Session Object

One of the key functions of Session Object is the session control on the server.

Session.Abandon Method

Session.Abandon method abandons or destroys a Session object and all related resources are released after finised processing the current page.

Syntax:

Abandon(
)

 Or in an ASP file. Imply

<% Session.Abandon %>

Parameters:

void

This method has no parameters.

Return Values:

void

This method has no return values. 

Remarks:

By default, the server destroys all session objects when the session is finished or times out. The Session.Abandon method allows the abandon of the current session of  a client by destroying all session object after finished processing the current page. And create a new session object for the subsequent request by same client. All variables and objects will then be stored in this new session object.

In other word, there is always a sesson object for each client. The session.Abandon method only set the flag for the deletion of all current session objects after the completion of all script commands on the current page. Therefore the Abandon method can be placed anywhere before the end of script commands in the same page. And therefore variables stored in the Session object are still available on the same page, but not in any subsequent web pages by the same client.

Examples:

• Use Session.Abandon to destroy the session objects

  ASP script command:

  ----Current Page----
  <%
  Session.Abandon
  Session("App") = "Page1value" 
  Response.write Session("App")
  %>
  

  HTTP response output:

  Page1value

  HTML web page ouput:

  Page1value

  ASP script command:

  ----Subsequent Page----
  <%
  Response.write "New Session: " & Session("App")
  %>
  

  HTTP response output:

  New Session:

  HTML web page ouput:

  New Session:

Session.Timeout Property

Session.Timeout property sets the length of time out period for the Session object of the application that allowing the client to refresh or request a page on the server before the end of session on the server.

Syntax:

Session.Timeout [=nMinutes]

 Or in an ASP file. Imply

<% Session.Timeout [=nMinutes]  %>

Parameters:

nMinutes

The parameter "nMinutes" is used to specify the allowed idle time, in minutes, of a session before the server terminates the session automatically. The default value is 10 minutes.

Remarks:

The Session.Timeout is related to the idle time of the client when the user does not refresh or request a page.

There is no hard-coded limit on the value of Session.Timeout. The value can be set to 8 minutes or less. It should not be set too low, i.e. lower than 4 minutes because clients rarely respond within that time resulting in a loss of session state. It should also not be set too high, i.e. higher than 20 minutes escept in some special cases because every open session is holding onto memory.

But in IIS 6.0, the minimum allowed value is 1 minute and the maximum is 1440 minuites.

Examples:

• Use Session.Timeout to specify the allowered idle time of a session

  ASP script command:

  ----Current Page----
  <%
  Session.Timeout=1
  Response.write Session.Timeout & "<br>"
  Session("App") = "Page1value" 
  Response.write Session("App")
  %>
  

  HTTP response output:

  1<br>
  Page1value

  HTML web page ouput:

  1
  Page1value

  ASP script command:

  ----Subsequent Page after 1 minute----
  <%
  Response.write "New Session: " & Session("App")
  %>
  

  HTTP response output:

  New Session:

  HTML web page ouput:

  New Session:

Session.SessionID Property

Session.SessionID property returns the unique of LONG data type session identifier generated by the server during the creation of the new session..

Syntax:

Session.SessionID

 Or in an ASP file.  Imply

<% Session.SessionID  %>

Parameters:

void

This method has no parameters.

Remarks:

Although the SessionID is a unique number on the running Web server. Some of the SessionID value may be the same as those SessionID generated before the web server stopped. Therefore SessionID property can not be used to generate the primary key values for an application.

Examples:

• Use Session.Timeout to specify the allowered idle time of a session

  ASP script command:

  <%
  Response.write Session.SessionID
  %>
  

  HTTP response output:

  123456789

  HTML web page ouput:

  123456789