ICustomExtractDriver Interface

When implemented, represents a custom driver used to write data to/read data from a data extract.

Namespace: DevExpress.DashboardCommon

Assembly: DevExpress.Dashboard.v24.2.Core.dll

Declaration

C#

public interface ICustomExtractDriver

VB.NET

Public Interface ICustomExtractDriver

Related API Members

The following members return ICustomExtractDriver objects:

• ExtractDriverStorage.DefaultDriver
• FileExtractDriver.Instance

Remarks

ICustomExtractDriver allows you to implement a custom logic for writing/reading data extracts (DashboardExtractDataSource). To facilitate these operations, a data extract is divided into special chunks called pages. Each page within a data extract can be accessed by a unique identifier (GUID).

The ICustomExtractDriver interface exposes two methods to be implemented.

• ICustomExtractDriver.CreateWriteSession - creates a session used to write data to an extract. This method returns an object implementing a IDriverWriteSession, which allows you to access and change extract pages.
• ICustomExtractDriver.CreateReadSession - creates a session used to read data from the data extract. This method returns a IDriverReadSession, which allows you to obtain extract page identifiers and corresponding pages. Thus, use a IDriverReadSession to implement a custom logic for reading data extracts created using FileExtractDriver.CreateWriteSession.

After you have implemented a custom driver, you can substitute a default extract driver using the ExtractDriverStorage.DefaultDriver property. In this case, a new driver will be used for all data extracts. As an alternative, you can use a new driver for the specific data extract. To do this, register a custom driver within the ExtractDriverStorage by calling the ExtractDriverStorage.RegisterCustomDriver method. Then, assign the name of this driver to the DashboardExtractDataSource.DriverName property.

Example

The following example demonstrates how to create a custom driver to encrypt/decrypt extract data. It implements the ICustomExtractDriver interface:

• The ICustomExtractDriver.CreateWriteSession method creates a write session that is used to encrypt extract pages.
• The ICustomExtractDriver.CreateReadSession method creates a read session that provides logic for reading encrypted pages.

ExtractEncryptionDriver.cs

using System;
using System.Collections.Generic;
using System.Security.Cryptography;
using DevExpress.DashboardCommon;

namespace Dashboard_CustomExtractDriver {
    public class ExtractEncryptionDriver : ICustomExtractDriver {

        public IDriverReadSession CreateReadSession(string resourceName) {
            return new EncryptionReadSession(FileExtractDriver.Instance.CreateReadSession(resourceName));
        }
        public IDriverWriteSession CreateWriteSession(string resourceName) {
            return new EncryptionWriteSession(FileExtractDriver.Instance.CreateWriteSession(resourceName));
        }
    }

    public class EncryptionWriteSession : IDriverWriteSession {
        IDriverWriteSession writeSession;

        public EncryptionWriteSession(IDriverWriteSession writeSession) {
            this.writeSession = writeSession; 
        }
        public void Dispose() {
            writeSession.Dispose();
        }
        public void SetPage(Guid pageID, byte[] data) {
            writeSession.SetPage(pageID, Encrypt(data));
        }
        byte[] Encrypt(byte[] page) {
            byte[] entropy = { 1, 2, 3 };
            byte[] encryptedPage = ProtectedData.Protect(page, entropy, DataProtectionScope.CurrentUser);
            return encryptedPage;
        }
    }

    public class EncryptionReadSession : IDriverReadSession {
        IDriverReadSession readSession;
        public EncryptionReadSession(IDriverReadSession readSession) {
            this.readSession = readSession;
        }
        public void Dispose() {
            readSession.Dispose();
        }
        byte[] Decrypt(byte[] page) {
            byte[] entropy = { 1, 2, 3 };
            byte[] decryptedPage = ProtectedData.Unprotect(page, entropy, DataProtectionScope.CurrentUser);
            return decryptedPage;
        }
        public byte[] GetPage(Guid pageID) {
            return Decrypt(readSession.GetPage(pageID));
        }
        public IEnumerable<Guid> GetPageIDs() {
            return readSession.GetPageIDs();
        }
    }
}

Form1.cs

using DevExpress.DashboardCommon;
using DevExpress.DataAccess.Excel;
using DevExpress.XtraEditors;
using System;

namespace Dashboard_CustomExtractDriver
{
    public partial class Form1 : XtraForm {
        const string extractFileNamePattern = "\"Extract_\"yyyyMMddHHmmssfff\".dat\"";
        public Form1()
        {
            InitializeComponent();
            ExtractDriverStorage.DefaultDriver = new ExtractEncryptionDriver();

            DashboardExtractDataSource extractDataSource = new DashboardExtractDataSource();
            extractDataSource.ExtractSourceOptions.DataSource = CreateExcelDataSource();
            extractDataSource.FileName = DateTime.Now.ToString(extractFileNamePattern);
            extractDataSource.UpdateExtractFile();

            dashboardViewer1.Dashboard = CreateDashboard(extractDataSource);
        }

        private static Dashboard CreateDashboard(DashboardExtractDataSource extractDataSource)
        {
            Dashboard dashboard = new Dashboard();
            dashboard.DataSources.Add(extractDataSource);
            PivotDashboardItem pivot = new PivotDashboardItem();
            pivot.DataSource = extractDataSource;
            pivot.Values.AddRange(new Measure("Extended Price"), new Measure("Quantity"));
            pivot.Columns.Add(new Dimension("OrderDate", DateTimeGroupInterval.Year));
            pivot.Rows.Add(new Dimension("ProductName"));
            dashboard.Items.Add(pivot);
            return dashboard;
        }

        private static DashboardExcelDataSource CreateExcelDataSource()
        {
            DashboardExcelDataSource excelDataSource = new DashboardExcelDataSource()
            {
                FileName = @"Data\SalesPerson.xlsx",
                SourceOptions = new ExcelSourceOptions()
                {
                    ImportSettings = new ExcelWorksheetSettings("Data")
                }
            };
            excelDataSource.Fill();
            return excelDataSource;
        }
    }
}

ExtractEncryptionDriver.vb

Imports System
Imports System.Collections.Generic
Imports System.Security.Cryptography
Imports DevExpress.DashboardCommon

Namespace Dashboard_CustomExtractDriver
    Public Class ExtractEncryptionDriver
        Implements ICustomExtractDriver

        Public Function CreateReadSession(ByVal resourceName As String) As IDriverReadSession Implements ICustomExtractDriver.CreateReadSession
            Return New EncryptionReadSession(FileExtractDriver.Instance.CreateReadSession(resourceName))
        End Function
        Public Function CreateWriteSession(ByVal resourceName As String) As IDriverWriteSession Implements ICustomExtractDriver.CreateWriteSession
            Return New EncryptionWriteSession(FileExtractDriver.Instance.CreateWriteSession(resourceName))
        End Function
    End Class

    Public Class EncryptionWriteSession
        Implements IDriverWriteSession

        Private writeSession As IDriverWriteSession

        Public Sub New(ByVal writeSession As IDriverWriteSession)
            Me.writeSession = writeSession
        End Sub
        Public Sub Dispose() Implements System.IDisposable.Dispose
            writeSession.Dispose()
        End Sub
        Public Sub SetPage(ByVal pageID As Guid, ByVal data() As Byte) Implements IDriverWriteSession.SetPage
            writeSession.SetPage(pageID, Encrypt(data))
        End Sub
        Private Function Encrypt(ByVal page() As Byte) As Byte()
            Dim entropy() As Byte = { 1, 2, 3 }
            Dim encryptedPage() As Byte = ProtectedData.Protect(page, entropy, DataProtectionScope.CurrentUser)
            Return encryptedPage
        End Function
    End Class

    Public Class EncryptionReadSession
        Implements IDriverReadSession

        Private readSession As IDriverReadSession
        Public Sub New(ByVal readSession As IDriverReadSession)
            Me.readSession = readSession
        End Sub
        Public Sub Dispose() Implements System.IDisposable.Dispose
            readSession.Dispose()
        End Sub
        Private Function Decrypt(ByVal page() As Byte) As Byte()
            Dim entropy() As Byte = { 1, 2, 3 }
            Dim decryptedPage() As Byte = ProtectedData.Unprotect(page, entropy, DataProtectionScope.CurrentUser)
            Return decryptedPage
        End Function
        Public Function GetPage(ByVal pageID As Guid) As Byte() Implements IDriverReadSession.GetPage
            Return Decrypt(readSession.GetPage(pageID))
        End Function
        Public Function GetPageIDs() As IEnumerable(Of Guid) Implements IDriverReadSession.GetPageIDs
            Return readSession.GetPageIDs()
        End Function
    End Class
End Namespace

Form1.vb

Imports DevExpress.DashboardCommon
Imports DevExpress.DataAccess.Excel
Imports DevExpress.XtraEditors
Imports System

Namespace Dashboard_CustomExtractDriver
    Partial Public Class Form1
        Inherits XtraForm

        Private Const extractFileNamePattern As String = """Extract_""yyyyMMddHHmmssfff"".dat"""
        Public Sub New()
            InitializeComponent()
            ExtractDriverStorage.DefaultDriver = New ExtractEncryptionDriver()

            Dim extractDataSource As New DashboardExtractDataSource()
            extractDataSource.ExtractSourceOptions.DataSource = CreateExcelDataSource()
            extractDataSource.FileName = Date.Now.ToString(extractFileNamePattern)
            extractDataSource.UpdateExtractFile()

            dashboardViewer1.Dashboard = CreateDashboard(extractDataSource)
        End Sub

        Private Shared Function CreateDashboard(ByVal extractDataSource As DashboardExtractDataSource) As Dashboard
            Dim dashboard As New Dashboard()
            dashboard.DataSources.Add(extractDataSource)
            Dim pivot As New PivotDashboardItem()
            pivot.DataSource = extractDataSource
            pivot.Values.AddRange(New Measure("Extended Price"), New Measure("Quantity"))
            pivot.Columns.Add(New Dimension("OrderDate", DateTimeGroupInterval.Year))
            pivot.Rows.Add(New Dimension("ProductName"))
            dashboard.Items.Add(pivot)
            Return dashboard
        End Function

        Private Shared Function CreateExcelDataSource() As DashboardExcelDataSource
            Dim excelDataSource As New DashboardExcelDataSource() With {
                .FileName = "Data\SalesPerson.xlsx", .SourceOptions = New ExcelSourceOptions() With {.ImportSettings = New ExcelWorksheetSettings("Data")}
            }
            excelDataSource.Fill()
            Return excelDataSource
        End Function
    End Class
End Namespace