ASP'NET

1
ASP.NET

• Dynamic Styles
• Response and Request Objects

2
Dynamic Styles

• DHTML is a browser phenomenon, using JavaScript
  to manipulate the properties and methods of HTML
  tags in response to user or browser events.
• Under ASP.NET these same style settings can take
  place, in this case through server scripts rather
  than browser scripts

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Dynamic Styles

• ltSCRIPT language"javascript"gt
• function Format()
• document.all.BROWSERButton.style.backgroundColor
  "FF0000
• document.all.BROWSERButton.style.fontFamily
  "comic sans ms
• document.all.BROWSERButton.style.fontSize
  "12pt
• document.all.BROWSERButton.style.width "150px
• document.all.BROWSERButton.value "Thank
  You"lt/SCRIPTgtltinput id"BROWSERButton"
  type"button" value"Click Me" onClick"Format()
  style"background-colorsteelblue
  colorFFFFFF font-familyarial font-size10pt
  width100 cursorhand"gt

4
Built-in ASP Objects

• Response Object
• Send text, data and cookies to the browser and
  control each stage of transmitting the page
• Server Object
• Overall scripting control, set the timeout
  variable for the script
• Request Object
• Read submitted form data, cookies and server
  variables

5
Built-in ASP Objects

• Session Object
• Allows to attach data to a specific user browsing
  the site that is isolated and invisible to other
  users (user session is identifiable by the cookie
  that is sent every time a user makes a request)
  (stay active by default until 20 minutes after
  the users last request or until the session is
  explicitly abandoned through the code)
• Application Object
• Allows to manipulate global data in the script
  that will be visible to all users browsing the
  site (ASP application itself)

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RESPONSE OBJECT

• Gives control over what data and data types sent
  to the client in the headers of HTTP response
• Gives control over what data and data types sent
  to the client in the body of HTTP response
• Gives control over when and how data is sent

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RESPONSE OBJECT- Properties/Methods

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RESPONSE OBJECT Write (ASP)

• Writes information directly to the HTTP response
  body.
• lt
• Response.Write lttable border1gt
• Response.Write lttrgt
• Response.Write lttdgt
• Response.Write Hello
• Response.Write lt/tdgt
• Response.Write lt/trgt
• Response.Write lt/tablegt
• gt

9
RESPONSE OBJECT Write (.NET)

• Response.Write() statements are placed throughout
  a script to trace the processing sequence and to
  write the contents of a variable.
• ltSCRIPT runat"server"gtSub ProcessThis (Src As
  Object, Args As EventArgs)  Response.Write("Start
  of ProcessThis" "ltbrgt")  ...  ...  Response.
  Write("End of ProcessThis" "ltbrgt")  ProcessThat
  End Sub

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RESPONSE OBJECT Write (.NET)
Sub ProcessThat  Response.Write("Start of
ProcessThat" "ltbrgt")  Dim VarA
"Howdy"  ...  ...  Response.Write("Value of
VarA " VarA "ltbrgt")  Response.Write("End
of ProcessThat" "ltbrgt")End Sub lt/SCRIPTgt

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RESPONSE OBJECT Write (.NET)
ltaspButton Text"Trace" OnClick"ProcessThis"
runat"server" /gt Result Start of
ProcessThisEnd of ProcessThisStart of
ProcessThatValue of VarA HowdyEnd of
ProcessThat

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RESPONSE OBJECT - Redirect

• Redirects the clients request to another URL.
• Response.Redirect http//www.mis.boun.edu.tr
• Response.Redirect x.asp
• x.asp resides in the same folder as the
  requested page
• If the script has written any content to the HTTP
  response body, that content is ignored by the
  script once the call to the Redirect method is
  executed.

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Response.Redirect (ASP)

• lt Response.Redirect "http//www.mis.boun.edu.tr"
  gt
• ltHTMLgt
• ltBODYgt
• xx
• lt/BODYgt
• lt/HTMLgt

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Response.Redirect (.NET)

• ltSCRIPT runat"server"gtSub GoBack (Src As
  Object, Args As EventArgs)  Response.Redirect("as
  pnet02-06.aspx")End Sublt/SCRIPTgtltaspButton
  Text"Go Back" OnClick"GoBack" runat"server" /gt

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RESPONSE OBJECT - IsClientConnected

• The Response.IsClientConnected property is useful
  when you need to make sure that the visitor is
  still connected to your Web site.
• This issue arises when, say, you are conducting
  e-commerce with a customer. If you have just
  completed processing a set of transactions for a
  purchase being made, you might wish to check that
  the customer has not abandoned your site before
  finalizing those transactions.

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RESPONSE OBJECT - Buffer

• Determines whether the content created by the
  script is delivered to the client browser as a
  whole or send immediately to the client browser
  as each line is created and entered into the HTML
  stream
• If set to TRUE, then all script on the page is
  run before the results of that script are sent to
  the client browser
• lt Response.Buffer True gt

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RESPONSE OBJECT - Clear

• Empties the current contents of the Response
  buffer.
• It does so without sending any of the buffered
  response to the client.

18
RESPONSE OBJECT - End

• Ends all storage of information in the response
  buffer and sends the current contents of the
  buffer immediately to the client.
• Any code present after the call to the End method
  is not processed.

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Response.Buffer/Clear/End

• lt Response.Buffer True gt
• ltHTMLgt ltBODYgt
• lt
• Dim err
• err 1
• If Err ltgt 0 Then
• Response.Clear
• Response.Write "Error Created"
• Response.End
• End If
• gt

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Example Get System Time (ASP)

• lt LANGUAGEVBSCRIPT gt
• lthtmlgt ltbodygt
• lt If Minute(Now) lt 30 Then gt
• Before Half
• lt Else gt
• After Half
• lt End If gt
• of
• lt response.write (Hour(Now)) gt
• lt/bodygt lt/htmlgt

• Screen
• After half of 9
• Source
• lthtmlgt ltbodygt
• After Half
• of
• 9
• lt/bodygt lt/htmlgt

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Example System Time

• lt whennow()
• twoweekslaterdateadd("w",2,when)
• monthlaterdateadd("m",1,when)
• sixminuteslaterdateadd("n",6,when)
• sixhourslaterdateadd("h",6,when)
• response.write "Now ltbgt" when "lt/bgtltbrgt"
• response.write "1 month from Now ltbgt"
  monthlater "lt/bgtltbrgt"
• response.write "2 weeks from Now ltbgt"
  twoweekslater "lt/bgtltbrgt" gt six minutes from
  now ltbgt
• ltsixminuteslatergt lt/bgtltbrgt six hours from now
  ltbgt
• ltsixhourslatergt lt/bgtltbrgt

22
ASP - REQUEST OBJECT

• Collections
• Form (POST)
• Server Variables
• QueryString (GET)
• Cookies
• ClientCertificate
• Method
• BinaryRead
• Properties
• TotalBytes

23
REQUEST OBJECT- HttpRequest Class
HttpRequest class provides a Request object that
contains information about a URL request issued
for a Web page. In general, the Request object
pertains to Web page input, with a set of
properties that provide information about the URL
request received by the page

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REQUEST OBJECT- ServerVariables
Contain several predefined environment variables
in the context of the clients specific HTTP
request of the web server.

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REQUEST OBJECT- ServerVariables
ltSCRIPT runat"server"gtSub Page_Load  Browser.
Text Request.Browser.Browser  BrowserVersion.Te
xt Request.Browser.Version  BrowserPlatform.Tex
t Request.Browser.PlatformEnd Sub lt/SCRIPTgt

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REQUEST OBJECT- ServerVariables
lthtmlgtltbodygtlth3gtProperties of your request for
this pagelt/h3gtltbgtBrowser Type lt/bgtltaspLabel
id"Browser" runat"server"/gtltbrgtltbgtBrowser
Version lt/bgtltaspLabel id"BrowserVersion"
runat"server"/gtltbrgtltbgtBrowser Platform
lt/bgtltaspLabel id"BrowserPlatform"
runat"server"/gtltbrgt lt/bodygtlt/htmlgt

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REQUEST OBJECT- ServerVariables
Output of the script is shown below Properties
of your request for this page Browser Type
IEBrowser Version 6.0Browser Platform WinXP

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- Browser Properties

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REQUEST OBJECT- ServerVariables

• Possible Keys
• REMOTE_ADDR TCP/IP of the client
• REMOTE_HOST The IP address from which the web
  server receives the request
• REQUEST_METHOD Get, Post, etc.
• SERVER_NAME Web servers TCP/IP
• HTTPS ON if the clients request is using SSL.
• ALL_HTTP One long string containing al the HTTP
  headers send by the clients browser.

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REQUEST OBJECT- ServerVariables

• Possible Keys
• LOGON_USER Windows NT account with which the
  user has logged onto the system
• URL The base URL requested by the client in its
  HTTP request.
• SERVER_PORT The server port to which the
  clients HTTP request is sent.
• lt
• Dim strUserName
• strUserNameRequest.ServerVariables(LOGON_USER)
• gt

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Get IP

• ltHTMLgt ltBODYgt
• lt Dim strUserName strUserNameRequest.ServerVaria
  bles
• ("REMOTE_ADDR")
• Response.Write strUserName
• gt
• merhaba
• lt/BODYgt lt/HTMLgt

40
GET vs. POST

• GET can be used to retrieve any document, POST
  cannot
• GET and POST can be used to pass data to the
  object indicated by the URL
• When POST is used, the data is passed to the
  server in the body of the request message
• When GET is used, the data is included in the URL
  as argument string and needs to be parsed

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REQUEST OBJECT- Form (POST)

• User enters input into the fields of a form
• When form is submitted, data in each field is
  transferred to the server, and then to ASP
• Data is sent in the format
• name value
• name (attribute of ltINPUTgt)

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HTTP Request Header

• Create the form
• lthtmlgt ltbodygt lth2gt Sample Order lt/h2gt
• ltform methodpost actionresponse.aspgt
• ltpgt First Name ltinput name fname size48gt
• ltpgt Last Name ltinput name lname size48gt

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HTTP Request Header

• ltpgt Title ltinput nametitle typeradio
• valuemrgt Mr.
• ltinput nametitle typeradio valuemsgt Ms.
• ltpgt ltinput typesubmitgt ltinput typeresetgt
• lt/formgt lt/bodygt lt/htmlgt

44
Response.asp

• You should use the Form collection of the
  Request object to manipulate information
• lt title request.form(title)
• lastname request.form(lname)
• If title mr Then gt
• Mr. lt lastname gt
• lt ElseIf title ms Then gt
• Ms. lt lastname gt
• lt Else gt
• lt request.form (fname) lastname gt
• lt End If gt

45
REQUEST OBJECT-TotalBytes

• TotalBytes property is a read-only value that
  specifies the total number of bytes posted to the
  web server by the client in the HTTP request
  body.
• Var Request.TotalBytes

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REQUEST OBJECT-Client Certificate

• Provides access to the certification fields of
  the clients digital certificate.
• Client certificates are sent to the web server
  when a clients browser supports the Secure
  Sockets Layer and that browser is connected to a
  web server running the SSL (https//).
• Request.ClientCertificate

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REQUEST OBJECT-Client Certificate

• Subject A list of comma-delimited strings that
  provide information about the owner of the
  digital certificate.
• Issuer Information about the issuer.
• ValidFrom and ValidUntil Validation dates
• SerialNumber An ASCII representation
• Ex 0A-B7-34-23
• Certificate A string value that contains the
  entire binary stream from the certificate
  content.
• Flags Provide additional information such as
  presence of certificate.

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REQUEST OBJECT-Client Certificate

• Request.ClientCertificate (IssuerC)
• Retrieve the country of origin for the Issuer.
• Request.ClientCertificate (SubjectO)
• Retrieve the organization of the Subject.

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Session Tracking

• HTTP is a stateless protocol that does not
  support persistent connections that would enable
  Web servers to maintain state information
  regarding clients.
• A session ID represents a unique client on the
  Internet. If the client leaves a site and returns
  later, the client will still be recognized as the
  same user.
• To help the server distinguish among clients,
  each client must identify itself to the server.
• The tracking of each individual clients, known as
  session tracking, can be achieved in a number of
  ways.

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Session Tracking

• Session tracking ways
• Use of input form elements of type hidden and
  sending them to the form handler on the Web
  server.
• Use of HttpSessionState object
• Cookies

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Cookies

• Cookie Small pieces of information stored by the
  web server on the web clients machine.
• This information is sent to the server each time
  the client requested a page from the same area
  from which the information was received.
• A cookie is a text file.

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Cookies

• Domain Returns a String containing the cookies
  domain. This determines which web server can
  receive the cookie.
• Expires Returns a DateTime object indicating
  when the browser can delete the cookie.
• Name Returns a String containing the cookies
  name.

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Cookies

• Path Returns a String containing the URL prefix
  for the cookie.
• Secure Returns a Boolean value indicating
  whether the cookie should be transmitted through
  a secure protocol. The value True causes a secure
  protocol to be used.
• Value Returns a String containing the cookies
  value.

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Cookies

• Send Cookie
• Response.Cookies("Cust").Name"BE"
• Response.Cookies("Cust").Expirestime.AddDays(10)
  
• Get Cookie
• Request.Cookies("Cust")
• Delete Cookie
• Response.Cookies("Cust").Expires Date 365
• ' Deleted by setting expiration date to a past
  date

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Session

• A user Session is created by ASP.NET whenever a
  visitor arrives at any Web page located in your
  root application directory.
• A Session Object maintains identification
  information about the visitor and allows ASP.NET
  to differentiate between visitors and their
  browsing status as they navigate the Web site.

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SessionID

• Your visit to this site, for instance, can be
  identified by the SessionID value,
• Session.SessionID "filyqavdzfnqrj45ofykaeel"
• SessionID value is a random number that was
  generated when you first arrived at the site.
• Session remains alive until 20 minutes after your
  last interaction with a page or until you close
  your browser.
• A revisit generates a new SessionID number.

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Session Variable

• The Session Object also serves as a global
  storage area that scripts can use to maintain
  data values between pages.
• A Session variable is created by assigning a
  value to a name
• Session("name") "value"

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HttpSessionState Properties

• Count Specifies the numebr of key-vaue pairs in
  the Session object.
• IsNewSession Indicates whether this is a new
  session.
• IsReadOnly Indicates whether the Session object
  is read only.
• Keys Returns an object containing the Session
  objects keys.

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HttpSessionState Properties

• SessionID Returns the sessions unique ID.
• Session.SessionID
• Timeout Specifies the maximum number of minutes
  during which a session can be inactive before the
  session expires.
• Session.Timeout
• Session.Add(TR,2005)
• Store in session as name-value pair

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HttpSessionState Properties

• SessionID Returns the sessions unique ID.
• Session.
• Timeout Specifies the maximum number of minutes
  during which a session can be inactive before the
  session expires.
• Session.Timeout