Question

I got this code to retrieve the browser language that was set by the user:

string cultureName = string.Empty;

try
{
    string[] languages = HttpContext.Current.Request.UserLanguages;
    cultureName = languages[0].ToLowerInvariant().Trim();
}
catch
{
    cultureName = "en-US";
}

System.Globalization.CultureInfo browserCulture = CultureInfo.CreateSpecificCulture(cultureName);
System.Threading.Thread.CurrentThread.CurrentCulture = browserCulture;
System.Threading.Thread.CurrentThread.CurrentUICulture = browserCulture;

I got these errors:

1. Culture name 'name' is not supported: From our error logs, found out that name is x-ns1xs4m8wixnxg, x-ns1dfk__jmpnx0 etc.. I do not know where this languages come from, or what are they, but I think these languages are retrieved when browsing from mobile.

2. The name 'name' contains characters that are not valid for a Culture or Region: Also found out that name is fr; q=1.0, en;q=1.0, en_us, en;q=0.9, etc… I’m thinking that I should parse it per character to see if it is a valid

I have already modified my code to handle these errors:

CultureInfo cultureInfo;

try
{
    string[] languages = HttpContext.Current.Request.UserLanguages;
    string cultureName = languages[0].ToLowerInvariant().Trim();
    cultureInfo = CultureInfo.CreateSpecificCulture(cultureName);
}
catch
{
    cultureInfo = CultureInfo.CreateSpecificCulture("en-US");
}

System.Globalization.CultureInfo browserCulture = cultureInfo;
System.Threading.Thread.CurrentThread.CurrentCulture = browserCulture;
System.Threading.Thread.CurrentThread.CurrentUICulture = browserCulture;

but I would like to know where these languages came from, or how to replicate them? This is to verify if my code is working properly. Thanks.

Answer 1

The only thing you should be aware of that UserLanguages will simply return corresponding HTTP header. Header values may have additional attributes separated by ;. So you should split that value on ; and get the first bit.

As for x-ns1dfk__jmpnx0 I would say ignore it. Falling back to your default language in this case is totally valid.

edit: I take the first part back. According to this the q parameter is the value of the language preference. So what you really should do is split on semicolon, then parse value of q attribute (assume 1 if not present), then sort on it and take the first one.