ASP by pengxiuhui

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									            ASP.NET

Dynamic Styles
Response and Request Objects
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
Dynamic Styles

<SCRIPT language="javascript">
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"
   }
   </SCRIPT>
  <input id="BROWSERButton" type="button" value="Click Me"
  onClick="Format()“ style="background-color:steelblue;
  color:#FFFFFF; font-family:arial; font-size:10pt; width:100;
  cursor:hand">
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
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 user’s 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)
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
RESPONSE OBJECT-
Properties/Methods

Response.IsClientConnected Whether a client browser is
                           still connect to a Web
                           page:
                           True
Response.Redirect("url")    Immediately redirects to
                            and loads a different Web
                            page.
Response.Write(content)     Writes text or variables to a
                            Web page:
                            Response.Write("Text
                            string"): Text string.
RESPONSE OBJECT – Write (ASP)

   Writes information directly to the HTTP response body.

<%
Response.Write “<table border=1>”
Response.Write “<tr>”
Response.Write “<td>”
Response.Write “Hello”
Response.Write “</td>”
Response.Write “</tr>”
Response.Write “</table>”
%>
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.
<SCRIPT runat="server">
  Void ProcessThis (Object Src,EventArgs Args){
    Response.Write("Start of ProcessThis" & "<br>")
    ...
    ...
    Response.Write("End of ProcessThis" & "<br>")
    ProcessThat
  }
RESPONSE OBJECT – Write (.NET)

 Void ProcessThat() {
    Response.Write("Start of ProcessThat" & "<br>")
    String VarA = "Howdy"
    ...
    ...
    Response.Write("Value of VarA = " & VarA & "<br>")
    Response.Write("End of ProcessThat" & "<br>")
  }
</SCRIPT>
RESPONSE OBJECT – Write (.NET)

 <asp:Button Text="Trace" OnClick="ProcessThis"
  runat="server" />


Result:
  Start of ProcessThis
  End of ProcessThis
  Start of ProcessThat
  Value of VarA = Howdy
  End of ProcessThat
RESPONSE OBJECT - Redirect

   Redirects the client’s 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.
Response.Redirect (ASP)

<% Response.Redirect
  "http://www.mis.boun.edu.tr" %>
<HTML>
<BODY>
xx
</BODY>
</HTML>
Response.Redirect (.NET)

<SCRIPT runat="server">

 void GoBack (Object Src, EventArgs Args) {
   Response.Redirect("aspnet02-06.aspx");
 }

 </SCRIPT>

 <asp:Button Text="Go Back"
 OnClick="GoBack" runat="server" />
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.
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
<% Response.Buffer = True %>
RESPONSE OBJECT - Clear


   Empties the current contents of the Response buffer.

   It does so without sending any of the buffered
    response to the client.
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.
Response.Buffer/Clear/End

<% Response.Buffer = True %>
<HTML> <BODY>
<%
int err;
err = 1;
If (Err <> 0) {
    Response.Clear();
    Response.Write("Error Created“) ;
    Response.End();
}
%>
Example: Get System Time (ASP)


<% LANGUAGE=“VBSCRIPT” %>           Screen:
<html> <body>                       After half of 9
<% If (Minute(Now) < 30) { %>
Before Half                         Source:
<% Else %>                          <html> <body>
After Half                          After Half
<% } %>                             of
of                                  9
<% response.write (Hour(Now)); %>   </body> </html>
</body> </html>
Example: System Time


<% when=now();
twoweekslater=dateadd("w",2,when);
monthlater=dateadd("m",1,when);
sixminuteslater=dateadd("n",6,when);
sixhourslater=dateadd("h",6,when);
response.write "Now <b>" & when & "</b><br>"
response.write "1 month from Now <b>" & monthlater & "</b><br>"
response.write "2 weeks from Now <b>" & twoweekslater & "</b><br>"
   %> six minutes from now <b>
<%=sixminuteslater%> </b><br> six hours from now <b>
<%=sixhourslater%> </b><br>
ASP - REQUEST OBJECT

     Collections
            Form (POST)
            Server Variables
            QueryString (GET)
            Cookies
            ClientCertificate
     Method
            BinaryRead
     Properties
            TotalBytes
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
REQUEST OBJECT-
ServerVariables


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

 <SCRIPT runat="server">

   void Page_Load() {

    Browser.Text = Request.Browser.Browser;
    BrowserVersion.Text = Request.Browser.Version;
    BrowserPlatform.Text = Request.Browser.Platform;

   }
 </SCRIPT>
REQUEST OBJECT-
ServerVariables

 <html><body>

   <h3>Properties of your request for this page:</h3>
   <b>Browser Type: </b><asp:Label id="Browser"
   runat="server"/><br>
   <b>Browser Version: </b><asp:Label
   id="BrowserVersion" runat="server"/><br>
   <b>Browser Platform: </b><asp:Label
   id="BrowserPlatform" runat="server"/><br>

 </body></html>
REQUEST OBJECT-
ServerVariables


 Output of the script is shown below:

   Properties of your request for this page:
   Browser Type: IE
   Browser Version: 6.0
   Browser Platform: WinXP
REQUEST OBJECT-
Browser Properties

Request.UserAgent       PropertiesThe full
                        identification of the browser
                        requesting the page:
                        Mozilla/4.0 (compatible;
                        MSIE 6.0; Windows NT 5.1;
                        SV1; .NET CLR 1.1.4322)
Request.Browser.Browser The type of browser making
                        the request:
                        IE
REQUEST OBJECT-
Browser Properties

 Request.Browser.Type     The type and major version
                          of the browser making the
                          request:
                          IE6
 Request.Browser.Version The major and minor
                         versions of the browser
                         request:
                         6.0
REQUEST OBJECT-
Browser Properties

 Request.Browser.MajorVersion The major version of the
                              browser making the
                              request:
                              6
 Request.Browser.MinorVersion The minor version of the
                              browser making the
                              request:
                              0
REQUEST OBJECT-
Browser Properties

 Request.Browser.AOL        Whether this is an AOL
                            browser:
                            False
 Request.Browser.Frames     Whether the browser
                            supports frames:
                            True

 Request.Browser.JavaScript Whether the browser
                            supports JavaScript:
                            True
REQUEST OBJECT-
Browser Properties

 Request.Browser.Platform   The type of operating
                            system under which the
                            browser is running:
                            WinXP
 Request.IsSecureConnection Whether the current
                            connection uses a
                            secure Web protocol:
                            False
REQUEST OBJECT-
Browser Properties

 Request.UserHostAddress The IP address from which
                         the browser is requesting the
                         page:
                         193.140.202.80Server
                         Properties
 Request.ServerVariables ("LOCAL_ADDR")The IP
                         address of the server hosting
                         the requested page.
                         168.16.176.28
REQUEST OBJECT-
Browser Properties

 Request.Url.Host    The URL of the server hosting the
                     requested page:
                     it.maconstate.edu
 Request.RawUrl     The portion of the URL request
                    following the domain information:
                    /Tutorials/ASPNET02/aspnet02.
                    aspx
 Request.Url.Scheme The type of URL request:
                    http
REQUEST OBJECT-
Browser Properties

 Request.Url.Port        The port through which the URL
                         request is made:
                         80
 Request.ApplicationPath The virtual path to the root
                         directory containing the page
                         requested by the browser:
                         /Tutorials
 Request.FilePath        The virtual path to the page
                         requested by the browser:
                         /Tutorials/ASPNET02/aspnet0
                         2.aspx
REQUEST OBJECT-
Browser Properties

 Request.PhysicalApplicationPath The physical path to
                                 the root directory of
                                 the page requested
                                 by the browser:
                                 D:\Tutorials\
 Request.PhysicalPath            The physical path to
                                 the page requested
                                 by the browser:
                                 D:\Tutorials\ASPNET
                                 02\aspnet02.aspx
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 server’s TCP/IP
 HTTPS: “ON” if the client’s request is using SSL.
 ALL_HTTP: One long string containing al the HTTP
  headers send by the client’s browser.
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 client’s
  HTTP request is sent.
<%
string strUserName;
strUserName=Request.ServerVariables(“LOGON_USER”);
%>
Get IP

 <HTML> <BODY>
 <% string strUserName;
   strUserName=Request.ServerVariables
               ("REMOTE_ADDR");
 Response.Write (strUserName);
 %>
 merhaba
 </BODY> </HTML>
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
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 <INPUT>)
HTTP Request Header

Create the form:
<html> <body> <h2> Sample Order </h2>
<form method=“post” action=“response.asp”>
<p> First Name: <input name = “fname”
  size=“48”>
<p> Last Name: <input name = “lname” size=“48”>
HTTP Request Header

<p> Title: <input name=“title” type=radio
      value=“mr”> Mr.
<input name=“title” type=radio value=“ms”> Ms.
<p> <input type=submit> <input type=reset>
</form> </body> </html>
Response.asp

* You should use the Form collection of the Request object
   to manipulate information

<% title = request.form(“title”);
lastname = request.form(“lname”);
If (title== “mr”) %>
Mr.        <% = lastname %>
<% Else If (title == “ms”) %>
Ms.        <% = lastname %>
<% Else %>
<% = request.form (“fname”) & “ “ & lastname %>
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
REQUEST OBJECT-
Client Certificate

Provides access to the certification fields of the client’s
  digital certificate.

Client certificates are sent to the web server when a
   client’s browser supports the Secure Sockets Layer
   and that browser is connected to a web server
   running the SSL (https://).

Request.ClientCertificate
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.
REQUEST OBJECT-
Client Certificate


Request.ClientCertificate (“IssuerC”);
  Retrieve the country of origin for the Issuer.

Request.ClientCertificate (“SubjectO”);
  Retrieve the organization of the Subject.
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.
Session Tracking

Session tracking ways:
1. Use of input form elements of type hidden and
   sending them to the form handler on the Web
   server.

2.   Use of HttpSessionState object

3.   Cookies
Cookies

Cookie: Small pieces of information stored by
 the web server on the web client’s 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.
Cookies

Domain: Returns a String containing the cookie’s
  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 cookie’s name.
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 cookie’s value.
Cookies

Send Cookie
  Response.Cookies("Cust").Name="BE"
  Response.Cookies("Cust").Expires=time.AddDays(10)

Get Cookie
  Request.Cookies("Cust")

Delete Cookie
  Response.Cookies("Cust").Expires = Date – 365

' Deleted by setting expiration date to a past date
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.
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.
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"
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
    object’s keys.
HttpSessionState Properties

   SessionID: Returns the session’s 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
HttpSessionState Properties

   SessionID: Returns the session’s unique ID.
       Session.

   Timeout: Specifies the maximum number of minutes
    during which a session can be inactive before the
    session expires.
        Session.Timeout

								
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