Lec08 : PHP

1
Lec08 PHP Session

• ??? ?. ??????? ????????
• http//www.siam2dev.com
• ???????????????????????? ?????????????????????????
  ?????????
• ???. ??????

2
????????? session

• Session ??????????????? ??????
• ???????????????????????? session
  ??????????????????? session ??????????????????????
  ??? session ???????????????????????????????
• ?????????????? Cookie ??? Session
  ????????????????

??????? Cookie ????????????????
??????? Session ????????????????????????????????
3
????????? session ???

• ?????????? session ???????????????????????????????
  ?????????? ???????????????????????????????????????
  ????????????? session PHP ??????????? session
  ????????????????????? session ???????? session ID
  ????????????????????????? ???? session ID
  ?????????????????? ??????????????????? ???
  session ID ?????????????????????????? session ????

4
????????? session ???

• ?????????????? Cookie ??? Session
  ????????????????

??????? Cookie ????????????????
??????? Session ????????????????????????????????
5
???????????? Session

• Session ???????????????????????????
  ??????????????????????????????????????????????????
  ?????
• ????????????????? session ????????????????????????
  ????? ????????????????????????????????
  (?????????????????????????????????)

6
Session ???????

• ??????????????????????????????????????????????????
  ?? ???
• ???????????????????????????? cookie
  ?????????????????????? ??????????????????????
  ??????????????????????????????????????????????????
  ??????????
• ????????????????????????????? ???????????????????
  ??????????????????????? ??????????????????????
  ?????????????????????????????????????????????
  ????? ????????? session ??????????????????????????

7
What are sessions?
HTTP a stateless protocol
Client 1
Web server
Client 2
Joe
Mary
1
2
3
4
5
6
8
Why do we need sessions?
A SESSION associates DATA with a USER for
duration of their entire visit

• e-commerce

• CUSTOM web pages for different users(users can
  log in to web database)

9
How to store session info
1. Cookies Cookies store client-specific data on
the client
N.B. client may reject cookie!Security
issues?Max cookie size 4k
2. Session files

• Sessions store client-specific data on the server
• Sessions are tagged with a unique session id

10
Cookies

• A cookie is a small piece of text containing
  identifying information
• Sent by server to browser on first interaction
• Sent by browser to the server that created the
  cookie on further interactions
• part of the HTTP protocol
• Server saves information about cookies it issued,
  and can use it when serving a request
• E.g., authentication information, and user
  preferences

Cookies can be stored permanently or for a
limited time
11
Session ids
Web server
Joe
Mary
Session ID
Session ID
12
Session management

• PHP4 includes functions to
• manage session data on the server
• generate random session ID to identify user
• saves session ID
• either with a cookie (N.B. session ID only)or
  in the query string

13
???????????? session

• ??????????????? session ?????????????
• ????????

session_register(name)
name ?????????????? session ???????????????? ?????
???????????????????????? ???? boolean
???????????????????????? ????????????????????????
???????? session ?????????????????????
session_register(Mysession)
14
??????????????? session

• ??????????????????? session ??????????????????????
  ?? session ???????????????????????????????????????
  ? session
• ?????????????????????????????? session
  ?????????????? ???????????????????????
  session_start() ????????????????????? session
  ????????????????? PHP ????????????????????????????
  ??? session ????

15
??????????????? session

• ?????????????? PHP (PHP variable)
• ????????

HTTP_SESSION_VARSname
lt? session_register(myweb) HTTP_SESSION_VARS
myweb http//www.siam2dev.com print
HTTP_SESSION_VARSmyweb ?gt
16
???????? session
Testsession1.php
lt? session_register(myweb) HTTP_SESSION_VARS
myweb http//www.siam2dev.com print
HTTP_SESSION_VARSmyweb ?gt
Testsession2.php
lt? session_start() Print Testsession2.phpltbrgt
print HTTP_SESSION_VARSmyweb ?gt
17
??????????? session ??????

• ??????????????? session ??????????
  ??????????????????? session ??????
  ???????????????????????? ??????????????
• ????????

session_unregister(name)
name ?????????????? session ???????????????? ?????
???????????????????????? ???? boolean
???????????????????????? ????????????????????????
??????? session ?????????????????????
session_unregister(Mysession)
18
??????????? session ??????

• ?????????????????? session ??????????????????
  ??????????????
• ?????????????????????????????? session
  ????????????????????? ?????????????????????????
  ???????????????????????????? session ??????
  ??????????????????????????

session_destroy( )
19
???? session ??????????

• ??????????????? php.ini ??????????????????????????
  ???????? session ??????
• ???? php ????????????????????????????

session.save_path .
20
????? ?????? php.ini

• ??????????????????????????????????? session
  ?????? ??????????????????? session_start()
  ??????????????????????
• ?????????????? session ?????????????????? cookie
  ???????????????? session ??????????????????????
  ????????

session.auto_start 1 ??????????? 0
session.cookie_lifetime ??????????
???????????? 0