app.UseRequestLocalization overwritten on deployed IIS

[Schoof-T]

Is there an existing issue for this?

• [x] I have searched the existing issues

Describe the bug

In Blazor Server, when setting the app.UseRequestLocalization("en-GB"); I was under the assumption that your application should always use the "en-GB" culture.

This works correctly locally in my Visual Studio, I can switch the "en-GB" to any other locale and the whole app will switch. However, I notice that after deploying my application to a local IIS server, the culture is still "en-GB" but for example the decimal seperator is different. (locally the decimal seperator is ".", deployed it's a ",")

It is still using the culture settings of the Windows user that is set as the identity of your application pool.

Expected Behavior

• Set app.UseRequestLocalization("en-GB");
• Application always uses the same "en-GB" culture.

Steps To Reproduce

• Create Blazor Web App (Server)
• Add app.UseRequestLocalization("en-GB");
• Build application self contained and for win-x64 (--self-contained true --runtime win-x64)
• Deploy application to IIS Application pool is as follows: The Identity is a an account, with limited access.

Exceptions (if any)

No response

.NET Version

8

Anything else?

ASP.NET CORE 8 Blazor Server Visual Studio 2022

cc: @guardrex https://github.com/dotnet/AspNetCore.Docs/issues/33847

[Schoof-T]

Investegating further I found that this has to do with the user account running the application pool. Looking in the registry I saw that the user has the Regional Settings of "en-GB", but the decimal seperator is set as ",". Which is different from the default.

I was under the assumption app.UseRequestLocalization("en-GB"); would ignore any user settings. Turns out this is not true. To fully ignore user settings I had to do the following:

    var english = new CultureInfo("en-GB", false);
    var englishRequestCulture = new RequestCulture(culture: english, uiCulture: english);

    var options = new RequestLocalizationOptions
    {
        DefaultRequestCulture = englishRequestCulture,
        SupportedCultures = [english],
        SupportedUICultures = [english]
    };

    app.UseRequestLocalization(options);

Specifically the false parameter of new CultureInfo("en-GB", false); is very important.

Is this expected behaviour and is this a correct solution I have implemented? If it is, It would be nice if this is documented somewhere. Apologies if I missed this in the documentation. :)

[guardrex]

You didn't miss it in the documentation AFAIK. This never came up in discussions with the team or with @hishamco.

I'm 👁 on this issue, and I'll work on the guidance using the original docs issue after the product unit responds and lets us know what's going on and how to resolve it.

[hishamco]

I'm in the mobile now, I will have a look once I open the laptop

[hishamco]

Before I dig into that could you try to set CultureInfoUseUserOverride = false in the RequestLocalizationOptions

[Schoof-T]

Before I dig into that could you try to set CultureInfoUseUserOverride = false in the RequestLocalizationOptions

Setting it as follows does not seem work:

    var configuredCulture = "en-GB";
    var supportedUICultures = new[] { configuredCulture };
    var localizationOptions = new RequestLocalizationOptions()
        .SetDefaultCulture(configuredCulture)
        .AddSupportedUICultures(supportedUICultures);
    localizationOptions.CultureInfoUseUserOverride = false;
    app.UseRequestLocalization(localizationOptions);