MONSTER: Rename Monorepo to Modules, only keep Projects under Modules.*

Interfaces/ActiveDirectoryInterface.vb

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+Imports System.DirectoryServices
+Imports System.DirectoryServices.AccountManagement
+Imports System.Text.RegularExpressions
+Imports DigitalData.Modules.Database
+Imports DigitalData.Modules.Logging
+
+Public Class ActiveDirectoryInterface
+    Private _logConfig As LogConfig
+    Private _logger As Logger
+
+    Private ReadOnly _rootPath As String
+
+    Private _rootNode As DirectoryEntry
+
+    Private Const SEARCH_LIMIT = 50000
+
+    Private Const SAMACCOUNTNAME = "samaccountname"
+    Private Const OBJECTCLASS = "objectClass"
+    Private Const CN = "cn"
+    Private Const DESCRIPTION = "description"
+    Private Const DISINGUISHEDNAME = "distinguishedName"
+    Private Const NAME = "name"
+    Private Const OBJECTCATEGORY = "objectCategory"
+
+    Public Const DEFAULT_USER_FILTER = "(&(objectClass=user)(samAccountName=@SAMACCOUNTNAME)(!(UserAccountControl:1.2.840.113556.1.4.803:=2)))"
+    Public Const DEFAULT_GROUP_FILTER = "(&(objectClass=group) (samAccountName=*))"
+
+    Public Sub New(LogConfig As LogConfig, Optional RootPath As String = Nothing)
+        _logConfig = LogConfig
+        _logger = _logConfig.GetLogger()
+
+        If RootPath Is Nothing Then
+            _rootPath = $"LDAP://{Environment.UserDomainName}"
+        Else
+            _rootPath = RootPath
+        End If
+        _logger.Info("Using RootPath {0}", _rootPath)
+    End Sub
+
+    Public Function SyncUsersForGroup(GroupName As String, Firebird As Firebird, MSSQL As MSSQLServer) As List(Of ADUser)
+        Try
+            Return SyncUsersForGroup(GroupName, New List(Of AttributeMapping), Firebird, MSSQL)
+        Catch ex As Exception
+            _logger.Error(ex)
+            Return Nothing
+        End Try
+    End Function
+
+    Public Function SyncUsersForGroup(GroupName As String, AttributeMappings As List(Of AttributeMapping), Firebird As Firebird, MSSQL As MSSQLServer, Optional Filter As String = DEFAULT_USER_FILTER) As List(Of ADUser)
+        Dim oUsers As New List(Of ADUser)
+        Dim oSyncedUsers As New List(Of ADUser)
+        Dim oGroupId As Int64 = Nothing
+
+        Dim oFirebirdSync As New SyncUsers.SyncUsersFirebird(_logConfig, Firebird)
+        Dim oSQLSync As New SyncUsers.SyncUsersMSSQL(_logConfig, MSSQL)
+        Dim oSyncedUsersFirebird, oSyncedUsersMSSQL As List(Of ADUser)
+
+        Try
+            _logger.Debug("Fetching users from ActiveDirectory")
+            oUsers = ListUsers(GroupName, AttributeMappings, Filter)
+            _logger.Debug("Found {0} users", oUsers.Count)
+        Catch ex As Exception
+            _logger.Error(ex)
+            Return Nothing
+        End Try
+
+        ' Do the actual sync into firebird
+        If Firebird IsNot Nothing Then
+            oSyncedUsersFirebird = oFirebirdSync.SyncUsers(GroupName, oUsers, AttributeMappings)
+            If oSyncedUsersFirebird.Count > 0 Then
+                _logger.Debug("Synced {0} users to Firebird", oSyncedUsersFirebird.Count)
+            End If
+        Else
+            _logger.Debug("SyncUsersForGroup: _firebird is nothing. ")
+        End If
+
+        ' Do the actual sync into MSSQL
+        If MSSQL IsNot Nothing Then
+            oSyncedUsersMSSQL = oSQLSync.SyncUsers(GroupName, oUsers, AttributeMappings)
+            If oSyncedUsersMSSQL.Count > 0 Then
+                _logger.Debug("Synced {0} users to MSSQLServer", oSyncedUsersMSSQL.Count)
+            End If
+        Else
+            _logger.Debug("SyncUsersForGroup: _mssql is nothing. ")
+        End If
+
+        Return oUsers
+    End Function
+
+    Public Function Authenticate() As Boolean
+        Try
+            Dim oEntry = GetRootNode()
+            oEntry.RefreshCache()
+
+            _rootNode = oEntry
+            Return True
+        Catch ex As Exception
+            _logger.Error(ex)
+            _logger.Warn("Could not authenticate with Active Directory.")
+            Return False
+        End Try
+    End Function
+    Public Function Authenticate(Username As String, Password As String) As Boolean
+        Try
+            Dim oEntry = GetRootNode(Username, Password)
+            oEntry.RefreshCache()
+
+            _rootNode = oEntry
+            Return True
+        Catch ex As Exception
+            _logger.Error(ex)
+            _logger.Warn("Could not authenticate with Active Directory.")
+            Return False
+        End Try
+    End Function
+
+    Public Function ListGroups(Optional Query As String = DEFAULT_GROUP_FILTER) As List(Of ADGroup)
+        Return ListGroups(_rootNode, Query)
+    End Function
+
+    Public Async Function ListGroupsAsync(Optional Query As String = DEFAULT_GROUP_FILTER) As Task(Of List(Of ADGroup))
+        Return Await Task.Run(Function() ListGroups(Query))
+    End Function
+
+    Public Function ListGroups(RootNode As DirectoryEntry, Optional Query As String = DEFAULT_GROUP_FILTER) As List(Of ADGroup)
+        Dim oGroups As New List(Of ADGroup)
+
+        Try
+            Dim oDirectorySearcher As New DirectorySearcher(RootNode) With {
+                .SearchScope = SearchScope.Subtree,
+                .SizeLimit = SEARCH_LIMIT,
+                .Filter = Query
+            }
+            Dim oResults As SearchResultCollection = oDirectorySearcher.FindAll()
+
+            _logger.Info("Found {0} Groups.", oResults.Count)
+
+            Return GroupResultsToList(oResults)
+        Catch ex As Exception
+            _logger.Error(ex)
+            Return oGroups
+        End Try
+    End Function
+
+    Public Function ListUsers(GroupName As String, Optional Filter As String = DEFAULT_USER_FILTER) As List(Of ADUser)
+        Return ListUsers(GroupName, New List(Of AttributeMapping), Filter)
+    End Function
+
+    Public Async Function ListUsersAsync(GroupName As String, Optional Filter As String = DEFAULT_USER_FILTER) As Task(Of List(Of ADUser))
+        Return Await Task.Run(Function() ListUsers(GroupName, Filter))
+    End Function
+
+    Public Function ListUsers(GroupName As String, AttributeMappings As List(Of AttributeMapping), Optional Filter As String = DEFAULT_USER_FILTER) As List(Of ADUser)
+        Dim oUsers As New List(Of ADUser)
+
+        Try
+            Using oContext As New PrincipalContext(ContextType.Domain)
+                Using oGroupPrincipal As GroupPrincipal = GroupPrincipal.FindByIdentity(oContext, IdentityType.Name, GroupName)
+                    If oGroupPrincipal Is Nothing Then
+                        _logger.Debug("Group {0} does not exist.", GroupName)
+                        Return oUsers
+                    End If
+
+                    _logger.Debug("Listing members of Group {0}", GroupName)
+
+                    Using oMembers = oGroupPrincipal.GetMembers(True)
+                        For Each oMember As Principal In oMembers
+                            Try
+                                If TypeOf oMember Is UserPrincipal Then
+                                    Dim oUser As UserPrincipal = DirectCast(oMember, UserPrincipal)
+                                    Dim oUserEx As UserPrincipalEx = UserPrincipalEx.FindByIdentity(oContext, IdentityType.SamAccountName, oUser.SamAccountName)
+                                    Dim oCustomAttributes As New List(Of ADUser.CustomAttribute)
+
+                                    Dim oUserFound = FindUserWithFilter(oUserEx, Filter)
+
+                                    If oUserFound = False Then
+                                        _logger.Debug("User [{0}] was skipped out due to user filter.", oUserEx.SamAccountName)
+                                        Continue For
+                                    End If
+                                    _logger.Debug("User [{0}] passed the filter.", oUserEx.SamAccountName)
+
+                                    ' TODO: Figure out why oUserEx can be nothing for certain users
+                                    If oUserEx IsNot Nothing Then
+                                        For Each oMap As AttributeMapping In AttributeMappings
+                                            Dim oAttributeValue = oUserEx.GetAttributeValue(oMap.AttributeName)
+
+                                            If oAttributeValue <> String.Empty Then
+                                                _logger.Debug("Attribute [{0}] is not empty.", oMap.AttributeName)
+
+                                                oCustomAttributes.Add(New ADUser.CustomAttribute() With {
+                                                    .Name = oMap.AttributeName,
+                                                    .Value = oAttributeValue,
+                                                    .FirebirdSyskey = oMap.FirebirdSyskey,
+                                                    .MSSQLColumn = oMap.MSSQLColumn
+                                                })
+                                            End If
+                                        Next
+                                    Else
+                                        _logger.Debug("Could not fetch CustomAttributes for user [{0}]", oUser)
+                                    End If
+
+                                    _logger.Debug("Trying to add User [{0}] to user list", oUser)
+
+                                    Dim oNewUser As New ADUser With {
+                                        .SId = oUser.Sid,
+                                        .samAccountName = oUser.SamAccountName,
+                                        .Middlename = oUser.MiddleName,
+                                        .GivenName = oUser.GivenName,
+                                        .Surname = oUser.Surname,
+                                        .GUID = oUser.Guid,
+                                        .Email = oUser.EmailAddress,
+                                        .CustomAttributes = oCustomAttributes
+                                    }
+
+                                    oUsers.Add(oNewUser)
+                                End If
+                            Catch ex As Exception
+                                _logger.Warn("User could not be processed")
+                                _logger.Error(ex)
+                            End Try
+                        Next
+                    End Using
+                End Using
+            End Using
+
+            Return oUsers
+        Catch ex As Exception
+            _logger.Error(ex)
+            Return oUsers
+        End Try
+    End Function
+
+    Public Function FindUserWithFilter(User As UserPrincipalEx, Filter As String) As Boolean
+        Try
+            Dim oRootPath = String.Join(","c, User.DistinguishedName.Split(","c).Skip(1))
+            Dim oPlaceholder = "@SAMACCOUNTNAME"
+            Dim oProtocol = "LDAP://"
+            Dim oEntry As New DirectoryEntry(oProtocol & oRootPath) With {
+                .Username = Nothing,
+                .Password = Nothing,
+                .AuthenticationType = AuthenticationTypes.Secure
+            }
+
+            If Filter = String.Empty Then
+                _logger.Debug("FindUserWithFilter: Filter was empty, returning True for User [{0}]", User.SamAccountName)
+                Return True
+            End If
+
+            If Filter.Contains(oPlaceholder) Then
+                Filter = Filter.Replace(oPlaceholder, User.SamAccountName)
+            Else
+                _logger.Warn("FindUserWithFilter: Placeholder [{0}] was not found in filter. Results may not be correct.")
+            End If
+
+            Dim oSearcher As New DirectorySearcher(oEntry, Filter)
+            Dim oResult As SearchResult = oSearcher.FindOne()
+
+            If oResult IsNot Nothing AndAlso oResult.Path.Replace(oProtocol, String.Empty) = User.DistinguishedName Then
+                Return True
+            Else
+                Return False
+            End If
+        Catch ex As Exception
+            _logger.Warn("FindUserWithFilter: Unhandled exception.")
+            _logger.Error(ex)
+            Return False
+        End Try
+    End Function
+
+    Private Function GetRootNode() As DirectoryEntry
+        Dim oEntry As New DirectoryEntry(_rootPath) With {
+            .AuthenticationType = AuthenticationTypes.Secure,
+            .Password = Nothing,
+            .Username = Nothing
+        }
+
+        Return oEntry
+    End Function
+    Private Function GetRootNode(Username As String, Password As String) As DirectoryEntry
+        Dim oEntry As New DirectoryEntry(_rootPath) With {
+            .AuthenticationType = AuthenticationTypes.Secure,
+            .Password = Username,
+            .Username = Password
+        }
+
+        Return oEntry
+    End Function
+
+    Private Function GroupResultsToList(Results As SearchResultCollection) As List(Of ADGroup)
+        Dim oGroups As New List(Of ADGroup)
+
+        For Each oResult As SearchResult In Results
+            oGroups.Add(New ADGroup() With {
+                .Name = TryGetProperty(oResult, NAME),
+                .SAMAccountName = TryGetProperty(oResult, SAMACCOUNTNAME),
+                .CN = TryGetProperty(oResult, CN),
+                .Description = TryGetProperty(oResult, DESCRIPTION),
+                .DistinguishedName = TryGetProperty(oResult, DISINGUISHEDNAME),
+                .ObjectCategory = TryGetProperty(oResult, OBJECTCATEGORY),
+                .ObjectClass = TryGetProperty(oResult, OBJECTCLASS)
+            })
+        Next
+
+        Return oGroups
+    End Function
+
+    Private Function TryGetProperty(Result As SearchResult, PropertyName As String) As String
+        Try
+            Return Result.Properties.Item(PropertyName).Item(0)
+        Catch ex As Exception
+            _logger.Debug("Property {0} not found", PropertyName)
+            Return String.Empty
+        End Try
+    End Function
+End Class

Interfaces/ActiveDirectoryInterface/ActiveDirectoryGroup.vb

@@ -0,0 +1,13 @@
+Public Class ADGroup
+    Public Property SAMAccountName As String
+    Public Property ObjectClass As String
+    Public Property CN As String
+    Public Property Description As String
+    Public Property DistinguishedName As String
+    Public Property Name As String
+    Public Property ObjectCategory As String
+
+    Public Overrides Function ToString() As String
+        Return SAMAccountName
+    End Function
+End Class

Interfaces/ActiveDirectoryInterface/ActiveDirectoryUser.vb

@@ -0,0 +1,28 @@
+Imports System.Security.Principal
+
+Public Class ADUser
+    Public Property GUID As Guid
+    Public Property samAccountName As String
+    Public Property SId As SecurityIdentifier
+    Public Property Surname As String
+    Public Property GivenName As String
+    Public Property Middlename As String
+    Public Property Email As String
+
+    Public CustomAttributes As List(Of CustomAttribute)
+
+    Public Overrides Function Equals(obj As Object) As Boolean
+        Return DirectCast(obj, ADUser).samAccountName
+    End Function
+
+    Public Overrides Function ToString() As String
+        Return samAccountName
+    End Function
+
+    Public Class CustomAttribute
+        Public Name As String
+        Public Value As Object
+        Public MSSQLColumn As String
+        Public FirebirdSyskey As String
+    End Class
+End Class

Interfaces/ActiveDirectoryInterface/AttributeMap.vb

@@ -0,0 +1,5 @@
+Public Class AttributeMapping
+    Public AttributeName As String
+    Public FirebirdSyskey As String
+    Public MSSQLColumn As String
+End Class

Interfaces/ActiveDirectoryInterface/ISyncUsers.vb

@@ -0,0 +1,8 @@
+Public Interface ISyncUsers
+    Function SyncUsers(GroupName As String, Users As List(Of ADUser), PropertyMapping As List(Of AttributeMapping)) As List(Of ADUser)
+    Function GetGroupId(GroupName As String) As Integer
+    Function GetUserId(UserName As String) As Integer
+    Function CreateUser(User As ADUser) As Integer
+    Function AddUserToGroup(UserId As Integer, GroupId As Integer) As Boolean
+    Sub AddCustomAttributesToUser(User As ADUser, UserId As Integer)
+End Interface

Interfaces/ActiveDirectoryInterface/SyncUsers.Firebird.vb

@@ -0,0 +1,145 @@
+Imports DigitalData.Modules.Database
+Imports DigitalData.Modules.Interfaces
+Imports DigitalData.Modules.Logging
+
+Namespace SyncUsers
+    Public Class SyncUsersFirebird
+        Implements ISyncUsers
+
+        Private ReadOnly _logConfig As LogConfig
+        Private ReadOnly _logger As Logger
+        Private ReadOnly _firebird As Database.Firebird
+
+        Public Sub New(LogConfig As LogConfig, Firebird As Database.Firebird)
+            _logConfig = LogConfig
+            _logger = LogConfig.GetLogger()
+            _firebird = Firebird
+        End Sub
+
+        Public Function SyncUsers(GroupName As String, Users As List(Of ADUser), PropertyMapping As List(Of AttributeMapping)) As List(Of ADUser) Implements ISyncUsers.SyncUsers
+            Dim oGroupId As Integer
+            Dim oSyncedUsers As New List(Of ADUser)
+
+            Try
+                _logger.Debug("Getting group Id for group [{0}]", GroupName)
+                oGroupId = GetGroupId(GroupName)
+
+                If oGroupId = 0 Then
+                    _logger.Debug("Group [{0}] does not exist in database or is not enabled for sync.", GroupName)
+                    Return oSyncedUsers
+                End If
+
+                _logger.Debug("Using group Id [{0}]", oGroupId)
+            Catch ex As Exception
+                _logger.Error(ex)
+                Return oSyncedUsers
+            End Try
+
+            For Each oUser In Users
+                Dim oUserId As Int64
+                Dim oUserExists As Boolean = False
+
+                ' Check if user already exists
+                Try
+                    _logger.Debug("Checking if user [{0}] exists", oUser)
+                    oUserId = GetUserId(oUser.samAccountName)
+                    oUserExists = Not IsNothing(oUserId)
+                    _logger.Debug("User [{0}] exists in database: ", oUser, oUserExists)
+                Catch ex As Exception
+                    _logger.Error(ex)
+                    _logger.Warn("Could not get UserId for user. Skipping")
+                    Continue For
+                End Try
+
+                ' I user does not exist, create a new user
+                Try
+                    If Not oUserExists Then
+                        _logger.Debug("Creating new user for [{0}]", oUser)
+                        oUserId = CreateUser(oUser)
+                        _logger.Debug("User created with Id [{0}]", oUserId)
+                    End If
+                Catch ex As Exception
+                    _logger.Error(ex)
+                    _logger.Warn("Could not create user. Skipping")
+                    Continue For
+                End Try
+
+                ' Add the user to group
+                Try
+                    AddUserToGroup(oUserId, oGroupId)
+                Catch ex As Exception
+                    _logger.Error(ex)
+                    _logger.Warn("Could not add user to group. Skipping")
+                    Continue For
+                End Try
+
+                oSyncedUsers.Add(oUser)
+            Next
+
+            Return oSyncedUsers
+        End Function
+
+        Private Function AddUserToGroup(UserId As Integer, GroupId As Integer) As Boolean Implements ISyncUsers.AddUserToGroup
+            Try
+                Dim oSQL = $"SELECT FNICM_RADM_NEW_USER2GROUP({UserId}, {GroupId}, 'AD-Sync') from RDB$DATABASE"
+                Dim oRecordId = _firebird.GetScalarValue(oSQL)
+
+                If IsDBNull(oRecordId) Then
+                    _logger.Warn("UserId {0} - GroupId {1} relation already exists.", UserId, GroupId)
+                    Return False
+                End If
+
+                Return True
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+        Private Function GetGroupId(GroupName As String) As Integer Implements ISyncUsers.GetGroupId
+            Try
+                Dim oSQL As String = $"SELECT FNICM_GET_RECORD4SYSKEY('{GroupName}','002-NAME') from RDB$DATABASE"
+                Dim oGroupId = _firebird.GetScalarValue(oSQL)
+
+                If IsDBNull(oGroupId) OrElse oGroupId = 0 Then
+                    _logger.Debug("Group {0} not found in database", GroupName)
+                    Return Nothing
+                End If
+
+                Return oGroupId
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+        Private Function GetUserId(UserName As String) As Integer Implements ISyncUsers.GetUserId
+            Try
+                Dim oSQL As String = $"SELECT FNICM_GET_RECORD4SYSKEY('{UserName}','001-USRNAME') from RDB$DATABASE"
+                Dim oResult = _firebird.GetScalarValue(oSQL)
+
+                If IsDBNull(oResult) Then
+                    Return Nothing
+                End If
+
+                Return oResult
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+        Private Function CreateUser(User As ADUser) As Integer Implements ISyncUsers.CreateUser
+            Try
+                Dim oSQL = $"SELECT FNICM_RADM_NEW_USER('{User?.GivenName}', '{User?.Surname}', '{User?.samAccountName}', 'AD-Sync') from RDB$DATABASE"
+                Dim oUserId As Integer = _firebird.GetScalarValue(oSQL)
+
+                Return oUserId
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+
+        Public Sub AddCustomAttributesToUser(User As ADUser, UserId As Integer) Implements ISyncUsers.AddCustomAttributesToUser
+            Throw New NotImplementedException()
+        End Sub
+    End Class
+End Namespace

Interfaces/ActiveDirectoryInterface/SyncUsers.MSSQL.vb

@@ -0,0 +1,284 @@
+Imports DigitalData.Modules.Database
+Imports DigitalData.Modules.Logging
+Imports DigitalData.Modules.Language
+
+Namespace SyncUsers
+    Public Class SyncUsersMSSQL
+        Implements ISyncUsers
+
+        Private _logConfig As LogConfig
+        Private _logger As Logger
+        Private _mssql As MSSQLServer
+
+        Private Const ADDED_WHO = "Active Directory Sync"
+
+        Public Sub New(LogConfig As LogConfig, MSSQL As MSSQLServer)
+            _logConfig = LogConfig
+            _logger = LogConfig.GetLogger()
+            _mssql = MSSQL
+        End Sub
+
+        Public Function SyncUsers(GroupName As String, Users As List(Of ADUser), PropertyMapping As List(Of AttributeMapping)) As List(Of ADUser) Implements ISyncUsers.SyncUsers
+            Dim oGroupId As Integer
+            Dim oSyncedUsers As New List(Of ADUser)
+            Dim oSyncedUserIds As New List(Of Int64)
+
+            Dim oCreatedUsers As New List(Of ADUser)
+            Dim oUpdatedUsers As New List(Of ADUser)
+
+            Try
+                _logger.Debug("Getting group Id for group {0}", GroupName)
+                oGroupId = GetGroupId(GroupName)
+
+                If oGroupId = 0 Then
+                    _logger.Debug("Group {0} does not exist in database. Exiting.", GroupName)
+                    Return oSyncedUsers
+                End If
+
+                _logger.Debug("Using group Id {0}", oGroupId)
+            Catch ex As Exception
+                _logger.Error(ex)
+                Return oSyncedUsers
+            End Try
+
+            For Each oUser In Users
+                Dim oUserId As Int64
+                Dim oUserExists As Boolean
+
+                ' Check if user already exists
+                Try
+                    _logger.Debug("Checking if user [{0}] exists", oUser)
+                    oUserId = GetUserId(oUser.samAccountName)
+                    oUserExists = oUserId > 0
+                    _logger.Debug("User [{0}] exists in database: [{1}]", oUser, oUserExists)
+                Catch ex As Exception
+                    _logger.Error(ex)
+                    _logger.Warn("Could not get UserId for user. Skipping.")
+                    Continue For
+                End Try
+
+                ' Collect user ids from existing users
+                If oUserExists Then
+                    oSyncedUserIds.Add(oUserId)
+                End If
+
+                ' Create or update user
+                Try
+                    If Not oUserExists Then
+                        _logger.Debug("Creating new user for [{0}]", oUser)
+                        oUserId = CreateUser(oUser)
+                        _logger.Debug("User created with Id [{0}]", oUserId)
+                        _logger.Info("Added new User [{0}]", oUser.samAccountName)
+
+                        oCreatedUsers.Add(oUser)
+                    Else
+                        _logger.Debug("Updating user [{0}]", oUser)
+                        oUserId = UpdateUser(oUser)
+                        If oUserId <> 0 Then
+                            _logger.Debug("User created with Id [{0}]", oUserId)
+                            _logger.Info("Updated User [{0}]", oUser.samAccountName)
+
+                            oUpdatedUsers.Add(oUser)
+                        End If
+                    End If
+
+                Catch ex As Exception
+                    _logger.Error(ex)
+                    _logger.Warn("Could Not create/update user [{0}]. Skipping.", oUser.samAccountName)
+                    Continue For
+                End Try
+
+                ' Add custom attributes to user
+                Try
+                    AddCustomAttributesToUser(oUser, oUserId)
+                Catch ex As Exception
+                    _logger.Error(ex)
+                    _logger.Debug("Could Not add custom attributes to user {0}. Continuing.", oUser)
+                End Try
+
+                ' Add the user to group
+                Try
+                    If AddUserToGroup(oUserId, oGroupId) Then
+                        _logger.Info("User [{0}] added to group [{1}]", oUser.samAccountName, GroupName)
+                    End If
+                Catch ex As Exception
+                    _logger.Error(ex)
+                    _logger.Warn("Could Not add user {0} to group {1}. Skipping.", oUser, GroupName)
+                    Continue For
+                End Try
+
+                oSyncedUsers.Add(oUser)
+            Next
+
+            ' Delete users that are assigned to the group but no longer exist in active directory
+            Dim oUserIdString = String.Join(",", oSyncedUserIds)
+            If oSyncedUserIds.Count = 0 Then
+                _logger.Info("Group {0} does not contain any users.", GroupName)
+                oUserIdString = 0
+            End If
+            Dim oSQL As String = $"DELETE FROM TBDD_GROUPS_USER WHERE USER_ID NOT IN ({oUserIdString}) AND GROUP_ID = {oGroupId}"
+            Dim oDeletedRelations = _mssql.GetScalarValue(oSQL)
+            If oCreatedUsers.Count > 0 Then
+                _logger.Info("Created [{0}] new users", oCreatedUsers.Count)
+            End If
+            _logger.Info("Updated [{0}] users", oUpdatedUsers.Count)
+            If oDeletedRelations > 0 Then
+                _logger.Info("Removed [{0}] users from Group [{1}]", oDeletedRelations, GroupName)
+            End If
+
+
+            Return oSyncedUsers
+        End Function
+
+        Private Function AddUserToGroup(UserId As Integer, GroupId As Integer) As Boolean Implements ISyncUsers.AddUserToGroup
+            Try
+                Dim oSQL = $"SELECT COUNT(*) FROM TBDD_GROUPS_USER WHERE USER_ID = {UserId} And GROUP_ID = {GroupId}"
+                Dim oResult = True
+                If _mssql.GetScalarValue(oSQL) = 0 Then
+                    oSQL = $"INSERT INTO TBDD_GROUPS_USER (USER_ID, GROUP_ID, ADDED_WHO) VALUES ({UserId}, {GroupId}, '{ADDED_WHO}')"
+                    oResult = _mssql.ExecuteNonQuery(oSQL)
+                Else
+                    _logger.Debug($"UserGroup-Relation [{UserId}/{GroupId}] already existing")
+                    Return False
+                End If
+
+                If oResult = False Then
+                    Throw New Exception("Error while adding user to group!")
+                End If
+
+                Return True
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+
+        Private Function GetGroupId(GroupName As String) As Integer Implements ISyncUsers.GetGroupId
+            Try
+                Dim oSQL As String = $"SELECT GUID FROM TBDD_GROUPS WHERE UPPER(NAME) = UPPER('{GroupName}') AND AD_SYNC = 1 AND ACTIVE = 1"
+                Dim oGroupId = _mssql.GetScalarValue(oSQL)
+
+                If IsDBNull(oGroupId) OrElse oGroupId = 0 Then
+                    _logger.Debug("Group {0} not found in database.", GroupName)
+                    Return 0
+                End If
+
+                Return oGroupId
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+
+        Private Function GetUserId(UserName As String) As Integer Implements ISyncUsers.GetUserId
+            Try
+                Dim oSQL As String = $"SELECT GUID FROM TBDD_USER WHERE UPPER(USERNAME) = UPPER('{UserName}')"
+                Dim oUserId = _mssql.GetScalarValue(oSQL)
+
+                If IsDBNull(oUserId) OrElse oUserId = 0 Then
+                    Return 0
+                End If
+
+                Return oUserId
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+
+        Private Function CreateUser(User As ADUser) As Integer Implements ISyncUsers.CreateUser
+            Try
+                If User Is Nothing Then
+                    _logger.Warn("Argument [User] is nothing. Exiting.")
+                    Throw New ArgumentNullException("User")
+                End If
+
+                Dim oUserId As Integer = GetUserId(User.samAccountName)
+
+                If oUserId = 0 Then
+                    Dim oSQL As String = $"INSERT INTO TBDD_USER (PRENAME, NAME, USERNAME, EMAIL, ADDED_WHO) VALUES ('{User?.GivenName}', '{User?.Surname?.Replace("'", "''")}', UPPER('{User?.samAccountName?.Replace("'", "''")}'), '{User?.Email?.Replace("'", "''")}', '{ADDED_WHO}')"
+                    Dim oResult = _mssql.ExecuteNonQuery(oSQL)
+
+                    If oResult = True Then
+                        oUserId = _mssql.GetScalarValue("SELECT MAX(GUID) FROM TBDD_USER")
+                        Return oUserId
+                    Else
+                        Throw New Exception($"Error while inserting user {User.samAccountName}!")
+                    End If
+                Else
+                    Return oUserId
+                End If
+
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+
+        Private Function UpdateUser(User As ADUser) As Integer
+            Try
+                If User Is Nothing Then
+                    _logger.Warn("Error in UpdateUser - User object is nothing")
+                    Return 0
+                End If
+
+                If User.samAccountName Is Nothing Then
+                    _logger.Warn("Error in UpdateUser - User samAccountName is nothing")
+                    Return 0
+                End If
+
+                Dim oUserId As Integer = GetUserId(User.samAccountName)
+                If Not IsNothing(oUserId) Then
+                    If oUserId > 0 Then
+                        Dim oGivenName As String = EscapeQuotes(User.GivenName)
+                        Dim oSurname As String = EscapeQuotes(User.Surname)
+                        Dim oEmail As String = EscapeQuotes(User.Email)
+
+                        Dim oSQL As String = $"UPDATE TBDD_USER SET PRENAME = '{oGivenName}', NAME = '{oSurname}', EMAIL = '{oEmail}', CHANGED_WHO = '{ADDED_WHO}' WHERE GUID = {oUserId}"
+                        Dim oResult = _mssql.ExecuteNonQuery(oSQL)
+
+                        If oResult = True Then
+                            Return oUserId
+                        Else
+                            Throw New Exception($"Error while updating user {User.samAccountName}!")
+                        End If
+                    Else
+                        Return oUserId
+                    End If
+                Else
+                    _logger.Warn("Error in UpdateUser - Could not get a userid for samAccountName: " + User.samAccountName)
+                    Return 0
+                End If
+
+            Catch ex As Exception
+                _logger.Error(ex)
+                Throw ex
+            End Try
+        End Function
+
+        Private Function EscapeQuotes(pString As String)
+            Dim oString = Utils.NotNull(pString, String.Empty)
+            Return oString.Replace("'", "''")
+        End Function
+
+        Public Sub AddCustomAttributesToUser(User As ADUser, UserId As Integer) Implements ISyncUsers.AddCustomAttributesToUser
+            Dim oCustomAttributes = User.CustomAttributes
+
+            _logger.Debug("Adding {0} Custom Attributes to User {1}", oCustomAttributes.Count, User)
+
+            For Each oAttribute In oCustomAttributes
+                _logger.Debug("Adding Custom Attribute [{0}] with value [{1}] to User [{2}]", oAttribute.MSSQLColumn, oAttribute.Value, User)
+                Dim oSQL As String = $"UPDATE TBDD_USER SET {oAttribute.MSSQLColumn} = '{oAttribute.Value}', CHANGED_WHO = '{ADDED_WHO}' WHERE GUID = {UserId}"
+                Dim oResult = _mssql.ExecuteNonQuery(oSQL)
+
+                If oResult = False Then
+                    _logger.Debug("Custom Attribute {0} could not be added to user {1}", oAttribute.Name, User.samAccountName)
+                    Continue For
+                End If
+            Next
+        End Sub
+    End Class
+
+End Namespace
+
+

Interfaces/ActiveDirectoryInterface/UserEqualityComparer.vb

@@ -0,0 +1,19 @@
+Imports DigitalData.Modules.Interfaces
+
+Public Class UserEqualityComparer
+    Implements IEqualityComparer(Of ADUser)
+
+    Public Overloads Function Equals(x As ADUser, y As ADUser) As Boolean Implements IEqualityComparer(Of ADUser).Equals
+        If ReferenceEquals(x, y) Then Return True
+        If x Is Nothing Or y Is Nothing Then Return False
+
+        Return x.SId = y.SId
+    End Function
+
+    Public Overloads Function GetHashCode(obj As ADUser) As Integer Implements IEqualityComparer(Of ADUser).GetHashCode
+        If obj Is Nothing Then Return 0
+
+        Dim oHashCode = obj.SId.GetHashCode()
+        Return oHashCode
+    End Function
+End Class

Interfaces/ActiveDirectoryInterface/UserPrincipalEx.vb

@@ -0,0 +1,36 @@
+Imports System.DirectoryServices.AccountManagement
+
+<DirectoryRdnPrefix("CN")>
+<DirectoryObjectClass("Person")>
+Public Class UserPrincipalEx
+    Inherits UserPrincipal
+
+    Public Sub New(Context As PrincipalContext)
+        MyBase.New(Context)
+    End Sub
+
+    Public Sub New(Context As PrincipalContext, samAccountName As String, Password As String, Enabled As Boolean)
+        MyBase.New(Context, samAccountName, Password, Enabled)
+    End Sub
+
+    Public Overloads Shared Function FindByIdentity(ByVal Context As PrincipalContext, ByVal IdentityValue As String) As UserPrincipalEx
+        Return CType(FindByIdentityWithType(Context, GetType(UserPrincipalEx), IdentityValue), UserPrincipalEx)
+    End Function
+
+    Public Overloads Shared Function FindByIdentity(ByVal Context As PrincipalContext, ByVal IdentityType As IdentityType, ByVal IdentityValue As String) As UserPrincipalEx
+        Return CType(FindByIdentityWithType(Context, GetType(UserPrincipalEx), IdentityType, IdentityValue), UserPrincipalEx)
+    End Function
+
+    Public Function GetAttributeValue(AttributeName As String) As String
+        Return TryGetAttribute(AttributeName)
+    End Function
+
+    Private Function TryGetAttribute(AttributeName As String) As String
+        Dim oAttribute = ExtensionGet(AttributeName)
+
+        If oAttribute.Length <> 1 Then
+            Return String.Empty
+        End If
+        Return CStr(oAttribute(0))
+    End Function
+End Class

Interfaces/GrapQLInterface/LoginData.vb

@@ -0,0 +1,4 @@
+Public Class LoginData
+    Public email As String
+    Public token As String
+End Class

Interfaces/GrapQLInterface/LogoutData.vb

@@ -0,0 +1,3 @@
+Public Class LogoutData
+    Public email As String
+End Class

Interfaces/GrapQLInterface/QueryData.vb

@@ -0,0 +1,5 @@
+Public Class QueryData
+    Public query As String
+    Public operationName As String
+    Public variables As New Object
+End Class

Interfaces/GraphQLInterface.vb

@@ -0,0 +1,181 @@
+Imports System.IO
+Imports System.Net
+Imports System.Security.Cryptography.X509Certificates
+Imports System.Text
+Imports DigitalData.Modules.Logging
+Imports Newtonsoft.Json
+
+Public Class GraphQLInterface
+    Private _logConfig As LogConfig
+    Private _logger As Logger
+    Private _baseUrl As String
+    Private _userEmail As String
+    Private _userPassword As String
+    Private _certificate As X509Certificate2
+    Private _cookieJar As CookieContainer
+    Private _Encoding As New UTF8Encoding
+
+    Private Const MAX_COOKIE_SIZE As Integer = 32768
+    Private Const MAX_COOKIE_COUNT As Integer = 300
+    Private Const MAX_COOKIE_COUNT_PER_DOMAIN As Integer = 20
+
+    Public Property Proxy As WebProxy
+    Public Property Credentials As NetworkCredential
+
+    Public Sub New(LogConfig As LogConfig, BaseUrl As String, Email As String, Password As String, CertificateFingerprint As String)
+        Try
+            _logConfig = LogConfig
+            _logger = LogConfig.GetLogger()
+            _baseUrl = BaseUrl
+            _userEmail = Email
+            _userPassword = Password
+
+            Dim oStore As New X509Store(StoreName.Root, StoreLocation.CurrentUser)
+            oStore.Open(OpenFlags.ReadOnly)
+
+
+            _logger.Debug("Available Certificates ({0}):", oStore.Certificates.Count)
+
+            For Each oCert In oStore.Certificates
+                _logger.Debug("FriendlyName: {0}", oCert.FriendlyName)
+                _logger.Debug("IssuerName: {0}", oCert.IssuerName.Name)
+                _logger.Debug("SubjectName: {0}", oCert.SubjectName.Name)
+                _logger.Debug("Fingerprint: {0}", oCert.Thumbprint)
+            Next
+
+            _logger.Debug("Looking for Certificate with Fingerprint [{0}]", CertificateFingerprint)
+
+            Dim oFoundCerts = oStore.Certificates.Find(X509FindType.FindByThumbprint, CertificateFingerprint, False)
+
+            If oFoundCerts.Count = 0 Then
+                _logger.Warn("Certificate could not be found! Exiting.")
+                Exit Sub
+            End If
+
+            _certificate = oFoundCerts.Item(0)
+        Catch ex As Exception
+            _logger.Error(ex)
+        End Try
+    End Sub
+
+    Public Sub SaveCookies(Cookie As Cookie)
+        GetCookies().Add(Cookie)
+    End Sub
+
+    Public Function Login() As HttpWebResponse
+        Try
+            Dim oLoginData As New LoginData() With {.email = _userEmail, .token = _userPassword}
+            Dim oBytes As Byte() = ToBytes(JsonConvert.SerializeObject(oLoginData))
+            Dim oRequest As HttpWebRequest = GetRequest("/login", oBytes)
+
+            Using oStream = oRequest.GetRequestStream()
+                oStream.Write(oBytes, 0, oBytes.Length)
+            End Using
+
+            Return oRequest.GetResponse()
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw ex
+        End Try
+    End Function
+
+    Public Function Logout() As HttpWebResponse
+        Try
+            Dim oLogoutData As New LogoutData() With {.email = _userEmail}
+            Dim oBytes As Byte() = ToBytes(JsonConvert.SerializeObject(oLogoutData))
+            Dim oRequest As HttpWebRequest = GetRequest("/logout", oBytes)
+
+            Using stream = oRequest.GetRequestStream()
+                stream.Write(oBytes, 0, oBytes.Length)
+            End Using
+
+            Return oRequest.GetResponse()
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw ex
+        End Try
+    End Function
+
+    Public Function GetData(Query As String, OperationName As String) As HttpWebResponse
+        Try
+            Dim oQueryData As New QueryData() With {
+                .operationName = OperationName,
+                .query = Query,
+                .variables = New Object
+            }
+            Dim oJson = JsonConvert.SerializeObject(oQueryData)
+            Dim oBytes = ToBytes(oJson)
+            Dim oRequest = GetRequest("/graphql", oBytes)
+
+            Using stream = oRequest.GetRequestStream()
+                stream.Write(oBytes, 0, oBytes.Length)
+            End Using
+
+            Return oRequest.GetResponse()
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw ex
+        End Try
+    End Function
+
+    Public Function ReadJSONPathFragmented(pObject As Linq.JObject, pJsonPath As String)
+        Dim oSplitPath As List(Of String) = pJsonPath.Split(".").ToList()
+        Dim oCurrentPath As String = String.Empty
+
+        For Each oPart In oSplitPath
+            If oCurrentPath = String.Empty Then
+                oCurrentPath = oPart
+            Else
+                oCurrentPath &= "." & oPart
+            End If
+
+            _logger.Debug("Selecting Path Fragment [{0}]", oCurrentPath)
+
+            Try
+                pObject.SelectToken(oCurrentPath, errorWhenNoMatch:=True)
+            Catch ex As Exception
+                _logger.Warn("Path Fragment [{0}] did not return a valid token", oCurrentPath)
+                Return False
+            End Try
+        Next
+
+        Return True
+    End Function
+
+    Private Function GetRequest(Url As String, PostData As Byte()) As HttpWebRequest
+        Try
+            Dim oRequest As HttpWebRequest = WebRequest.Create($"{_baseUrl}{Url}")
+            oRequest.Method = "POST"
+            oRequest.ContentType = "application/json"
+            oRequest.ContentLength = PostData.Length
+            oRequest.ClientCertificates.Add(_certificate)
+            oRequest.CookieContainer = GetCookies()
+
+            oRequest.Proxy = Nothing
+
+            If Proxy Is Nothing Then
+                oRequest.Proxy = Nothing
+            Else
+                oRequest.Proxy = Proxy
+                oRequest.Credentials = Credentials
+            End If
+
+            Return oRequest
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw ex
+        End Try
+    End Function
+
+    Private Function GetCookies() As CookieContainer
+        If _cookieJar Is Nothing Then
+            _cookieJar = New CookieContainer(MAX_COOKIE_COUNT, MAX_COOKIE_COUNT_PER_DOMAIN, MAX_COOKIE_SIZE)
+        End If
+
+        Return _cookieJar
+    End Function
+
+    Private Function ToBytes(Str As String) As Byte()
+        Return _Encoding.GetBytes(Str)
+    End Function
+End Class

Interfaces/Interfaces.vbproj

@@ -0,0 +1,169 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{AB6F09BF-E794-4F6A-94BB-C97C0BA84D64}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <RootNamespace>DigitalData.Modules.Interfaces</RootNamespace>
+    <AssemblyName>DigitalData.Modules.Interfaces</AssemblyName>
+    <FileAlignment>512</FileAlignment>
+    <MyType>Windows</MyType>
+    <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <DefineDebug>true</DefineDebug>
+    <DefineTrace>true</DefineTrace>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DocumentationFile>DigitalData.Modules.Interfaces.xml</DocumentationFile>
+    <NoWarn>42016,41999,42017,42018,42019,42032,42036,42020,42021,42022</NoWarn>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <DefineDebug>false</DefineDebug>
+    <DefineTrace>true</DefineTrace>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DocumentationFile>DigitalData.Modules.Interfaces.xml</DocumentationFile>
+    <NoWarn>42016,41999,42017,42018,42019,42032,42036,42020,42021,42022</NoWarn>
+  </PropertyGroup>
+  <PropertyGroup>
+    <OptionExplicit>On</OptionExplicit>
+  </PropertyGroup>
+  <PropertyGroup>
+    <OptionCompare>Binary</OptionCompare>
+  </PropertyGroup>
+  <PropertyGroup>
+    <OptionStrict>Off</OptionStrict>
+  </PropertyGroup>
+  <PropertyGroup>
+    <OptionInfer>On</OptionInfer>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="GdPicture.NET.14">
+      <HintPath>D:\ProgramFiles\GdPicture.NET 14\Redist\GdPicture.NET (.NET Framework 4.5)\GdPicture.NET.14.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="Newtonsoft.Json, Version=12.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
+      <HintPath>..\packages\Newtonsoft.Json.12.0.3\lib\net45\Newtonsoft.Json.dll</HintPath>
+    </Reference>
+    <Reference Include="NLog, Version=4.0.0.0, Culture=neutral, PublicKeyToken=5120e14c03d0593c, processorArchitecture=MSIL">
+      <HintPath>..\packages\NLog.4.7.15\lib\net45\NLog.dll</HintPath>
+    </Reference>
+    <Reference Include="System" />
+    <Reference Include="System.Configuration" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.DirectoryServices" />
+    <Reference Include="System.DirectoryServices.AccountManagement" />
+    <Reference Include="System.IO.Compression" />
+    <Reference Include="System.Runtime.Serialization" />
+    <Reference Include="System.ServiceModel" />
+    <Reference Include="System.Transactions" />
+    <Reference Include="System.Xml" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="System.Net.Http" />
+  </ItemGroup>
+  <ItemGroup>
+    <Import Include="Microsoft.VisualBasic" />
+    <Import Include="System" />
+    <Import Include="System.Collections" />
+    <Import Include="System.Collections.Generic" />
+    <Import Include="System.Data" />
+    <Import Include="System.Diagnostics" />
+    <Import Include="System.Linq" />
+    <Import Include="System.Xml.Linq" />
+    <Import Include="System.Threading.Tasks" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="ActiveDirectoryInterface.vb" />
+    <Compile Include="ActiveDirectoryInterface\ActiveDirectoryGroup.vb" />
+    <Compile Include="ActiveDirectoryInterface\ActiveDirectoryUser.vb" />
+    <Compile Include="ActiveDirectoryInterface\AttributeMap.vb" />
+    <Compile Include="ActiveDirectoryInterface\ISyncUsers.vb" />
+    <Compile Include="ActiveDirectoryInterface\SyncUsers.Firebird.vb" />
+    <Compile Include="ActiveDirectoryInterface\SyncUsers.MSSQL.vb" />
+    <Compile Include="ActiveDirectoryInterface\UserEqualityComparer.vb" />
+    <Compile Include="ActiveDirectoryInterface\UserPrincipalEx.vb" />
+    <Compile Include="GraphQLInterface.vb" />
+    <Compile Include="GrapQLInterface\LoginData.vb" />
+    <Compile Include="GrapQLInterface\LogoutData.vb" />
+    <Compile Include="GrapQLInterface\QueryData.vb" />
+    <Compile Include="ZUGFeRDInterface\Exceptions.vb" />
+    <Compile Include="My Project\AssemblyInfo.vb" />
+    <Compile Include="My Project\Application.Designer.vb">
+      <AutoGen>True</AutoGen>
+      <DependentUpon>Application.myapp</DependentUpon>
+    </Compile>
+    <Compile Include="My Project\Resources.Designer.vb">
+      <AutoGen>True</AutoGen>
+      <DesignTime>True</DesignTime>
+      <DependentUpon>Resources.resx</DependentUpon>
+    </Compile>
+    <Compile Include="My Project\Settings.Designer.vb">
+      <AutoGen>True</AutoGen>
+      <DependentUpon>Settings.settings</DependentUpon>
+      <DesignTimeSharedInput>True</DesignTimeSharedInput>
+    </Compile>
+    <Compile Include="ZUGFeRDInterface\Version1.0\CrossIndustryDocumentType.vb" />
+    <Compile Include="ZUGFeRDInterface.vb" />
+    <Compile Include="ZUGFeRDInterface\FileGroups.vb" />
+    <Compile Include="ZUGFeRDInterface\PDFEmbeds.vb" />
+    <Compile Include="ZUGFeRDInterface\PropertyValues.vb" />
+    <Compile Include="ZUGFeRDInterface\Version2.0\CrossIndustryInvoiceType.vb" />
+    <Compile Include="ZUGFeRDInterface\Version2.1.1\CrossIndustryInvoiceType.vb" />
+    <Compile Include="ZUGFeRDInterface\Version2.2_FacturX\CrossIndustryInvoiceType.vb" />
+    <Compile Include="ZUGFeRDInterface\XmlItemProperty.vb" />
+  </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="My Project\Resources.resx">
+      <Generator>VbMyResourcesResXFileCodeGenerator</Generator>
+      <LastGenOutput>Resources.Designer.vb</LastGenOutput>
+      <CustomToolNamespace>My.Resources</CustomToolNamespace>
+      <SubType>Designer</SubType>
+    </EmbeddedResource>
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="app.config" />
+    <None Include="My Project\Application.myapp">
+      <Generator>MyApplicationCodeGenerator</Generator>
+      <LastGenOutput>Application.Designer.vb</LastGenOutput>
+    </None>
+    <None Include="My Project\Settings.settings">
+      <Generator>SettingsSingleFileGenerator</Generator>
+      <CustomToolNamespace>My</CustomToolNamespace>
+      <LastGenOutput>Settings.Designer.vb</LastGenOutput>
+    </None>
+    <None Include="packages.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <AdditionalFiles Include="GdPicture.NET.14.filters.dll">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </AdditionalFiles>
+    <AdditionalFiles Include="GdPicture.NET.14.image.gdimgplug.dll">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </AdditionalFiles>
+    <AdditionalFiles Include="GdPicture.NET.14.Imaging.Rendering.Skia.dll">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </AdditionalFiles>
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\Database\Database.vbproj">
+      <Project>{eaf0ea75-5fa7-485d-89c7-b2d843b03a96}</Project>
+      <Name>Database</Name>
+    </ProjectReference>
+    <ProjectReference Include="..\Language\Language.vbproj">
+      <Project>{d3c8cfed-d6f6-43a8-9bdf-454145d0352f}</Project>
+      <Name>Language</Name>
+    </ProjectReference>
+    <ProjectReference Include="..\Logging\Logging.vbproj">
+      <Project>{903b2d7d-3b80-4be9-8713-7447b704e1b0}</Project>
+      <Name>Logging</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.VisualBasic.targets" />
+</Project>

Interfaces/My Project/Application.Designer.vb

@@ -0,0 +1,13 @@
+'------------------------------------------------------------------------------
+' <auto-generated>
+'     Dieser Code wurde von einem Tool generiert.
+'     Laufzeitversion:4.0.30319.42000
+'
+'     Änderungen an dieser Datei können falsches Verhalten verursachen und gehen verloren, wenn
+'     der Code erneut generiert wird.
+' </auto-generated>
+'------------------------------------------------------------------------------
+
+Option Strict On
+Option Explicit On
+

Interfaces/My Project/Application.myapp

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<MyApplicationData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
+  <MySubMain>false</MySubMain>
+  <SingleInstance>false</SingleInstance>
+  <ShutdownMode>0</ShutdownMode>
+  <EnableVisualStyles>true</EnableVisualStyles>
+  <AuthenticationMode>0</AuthenticationMode>
+  <ApplicationType>1</ApplicationType>
+  <SaveMySettingsOnExit>true</SaveMySettingsOnExit>
+</MyApplicationData>

Interfaces/My Project/AssemblyInfo.vb

@@ -0,0 +1,35 @@
+Imports System
+Imports System.Reflection
+Imports System.Runtime.InteropServices
+
+' Allgemeine Informationen über eine Assembly werden über die folgenden
+' Attribute gesteuert. Ändern Sie diese Attributwerte, um die Informationen zu ändern,
+' die einer Assembly zugeordnet sind.
+
+' Werte der Assemblyattribute überprüfen
+
+<Assembly: AssemblyTitle("Modules.Interfaces")>
+<Assembly: AssemblyDescription("")>
+<Assembly: AssemblyCompany("Digital Data")>
+<Assembly: AssemblyProduct("Modules.Interfaces")>
+<Assembly: AssemblyCopyright("Copyright © 2021")>
+<Assembly: AssemblyTrademark("1.7.0.0")>
+
+<Assembly: ComVisible(False)>
+
+'Die folgende GUID bestimmt die ID der Typbibliothek, wenn dieses Projekt für COM verfügbar gemacht wird.
+<Assembly: Guid("f0de0536-a336-40cb-bb8b-957942174eed")>
+
+' Versionsinformationen für eine Assembly bestehen aus den folgenden vier Werten:
+'
+'      Hauptversion
+'      Nebenversion
+'      Buildnummer
+'      Revision
+'
+' Sie können alle Werte angeben oder Standardwerte für die Build- und Revisionsnummern verwenden,
+' übernehmen, indem Sie "*" eingeben:
+' <Assembly: AssemblyVersion("1.0.*")>
+
+<Assembly: AssemblyVersion("1.7.1.0")>
+<Assembly: AssemblyFileVersion("1.7.1.0")>

Interfaces/My Project/Resources.Designer.vb

@@ -0,0 +1,63 @@
+'------------------------------------------------------------------------------
+' <auto-generated>
+'     Dieser Code wurde von einem Tool generiert.
+'     Laufzeitversion:4.0.30319.42000
+'
+'     Änderungen an dieser Datei können falsches Verhalten verursachen und gehen verloren, wenn
+'     der Code erneut generiert wird.
+' </auto-generated>
+'------------------------------------------------------------------------------
+
+Option Strict On
+Option Explicit On
+
+Imports System
+
+Namespace My.Resources
+    
+    'Diese Klasse wurde von der StronglyTypedResourceBuilder automatisch generiert
+    '-Klasse über ein Tool wie ResGen oder Visual Studio automatisch generiert.
+    'Um einen Member hinzuzufügen oder zu entfernen, bearbeiten Sie die .ResX-Datei und führen dann ResGen
+    'mit der /str-Option erneut aus, oder Sie erstellen Ihr VS-Projekt neu.
+    '''<summary>
+    '''  Eine stark typisierte Ressourcenklasse zum Suchen von lokalisierten Zeichenfolgen usw.
+    '''</summary>
+    <Global.System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "15.0.0.0"),  _
+     Global.System.Diagnostics.DebuggerNonUserCodeAttribute(),  _
+     Global.System.Runtime.CompilerServices.CompilerGeneratedAttribute(),  _
+     Global.Microsoft.VisualBasic.HideModuleNameAttribute()>  _
+    Friend Module Resources
+        
+        Private resourceMan As Global.System.Resources.ResourceManager
+        
+        Private resourceCulture As Global.System.Globalization.CultureInfo
+        
+        '''<summary>
+        '''  Gibt die zwischengespeicherte ResourceManager-Instanz zurück, die von dieser Klasse verwendet wird.
+        '''</summary>
+        <Global.System.ComponentModel.EditorBrowsableAttribute(Global.System.ComponentModel.EditorBrowsableState.Advanced)>  _
+        Friend ReadOnly Property ResourceManager() As Global.System.Resources.ResourceManager
+            Get
+                If Object.ReferenceEquals(resourceMan, Nothing) Then
+                    Dim temp As Global.System.Resources.ResourceManager = New Global.System.Resources.ResourceManager("DigitalData.Modules.Interfaces.Resources", GetType(Resources).Assembly)
+                    resourceMan = temp
+                End If
+                Return resourceMan
+            End Get
+        End Property
+        
+        '''<summary>
+        '''  Überschreibt die CurrentUICulture-Eigenschaft des aktuellen Threads für alle
+        '''  Ressourcenzuordnungen, die diese stark typisierte Ressourcenklasse verwenden.
+        '''</summary>
+        <Global.System.ComponentModel.EditorBrowsableAttribute(Global.System.ComponentModel.EditorBrowsableState.Advanced)>  _
+        Friend Property Culture() As Global.System.Globalization.CultureInfo
+            Get
+                Return resourceCulture
+            End Get
+            Set
+                resourceCulture = value
+            End Set
+        End Property
+    End Module
+End Namespace

Interfaces/My Project/Resources.resx

@@ -0,0 +1,117 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>

Interfaces/My Project/Settings.Designer.vb

@@ -0,0 +1,73 @@
+'------------------------------------------------------------------------------
+' <auto-generated>
+'     Dieser Code wurde von einem Tool generiert.
+'     Laufzeitversion:4.0.30319.42000
+'
+'     Änderungen an dieser Datei können falsches Verhalten verursachen und gehen verloren, wenn
+'     der Code erneut generiert wird.
+' </auto-generated>
+'------------------------------------------------------------------------------
+
+Option Strict On
+Option Explicit On
+
+
+Namespace My
+    
+    <Global.System.Runtime.CompilerServices.CompilerGeneratedAttribute(),  _
+     Global.System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.VisualStudio.Editors.SettingsDesigner.SettingsSingleFileGenerator", "15.7.0.0"),  _
+     Global.System.ComponentModel.EditorBrowsableAttribute(Global.System.ComponentModel.EditorBrowsableState.Advanced)>  _
+    Partial Friend NotInheritable Class MySettings
+        Inherits Global.System.Configuration.ApplicationSettingsBase
+        
+        Private Shared defaultInstance As MySettings = CType(Global.System.Configuration.ApplicationSettingsBase.Synchronized(New MySettings()),MySettings)
+        
+#Region "Automatische My.Settings-Speicherfunktion"
+#If _MyType = "WindowsForms" Then
+    Private Shared addedHandler As Boolean
+
+    Private Shared addedHandlerLockObject As New Object
+
+    <Global.System.Diagnostics.DebuggerNonUserCodeAttribute(), Global.System.ComponentModel.EditorBrowsableAttribute(Global.System.ComponentModel.EditorBrowsableState.Advanced)> _
+    Private Shared Sub AutoSaveSettings(sender As Global.System.Object, e As Global.System.EventArgs)
+        If My.Application.SaveMySettingsOnExit Then
+            My.Settings.Save()
+        End If
+    End Sub
+#End If
+#End Region
+        
+        Public Shared ReadOnly Property [Default]() As MySettings
+            Get
+                
+#If _MyType = "WindowsForms" Then
+               If Not addedHandler Then
+                    SyncLock addedHandlerLockObject
+                        If Not addedHandler Then
+                            AddHandler My.Application.Shutdown, AddressOf AutoSaveSettings
+                            addedHandler = True
+                        End If
+                    End SyncLock
+                End If
+#End If
+                Return defaultInstance
+            End Get
+        End Property
+    End Class
+End Namespace
+
+Namespace My
+    
+    <Global.Microsoft.VisualBasic.HideModuleNameAttribute(),  _
+     Global.System.Diagnostics.DebuggerNonUserCodeAttribute(),  _
+     Global.System.Runtime.CompilerServices.CompilerGeneratedAttribute()>  _
+    Friend Module MySettingsProperty
+        
+        <Global.System.ComponentModel.Design.HelpKeywordAttribute("My.Settings")>  _
+        Friend ReadOnly Property Settings() As Global.DigitalData.Modules.Interfaces.My.MySettings
+            Get
+                Return Global.DigitalData.Modules.Interfaces.My.MySettings.Default
+            End Get
+        End Property
+    End Module
+End Namespace

Interfaces/My Project/Settings.settings

@@ -0,0 +1,7 @@
+<?xml version='1.0' encoding='utf-8'?>
+<SettingsFile xmlns="http://schemas.microsoft.com/VisualStudio/2004/01/settings" CurrentProfile="(Default)" UseMySettingsClassName="true">
+  <Profiles>
+    <Profile Name="(Default)" />
+  </Profiles>
+  <Settings />
+</SettingsFile>

Interfaces/ZUGFeRDInterface.vb

@@ -0,0 +1,207 @@
+Imports System.IO
+Imports System.Xml
+Imports System.Xml.Serialization
+Imports System.Xml.XPath
+Imports System.Xml.Xsl
+Imports DigitalData.Modules.Interfaces.Exceptions
+Imports DigitalData.Modules.Logging
+Imports GdPicture14
+
+Public Class ZUGFeRDInterface
+    Private _logConfig As LogConfig
+    Private _logger As Logger
+
+    Public Enum ErrorType
+        NoValidFile
+        NoZugferd
+        NoValidZugferd
+        MissingProperties
+    End Enum
+
+    Public ReadOnly Property FileGroup As FileGroups
+    Public ReadOnly Property PropertyValues As PropertyValues
+
+    Public Sub New(LogConfig As LogConfig, GDPictureKey As String)
+        _logConfig = LogConfig
+        _logger = _logConfig.GetLogger()
+
+        FileGroup = New FileGroups(_logConfig)
+        PropertyValues = New PropertyValues(_logConfig)
+
+        Try
+            Dim oLicenseManager As New LicenseManager
+            oLicenseManager.RegisterKEY(GDPictureKey)
+        Catch ex As Exception
+            _logger.Warn("GDPicture License could not be registered!")
+            _logger.Error(ex)
+        End Try
+    End Sub
+
+    ''' <summary>
+    ''' Validates a ZUGFeRD File and extracts the XML Document from it
+    ''' </summary>
+    ''' <param name="Path"></param>
+    ''' <exception cref="ZUGFeRDExecption"></exception>
+    ''' <returns></returns>
+    Public Function ExtractZUGFeRDFileWithGDPicture(Path As String) As Object
+        Dim oXmlDocument = ValidateZUGFeRDFileWithGDPicture(Path)
+
+        If IsNothing(oXmlDocument) Then
+            Throw New ZUGFeRDExecption(ErrorType.NoZugferd, "Datei ist keine ZUGFeRD Datei.")
+        End If
+
+        Return SerializeZUGFeRDDocument(oXmlDocument)
+    End Function
+
+    ''' <summary>
+    ''' Validates a ZUGFeRD File and extracts the XML Document from it
+    ''' </summary>
+    ''' <param name="Stream"></param>
+    ''' <exception cref="ZUGFeRDExecption"></exception>
+    ''' <returns></returns>
+    Public Function ExtractZUGFeRDFileWithGDPicture(Stream As Stream) As Object
+        Dim oXmlDocument = ValidateZUGFeRDFileWithGDPicture(Stream)
+
+        If IsNothing(oXmlDocument) Then
+            Throw New ZUGFeRDExecption(ErrorType.NoZugferd, "Datei ist keine ZUGFeRD Datei.")
+        End If
+
+        Return SerializeZUGFeRDDocument(oXmlDocument)
+    End Function
+
+    ''' <summary>
+    ''' Validates a ZUGFeRD File and extracts the XML Document from it
+    ''' </summary>
+    ''' <param name="Stream"></param>
+    ''' <exception cref="ZUGFeRDExecption"></exception>
+    ''' <returns></returns>
+    Public Function ValidateZUGFeRDFileWithGDPicture(Stream As Stream) As XPathDocument
+        Dim oEmbedExtractor = New PDFEmbeds(_logConfig)
+        Dim oAllowedExtensions = New List(Of String) From {"xml"}
+
+        Try
+            Dim oFiles = oEmbedExtractor.Extract(Stream, oAllowedExtensions)
+
+            ' Attachments are in this case the files that are embedded into a pdf file,
+            ' like for example the zugferd-invoice.xml file
+            Return HandleEmbeddedFiles(oFiles)
+
+        Catch ex As ZUGFeRDExecption
+            ' Don't log ZUGFeRD Exceptions here, they should be handled by the calling code.
+            ' It also produces misleading error messages when checking if an attachment is a zugferd file.
+            Throw ex
+
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw ex
+        End Try
+    End Function
+
+    Public Function ValidateZUGFeRDFileWithGDPicture(Path As String) As XPathDocument
+        Dim oEmbedExtractor = New PDFEmbeds(_logConfig)
+        Dim oAllowedExtensions = New List(Of String) From {"xml"}
+
+        Try
+            Dim oFiles = oEmbedExtractor.Extract(Path, oAllowedExtensions)
+
+            ' Attachments are in this case the files that are embedded into a pdf file,
+            ' like for example the zugferd-invoice.xml file
+            Return HandleEmbeddedFiles(oFiles)
+
+        Catch ex As ZUGFeRDExecption
+            ' Don't log ZUGFeRD Exceptions here, they should be handled by the calling code.
+            ' It also produces misleading error messages when checking if an attachment is a zugferd file.
+            Throw ex
+
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw ex
+        End Try
+    End Function
+
+    Private Function HandleEmbeddedFiles(Results As List(Of PDFEmbeds.EmbeddedFile)) As XPathDocument
+        Dim oXmlDocument As XPathDocument
+
+        If Results Is Nothing Then
+            Throw New ZUGFeRDExecption(ErrorType.NoZugferd, "Datei ist keine ZUGFeRD Datei, weil die Attachments nicht gelesen werden konnten.")
+        End If
+
+        If Results.Count = 0 Then
+            Throw New ZUGFeRDExecption(ErrorType.NoZugferd, "Datei ist keine ZUGFeRD Datei, weil sie keine Attachments enthält.")
+        End If
+
+        Dim oValidFilenames As New List(Of String) From {
+            PDFEmbeds.ZUGFERD_XML_FILENAME.ToUpper,
+            PDFEmbeds.FACTUR_X_XML_FILENAME_DE.ToUpper,
+            PDFEmbeds.FACTUR_X_XML_FILENAME_FR.ToUpper
+        }
+
+        ' Find the first file which filename matches the valid filenames for embedded invoice files
+        Dim oFoundResult As PDFEmbeds.EmbeddedFile = Results.
+            Where(Function(result) oValidFilenames.Contains(result.FileName.ToUpper)).
+            FirstOrDefault()
+
+        If oFoundResult Is Nothing Then
+            Throw New ZUGFeRDExecption(ErrorType.NoZugferd, "Datei ist keine ZUGFeRD Datei, weil die zugferd-invoice.xml nicht gefunden wurde.")
+        End If
+
+        Try
+            Using oStream As New MemoryStream(oFoundResult.FileContents)
+                oXmlDocument = New XPathDocument(oStream)
+            End Using
+
+            Return oXmlDocument
+        Catch ex As ZUGFeRDExecption
+            ' Don't log ZUGFeRD Exceptions here, they should be handled by the calling code.
+            ' It also produces misleading error messages when checking if an attachment is a zugferd file.
+            Throw ex
+
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw New ZUGFeRDExecption(ErrorType.NoValidZugferd, "Datei ist eine ungültige ZUGFeRD Datei.")
+        End Try
+    End Function
+
+    Public Function SerializeZUGFeRDDocument(Document As XPathDocument) As Object
+        Try
+            Dim oNavigator As XPathNavigator = Document.CreateNavigator()
+            Dim oReader As XmlReader
+            Dim oResult = Nothing
+
+            Dim oTypes As New List(Of Type) From {
+                GetType(ZUGFeRD.Version1_0.CrossIndustryDocumentType),
+                GetType(ZUGFeRD.Version2_0.CrossIndustryInvoiceType),
+                GetType(ZUGFeRD.Version2_1_1.CrossIndustryInvoiceType),
+                GetType(ZUGFeRD.Version2_2_FacturX.CrossIndustryInvoiceType)
+            }
+
+            For Each oType In oTypes
+                _logger.Debug("Trying Type [{0}]", oType.FullName)
+                Dim oSerializer As New XmlSerializer(oType)
+
+                Try
+                    oReader = oNavigator.ReadSubtree()
+                    oResult = oSerializer.Deserialize(oReader)
+                    _logger.Debug("Serializing with type [{0}] succeeded", oType.FullName)
+                    Exit For
+                Catch ex As Exception
+                    _logger.Debug("Serializing with type [{0}] failed", oType.FullName)
+                    _logger.Debug(ex.Message)
+                    _logger.Error(ex.InnerException?.Message)
+                End Try
+            Next
+
+            If oResult Is Nothing Then
+                Throw New ApplicationException("No Types matched the given document. Document could not be serialized.")
+            End If
+
+            Return oResult
+
+        Catch ex As Exception
+            _logger.Error(ex)
+            Throw New ZUGFeRDExecption(ErrorType.NoValidZugferd, "Datei ist eine ungültige ZUGFeRD Datei.")
+        End Try
+    End Function
+
+
+End Class

Interfaces/ZUGFeRDInterface/Exceptions.vb

@@ -0,0 +1,13 @@
+Public Class Exceptions
+    Public Class ZUGFeRDExecption
+        Inherits ApplicationException
+
+        Public ReadOnly Property ErrorType() As ZUGFeRDInterface.ErrorType
+
+        Public Sub New(ErrorType As ZUGFeRDInterface.ErrorType, Message As String)
+            MyBase.New(Message)
+
+            _ErrorType = ErrorType
+        End Sub
+    End Class
+End Class

Interfaces/ZUGFeRDInterface/FileGroups.vb

@@ -0,0 +1,82 @@
+Imports System.IO
+Imports System.Text.RegularExpressions
+Imports DigitalData.Modules.Logging
+
+Public Class FileGroups
+    Private _logger As Logger
+
+    Public Sub New(LogConfig As LogConfig)
+        _logger = LogConfig.GetLogger()
+    End Sub
+
+    ''' <summary>
+    ''' Group files by message id. Message id is extracted from filename.
+    ''' Filename is expected to be in the form: 1234@subdomain.company.com
+    ''' <param name="Files">The list of files to process</param>
+    ''' </summary>
+    Public Function GroupFiles(Files As List(Of FileInfo)) As Dictionary(Of String, List(Of FileInfo))
+        Dim oGrouped As New Dictionary(Of String, List(Of FileInfo))
+
+        If Files.Count = 0 Then
+            Return oGrouped
+        End If
+
+        For Each oFile In Files
+            Dim oMessageId = GetMessageIdFromFileName(oFile.Name)
+
+            If oMessageId Is Nothing Then
+                _logger.Warn("File {0} did not have the required filename-format!", oMessageId)
+                Continue For
+            End If
+
+            If oGrouped.ContainsKey(oMessageId) Then
+                oGrouped.Item(oMessageId).Add(oFile)
+            Else
+                oGrouped.Add(oMessageId, New List(Of FileInfo) From {oFile})
+            End If
+        Next
+
+        Return oGrouped
+    End Function
+
+    ''' <summary>
+    ''' Group files by message id. Message id is created from `FakeMessageIdDomain` and a random string 
+    ''' </summary>
+    ''' <param name="Files">The list of files to process</param>
+    ''' <param name="FakeMessageIdDomain">Arbitrary domain for message id generation. Example: sub.company.com</param>
+    ''' <returns></returns>
+    Public Function GroupFiles(Files As List(Of FileInfo), FakeMessageIdDomain As String) As Dictionary(Of String, List(Of FileInfo))
+        Dim oGrouped As New Dictionary(Of String, List(Of FileInfo))
+
+        If Files.Count = 0 Then
+            Return oGrouped
+        End If
+
+        For Each oFile In Files
+            Dim oIdentifier = Guid.NewGuid().ToString()
+            Dim oMessageId = $"{oIdentifier}@{FakeMessageIdDomain}"
+
+            If oGrouped.ContainsKey(oMessageId) Then
+                oGrouped.Item(oMessageId).Add(oFile)
+            Else
+                oGrouped.Add(oMessageId, New List(Of FileInfo) From {oFile})
+            End If
+        Next
+
+        Return oGrouped
+    End Function
+
+    Private Function GetMessageIdFromFileName(Filename As String) As String
+        ' Regex to find MessageId
+        ' See also: https://stackoverflow.com/questions/3968500/regex-to-validate-a-message-id-as-per-rfc2822
+        Dim oRegex = "(((([a-zA-Z0-9!#$%&'*+/=?^_`{|}~-]+(\.[a-zA-Z0-9!#$%&'*+/=?^_`{|}~-]+)*)|(""(([\x01-\x08\x0B\x0C\x0E-\x1F\x7F]|[\x21\x23-\x5B\x5D-\x7E])|(\\[\x01-\x09\x0B\x0C\x0E-\x7F]))*""))@(([a-zA-Z0-9!#$%&'*+/=?^_`{|}~-]+(\.[a-zA-Z0-9!#$%&'*+/=?^_`{|}~-]+)*)|(\[(([\x01-\x08\x0B\x0C\x0E-\x1F\x7F]|[\x21-\x5A\x5E-\x7E])|(\\[\x01-\x09\x0B\x0C\x0E-\x7F]))*\]))))~.+"
+        Dim oMatch = Regex.Match(Filename, oRegex, RegexOptions.IgnoreCase)
+
+        If oMatch.Success Then
+            Dim oMessageId = oMatch.Groups(1).Value
+            Return oMessageId
+        Else
+            Return Nothing
+        End If
+    End Function
+End Class

Interfaces/ZUGFeRDInterface/PDFEmbeds.vb

@@ -0,0 +1,150 @@
+Imports System.Collections.Generic
+Imports System.IO
+Imports DigitalData.Modules.Logging
+Imports GdPicture14
+
+Public Class PDFEmbeds
+    Private ReadOnly Logger As Logger
+
+    Public Const ZUGFERD_XML_FILENAME = "ZUGFeRD-invoice.xml"
+    Public Const FACTUR_X_XML_FILENAME_FR = "factur-x.xml"
+    Public Const FACTUR_X_XML_FILENAME_DE = "xrechnung.xml"
+
+    Public Class EmbeddedFile
+        Public FileName As String
+        Public FileContents As Byte()
+    End Class
+
+    Public Sub New(LogConfig As LogConfig)
+        Logger = LogConfig.GetLogger
+    End Sub
+
+    ''' <summary>
+    ''' Extracts all embedded files from a PDF file.
+    ''' Note: This does NOT filter out `ZUGFeRD-invoice.xml` anymore to allow for a more generic use.
+    ''' </summary>
+    ''' <param name="FilePath">Filepath of the pdf</param>
+    ''' <param name="AllowedExtensions">List of allowed extensions to be extracted</param>
+    Public Function Extract(FilePath As String, AllowedExtensions As List(Of String)) As List(Of EmbeddedFile)
+        Dim oFile As New List(Of EmbeddedFile)
+        Dim oFileInfo As FileInfo
+        Dim oExtensions = AllowedExtensions.ConvertAll(New Converter(Of String, String)(Function(ext) ext.ToUpper))
+
+        Logger.Debug("Extracting embedded files from [{0}]", FilePath)
+
+        Try
+            oFileInfo = New FileInfo(FilePath)
+
+            Logger.Debug("Filename: {0}", oFileInfo.Name)
+            Logger.Debug("Filesize: {0} bytes", oFileInfo.Length)
+            Logger.Debug("Exists: {0}", oFileInfo.Exists)
+        Catch ex As Exception
+            Logger.Warn("File information for [{0}] could not be read!", FilePath)
+            Logger.Error(ex)
+        End Try
+
+        Try
+            Using oGDPicturePDF As New GdPicturePDF()
+                If oGDPicturePDF.LoadFromFile(FilePath, False) = GdPictureStatus.OK Then
+                    oFile = DoExtract(oGDPicturePDF, oExtensions)
+                Else
+                    Dim oMessage = String.Format("The file [{0}] can't be loaded. Status: [{1}]", FilePath, oGDPicturePDF.GetStat().ToString())
+                    Throw New ApplicationException(oMessage)
+                End If
+            End Using
+
+            Return oFile
+        Catch ex As Exception
+            Logger.Warn("Unexpected Error while Extracting attachments from File [{0}]", FilePath)
+            Logger.Error(ex)
+            Return Nothing
+        End Try
+    End Function
+
+    ''' <summary>
+    ''' Extracts all embedded files from a PDF file.
+    ''' Note: This does NOT filter out `ZUGFeRD-invoice.xml` anymore to allow for a more generic use.
+    ''' </summary>
+    ''' <param name="Stream">Filestream of the pdf</param>
+    ''' <param name="AllowedExtensions">List of allowed extensions to be extracted</param>
+    Public Function Extract(Stream As Stream, AllowedExtensions As List(Of String)) As List(Of EmbeddedFile)
+        Dim oResults As New List(Of EmbeddedFile)
+        Dim oExtensions = AllowedExtensions.ConvertAll(New Converter(Of String, String)(Function(ext) ext.ToUpper))
+
+        Logger.Debug("Extracting embedded files from stream")
+
+        Try
+            Using oGDPicturePDF As New GdPicturePDF()
+                If oGDPicturePDF.LoadFromStream(Stream, False) = GdPictureStatus.OK Then
+                    oResults = DoExtract(oGDPicturePDF, oExtensions)
+                Else
+                    Dim oMessage = String.Format("The filestream can't be loaded. Status: [{0}]", oGDPicturePDF.GetStat().ToString())
+                    Throw New ApplicationException(oMessage)
+                End If
+            End Using
+
+            Return oResults
+        Catch ex As Exception
+            Logger.Warn("Unexpected Error while Extracting attachments from Filestream")
+            Logger.Error(ex)
+            Return Nothing
+        End Try
+    End Function
+
+    Private Function DoExtract(GDPicturePDF As GdPicturePDF, pExtensions As List(Of String)) As List(Of EmbeddedFile)
+        Dim oResults As New List(Of EmbeddedFile)
+        Dim oEmbeddedFileCount As Integer = GDPicturePDF.GetEmbeddedFileCount()
+
+        If GDPicturePDF.GetStat() = GdPictureStatus.OK Then
+            Logger.Debug("Embedded file count is: [{0}]", oEmbeddedFileCount)
+
+            If oEmbeddedFileCount > 0 Then
+                For oIndex = 0 To oEmbeddedFileCount - 1
+                    Dim oFileName As String = GDPicturePDF.GetEmbeddedFileName(oIndex)
+
+                    If GDPicturePDF.GetStat() = GdPictureStatus.OK Then
+                        Logger.Debug("Extracting embedded file [{0}]", oFileName)
+
+                        Dim oExtension = New FileInfo(oFileName).Extension.ToUpper.Substring(1)
+                        If pExtensions.Contains(oExtension) Then
+                            Dim oFileSize As Integer = GDPicturePDF.GetEmbeddedFileSize(oIndex)
+
+                            If GDPicturePDF.GetStat() = GdPictureStatus.OK Then
+                                Logger.Debug("Filesize of embedded file is [{0}]", oFileSize)
+
+                                Dim oFileData As Byte() = New Byte(oFileSize) {}
+                                Dim oStatus As GdPictureStatus = GDPicturePDF.ExtractEmbeddedFile(oIndex, oFileData)
+
+                                If oStatus = GdPictureStatus.OK Then
+                                    Logger.Debug("Embedded file [{0}] extracted sucessfully!", oFileName)
+
+                                    oResults.Add(New EmbeddedFile() With {
+                                        .FileContents = oFileData,
+                                        .FileName = oFileName
+                                    })
+                                Else
+                                    Logger.Error("The embedded file [{0}] has failed to extract. Status: {1}", oFileName, GDPicturePDF.GetStat().ToString())
+                                    Continue For
+                                End If
+                            Else
+                                Logger.Error("An error occurred getting the file size for [{0}]. Status: {1}", oFileName, GDPicturePDF.GetStat().ToString())
+                                Continue For
+                            End If
+                        Else
+                            Logger.Debug("File [{0}] was skipped because its extension [{1}] is not allowed.", oFileName, oExtension)
+                            Continue For
+                        End If
+                    Else
+                        Logger.Error("An error occurred getting the file name for [{0}]. Status: {1}", oFileName, GDPicturePDF.GetStat().ToString())
+                        Continue For
+                    End If
+                Next
+            End If
+
+            Return oResults
+        Else
+            Dim oMessage = String.Format("An error occurred getting the number of embedded files. Status: {0}", GDPicturePDF.GetStat().ToString())
+            Throw New ApplicationException(oMessage)
+        End If
+    End Function
+End Class

Interfaces/ZUGFeRDInterface/PropertyValues.vb

@@ -0,0 +1,325 @@
+Imports System.Reflection
+Imports System.Text.RegularExpressions
+Imports DigitalData.Modules.Logging
+
+Public Class PropertyValues
+    Private _logger As Logger
+    Private _logConfig As LogConfig
+
+    Private _indexPattern = "\((\d+)\)"
+    Private _indexRegex As New Regex(_indexPattern)
+
+    Public Sub New(LogConfig As LogConfig)
+        _logConfig = LogConfig
+        _logger = LogConfig.GetLogger()
+    End Sub
+
+    Public Class CheckPropertyValuesResult
+        Public MissingProperties As New List(Of String)
+        Public ValidProperties As New List(Of ValidProperty)
+    End Class
+
+    Public Class ValidProperty
+        Public MessageId As String
+        Public TableName As String
+        Public TableColumn As String
+
+        Public ISRequired As Boolean
+        Public GroupCounter As Integer = -1
+
+        Public Description As String
+        Public Value As String
+    End Class
+
+    Public Function CheckPropertyValues(Document As Object, PropertyMap As Dictionary(Of String, XmlItemProperty), MessageId As String) As CheckPropertyValuesResult
+        Dim oGlobalGroupCounter = 0
+        Dim oMissingProperties As New List(Of String)
+        Dim oResult As New CheckPropertyValuesResult()
+
+        ' PropertyMap items with `IsGrouped = False` are handled normally
+        Dim oDefaultProperties As Dictionary(Of String, XmlItemProperty) = PropertyMap.
+            Where(Function(Item) Item.Value.IsGrouped = False).
+            ToDictionary(Function(Item) Item.Key,
+                         Function(Item) Item.Value)
+
+        _logger.Debug("Found {0} default properties.", oDefaultProperties.Count)
+
+        ' PropertyMap items with `IsGrouped = True` are grouped by group scope
+        Dim oGroupedProperties = PropertyMap.
+            Where(Function(Item) Item.Value.IsGrouped = True).
+            ToLookup(Function(Item) Item.Value.GroupScope, ' Lookup key is group scope
+                     Function(Item) Item)
+
+        _logger.Debug($"Found [{PropertyMap.Count - oDefaultProperties.Count}] properties grouped in [{oGroupedProperties.Count}] group(s)")
+        ' Iterate through groups to get group scope and group items
+        For Each oGroup In oGroupedProperties
+            Dim oGroupScope As String = oGroup.Key
+
+            Dim oPropertyList As New Dictionary(Of XmlItemProperty, List(Of Object))
+            Dim oRowCount = 0
+
+            _logger.Debug($"Fetching Property values for group [{oGroupScope}].")
+
+            ' get properties as a nested object, see `oPropertyList`
+            For Each oProperty As KeyValuePair(Of String, XmlItemProperty) In oGroup
+                Dim oPropertyValues As List(Of Object)
+                _logger.Debug($"Fetching value for itemSpecification [{oProperty.Value.TableColumn}].")
+                Try
+                    oPropertyValues = GetPropValue(Document, oProperty.Key)
+                Catch ex As Exception
+                    _logger.Warn($"{MessageId} - Unknown error occurred while fetching property/TColumn [{0}] in group [{1}]:", oProperty.Value.TableColumn, oGroupScope)
+                    _logger.Error(ex)
+                    oPropertyValues = New List(Of Object)
+                End Try
+
+                ' Flatten result value
+                oPropertyValues = GetFinalPropValue(oPropertyValues)
+
+                ' Add to list
+                oPropertyList.Add(oProperty.Value, oPropertyValues)
+
+                ' check the first batch of values to determine the row count
+                If oRowCount = 0 Then
+                    oRowCount = oPropertyValues.Count
+                End If
+            Next
+
+            ' Structure of oPropertyList
+            ' [ # Propertyname       # Row 1              # Row 2
+            '   PositionsMenge:      [BilledQuantity1,    BilledQuantity2, ...],
+            '   PositionsSteuersatz: [ApplicablePercent1, ApplicablePercent2, ...],
+            '   ...
+            ' ]
+            For oRowIndex = 0 To oRowCount - 1
+                _logger.Debug("Processing row {0}", oRowIndex)
+
+                For Each oColumn As KeyValuePair(Of XmlItemProperty, List(Of Object)) In oPropertyList
+                    Dim oTableName As String = oColumn.Key.TableName
+                    Dim oTableColumn As String = oColumn.Key.TableColumn
+                    Dim oIsRequired As Boolean = oColumn.Key.IsRequired
+                    Dim oPropertyDescription As String = oColumn.Key.Description
+                    Dim oRowCounter = oRowIndex + oGlobalGroupCounter + 1
+                    If IsNothing(oRowCounter) Then
+
+                    End If
+                    ' Returns nothing if oColumn.Value contains an empty list
+                    Dim oPropertyValue = oColumn.Value.ElementAtOrDefault(oRowIndex)
+
+                    _logger.Debug("Processing itemSpecification *TableColumn* [{0}].", oTableColumn)
+
+                    If IsNothing(oPropertyValue) OrElse String.IsNullOrEmpty(oPropertyValue) Then
+                        If oColumn.Key.IsRequired Then
+                            _logger.Warn($"{MessageId} # oPropertyValue for specification [{oTableColumn}] is empty or not found but is required. Continuing with Empty String.")
+                            oResult.MissingProperties.Add(oPropertyDescription)
+                        Else
+                            _logger.Debug($"{MessageId} # oPropertyValue for specification [{oTableColumn}] is empty or not found. Continuing with Empty String.")
+                        End If
+
+                        oPropertyValue = String.Empty
+                    End If
+
+                    _logger.Debug("ItemSpecification [{0}] has value '{1}'", oTableColumn, oPropertyValue)
+
+                    oResult.ValidProperties.Add(New ValidProperty() With {
+                        .MessageId = MessageId,
+                        .Description = oPropertyDescription,
+                        .Value = oPropertyValue,
+                        .GroupCounter = oRowCounter,
+                        .TableName = oTableName,
+                        .TableColumn = oTableColumn,
+                        .ISRequired = oIsRequired
+                    })
+                Next
+            Next
+
+            oGlobalGroupCounter += oRowCount
+        Next
+
+        ' Iterate through default properties
+        For Each oItem As KeyValuePair(Of String, XmlItemProperty) In oDefaultProperties
+            Dim oPropertyValueList As List(Of Object)
+            Dim oTableColumn As String = oItem.Value.TableColumn
+            Dim oPropertyValue As Object = Nothing
+            Dim oTableName = oItem.Value.TableName
+            Dim oIsRequired = oItem.Value.IsRequired
+            Dim oDescription = oItem.Value.Description
+            Try
+                oPropertyValueList = GetPropValue(Document, oItem.Key)
+            Catch ex As Exception
+                _logger.Warn("{2} # Unknown error occurred while fetching specification [{0}] in group [{1}]:", oTableColumn, oItem.Value.GroupScope, MessageId)
+                _logger.Error(ex)
+                oPropertyValueList = New List(Of Object)
+            End Try
+
+            Try
+                If IsNothing(oPropertyValueList) Then
+                    oPropertyValue = Nothing
+                ElseIf TypeOf oPropertyValueList Is List(Of Object) Then
+                    Select Case oPropertyValueList.Count
+                        Case 0
+                            oPropertyValue = Nothing
+                        Case Else
+                            Dim oList As List(Of Object) = DirectCast(oPropertyValueList, List(Of Object))
+                            oPropertyValue = oList.Item(0)
+
+                            ' This should hopefully show config errors
+                            If TypeOf oPropertyValue Is List(Of Object) Then
+                                _logger.Warn("Item with TableColumn [{0}] may be configured incorrectly", oTableColumn)
+                                oPropertyValue = Nothing
+                            End If
+                    End Select
+                End If
+            Catch ex As Exception
+                _logger.Warn("Unknown error occurred while processing specification [{0}]:", oTableColumn)
+                _logger.Error(ex)
+                oPropertyValue = Nothing
+            End Try
+
+            If IsNothing(oPropertyValue) OrElse String.IsNullOrEmpty(oPropertyValue) Then
+                If oItem.Value.IsRequired Then
+                    _logger.Warn("{0} # Specification [{1}] is empty, but marked as required! Skipping.", MessageId, oTableColumn)
+                    oResult.MissingProperties.Add(oTableColumn)
+                    Continue For
+                Else
+                    _logger.Debug("{0} # oPropertyValue for specification [{1}] is empty or not found. Skipping.", MessageId, oTableColumn)
+
+                    Continue For
+                End If
+            End If
+
+            oResult.ValidProperties.Add(New ValidProperty() With {
+                .MessageId = MessageId,
+                .Description = oDescription,
+                .Value = oPropertyValue,
+                .TableName = oTableName,
+                .TableColumn = oTableColumn,
+                .ISRequired = oIsRequired
+             })
+        Next
+
+        Return oResult
+    End Function
+
+    Public Function GetPropValue(Obj As Object, PropertyName As String) As List(Of Object)
+        Dim oNameParts As String() = PropertyName.Split("."c)
+
+        If IsNothing(Obj) Then
+            _logger.Debug("`Obj` is Nothing. Exiting.")
+            Return New List(Of Object)
+        End If
+
+        If oNameParts.Length = 1 Then
+            Dim oPropInfo As PropertyInfo = Obj.GetType().GetProperty(PropertyName)
+
+            If IsNothing(oPropInfo) Then
+                _logger.Debug("Property [{0}] does not exist(1).", PropertyName)
+                Return New List(Of Object)
+            Else
+                Dim oPropValue = oPropInfo.GetValue(Obj, Nothing)
+                Return New List(Of Object) From {oPropValue}
+            End If
+        End If
+
+        For Each oPart As String In oNameParts
+            Dim oType As Type = Obj.GetType()
+            Dim oPartName = oPart
+            Dim oIndex As Integer = Nothing
+            Dim oHasIndex As Boolean = HasIndex(oPartName)
+
+            If oHasIndex Then
+                oPartName = StripIndex(oPart)
+                oIndex = GetIndex(oPart)
+            End If
+
+            Dim oInfo As PropertyInfo = oType.GetProperty(oPartName)
+
+            If IsNothing(oInfo) OrElse IsNothing(oInfo.GetValue(Obj, Nothing)) Then
+                _logger.Debug("Property [{0}] does not exist(2).", oPartName)
+                Return New List(Of Object)
+            End If
+
+            Obj = oInfo.GetValue(Obj, Nothing)
+
+            If oHasIndex Then
+                Obj = Obj(0)
+            End If
+
+            If IsArray(Obj) And Not oHasIndex Then
+                Dim oCurrentPart As String = oPart
+                Dim oSplitString As String() = New String() {oCurrentPart & "."}
+                Dim oPathFragments = PropertyName.Split(oSplitString, StringSplitOptions.None)
+                Dim oResults As New List(Of Object)
+
+                ' if path has no more subitems, return an empty list
+                If oPathFragments.Length = 1 Then
+                    Return oResults
+                End If
+
+                For Each oArrayItem In Obj
+                    Dim oResult As List(Of Object) = GetPropValue(oArrayItem, oPathFragments(1))
+
+                    If Not IsNothing(oResult) Then
+                        oResults.Add(oResult)
+                    End If
+                Next
+
+                Return oResults
+            End If
+        Next
+
+        Return New List(Of Object) From {Obj}
+    End Function
+
+    Public Function GetFinalPropValue(List As List(Of Object)) As List(Of Object)
+        Dim oResult As New List(Of Object)
+
+        For Each Item In List
+            Dim oItemValue = DoGetFinalPropValue(Item)
+
+            If Not IsNothing(oItemValue) Then
+                oResult.Add(oItemValue)
+            End If
+        Next
+
+        Return oResult
+    End Function
+
+    Private Function DoGetFinalPropValue(Value As Object) As String
+        If TypeOf Value Is List(Of Object) Then
+            Dim oList = DirectCast(Value, List(Of Object))
+            Dim oCount = oList.Count
+
+            Select Case oCount
+                Case 0
+                    Return Nothing
+                Case Else
+                    Return DoGetFinalPropValue(oList.First())
+            End Select
+
+            Return DoGetFinalPropValue(Value)
+        Else
+            Return Value.ToString
+        End If
+    End Function
+
+    Private Function GetIndex(Prop As String) As Integer
+        If Regex.IsMatch(Prop, _indexPattern) Then
+            Dim oMatch = _indexRegex.Match(Prop)
+            Dim oGroup = oMatch.Groups.Item(1)
+            Dim oValue = oGroup.Value
+
+            Return Integer.Parse(oValue)
+        End If
+
+        Return Nothing
+    End Function
+
+    Private Function StripIndex(Prop As String) As String
+        Return Regex.Replace(Prop, _indexPattern, "")
+    End Function
+
+    Private Function HasIndex(Prop As String) As Boolean
+        Return Regex.IsMatch(Prop, _indexPattern)
+    End Function
+
+End Class

Interfaces/ZUGFeRDInterface/XmlItemProperty.vb

@@ -0,0 +1,8 @@
+Public Class XmlItemProperty
+    Public TableName As String
+    Public TableColumn As String
+    Public Description As String
+    Public IsRequired As Boolean
+    Public IsGrouped As Boolean
+    Public GroupScope As String
+End Class

Interfaces/app.config

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="FirebirdSql.Data.FirebirdClient" publicKeyToken="3750abcc3150b00c" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-7.5.0.0" newVersion="7.5.0.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
+</configuration>

Interfaces/packages.config

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="Newtonsoft.Json" version="12.0.3" targetFramework="net461" />
+  <package id="NLog" version="4.7.15" targetFramework="net461" />
+</packages>