B4J Tutorial [BANano] Authentication to a B4J server (REST API)

'Filter class
Sub Class_Globals
   Dim NumberOfDays As Int = 90
End Sub

Public Sub Initialize

End Sub

'Return True to allow the request to proceed.
Public Sub Filter(req As ServletRequest, resp As ServletResponse) As Boolean
   Dim auths As List = req.GetHeaders("Authorization")
   Dim success As Boolean = False
   resp.SetHeader("Access-Control-Allow-Origin","*")
   resp.SetHeader("Access-Control-Allow-Methods" ,"GET, POST, OPTIONS")
   resp.SetHeader("Access-Control-Allow-Headers", "Access-Control-Allow-Headers, Origin, Accept, X-Requested-With, Content-Type, Access-Control-Request-Method, Access-Control-Request-Headers, Authorization")
   If auths.Size > 0 Then
       Dim auth As String = auths.Get(0)
       If auth.StartsWith("BANBasic") = True Then
           Dim b64 As String = auth.SubString("BANBasic ".Length)
           Dim su As StringUtils
           Dim b() As Byte = su.DecodeBase64(b64)
           Dim raw As String = BytesToString(b, 0, b.Length, "utf8")
           Dim UsernameAndPassword() As String = Regex.Split(":", raw)
           If CheckUsernameAndPassword(UsernameAndPassword) Then
               resp.Write($"{"BANanoStatus": 801, "BANToken": "${EncryptText(UsernameAndPassword(0) & ":" & UsernameAndPassword(1), "MyTopSecretPassword")}", "BANExpires": ${NumberOfDays}}"$)
               Return False           
           End If
       End If
       If auth.StartsWith("BANBearer") = True Then
           Dim b64 As String = auth.SubString("BANBearer ".Length)
           Dim dec As String = DecryptText(b64, "MyTopSecretPassword")
           Dim UsernameAndPassword() As String = Regex.Split(":", dec)
           success = CheckUsernameAndPassword(UsernameAndPassword)   
       End If
   End If
   If success = False Then
       ' we need to login
       resp.Write($"{"BANanoStatus": 800}"$)   
   End If
   Return success
End Sub

Sub CheckUsernameAndPassword(UsernameAndPassword() As String) As Boolean
   If UsernameAndPassword.Length = 2 Then
       'up to you to decide which credentials are allowed <---------------------------
       If UsernameAndPassword(0) = "UserName" And UsernameAndPassword(1) = "Password" Then
           Return True
       End If
   End If
   Return False
End Sub

' some helper functions
Sub EncryptText(text As String, password As String) As String
   Try
       Dim Su As StringUtils
       Dim c As B4XCipher
       Dim Crypt() As Byte = c.Encrypt(text.GetBytes("utf8"), password)
       Return Su.EncodeBase64(Crypt)
   Catch
       Return ""
   End Try
End Sub

Sub DecryptText(text As String, password As String) As String
   Try
       Dim Su As StringUtils
       Dim c As B4XCipher
       Dim BtCrypt() As Byte  = Su.DecodeBase64(text)
       Dim b() As Byte = c.Decrypt(BtCrypt, password)
       Return BytesToString(b, 0, b.Length, "utf8")
   Catch
       Return ""
   End Try
End Sub

public Sub BANano_Ready()
   Dim rows As List = MiniCSS.AddRows("r", 3, "row")
   MiniCSS.AddColumns("c",rows.get(0),2, "col-sm-6")
   MiniCSS.AddColumns("c",rows.get(1),1, "col-sm-12")
   MiniCSS.AddColumns("c",rows.get(2),1, "col-sm-12")
   MiniCSS.BuildGrid("body", rows)

   ' show a login or logoff button, depends if we have the Cookie
   Dim Token As String = BANano.GetCookie("BANanoDemoCookie")
   If Token = "" Then
       MiniCSS.Button("r1c1", "login", "Login", "primary", Me, False)
   Else
       MiniCSS.Button("r1c1", "login", "Log off", "primary", Me, False)
   End If
   MiniCSS.LoginForm("r1c1", "loginForm", Me)

   ' button to test our REST Api
   MiniCSS.Button("r2c1", "info", "Get Info", "", Me, False)
End Sub

public Sub Login_Clicked(event As BANanoEvent)
   Dim Token As String = BANano.GetCookie("BANanoDemoCookie")
   If Token = "" Then
       If BANano.CheckInternetConnectionWait Then
           ' open the popup
           BANano.GetElement("#loginform").SetChecked(True)
       Else
           ' no use to try to login
           MiniCSS.Content("r3c1", "contajax", "You are not connected to the internet!")
       End If
   Else
       BANano.RemoveCookie("BANanoDemoCookie", "")
       ' set to a log on button
       MiniCSS.Button("r1c1", "login", "Login", "primary", Me, True)
       MiniCSS.Content("r3c1", "contajax", "You are now logged off from the server!")
   End If
End Sub

public Sub Info_Clicked(event As BANanoEvent)
   If BANano.CheckInternetConnectionWait Then
       Dim Token As String = BANano.GetCookie("BANanoDemoCookie")
       If Token = "" Then
           ' we will have to login
           MiniCSS.Content("r3c1", "contajax", "You are not logged in on the server!")
           Return
       End If
       ' we are logged in, so lets get some REST api running
       Dim headers As Map
       headers.Initialize
       headers.put("Content-Type", "application/json")
       headers.Put("Authorization", $"BANBearer ${Token}"$)
       Dim res As String = BANano.CallAjaxWait("http://localhost:51042/getinfo","POST","json", "", False, headers)
       MiniCSS.Content("r3c1", "contajax", res)
   Else
       MiniCSS.Content("r3c1", "contajax", "You are not connected to the internet!")
   End If
End Sub

public Sub LoginformBtnLogin_Clicked(event As BANanoEvent)
   ' get the username and password
   Dim User As String = BANano.GetElement("#loginformusername").GetValue
   Dim Password As String = BANano.GetElement("#loginformpassword").GetValue

   ' close the popup
   BANano.GetElement("#loginform").SetChecked(False)

   ' try to logon to our server
   Dim headers As Map
   headers.Initialize
   headers.put("Content-Type", "application/json")
   headers.Put("Authorization", "BANBasic " & BANano.ToBase64(User & ":" & Password))
   Dim res As String = BANano.CallAjaxWait("http://localhost:51042/","POST","json", $""$, False, headers)
   Dim json As BANanoJSONParser
   json.Initialize(res)
   Dim m As Map = json.NextObject
   Dim CheckStatus As Int = m.GetDefault("BANanoStatus",0)
   Select Case CheckStatus
       Case 801 ' login is ok
           MiniCSS.Content("r3c1", "contajax", "You are logged in on the server!")
           Dim expires As Int = m.GetDefault("BANExpires", 0)
           BANano.SetCookie("BANanoDemoCookie", m.GetDefault("BANToken", ""), $"{"expires": ${expires}}"$)
           ' set to a logoff button
           MiniCSS.Button("r1c1", "login", "Log off", "primary", Me, True)
       Case Else ' login is not ok
           MiniCSS.Content("r3c1", "contajax", "You are not logged in on the server (wrong password?)!")
   End Select
End Sub

Dim res As String = BANano.CallAjaxWait("http://localhost:51042/getinfo","POST","json", "", False, headers)
MiniCSS.Content("r3c1", "contajax", res)

BANano.ToBase64 ' to send the username and password
.GetValue/.SetValue ' Umbrella had no methods for this, so I build them in
.GetChecked/.SetChecked ' Umbrella had no methods for this, so I build them in
BANano.Msgbox ' shows an alert