Cookie value to enum

Question

Users can have a Cookie called lang that contains either the value "default=1" (English) or "default=2" (French). This cookie is used to determine their preferred language. I have a function that needs to take the cookie and return the language has an Enum. If the cookie doesn't exist, I want to return English. I cannot change the cookie value.

Language enum:

 Public Enum Language
 Undefined = 0
 English = 1
 French = 2
 End Enum

Function:

 Public Function GetLangFromCookie() As Language
 If HttpContext.Current.Request.Cookies.Get("lang") IsNot Nothing Then
 Dim langCookie = HttpContext.Current.Request.Cookies.Get("lang").Value
 Return If(langCookie(langCookie.Length - 1) = "1", Language.English, Language.French)
 End If
 Return Language.English
 End Function

I feel like this is not efficient and not secure but I don't know how to improve it. Any suggestions?

Answer 1

• You query HttpContext.Current.Request.Cookies.Get("lang") twice. Access it once and store it in a variable.
• You will get a problem if in the future you have to support more than 9 languages. Instead of accessing the last char from langCookie you should Split() langCookie by = and take the second array element. You can then use [Enum].TryParse() to get the enum.
• Some horizontal spacing (new lines) would help to easier read the code.

Your code could look like so

Public Function GetLangFromCookie() As Language
 Dim langCookie = HttpContext.Current.Request.Cookies.Get("lang")
 If langCookie Is Nothing Then
 Return Language.English
 Else
 Return GetLanguage(langCookie.Value)
 End If
End Function
Private Function GetLanguage(languageCookieValue As String) As Language
 Dim splittetCookieValue As String() = languageCookieValue.Split(New String() {"="}, StringSplitOptions.RemoveEmptyEntries)
 Dim languageIdentifier As String = splittetCookieValue.LastOrDefault()
 Dim foundLanguage As Language
 ' We don't care about the success of the TryParse() call
 [Enum].TryParse(Of Language)(languageIdentifier, foundLanguage)
 ' because foundLanguage will be 0 if it doesn't succeed and will be checked here
 Return If(foundLanguage = Language.Undefined, Language.English, foundLanguage)
End Function