Software Testing and Quality Assurance

1
Software Testing and Quality Assurance

• Lecture 33
• SWE 205
• Course Objective
• Basics of Programming Languages Software
  Construction Techniques

2
Lecture Outline

• Script code
• Submitting the Form data
• Introduction to Active Server Pages (ASP)

3
Client Side Scripting

• Any given .html file may contain blocks script
  code
• Processed by the requesting browsers.
• Reasons client side scripting is used
• To validate user input before posting back to the
  web server.
• To interact with Document Object Model (DOM) of
  the target browser.

4
Client Side Scripting

• Many scripting languages for example
• VBScript and JavaScript.

5
Client Side Scripting - Example

• lthtmlgt
• ltheadgt
• lttitlegt This is Cars web sitelt/titlegt
• lt/headgt
• ltscript idclientEventHandlersJS
  languagejavascriptgt
• lt!- -
• function btnhelp_onclick()
• //Help the user along.
• alert (Please click Submit.)
• //--gt
• ltbody BGCOLOR66ccffgt
• lt!--
• ltform nameMainForm ID Form1gt
• ltp aligncentergtltinput idbtnHelp
  typebutton valuehelp
• NamebtnHelp onClickreturn btnHelp_onClick()gt
  lt/Pgt
• lt/formgt
• lt/bodygt
• lt/htmlgt

6
Submitting the Form Data

• Once you have a simple HTML page
• Need to examine how to transmit the form data
  back to the Web Server for processing.
• While building an HTML form,
• We typically supply an action attribute on the
  opening ltformgt tag

To specify the recipient of the incoming form
data.
7
Submitting the Form Data - GET

• Possible receivers include
• Mail servers, other HTML files,
• An Active Server Page (ASP) etc.
• For example,
• ltform nameMainForm IDMainForm
• Actionhttp//localhost/Cars/xxxxx.asp method
  GETgt
• ..
• lt/formgt

8
Submitting the Form Data - GET

• When the submit button for current form is
  clicked,
• the form data should be sent to the xxxx.asp file
  located within the Cars virtual directory.

9
Submitting the Form Data - GET

• GET as a mode of transimission
• The form data is appended to the query string as
  a set of name/value pairs
• For example,
• http//localhost/Cars/xxxxx.asp?txtUserNameAhmed
  txtPasswordmypasswordbtnSubmitSubmit

10
Submitting the Form Data - POST

• The other method of transmitting form data to the
  Web Server is
• To specify method POST
• ltform nameMainForm IDMainForm
• Actionhttp//localhost/Cars/xxxxx.asp method
  POSTgt
• ..
• lt/formgt

11
Submitting the Form Data - POST

• The data is not appended to the query string
• But instead is written to a separate line within
  the HTTP header.
• The data is directly visible to the outside word
  and
• A wee bit more secure.

12
A classic Active Server Page

• Goal of ASP is to
• Dynamically build HTML on the fly using
  server-side script logic and
• A small set of classic COM objects and related
  COM libraries.
• For example,
• A server side VBScript (or JavaScript) block that
  reads a table from a data source
• Using classic ADO and returns
• The rows as a generic HTML Table.

13
A classic Active Server Page - Example

• lt_at_ languageVBScript gt
• lthtmlgt
• ltheadgt
• lttitlegtThe Cars Pagelt/titlegt
• lt/headgt
• ltbodygt
• lth1 aligncenterHere is what you sent me
  lt/h1gt
• ltP aligncenterltbgtUser Name lt/bgt
• ltRequest.QueryString(txtUserName) gt
• ltbgtPassword lt/bgt
• ltRequest.QueryString(txtPassword) gt
• lt/Pgt
• lt/bodygt
• lt/hmtlgt

Begins and ends with standard tags.
To examine the values contained in each HTML
widget submitted via method GET
14
A classic Active Server Page - Example

• lt_at_ languageVBScript gt
• lthtmlgt
• ltheadgt
• lttitlegtThe Cars Pagelt/titlegt
• lt/headgt
• ltbodygt
• lth1 aligncenterHere is what you sent me
  lt/h1gt
• ltP aligncenterltbgtUser Name lt/bgt
• ltRequest.QueryString(txtUserName) gt
• ltbgtPassword lt/bgt
• ltRequest.QueryString(txtPassword) gt
• lt/Pgt
• lt/bodygt
• lt/hmtlgt

lt gt ? Insert the following directly into the
HTTP response.
15
A classic Active Server Page - Example

• Load the default.html page and submit the data.
• Once script is processed on the web server, a
  dynamic HTML page is displayed.

16
Responding the POST submissions

• ltbodygt
• lth1 aligncenterHere is what you sent me
  lt/h1gt
• ltP aligncenterltbgtUser Name lt/bgt
• ltRequest.Form(txtUserName) gt
• ltbgtPassword lt/bgt
• ltRequest.Form(txtPassword) gt
• lt/Pgt
• lt/bodygt

Note Request.QueryString() method is only able
extract data submitted via the GET method.
17
Problems with Classic ASP

• Perhaps, the biggest downfall of classic ASP is
  the same point that makes it a powerful platform.
  
• Server side scripting language.
• Scripting languages are interpreted
• Thus, not robust as OO programming techniques.

18
Problems with Classic ASP

• For example, under classic ASP
• There were not concept of classical inheritance
  or classical polymorphism.
• It does not generate very modularized code.

19
Problems with Classic ASP

• ASP is a blind of HTML and script in a single
  page
• Most ASP web applications are a confused mix of
  two very different programming techniques.
• A web framework would allow the presentation
  logic (i.e. HTML tags) to
• Exist independently from the business logic (i.e.
  functional code).

20
Problems with Classic ASP

• Classic ASP demands a good deal of
• Redundant script code that tends to repeat
  between projects.

21
Key Points

• HTML files usually contain blocks of script code.
• GET and POST methods to transmit the data
  back to the web servers for processing.
• ASP aim to dynamically build HTML using script
  logic and small set of COM objects.