally, I've always disliked relying on CurrentCulture, and would rather explicitly use a culture object for just those items that require it)

[ollie10]

Hi @Clockwork-Muse thanks for reply, the use case of the route is to select a specific area more than a language, even if I see what you mean anyway for now I'm not planning to accept multiple languages for each country (not planning to publish in those countries right now).

So the question is another and very simple: how to pass the value 55.7539619 passed me from google selectedPlace.geometry.location.lat(); to a controller via ajax in a website perhaps that (not caring all the discourse of routing etc etc) has a culture fixed on whatever European country (or that accept the culture from the Accept-Language) where the decimal separator is the comma?
Many thanks for your time

[ollie10]

Just to verify your thesis I made another test, I added all the configuration to support the culture en-US just adding the route site.com/usa/...

Nothing else added, no code changed on the client side, and with that everything works like a charm

About my controller code is a very normal controller accepting a ViewModel which has all the properties that I'm passing:

[Authorize]
[ValidateAntiForgeryToken]
[HttpPost]
public async Task<JsonResult> Submit(PropertyViewModel property)
{
...
]

public class PropertyViewModel
{
...
   [Required]
   public decimal Latitude { get; set; }

   [Required]
   public decimal Longitude { get; set; }

   [Required]
   public string LatLng { get; set; }
...
}

[ollie10]

Just made another test to be sure: changing the type of the property to double instead of decimal solves the problem, so there should be some problem specific with decimal and the serialization

[Clockwork-Muse]

Just to verify your thesis I made another test, I added all the configuration to support the culture en-US just adding the route site.com/usa/...

... if you actually want the route to drive localization, actually use the locale or language codes, like a number of sites already do. If you're just getting resources about a specific country, don't do localization, because it's unrelated.

[ollie10]

Hum, you seems not understanding correctly the problem... There websites that have a localization set in the configuration statically or taking localization with the header, at the end it doesn't matter, the problem is that when the CurrentCulture is for any reason (settings, header, querystring etc etc) set to something different than en-US the decimal number are not readed

That's the problem, what there is on top of it it doesn't matter, I can make a simple web app to show you without any code just with a Page and a Controller and using using the default culture of my PC and sending an object (with decimals) in JSON to the controller with ajax and the problem will arise anyway...

[danmoseley]

I can make a simple web app to show you

@ollie10 perhaps you could make such a repro and push it up as a github repo? That's what many people do. Best of all, though, is a repro short enough (say up to 50 lines) that you can paste it in here and run it in a console app.

[ollie10]

Hello @danmosemsft, @Clockwork-Muse I just pushed the repo with the example, you can find it here:

https://github.com/ollie10/test.json.decimals/tree/master/Json.Test

Here the view:
https://github.com/ollie10/test.json.decimals/blob/master/Json.Test/Json.Test/Views/Home/Index.cshtml

Here the controller:
https://github.com/ollie10/test.json.decimals/blob/master/Json.Test/Json.Test/Controllers/HomeController.cs

I publish also the results now I have another problem, the number is interpreted but the period is not taken into account if the Culture is not en-US, i show you the results:

The culture is taken in this case only from the header, nothing to do with the case I told you at the begging, standard .net Core code without any customization in CultureProviders and so on and the decimal is still misinterpeted.

en-US Culture:

it-IT Culture:

In this example I just created a new Web Application with nothing inside except the page that sends the data via ajax, I added the code in the startup for allowing the localization

CultureInfo[] supportedCultures = new[] { new CultureInfo("en-US"), new CultureInfo("it-IT"), new CultureInfo("es-ES") };

app.UseRequestLocalization(new RequestLocalizationOptions() { SupportedCultures = supportedCultures, SupportedUICultures = supportedCultures }).UseEndpoints(endpoints =>
   	   {
   		   endpoints.MapControllerRoute(
   			   name: "default",
   			   pattern: "{controller=Home}/{action=Index}/{id?}");
   	   });

[danmoseley]

Moving to dotnet/runtime where new issues go.