Software Developer, Technology Enthusiast, Husband and Dad based in Melbourne.

C#

Simple 301 Redirect for ASP.NET

A 301 Redirect is a way of sending search engines and user traffic to a specific? URL ,? also telling the search engines to do a permanently move on? that URL.

Implementing 301 redirect in ASP.NET Webforms or ASP.NET MVC; Simply use the Application_BeginRequest event in Global.asax. Then retrieve the URL from the Web.Config file or a Repository.

protected void Application_BeginRequest(Object sender, EventArgs e)
{
string path = "";
switch (Request.Url.Scheme)
{

case "https":
Response.AddHeader("Strict-Transport-Security", "max-age=300");
break;
case "http":
    if (Request.Url.PathAndQuery == "/")
     {

    path = "https://" + WebUtils.WebConfigUtils.GetAppSettingskey("SiteURL") + "/";

    }
else
    {
     path = "https://" + WebUtils.WebConfigUtils.GetAppSettingskey("SiteURL") + "/" + Request.Url.PathAndQuery;

    }
    Response.Status = "301 Moved Permanently";
    Response.AddHeader("Location", path);
    break;
   }
}

  • When a URL request for an http is made, the switch statement responses by inserting a 301 Moved Permanently and the new location path into the HTTP header .
  • Store the SiteURL in the Web.Config or a Repository.
  • When a URL request for an https is made,the switch statement responses by in inserting Strict-Transport-Security telling the browser to prevent any communications from being sent for HTTP.

Test this function locally in your development environment use IIS Express SSL option.?

References

301 Moved Permanently
http://moz.com/learn/seo/redirection

HTTP Strict Transport Security
https://www.owasp.org/index.php/HTTP_Strict_Transport_Security

Global.asax
http://msdn.microsoft.com/en-us/library/1xaas8a2%28v=vs.71%29.aspx

NovusCodeLibrary.NET – Utilities Library for .NET
https://github.com/novuslogic/NovuscodeLibrary.NET

Working with SSL at Development Time is easier with IISExpress
Working with SSL at Development Time is easier with IISExpress

Delphi and .NET Interop with JVCL

There are different methods for Delphi to communicate with the .NET Framework:

  • Commercial projects e.g. Remobjects Hydra, Atozed CrossTalk and Managed VCL etc.
  • Importing .NET Assembly using the Import Component Wizard.
  • Or Open Source method using JVCL.

Why choose JVCL over the commercial projects and the Import Component Wizard which is part of Delphi?

  • Open Source e.g. free as in beer.
  • Independent of regasm.exe which registers Class Libraries into the Global Assemble Cache (GAC)

How does JclDotNet work?

JVCL provides communication to the .NET Framework using the JclDotNet unit, by providing variant based
late bound automation to the .NET class library.

This post will provide two examples by stepping through each part, which should provide a basic grounding on how the 
JVCL JclDotNet unit communicates with .NET Framework.

For these examples your Delphi must have JVCL 3.45 or higher installed and for  the C# Class Library .NET 4.5 Framework
 (Visual Studio 2012).

Example 1

This example demonstrates a basic adding of two numbers together, by calling the C# class library Example1ClassLibrary.DLL

Delphi Example
  • To start the TJclClrHost class must initialize a .NET Framework – Common Language Runtime (CLR) and start the host:
Host := TJclClrHost.Create('v4.0.30319');
Host.Start();
  • NOTE: By default if you leave the ClrVer variable blank, it defaults to v2.0.50727.
Host := TJclClrHost.Create;
  • For this example we will be using CLR v4.0.30319 which supports either .NET 4.5 or .NET 4 Framework.
  • C# Class Library must now be initialize and Obj: OleVariant for the access to method:
Obj := Host.DefaultAppDomain
.CreateInstance('Example1ClassLibrary' {.NET Assemble Name},

'Example1ClassLibrary.Example1' {Namespace.Classname})

.UnWrap();
  • First part is the name of .NET Assemble File ‘Example1ClassLibrary.dll’.
  • ‘Example1ClassLibrary.Example1‘ next part is the namespace and the classname
  • Accessing this method from the C# Class Library as simple has keeping the name and the parameters the same as the class library:
Result := Obj.AddFunction(aXValue, aYValue);
  • Release the CLR host just stop and free the TJclClrHost class:
Host.Stop();
Host.Free;
Full Function
function TfrmMain.AddFunction(aXValue: Integer; aYValue:Integer): Integer;
var
  Host: TJclClrHost;
  Obj: OleVariant;
begin
  try
    Host := TJclClrHost.Create('v4.0.30319');
    Host.Start();

    Obj := Host.DefaultAppDomain
        .CreateInstance('Example1ClassLibrary',
        'Example1ClassLibrary.Example1')
        .UnWrap();

     Result := Obj.AddFunction(aXValue, aYValue);

    Host.Stop();
    Host.Free;
  Except
     on E : Exception do
     begin
       ShowMessage('Exception class name = '+E.ClassName + ' ' + 'Exception message = '+E.Message);
     end;
  end;
end;

C# Class Library

Some basic setting up of example 1 Class Library allowing Delphi work with Interop Services:

  • Include in your namespace for the Interop Services
using System.Runtime.InteropServices;
  • To expose the class to COM access to Delphi
[ComVisible(true)]
public class Example1
  • All functions must be public
public int AddFunction(int aXValue, int aYValue)
{
return aXValue + aYValue;
}
Class Library
namespace Example1ClassLibrary
{
    [ComVisible(true)]
    public class Example1
    {
        public int AddFunction(int aXValue, int aYValue)
        {
            return aXValue + aYValue;
        }
    }
}

Example 2

In this example we take the basic adding of two numbers together and expand out how Delphi can access the Example2ClassLibrary.DLL using the mscorlib_TLB import library:

Delphi Example
uses
mscorlib_TLB, Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs,? StdCtrls, JclDotNet;
  • NOTE: mscorlib_TLB should be the first unit.
  • Initializing the host to .NET Framework in the formcreate event:
procedure TfrmMain.FormCreate(Sender: TObject);
begin
   FClrHost := TJclClrHost.Create('v4.0.30319');

   FClrHost.Start;
end;
  • Setup the access to the Class Library path and application:
Fads.ApplicationBase := '..\Example2\Debug\Win32\';
Fad := FClrHost.CreateAppDomain('myNET', Fads);
  • NOTE: CreateAppDomain(‘myNET’ should be a different name if two or more a being called.
  • The C# Class Library must now be initialize and Obj: OleVariant for the access to the method:
obj := (Fad as _AppDomain).CreateInstanceFrom('Example2ClassLibrary.dll',
     'Example2ClassLibrary.Example2');
ov := obj.Unwrap;result := ov.AddFunction(aXValue, aYValue);
  • To release the CLR host just stop and free has been setup on the FormDestory event:
procedure TfrmMain.FormDestroy(Sender: TObject);
begin
  FClrHost.Stop();
  FClrHost.Free;
end;
Full Function
function TfrmMain.AddFunction(aXValue: Integer; aYValue:Integer): Integer;
var
  Fads: TJclClrAppDomainSetup;
  Fad: TJclClrAppDomain;
  Ov: OleVariant;
  obj: _ObjectHandle;
begin
  try
    Fads := FClrhost.CreateDomainSetup;

    Fads.ApplicationBase := '..\Example2\Debug\Win32\';
    Fad := FClrHost.CreateAppDomain('myNET', Fads);
    obj := (Fad as _AppDomain).CreateInstanceFrom('Example2ClassLibrary.dll',
         'Example2ClassLibrary.Example2');
    ov := obj.Unwrap;
    result := ov.AddFunction(aXValue, aYValue);
  except
    on E : Exception do
     begin
       ShowMessage('Exception class name = '+E.ClassName +
          ' ' + 'Exception message = '+E.Message);     end;
  end;
end;

Download Examples

https://github.com/acj1971/DelphiDotNETInteropJVCLExamples

Links

JVCL
http://jvcl.delphi-jedi.org/

.NET 4.5 Framework
http://www.microsoft.com/en-au/download/details.aspx?id=30653

Common Language Runtime (CLR)
http://msdn.microsoft.com/en-us/library/8bs2ecf4.aspx

Remobjects Hydra
http://www.remobjects.com/hydra/

Atozed CrossTalk
http://www.atozed.com/CrossTalk/index.en.aspx

Managed VCL
http://www.managed-vcl.com/

Import Component Wizard
http://docwiki.embarcadero.com/RADStudio/XE3/en/Import_Component_Wizard

Encrypting ASP.NET appSettings Web.Config File

It is recommended to encrypt the AppSettings key in the ASP.NET Web.Config file for security reason. The simplest method is using aspnet_regiis.exe command-line utility; this command-line utility is available from .NET 2 Framework or higher, for this blog I will be using .NET Framework 4.0.

aspnet_regiis.exe

The location of aspnet_regiis.exe command-line utility is:
C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe

Encryption

To encrypt the appSettings key at the command-line:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe ?pef appSettings “c:\project\directory” -prov “DataProtectionConfigurationProvider”

  1. Specify the full path to aspnet_regiis.exe command-line utility
  2. Use -pef appSettings to set the appSettings key
  3. Use -prov “DataProtectionConfigurationProvider”

.NET Framework 4.0 has two built-in providers for encrypting the appSettings key in ASP.NET Web.Config file:

  • DataProtectionConfigurationProvider Windows data protection API (DPAPI)
  • RSAProtectedConfigurationProvider RSA encryption

The simplest provider to use is the DataProtectionConfigurationProvider, there are no RSA keys to be created and setup, with the DataProtectionConfigurationProvider it’s server -specific.

When copying the Web.Config file from your development environment, encrypt the appSettings key on the server using DataProtectionConfigurationProvider provider otherwise the appSettings key will not be decrypted correctly.

The RSAProtectedConfigurationProvider RSA encryption, the RSA keys can be copied from development environment to server without change.

Decryption

To decrypt the appSettings key at the command-line:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -pdf appSettings “c:\project\directory ”

  1. Specify the full path to aspnet_regiis.exe command-line utility
  2. Use ?pdf appSettings to set the appSettings key

C# Example reading appSettings Key

With this example the appSettings key is read and decrypted automatically:

using System.Configuration;
using System.Web.Configuration;

private void EncryptAppSettings()        {
           Configuration objConfig = WebConfigurationManager.OpenWebConfiguration(
                  Request.ApplicationPath);
           AppSettingsSection objAppsettings =
            (AppSettingsSection)objConfig.GetSection("appSettings");
          if (!objAppsettings.SectionInformation.IsProtected)
            {
            objAppsettings.SectionInformation.ProtectSection
                            ("DataProtectionConfigurationProvider");
                  objAppsettings.SectionInformation.ForceSave = true;
                 objConfig.Save(ConfigurationSaveMode.Modified);
            }
        }

Links

ASP.NET IIS Registration Tool (Aspnet_regiis.exe)
http://msdn.microsoft.com/en-us/library/k6h9cz8h%28v=vs.100%29.aspx

How To: Encrypt Configuration Sections in ASP.NET 2.0 Using DPAPI
http://msdn.microsoft.com/en-us/library/ff647398.aspx

How To: Encrypt Configuration Sections in ASP.NET 2.0 Using RSA
http://msdn.microsoft.com/en-us/library/ms998283.aspx

DpapiProtectedConfigurationProvider Class
http://msdn.microsoft.com/en-us/library/system.configuration.dpapiprotectedconfigurationprovider%28v=vs.100%29.aspx

RsaProtectedConfigurationProvider Class
http://msdn.microsoft.com/en-us/library/system.configuration.rsaprotectedconfigurationprovider%28v=vs.100%29.aspx