CE Festival

1
CE Festival PHP Course

• PHP Course
• by Tabris
• Organized by Computer Engineering Association

2
Schedule

• Schedule
• 2 lessons (tonight, and next Friday)
• Tonight
• Introduction to PHP
• Basic programming skill in PHP
• Magic you can do with PHP
• QA

3
Schedule (Cont)

• Next Friday
• Write your PHP Applications
• E.g., Discussion board, File uploader
• Database access of PHP (optional?)
• QA

4
Whats PHP??

• Its a server-side language
• Its compiled (parsed) before sending to
  end-users browser
• Apart from PHP, CGI, JSP, ASP are also
• Source code is hided
• PHP can be code-mixing (i.e., mixing with HTML
  code)
• So its very convenient

5
What can PHP done?

• Provides Dynamic Content (interactive)
• Normal HTML is static
• Javascript is only client-side
• Form Handling
• Data Access (File, Database)

6
Yours 1st PHP Program

• Very simple, just a hello world program
• lt?php
• echo Hello World!
• ?gt
• But how to run??

7
How to run a PHP Program

• To run a PHP Program, you must have a web space
  with web server supporting PHP (usually by
  module)
• Do we have??
• YES! OUR CSIS webserver is using Apache and it
  supports PHP
• The pity is that only CSIS server supports while
  EEE and HKUSUA server dont

8
How to run a PHP Program

• Save your file as helloworld.php in
  W\public_html
• telnet to virtue
• goto /homepage/students/ce/xx/yr_login/public_html
  
• Change Permission chmod 644 helloworld.php
• Access from your browser http//www.csis.hku.hk/y
  r_login/helloworld.php

9
Structure of PHP Program

• Normal Structure
• lt?php
• PHP Code here
• ?gt
• Mixed with HTML (save it as test.php)
• lthtmlgt
• ltheadgtlttitlegtPHP Courselt/titlegtlt/headgt
• ltbodygt
• Im from HTML! ltbrgt
• lt?php // this is all PHP code
• echo "ltbgtIm from PHP!lt/bgt"
• ?gt
• lt/bodygt lt/htmlgt

10
Output?

• So whats the parsed output?
• lthtmlgt
• ltheadgtlttitlegtPHP Courselt/titlegtlt/headgt
• ltbodygt
• Im from HTML! ltbrgt
• ltbgtIm from PHP!lt/bgt
• lt/bodygt lt/htmlgt
• the string ltbgtIm from PHP!lt/bgt is echoed to
  the output
• echo likes printf() in C or cout in C
• Thats why the source code can be hided

11
Syntax of PHP

• You all must be familiar
• Very similar like that of C/C/JAVA
• But variable starts with
• NO NEED TO DECLARE!!!!
• lt?php //actually it can be lt?
• var1Im a string!
• var2123
• echo Hello! var1 var2
• ?gt

12
Syntax of PHP

• Control structure
• If-then-else, for loop, while loop, switch case
• Boolean Operator , ,
• Arithmetic Operator - /
• PHP is not rigorous, frankly speaking

13
Syntax of PHP

• See the following example (save as price.php)
• lthtmlgt
• lt?php
• unit_price3
• quantity5
• costunit_pricequantity
• ?gt
• The price is lt? echo cost?gt.ltbrgt
• lt/htmlgt

14
Syntax of PHP

• From last example, PHP code can be cut into
  fragments with HTML code
• Also, it can be included like C/C
• Make more flexible and convenient
• One example is header and footer for a homepage,
  but its not directly related to PHP

15
Magic you can do with PHP

• The Magic is HTML Form Processing
• Form is commonly used in the Internet
• Get information from user
• Let user to post data
• Verification
• A lot more!

16
Magic you can do with PHP

• Form Let user enter information or data from
  browser
• ltform actionform.php methodpostgt
• Name ltinput typetext namenamegtltbrgt
• Class ltinput typeradio nameclass
  value1gt CE1
• ltinput typeradio nameclass value2gt CE2
• ltinput typeradio nameclass value3gt
  CE3ltbrgt
• ltinput typesubmit namesubmitgt
• ltinput typeresetgt
• lt/formgt
• Save above as form.html
• Must have a destination of data post to
  (form.php) this case

17
Form Processing

• Browser form.html in your browser
• http//www.csis.hku.hk/yr_login/form.html
• Anyone browsing your page can enter data, but how
  we can get and process those data?
• Recall that the data is posted to form.php
• So of coz we can back the data in that php file,
  but how??

18
Form Processing

• Actually PHP does all for us
• In form.php file, if weve posted some data to
  it, it AUTOMATICALLY declare those variables
• So now name and class store the name and class
  from the Form
• The variable name depends on the name of the
  entry on the form
• MAGIC?

19
What do we want to do?

• Check whether theyve enter both field
• check whether name and class
• Printout what class they belong to
• class1 -gt Part I
• class2 -gt Part II
• class3 -gt Part III

20
form.php

• lthtmlgtltbodygt
• lt?php
• if (name"" class"")
• echo "You have not entered enough..."
• else
• echo "Hi! name.ltbrgt"
• switch(class)
• case "1" echo "You're CE Part Iltbrgt" break
• case "2" echo "You're CE Part IIltbrgt" break
• case "3" echo "You're CE Part IIIltbrgt" break
• default break
• ?gt
• lt/bodygtlt/htmlgt

21
Form processing

• So If I enter Tabris as name and I choose
  CE2, then form.php is processed and output the
  following
• lthtmlgt
• ltbodygt
• Hi! Tabris.ltbrgtYou're CE Part IIltbrgtlt/bodygt
• lt/htmlgt

22
Form Processing

• If an user miss an entry, the first IF will be
  true and then
• You have not entered enough
• will be printed
• By this example, you may think some other
  application of Form using PHP
• User verification
• Application Form

23
String Processing

• From the source code, notice that class is a
  string not a integer
• Basically all values returned from Form should be
  string
• PHP is very similar to C that support direct
  compare of string literal
• But all the member function of String can also be
  used, for example
• strlen(), substr()

24
Seems Clumsy?

• Now have 2 files form.html and form.php
• Actually they can be combined
• Can you think how?
• Try to think that the file can even post the form
  data to itself

25
Combine form2.php

• The flow is that
• First check whether user has input or not
• If input, does what like form.php does
• If not yet, does what like form.html does
• Seems simple?

26
form2.php 1st part

• lthtmlgt
• lt?
• if (!submit)
• ?gt
• ltform action"form2.php" method"post"gt
• Name ltinput type"text" name"name"gtltbrgt
• Class ltinput type"radio" name"class"
  value"1"gtCE1
• ltinput type"radio" name"class" value"2"gtCE2
• ltinput type"radio" name"class"
  value"3"gtCE3ltbrgtltbrgt
• ltinput type"hidden" name"entered"gt
• ltinput type"submit" namesubmit"gt ltinput
  type"reset"gt
• lt/formgt
• lt?

27
form2.php 2nd part

• else
• if (name"" class"")
• echo "You have not entered enough..."
• else
• echo "Hi! name.ltbrgt"
• switch(class)
• case "1" echo "You're CE Part Iltbrgt" break
• case "2" echo "You're CE Part IIltbrgt" break
• case "3" echo "You're CE Part IIIltbrgt" break
• default break
• ?gt
• lt/htmlgt

28
Form Processing

• So now just need 1 file to do the MAGIC!
• You can try more on your own

29
QA

• Todays session is nearly finished
• Any questions can ask me now
• Thank you very much.