Session Management

1
Session Management
2
Session

• A series of transactions between a browser and
  server.

3
The Issue

• Passing information between the browser and
  server over the series of transactions

4
The Hidden Approach

• Use hidden input tags in a form to send
  information from the server to the browser and
  back to the server for the next part of the
  transaction

5
Analysis Hidden Approach

• Pretty simple and straightforward.
• The Concern a view source of the HTML page can
  reveal the contents of the hidden tags, which may
  cause a security breach.
• Remember, the pages might be cached, so someone
  else can view the cache and view the hidden tags.

6
The Session Approach

• Instead of passing information to the browser, a
  unique Session ID is passed to the browser.
  Information is maintained on the server in a
  temporary file that is associated to the Session
  ID

7
The Session Approach

• When the reply is returned from the browser, the
  Session ID is returned with the form
  information.

8
The Session Approach

• The server matches up the Session ID with the
  appropriate temporary file and restores the
  information that was saved is placed in the
  session hash
• _SESSIONkey
• For all keys set by the session software
  developer

9
The Session Approach

• If the session is continued, the contents of
  _SESSION is saved in a temporary file associated
  with the Session ID, and the session continues.

10
PHP Sessions

• All you do is include the statement,
• session_start()
• as the first line in the PHP script, PHP does
  the rest.

11
PHP Sessions

• To place the current contents of a variable into
  session hash,
• _SESSIONnamename
• To restore a variable,
• name _SESSIONname
• To erase a variable from the session hash,
• session_unregister(name)

12
PHP Sessions

• The contents of _SESSION is save in the
  temporary file when the script terminates
  successfully.

13
Passing The Session ID

• Take all the PHP defaults and it is handled
  automatically.
• Otherwise, you are on your own.