Migrating Existing ASP Applications to ASP.NET An in-depth look at the paradigm shifts and upgrade strategies when moving from ASP to ASP.NET architectures.
By
Carl Prothman
Microsoft “Most Valuable Professional” (MVP)
“Certified Computer Professional” (CCP)
Migrating Existing ASP Applications to ASP.NET An in-depth look at the paradigm shifts and upgrade strategies when moving from ASP to ASP.NET architectures.
By
Carl Prothman
Microsoft “Most Valuable Professional” (MVP)
“Certified Computer Professional” (CCP)
Hello my name is Carl Prothman
In this session, I will be talking about “migrating existing asp applications to asp.net applications.
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Introductions
Carl Prothman
Microsoft “Most Valuable Professional” (MVP)
Visual Basic MVP 1998/2002
ASP.NET MVP 2002/2003
Certified Computer Professional (CCP)
Microsoft Certified Professional (MCP)
Over 22 years of experience in Software Industry
Bachelor of Science in Aeronautics and Astronautics (BSAA) from University of Washington
Email: carlpr@spamcop.net
Able Consulting, Inc.
Owner http://www.able-consulting.com
First a little about my self…
I’m one Microsoft’s most valuable professionals (MVP).
In fact I just got award the MVP status for 2002/2003
I’m also a Certified Computer Professional, and a Microsoft Certified Professional
I have over 22 years of experience in the software industry
Plus I have a degree in Aeronautics and Astronautics from the University of Washington
I’m the owner of Able Consulting.
You can reach me at the email listed or though my web site.
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Agenda
.NET Overview 1 min
What is it?
Paradigm Shifts 35 mins
Top 10 (make that 11)
Migration Strategies 15 mins
Side-by-Side Conversion
Tier-by-Tier
Summary 9 mins
Q&A
Total: 60 mins
So the adenda is as follows
I’m going to show you my top 10 (make that 11) paradigm shifts
These are the things you must think and do differently when switching from ASP to ASP.NET
Then I’m going to show you some strategies on how to migrate from ASP to ASP.NET
I will actually convert an ASP file to an ASPX file
At the end, if we have time, I’ll try to answer a few questions.
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Overview
What is Microsoft’s .NET?
Set of Microsoft software technologies connecting your world of information, people, systems, and devices
Enables an unprecedented level of software integration through the use of XML Web services:
Small, discrete, building-block applications
Connected to each other via the Internet
What is ASP.NET?
The development platform for building server-based Web applications
Web Forms and XML Web Services
HTTP Runtime Architecture with IIS
So what is .NET?
Here is the official Microsoft marketing definition…
Note that it focus on XML Web Services
And what is ASP.NET?
Again here is the official Microsoft marketing definition…
Scott Guthrie will be speaking more on the HTTP Runtime Architecture on the Dec 4 meeting
My point here is that when I think of ASP.NET, not only do I think of XML Web Services, but I also think of Web Forms!
But there is my view of all of it.
[Next slide]
ASP.NET– Overall View
This diagram shows the different way you can connect the different pieces of ASP.NET
If the client side user is communicating over the Internet, then go through an XML Web Service.
If the client side user is communicating on an Intranet / LAN, then go though a business class or the database directly.
When using web forms, the fastest way to get data from a SQL Server database is to use ADO.NET’s SQL Client .NET Data Provider to call a Stored Procedure in SQL Server, and return a DataReader, which you bind to Web Controls on the Web Form.
If the query is expensive to make (lots of joins / calculations), then return a DataSet and put the DataSet into ASP.NET’s Cache on the first request. Then when requests come in for the same data, use the DataSet from the cache.
- The recommendation is to use XML Web services to communicate between internet apps.
- Xml web services should not be positioned as a replacement for binary protocols between servers on the same network/environment.
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Agenda
.NET Overview
Paradigm Shifts 25 mins
Migration Strategies
Summary
Next, I’m going to talk about my top 10 paradigm shift that have occurred from ASP to ASP.NET
But first, what is a paradigm shift?
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ASP.NET Paradigm Shifts
What is a Paradigm Shift?
A set of concepts, values, practices and assumptions that constitutes a way of viewing reality for the community that shares them.
When one paradigm looses influence and another paradigm takes over, then there is a paradigm shift!
Knowing in advance how a Paradigm Shift might occur gives you an advantage over others!
A paradigm shift is…
A set of concepts, values, practices and assumptions that constitutes a way of viewing reality for the community that shares them.
When one paradigm looses influence and another paradigm takes over, then there is a paradigm shift!
Knowing in advance how a Paradigm Shift might occur gives you an advantage over others!
That is where you benefit. I’m going to show you the details of each paradigm shift (at least my top 10 ones).
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ASP.NET - Paradigm Shift 0) Remote Application Communication
In ASP, you used the RDS DataSpace to communicate to a remote COM+ Component over DCOM or HTTP(S)
RDS is a major security hole!
RDS DataFactory MS99-025
RDS Data Stub MS02-065
In ASP.NET, you now use an XML Web Services to communication to remote applications
Standard protocol (SOAP) for distributed environments
Over HTTP with XML SOAP Envelop / Payload
The first paradigm shift is called “Remote Application Communication”
Note, This paradigm shift starts a zero, since .NET arrays are zero based – you better get use to it… ha ha…
Demo:
Create a simple Hello World XML Web Service
=> Run and Test
Create a WebForm with a Label and Button
Add a reference to the XML Web Service (creates a proxy class)
In the Button click event, call the XML Web Services and display the returned text into the Label
= Run and Test
Paradigm Shift:
You now have the ability to communicate with remote applications (on different platforms) using the SOAP standard.
XML Web Services implements the SOAP standards for you automatically.
- The recommendation is to use XML Web services to communicate between internet apps.
- Xml web services should not be positioned as a replacement for binary protocols between servers on the same network/environment.
ASP.NET - Paradigm Shift 1) Server-Side Web Controls
In ASP, you used Response.Write or <%= % to send HTML / script to the Web browser
In ASP.NET, you can now program against server-side Web Controls which generate the HTML
HTML Server Controls
HTML Tag with and ID= and RunAt=Server attributes
Web Server Controls
ASP.NET control with ID= and RunAt=Server attributes
Form Validation Controls
Client-side and Server-side Validation
User Control Page (.ASCX)
Replaces the HTML Include command
Custom Control Assembly (.DLL)
Demo
Create a new Web Form
Add a Label, TextBox and a Button
Double click Button
Make it so value in TextBox gets shown in Label
Set a break point in the Button on-click event
=> Notice that you are programming against server-side Web Control
6) Run => Notice that the Form Load event fires on each GET and POST
7) Enter “Hello World” in textbox
8) Click Submit button
=> By default AutoPostback is false for all controls, except for Button Web Control
=> Notice the event is raised on the server when button is clicked on client!
Paradigm Shift:
You are programming against **server-side** Web Controls which display HTML on the client!
All client-side events for the Web Controls are raised on the server during postback!
ASP.NET - Paradigm Shift 2) Automatic HTML Code Generation
In ASP, you created custom pages for each browser type
Use browscap.ini file with the BrowserType object
In ASP.NET, you use server-side Web Controls and Web Forms to generate the HTML
ASP.NET figure out the browser type
Automatically renders the correct, browser-compliant HTML for features such as Styles, Layout, and so on.
In Visual Studio .NET, set TargetSchema Property on the Page
Internet Explorer 3.02 / Navigator 3.0
Internet Explorer 5.0
Navigator 4.0
How many of you remember coding to Netscape and IE browsers?
Demo
Show web form with label, textbox, and button web controls using **GridLayout** (which uses absolute positioning)
Set TargetSchema to Internet Explorer 5.0
=> View source reveals absolute position HTML code
Set TargetSchema to Internet Explorer 3.02 / Navigator 3.0
=> View source reveals table HTML code
Paradigm Shift:
You let the Web Form / Web Controls generate the **browser specific** HTML, rather than coding it yourself!
You no longer need to use the old “table placement” trick!
Paradigm Shift 3) Automatic Web Control State
In ASP, you had to fill the control with user entered values on POST back
Show the web page again with an error message
In ASP.NET, the controls automatically retain the user entered values on POST back
ViewState is used to store Control State
User selection, Control Info…
Control values are automatically filled in for you during post back.
Can store values in ViewState between round trips
Must only use one FORM on page
Must post to the same page for ViewState to work!
Demo
Show Web Form with Listbox
Select a value
Click Submit button
=> On post back the control retains its selected value
View the Source
=> Show ViewState hidden input control
Paradigm Shift:
Controls are automatically recreated with user selection during post back.
You don't have to worry about resetting controls to last state
Paradigm Shift 4) HTML Separate from Code
In ASP, you could mix HTML with client-side and server-side script
Hard to read and maintain
Some used “.vbs” or “.js” files to separate out the script
In ASP.NET, you can either
Put the code in-line with SCRIPT tags
Or put code in a “code-behind” page
Visual Studio .NET creates code-behind pages by default
ASP.NET Web Matrix creates in-line SCRIPT tags by default
In VS.NET click “Show All Files”
Shows HTML file and Code File
In Web Matrix, open web form
show In-Line Code
Paradigm Shift:
Now use code behind pages rather than mixed HTML/Script or .vbs files
Separate out the UI Controls from the code!
Paradigm Shift 5) Compiled ASP.NET Code
In ASP, you used server-side VBScript (or JavaScript) which was interpreted, hence slower!
So most folks just pulled the server-side script out and put it into a VB 6.0 / C++ COM+ Components (N-Tier)
Presentation Tier Classes
Business Tier Classes
Data Tier Classes
In ASP.NET, everything is compiled, which is faster!
In-line SCRIPT tags with RunAt=Server
Code Behind page (must compile)
Debug –vs- Release mode
Demo
Create new web form page, with TextBox and Button
Double click on the button to create a code behind page
Put some code in
Browse to the new web page
=> “Could not load type 'ASPNET.WebForm2‘”
=> Need to compile “code behind page” since Inherits="ASPNET.WebForm2"
Compile the project (Ctrl Shift B)
Refresh web page
=> Now page is found
Paradigm Shift:
Everything is compiled, not interpreted, which means greater performance!
You must compile code-behind pages before you can browse to the page!
Paradigm Shift 6) Registering Client-Side Script
In ASP, you could directly add client-side event handlers to HTML controls
In ASP.NET, you add client-side event handlers to Web Controls via Attribute.Add
Button1.Attributes.Add(“onclick”, “alert(‘Hello’)”)
You can also register a client script block
RegisterClientScriptBlock
Client-side JavaScript / JScript
VBScript
Demo
Show WebControl
Add code for client-side onclick event
Add script block
Run
Paradigm Shift:
Must add / register client-side script with Web Controls
Paradigm Shift 7) User Controls Instead of Includes
In ASP, you used includes files to include common script code
In ASP.NET, you now use User Controls (ASCX) for common code
Headers, Footers, etc..
Public Properties and Methods
Inheritance from BaseControl
Reuse common Properties, Methods, and settings
Demo
Show User Control
Drag and drop onto a page
Write code to set user control
Run
Paradigm Shift:
Use User Control Pages instead of server-side Includes
User Controls are object oriented
=> Inherit from base user control and reuse common properties, methods, and events.
Paradigm Shift 8) XML Configuration Files
In ASP, you used System Registry (or IIS Metadata db) to store Application settings
In ASP.NET, you use XML files to store Application settings
Machine.config (for all projects on the machine)
C:\WINNT\Microsoft.NET\Framework\v1.0.3705\CONFIG\machine.config
Web.config (for each project)
Read in configuration settings using
System.Resources.ConfigurationSettings.AppSettings[“myKeyName"]
Demo
Show the web.config file
Show the machine.config file
We can read in the configuration setting from these config file using
System.Resources.ConfigurationSettings.AppSettings[“myKeyName"]
Paradigm Shift:
Use XML files to store configuration rather than System Registry or IIS MetaData
Paradigm Shift 9) ASP.NET Worker Process
In ASP, IIS used the ASP.DLL to handle each web request
In ASP.NET, IIS calls an ASPNET worker process (aspnet_wp.exe)
Identity of ASP.NET Worker process controlled by
machine.config, processModel element, userName attribute
C:\WINNT\Microsoft.NET\Framework\v1.0.3705\CONFIG\machine.config
"MACHINE": runs as low privilege user account named "ASPNET".
"SYSTEM": runs as localsystem (high privilege admin) account.
Running IISRESET stops the Worker process
Demo
Browse to WebForm2.aspx
Show Windows Task Manager
=> aspnet_wp.exe is running
Run IISRESET
=> aspnet_wp.exe stops running
Refresh WebForm2.aspx
=> aspnet_wp.exe is running again
Paradigm Shift:
IIS now calls an ASP.NET Work Process to handle the request rather than handling the request itself!
ASP.NET Work Process runs as the “low privilege” ASPNET User Account by default!
This mean stronger security by default. Hence you must enabled the correct permissions!
Paradigm Shift 10) Windows Impersonation
In ASP, impersonation was enabled by default
Using Anon Access, ASP would impersonate IUSR_XXXX
Using NTLM / Basic, ASP would impersonate calling User
In ASP.NET, impersonation is disabled by default
You must explicitly enable impersonation in web.config or machine .config file
System.Security.Principal.WindowsIdentity.GetCurrent().Name
CARLP7\ASPNET (ASP.NET User account)
CARLP7\IUSR_CARLP7 (IIS Anon User account)
CARLP7\Administrator (User account that I’m logged as)
Demo
Open up the web.config file
- Show that we are using Windows authentication
- Show the Identity tag with impersonate attribute = false (default)
Open up IIS MMC and show the security for the IIS Application
- Chance to anon and refresh the page
- Identity impersonate=“false“ and IIS Anonymous Access
=> WindowsIdentity.GetCurrent().Name = CARLP7\ASPNET
- Identity impersonate=“false“ and IIS NTLM
=> WindowsIdentity.GetCurrent().Name = CARLP7\ASPNET
- Identity impersonate=“true“ and IIS Anonymous Access
=> WindowsIdentity.GetCurrent().Name = CARLP7\IUSR_CARLP7
- Identity impersonate=“true“ and IIS NTLM
=> WindowsIdentity.GetCurrent().Name = CARLP7\Administrator
Paradigm Shift:
Windows Impersonation is OFF by default in ASP.NET
Must use for ASP.NET worker process to impersonate client.
Agenda
.NET Overview
Paradigm Shifts
Migration Strategies 20 mins
Summary
So that concludes my top 10 Paradigm Shifts.
Now I want to focus on strategies to migrate ASP to ASP.NET
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Migration Strategies Side-by-Side
ASP and ASP.NET Side-by-Side
Both ASP and ASP.NET files can run side-by-side in same IIS Web Application
However, you cannot share Session variables between them directly
Steps to “convert” ASP to ASP.NET
Rename the ASP file to use the “.ASPX” file extension
Browse to the page and update server-side code as needed
Option Explicit is the default. Remove Option Explicit line.
Method calls with parameters require “(“ and “)”.
Don’t need Set or Let anymore. Remove them.
For ADO/COM objects, use “aspcompat=true” in the Page directive
“&” must have spaces around it. No more s = str1&str2
No more Default Properties. Must state explicitly: oRs(0).Value
No more VBScript Variants => Objects / .NET Framework Class Library
ByValue is now the default. Was ByRef in VB 6.0.
VB.NET is now 0 based. Was 1 based (in some cases) in VB 6.0
Integer data type is now 32 bits. Was 16 bit in VB 6.0
…
The first migration strategy is called Side-by-Side.
This is where both your ASP and ASP.NET pages live in the same IIS application.
Both ASP and ASP.NET applications use different file extension. So they both can be in the same directory.
However, even if they are in the same IIS application, you cannot share Session or Application variables between them.
The steps to convert an ASP file to an ASPX fie are as follows:
1) First rename the ASP file extension to an ASPX file extension
2) Next update the code as necessary
For example:
Open up sidebyside.asp
Step through code and comment about what it does
Make a copy of the file and call it sidebyside.aspx
Browse to sidebyside.aspx
FIX #1 – Noticed it moved the VBSCRIPT language tag automatically to the page directive.
FIX #2 – Add Explicit="True" to Page, and remove Option Explicit line
SET and LET???
FIX #3 – Add ( and ) to Response.Write line
Fix #4 – Add aspcompat=true to the page directive.
=> The ASP page now has been converted to ASPX page
Note a VB.NET page in a C# Project
=> But the page is still using classic ADO via COM Interup (slow).
Need to convet to ADO.NET with SqlClient .NET Data Provider
=> Also the page is still using HTML controls.
Need to convert over to Web Controls
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