1. Mark Dixon 1 18 – Web applications: Server-side code (ASP.Net)

2. Mark Dixon 2 Session Aims & Objectives Aims –To introduce the fundamental ideas involved in server-side code Objectives, by end of this week’s sessions, you should be able to: –create an asp web-page, including: HTML, and server-side VB.Net

3. Mark Dixon 3 Example: Logon (analysis) SPECIFICATION User Requirements –protection from fraud and invasion of privacy Software Requirements –Functional: –logon page, user must type name and password –following pages can only be accessed after successful logon –Non-functional should be very difficult to hack hotmail, Amazon, University portal, utility bills (gas, electricity, phone, internet), Travel (flights, ferry, car rental)

4. Mark Dixon 4 Example: Logon (design) Restrict access to home page

5. Mark Dixon 5 Example: Logon (code v1) Using Client-side VB Script Please logon: Sub btnLogon_onClick() Dim un Dim pw un = txtUserName.value pw = txtPassWord.value If un = "mark" And pw = "soft051" Then window.navigate "home.htm" Else patMsg.innerText = "Login details incorrect." End If End Sub Logon.htm My Home page Welcome to my home page. Home.htm

6. Mark Dixon 6 Example: Login (Problem) View Source – shows client-side script: Reveals both username & password

7. Mark Dixon 7 network connection Web Hardware and Software Client Server Browser Application (MS Explorer, Chrome, Safari) Web-server Application (MS IIS, Apache)

8. Mark Dixon 8 Browser Application (MS Explorer, Firefox) Request-Response Cycle Web-server Application (MS IIS, Apache) Logon.htm Request Please logon: Sub btnLogon_OnClick() Dim un Dim pw un = txtUserName.value pw = txtPassWord.value If un = "mark" And pw = "soft051" Then window.navigate "home.htm" Else parMsg.innerText = "Login details incorrect." End If End Sub Response Client-side code: Code sent to Client Interpreted by browser

9. Mark Dixon 9 Client-side limitations Insecure (code visible to client) Cannot interact directly with Database (on server)

10. Mark Dixon 10 Server-side Code So far – all code executes on client (IE) –VBScript –JavaScript Server-side Code – executes on server –classic ASP – VBScript –ASP.Net VB.Net C# –JSP (Java) –PhP

11. Mark Dixon 11 Server-side Script (what) ASP – active server pages –code not sent to client code secure (can't be viewed by client) –executed on server takes time – request-response cycle requires server software (e.g. IIS) ASP pages will NOT work by double clicking on file

12. Mark Dixon 12 Example: Empty Page ASP.Net code: –.aspx (not.htm) –VB (not vbscript) –runat="server" runs code on server Empty.aspx

13. Mark Dixon 13 Example: Date ASP code: –.aspx (not.htm) –VB (not vbscript) –variables have type –Now is current date and time (on server) –runat="server" gives server code access to object Sub Page_Load () Dim s As String s = "The date today is " s = s & Now ().ToString("ddd d MMM yyyy") parD.InnerText = s s = "The time now is " s = s & Now().ToString("HH:mm") parT.InnerText = s End Sub Today's Date Date.aspx

14. Mark Dixon 14 Request-Response Cycle Browser Application (MS Explorer, Firefox) Web-server Application (MS IIS, Apache) Date.aspx Request Today's Date The date today is Mon 9 Feb 2009 The time now is 00:57 Response Sub Page_Load() Dim s As String s = "The date today is " s = s & Now().ToString("ddd d MMM yyyy") parD.InnerText = s s = "The time now is " s = s & Now().ToString("HH:mm") parT.InnerText = s End Sub Today's Date Server-side code: run on server (never sent to Client)

15. Mark Dixon 15 View Source Code executed at server –code is never sent to client View, Source – does not show code:

16. Mark Dixon 16 Data Types Variant – all types of data –slow, memory hungry Boolean – true or false (on/off, yes/no) Integer – whole numbers (-32768 to 32768) Long – whole numbers (large) Single – decimal numbers Double – decimal numbers (more precise) String – text Object – object instances

17. Mark Dixon 17 Data Type Selection Number ofe.g. 4 Integer/Long Rooms Heighte.g. 1.87m Single/Double Surnamee.g. Smith String Car Rege.g. XY55 ABC String

18. Mark Dixon 18 Using data types Variable declaration Dim x As Long Parameters Sub Thing(boo As String, y As Long) Functions Function IsTall() As Boolean

19. Mark Dixon 19 Question: Data types Declare a variable to store: –an animal's weight in kg (e.g. 34.6) –whether a person has a driving licence or not –the title of a book –a phone number (e.g. 01752 586225) Dim weight As Double Dim licence As Boolean Dim title As String Dim phone As String

20. Mark Dixon 20 Example: AddNum (server-side) Sub btnAdd_Click(s As Object, e As EventArgs) Handles btnAdd.ServerClick Dim N1 As Double Dim N2 As Double N1 = txtN1.Value N2 = txtN2.Value parRes.InnerText = N1 + N2 End Sub AddNum.aspx input tags inside form button: runat server button: submit refreshes page (sending data to server)

21. Mark Dixon 21 Sub btnAdd_onClick () Dim N1 Dim N2 N1 = txtN1.Value N2 = txtN2.Value parRes.InnerText = N1 + CDbl (N2) End Sub Sub btnAdd_Click(s As Object, e As EventArgs) Handles btnAdd.ServerClick Dim N1 As Double Dim N2 As Double N1 = txtN1.Value N2 = txtN2.Value parRes.InnerText = N1 + N2 End Sub AddNum.aspxAddNum.htm Client-side vs. Server-side Code Both use VB language (i.e. Sub, If, Dim, For, etc.)

22. Mark Dixon 22 Example: Apples Sub btnGo_Click(s As Object, e As EventArgs) Handles btnGo.ServerClick parRes.InnerHtml = parRes.InnerHtml & " " End Sub Apples Apples.aspx

23. Mark Dixon 23 Errors Sub Page_Load() Dim s As String s = "The date today is " s = s & Format(Now, "ddd d MMM yyyy") parD.InnerText = s s = "The time now is " s = s & Format(Now, "HH:mm") parT.InnerText = s End Sub parD.innerText = "" Today's Date vbscript cannot run at server (should be VB) parT is undefined (should have runat="server") Declaration expected (assignment must be in sub) Date.aspx

24. Mark Dixon 24 Running your ASP pages within Visual Studio –Run (play) button (F5) –only available to you on development PC using Internet Information Services (IIS) –makes PC a server –page available to all computers on internet

25. Mark Dixon 25 IIS / personal web server on Windows CD Start, Control Panel, Programs and Features IIS - Installing Windows Features IIS ASP.Net

26. Mark Dixon 26 IIS: Enabling/Disabling Start, Control Panel, Administrative Tools, Internet Services Manager Stop Start

27. Mark Dixon 27 IIS: Exposing pages Put ASP pages in: –C:\INetPub\wwwRoot (this part of hard disk exposed to outside world) Execute pages by putting: –localhost (in web browser, e.g. IE, means local machine) ASP pages don't work by double-clicking

28. Mark Dixon 28 IIS – Date.asp localhost/test/date.aspx C:\INetPub\wwwRoot\Date.aspx

29. Mark Dixon 29 Tutorial Demo: First.htm Create a new text file in web server's root folder: –Open Windows Explorer (My Computer) –Ensure folders are displayed –Navigate to: C:\INetPub\wwwRoot –Right click on the background –Click New –Click Text Document Rename file –Right click –Click Rename –Type file name (First.htm) –Click Yes (when asked to confirm change of extension)

30. Mark Dixon 30 Tutorial Demo: First.htm Put some code in the file: –Right Click on the file –Click Open with Notepad –Type the following code: Hello world! View the file –Open Internet Explorer –Navigate to: http://localhost/First.htm

31. Mark Dixon 31 Tutorial Demo: First.htm View each others' pages –In your browser, type: http://SMB109xx/First.htm where xx is the machine number of someone else's computer you should see their page See changes take effect: –One person change their page (colour, etc.) –Other person refresh browser you should see changes

32. Mark Dixon 32 Tutorial Demo: Date.aspx Create a web-site page (same as before): –Open Visual Studio –Click the File menu –Click the New Web Site… item –Click the Browse button –Select an existing folder to put your work in –Type the name of a subfolder –Click Yes to create the subfolder –Click Empty Web Site –Click OK

33. Mark Dixon 33 Tutorial Demo: Date.aspx Create a new aspx page: –Click Add New Item icon on tool bar –Double Click html page icon –Right click file –Click Rename item –Change name (date.aspx) –Click Yes to confirm extension change –Paste the code in from the lecture slides –Click the Run button

34. Mark Dixon 34 Tutorial Exercise: Login (client-side) LEARNING OBJECTIVE: see how vulnerable client-side code is Task 1: Get the Login (v1) example from the lecture working. Task 2: Use view source – you should be able to see the code.

35. Mark Dixon 35 Tutorial Exercise: Date LEARNING OBJECTIVE: create an ASP page, including HTML and server-side VB Script Task 1: Get the Date example from the lecture working. Task 2: Add code that displays good morning/afternoon/evening/night, depending on the time of day.

36. Mark Dixon 36 Tutorial Exercise: Student Loan LEARNING OBJECTIVE: create an ASP page, including HTML and server-side VB Script from scratch to solve a problem Task 1: Create a web page that allows the user to enter their salary and the computer calculates the annual and monthly payments for their student loan. Hint: Use your client-side code (from term 1), and the AddNum example from the lecture.

37. Mark Dixon 37 Tutorial Exercise: Login (client-side) LEARNING OBJECTIVE: create an ASP page, including HTML and server-side VB Script from scratch to solve a problem Task 1: Create a login page that uses server-side code to check the username and password entered by the user. Hint: Use the AddNum example as inspiration. Hint2: Use the following code to send the user to the homepage: Response.Redirect("Home.htm") Task 2: Use view source – you should NOT be able to see the code.

38. Mark Dixon 38 Tutorial Exercise: Apples LEARNING OBJECTIVE: use variables with specific data types in ASP code Task 1: Get the apples example (from the lecture) working. Task 2: Modify your program so that the user enters a number, and the code adds that number of apple images. Task 3: Modify your program so that the user enters another number, and the code adds a new line tag for that number of apples. Hint: Within the loop divide the number of apples by the second number, if the result is a whole number add a new line tag.