Migration to PHP 5'1

1
Migration to PHP 5.1
Davey Shafik
davey_at_php.net
2
About Me

• Davey Shafik is
• A long time contributor to PEAR
• http//pear.php.net
• A long time blogger
• http//pixelated-dreams.com
• A long time helper
• irc.freenode.net PHP php.thinktank
• Contributor to the Zend PHP Framework
• http//framework.zend.com
• Hard of hearing, so speak up!

3
This Session

• We will be covering
• Migrating the Developer
• From PHP 4.x
• From PHP 5.0
• Migrating the Code
• Pratical Examples
• New Stuff
• Warning Lots of Object Orientated Code Follows.

4
Questions?
Feel free to interrupt me!
5
Migrating the Developer
6
I Want THAT One!

• References are one of the few changes that
  effects procedural code.
• All objects are now returned as references not
  copies.
• You must now return a variable if returning by
  references.
• Foreach can use References
• Referenced arguments can now have a default value
• New clone keyword to unreference objects.

7
Object References

• lt?phpobj  new stdClassobj-gtfoo  'bar'o
  bj2  objobj2-gtfoo  'qux'obj3  clone o
  bjobj3-gtfoo  'bat'var_dump(obj, obj2, o
  bj3)?gt

Output object(stdClass)1 (1) "foo"gt
string(3) "qux" object(stdClass)1 (1)
"foo"gt string(3) "qux" object(stdClass)2
(1) "foo"gt string(3) "bat"
8
Return by Reference

• lt?phpfunction foo()    return nullfoo()
  ?gt

Notice Only variable references should be
returned by reference in filename on line 5
9
Foreach Using References

• lt?phparray  array(2,4,6,8,10)foreach (arra
  y as value)     value - 1var_dump(arra
  y)?gt

Output array(5) 0gt int(1) 1gt
int(3) 2gt int(5) 3gt int(7)
4gt int(9)
10
Reference Argument Defaults

• lt?phpfunction foo(bar  'baz')     echo bar
  foo()?gt

Output bar
11
Build It and then Break It

• Unified __construct() method no longer named
  after the class.
• The PHP 4 way still works.
• parent__construct() still not called.
• Unified __destruct() method now you can
  shutdown your objects.

12
Constructors Destructors

• lt?phpclass foo     public function __construc
  t()            echo __METHOD__ . PHP_EOL    
      public function __destruct()            e
  cho __METHOD__    foo  new foo()?gt

Output foo__construct foo__destruct
13
Yours, Mine and Everybodys

• PHP 5.0 supports Class method and member
  visibility.
• Public Anyone can use them
• Protected Only the class and sub-classes can
  use them
• Private Only the class can use them
• Final Subclasses cannot override it, or in the
  case of a final class, cannot extend it.

14
Public, Private, Protected

• lt?php class foo      public foo  'bar'
      protected baz  'bat'     private qux  '
  bingo'          function __construct() 
          var_dump(get_object_vars(this))     
  class bar extends foo      function __const
  ruct()          var_dump(get_object_vars(this))
       class baz      function __construc
  t()          foo  new foo         var_dump(g
  et_object_vars(foo))     
  new foo new bar new baz
• ?gt

Output array(3) "foo"gt string(3) "bar"
"baz"gt string(3) "bat" "qux"gt
string(5) "bingo" array(2) "foo"gt
string(3) "bar" "baz"gt string(3)
"bat" array(1) "foo"gt string(3) "bar"
15
Static Shock

• PHP 5 introduces static properties/methods and
  class constants.
• Static Properties Methods are
• Accessible class-wide
• Attached to the class
• Called using the operator
• Class Constants are
• Immutable just like standard constants
• Accessible class-wide
• Attached to the class

16
Static Properties

• lt?phpclass foo     public static bar  "baz"
      private static bat  "qux"        public 
  static function getBat()         return selfb
  at    echo foobar . PHP_EOLecho foog
  etBat() . PHP_EOLecho foobat . PHP_EOL?gt

Output baz qux Fatal error Cannot access
private property foobat in file on line 14
17
Class Constants

• lt?phpclass foo     const BAR  'bat'    cons
  t BAZ  'qux'echo fooBARecho fooBAZ?
  gt

Output batqux
18
Round Peg, Round Hole

• With PHP 5 comes the introduction of Interfaces
  and Abstract classes
• Interfaces define rigid APIs
• Interfaces define API only.
• Your Class must conform to the API
• Abstract classes define partial classes
• Cannot be instantiated themselves
• Must be extended
• May contain method bodies
• Your class must conform to the API

19
Interfaces

• lt?php interface DBAdapter      public function
   connect(user, pass)          public function
   query(sql, options)          public function
   getRow()          public function getAll()
           public function close()
  class foo implements DBAdapter   ?gt

Fatal error Class foo contains 5 abstract
methods and must therefore be declared abstract
or implement the remaining methods
(DBAdapterconnect, DBAdapterquery,
DBAdaptergetRow, ...) in file on line 15
20
Interfaces

• lt?php interface DBAdapter      public function
   connect(user, pass)          public function
   query(sql, options)     
  class foo implements DBAdapter  
• public function connect(user, pass)
• public function query(sql)
• ?gt

Fatal error Declaration of fooquery() must be
compatible with that of DBAdapterquery() file
on line 9
21
Extending Interfaces

• lt?phpinterface DBAdapter     public function co
  nnect(user, pass)        public function quer
  y(sql, options)        public function getRow
  ()        public function getAll()        pu
  blic function close()interface MysqlDBAdapter
   extends DBAdapter     public function escape(s
  tring)
• ?gt

22
Abstract Classes

• lt?phpabstract class foo     new foo?gt

Fatal error Cannot instantiate abstract class
foo in file on line 6
23
Abstract Classes (cont.)

• lt?phpabstract class foo     function bar()  
  class baz extends foo  abstract class bar 
      abstract function bat()class qux extends
   bar     ?gt

function bat()  
Fatal error Class qux contains 1 abstract method
and must therefore be declared abstract or
implement the remaining methods (barbat) in
file on line 14
24
Who's Your Daddy?

• Classes can still only inherit from one class.
• Classes can implement multiple interfaces.
• Parent constructors/destructors not called.
• New self keyword added, works like parent but
  references the current class.

25
Multiple Interfaces

• lt?phpinterface foo  interface bar  class
   MyClass implements foo,bar  ?gt

26
Multiple Interfaces (Cont.)

• lt?phpinterface foo      function doFoo()    
  interface bar     function doBar()class
   MyClass implements foo,bar     function doFoo()
    ?gt

Fatal error Class MyClass contains 1 abstract
method and must therefore be declared abstract or
implement the remaining methods (bardoBar) in
file on line 16
27
Migrating The Code
28
And... wakeup!

• Insert Exciting and Witty Comment Here

29
Introducing XML. Again.

• XML is considered one of the largest changes
  between PHP 4 and PHP 5.
• All extensions now based on libxml2
• New DOM extension W3C Compliant
• New XSLT extension Supports EXSLT and User
  Defined Functions
• New SimpleXML extension super easy XML reading
• New XMLReader and XMLWriter extensions
• Expat extension deprecated
• DOMXML and Sablotron no longer supported

30
Example 1 RSS Feed

• lt?xml version"1.0" encoding"utf-8" ?gt
• ltrss version"0.91" gt
• ltchannelgt
• lttitlegtPixelated Dreamslt/titlegt
• ltlinkgthttp//pixelated-dreams.com/lt/linkgt
• ltdescriptiongtAs close to my brain as you can
  safely getlt/descriptiongt
• ltlanguagegtenlt/languagegt
• ltimagegt
• lturlgthttp//pixelated-dreams.com/templates/defa
  ult/img/s9y_banner_small.pnglt/urlgt
•        lttitlegtRSS Pixelated Dreams - As close
  to my brain as you can safely getlt/titlegt
•            ltlinkgthttp//pixelated-dreams.com/lt
  /linkgt
• ltwidthgt100lt/widthgt
•          ltheightgt21lt/heightgt
• lt/imagegt
•     ltitemgt
• lttitlegtphptek Day 1lt/titlegt
• ltlinkgthttp//pixelated-dreams.com/archives/226-
  phptek-Day-1.htmllt/linkgt
•   ltdescriptiongt
• POST CONTENT

31
Example 1 Output

• Pixelated Dreams
• phptek Day 1
• I gave my "Future Deployment of PHP Applications"
  talk today. Unfortunately, I had quite a few
  technical issues with the internet and such,
  meaning I had to scrabble around to get the end
  result working - but, I did manage it, though a
  little sloppily still, it was my first time and
  I'm looking forward to tomorrow with gusto.
• My talk tomorrow is on "Migration to PHP 5.1" and
  due to having no "live" examples, should go
  without a hitch.
• Other than preparing for my own talk, and taking
  the afternoon off to get over it, I haven't
  attended much. I got some good feedback on my
  talk - and I promised to post my slides and
  links, so I will do that shortly
• To everybody that attended, thank you.
• I did video the talk, but have a break in the
  continuity of about 5 or so minutes, so I'm going
  to see what I can do about filling in that blank
  and producing a Flash movie with the video and
  slides in sync - it could be a while
• - Davey

32
Databases. All of them.

• Another great addition to PHP 5, is the PHP Data
  Objects extension PDO.
• PDO allows interation with many different RDBMSs
• PDO is
• bundled with PHP 5.1
• available as a PECL extensin for PHP 5.0
• not an abstraction layer. Kinda.

33
PDO

• PDO Currently Supports
• MySQL
• PostgreSQL
• SQLite
• Oracle
• Firebird
• Informix
• DBLIB
• ODBC

34
Why Using Databases Sucks

• MySQL
• mysql_connect(host, user, pass)
• MySQLi
• new mysqli(host, user, pass)
• PostgreSQL
• pg_connect(hosthost portport dbnamedb)
• SQLite
• new sqlite_database(db.sqlite)

35
Why Things Dont Suck Anymore

• lt?php dsn  "mysqlhosthost
              usernameuser             password
  pass" // or  dsn  "pgsqlhosthost 
              portport              dbnamedb 
              useruser              passwordpa
  ss" // or dsn  "sqlite/opt/db.sqlite"
  pdo  new PDO(dsn, user, pass) ?gt

36
Realistic Examples? Yeah. Right.

• lt?phppdo  new PDO("mysqlhostlocalhostdbname
  pear", "pear", "pear")stmt  pdo-gtprepare(
• "INSERT INTO table ( username, password , is_admin
   ) VALUES ( username, password, isadmin )
• )values'username'  _POST'username'va
  lues'password'  _POST'password'values'
  isadmin'  _POST'is_admin'stmt-gtexecute(v
  alues)?gt

37
New Goodies
38
Ooooh Shiny

• PHP 5.0 and 5.1 also bring many things to the
  table that never existed before.
• Object Overloading
• Properties
• Methods
• Type hints
• For objects and arrays
• Iterators
• The Standard PHP Library SPL
• Provides Exciting new capabilities for objects

39
Object Overloading

• Overloading Setting Properties
• function __set(name, value)
• Overloading Getting Properties
• function __get(name)
• Overloading Methods
• function __call(method, args)
• Overloading Isset and Unset
• function __isset(name)
• function __unset(name)

40
Type Hints

• PHP 5 introduces object type hints. With PHP 5.1
  we also have Array type hints.
• lt?phpfunction require_class (stdClass obj)  r
  equire_class("foo")?gt
• lt?phpfunction require_array(Array array)  req
  uire_array("bar")?gt

Fatal error Argument 1 passed to
require_class() must be an object of class
stdClass, called in file on line 3 and defined
in file on line 2
Fatal error Argument 1 passed to require_array()
must be an array, called in file on line 9 and
defined in file on line 8
41
Iterators

• Iterators are one of the most advanced new
  features added to PHP 5. Iterators deserve a talk
  to themselves.
• Iterators allow
• Simple Iteration over a set of data
• Recursive Iteration
• Filtered Iteration
• Seekable Iteration
• Aggregated Iterations

42
Simple Iterators

• A simple iterator implements the Iterator
  interface and allows iteration over a set of data

lt?phpinterface Iterator     function current()
        function next()        function rewin
d()        function key()        function va
lid()?gt
43
Seekable Iterators

• Seekable iterators add the ability to move to a
  specific key.

lt?phpinterface SeekableIterator     function cu
rrent()        function next()        functi
on rewind()        function key()        fun
ction valid()        function seek(index)?
gt
44
Aggregated Iteration

• lt?phpinterface IteratorAggregate     function g
  etIterator()?gt

45
Meet, Super Object

lt?phpinterface ArrayAccess     function offsetE
xists(offset)        function offsetGet(offse
t)        function offsetSet(offset, value)
        function offsetUnset(offset)?gt