Migration Concepts For Enterprise PHP Applications

Migration concepts for enterprise PHP applications
International PHP Conference 2008 – Spring Edition
Thorsten Rinne

Introduction

❙ Thorsten Rinne
❙ 31 years old
❙ Graduated in computer science
❙ Project manager at Mayflower GmbH, Munich
❙ Reporting applications
❙ Critical bank applications
❙ PHP Consulting
❙ PHP software development since 1999
❙ Founder and main developer of Open Source FAQ-
management software phpMyFAQ since 2001
❙ Zend Certified Engineer (PHP 5)
„Migration concepts for enterprise
PHP applications“
© MAYFLOWER GmbH 2008 2

Summary

❙ Introduction
❙ Why upgrade?
❙ Process model
❙ MySQL upgrade process
❙ PHP upgrade process
❙ Migration
❙ Conclusion
❙ Questions and answers

PHP applications“

Introduction: Why upgrade?

❙ MySQL 4 support will end
❙ Active support already ended by the end of 2006
❙ Only extended support until 2008 for MySQL 4.0 and
2009 for MySQL 4.1
❙ MySQL 5 has more and advanced features like stored
procedures, trigger, better SQL support
❙ PHP 4 support will end
❙ PHP 4 is dead, dead, dead
❙ Only security relevant fixes until 2008-08-08
❙ PHP 5.2 is faster and more stable than every PHP 4
version

PHP applications“

Introduction: Requirements

❙ No qualitative changes like new features
❙ No technical changes like
❙ new database layer
❙ new template engine
❙ Using new PHP 5 features
❙ No influences for productive services like
❙ External systems
❙ End user frontends
❙ Minimization of time and effort

PHP applications“

Introduction: What is porting?
Innovation potential
❙ Reasons
❙ Most simple form of
migration

ive
sit
Rewrite
❙ Manageble risks

po
❙ Small complexity because of
the lack of qualitive and
Reengineering
technical changes

e
tiv
❙ Requirement

ga
ne
❙ Minor differences between
Porting
current and future
application platform
complexity

PHP applications“

Process model

❙ Reducing of complexity with a planned procedure
❙ Coverage of the complete porting
❙ Methodical description of the process
❙ Tool support

PHP applications“

Process model: Preparations

❙ Targets
❙ Porting without any technical or qualitative changes
❙ Recovery of support (MySQL/PHP)
❙ Minimizing the interferences of services and reduction
of change times
❙ Interferences
❙ Porting problems between MySQL and PHP versions
❙ Application complexity
❙ missing documentation and missing contact persons
❙ Communication between all team members

PHP applications“

Process modell: Upgrading MySQL

❙ Upgrade in two steps
❙ MySQL 4.0 to MySQL 4.1
❙ MySQL 4.1 to MySQL 5.0
❙ Why two steps?
❙ Big changes between 4.0 and 4.1
❙ Password changes
❙ Character sets
❙ Collations
❙ Many minor BC breaks

PHP applications“

Upgrade path for MySQL

❙ First dump your current database, if it‘s InnoDB. If you use
MyISAM, just backup everything.
❙ upgrade your development machine
❙ Reload your tables
❙ Test, test, test with MySQL 5.0
❙ Fix your queries and application if you have problems
❙ Use the STRICT MODE in MySQL 5.0
❙ Test, test, test with MySQL 5.0
❙ Upgrade your production machine
❙ Reload your production database

PHP applications“

How to dump MySQL?

❙ Use the MySQL 4.1 mysqldump binary!
shell> mysqldump –uroot -p
–-database mydatabase
--single-transaction
--default-character-set=utf-8
--disable-keys
--extended-insert
| bzip2 –c > backup.sql.bz2
Warning: This can lock all tables!
❙ Fix the password column in the MySQL user table
shell> mysql_fix_privilege_tables
--password=root_password

PHP applications“

MySQL Pitfalls

❙ Rebuild your TIMESTAMPs, check this also in your application
❙ TIMESTAMP now has the format
'YYYY-MM-DD HH:MM:SS'
❙ DECIMAL(14,2) in MySQL 4.0 is not the same as
DECIMAL(14,2) in MySQL 4.1/5.0
❙ using DECIMAL(10,5): 100000 will be 99999.99999
❙ using DECIMAL(11,5): 100000 will be 100000.00000
❙ New reserved words
❙ SQL2003 standard for your SQL queries with natural JOINs
and JOINs with USING may produce different results
❙ http://dev.mysql.com/doc/refman/5.0/en/upgrading-from-
4-1.html
PHP applications“

After MySQL upgrade

❙ Release the current combination
❙ PHP 4 / MySQL 5
❙ Why?
❙ You never find all problems during your tests
❙ PHP porting may took longer than the MySQL porting
❙ Increase your experience with MySQL 5
❙ Prepare the PHP 5 update

PHP applications“

Process model: Upgrading PHP

❙ Which PHP version?
❙ Latest PHP 5.2 release for production, if you build by
yourself or current PHP 5.2 package from your
Linux/Unix/*BSD/Solaris distribution
❙ Testing with PHP 5.3-dev if you have time and money
❙ Please don‘t use
❙ PHP 5.0.x
❙ PHP 5.1.x
❙ PHP 6.0.0-dev

PHP applications“

Upgrade path for PHP

❙ upgrade your development machine to latest PHP 5.2
release
❙ Test, test, test
❙ Fix your code if you have problems
❙ register_globals = off
❙ error_reporting = E_ALL & E_STRICT
❙ display_errors = on
❙ log_errors = on
❙ Test, test, test
❙ Upgrade your production machine
❙ Release your ported application
PHP applications“

Migrate configuration files

❙ httpd.conf
❙ change this line:
LoadModule php4_module php/sapi/php4apache2.dll
❙ with this one:
LoadModule php5_module /php/php5apache2.dll
❙ php.ini
❙ You should use the php.ini-recommended file, but check, if
you need magic quotes on…. Otherwise your application could
be insecure!

PHP applications“

PHP 5 Pitfalls:
New reserved keyords

❙ abstract ❙ public
❙ catch ❙ throw
❙ clone ❙ try
❙ extends ❙ use
❙ final ❙ namespace
❙ implements
❙ instanceof
❙ interface
❙ goto
❙ private
❙ protected
PHP applications“

PHP 5 Pitfalls
Constructor / Destructor

❙ PHP 4
❙ construct method has the name of the class
❙ No destruct method
❙ PHP 5
❙ construct method: __construct()
❙ If not available, fallback to PHP4 handling
❙ destruct method: __destruct()
❙ Executed at the end of the request

PHP applications“

PHP 5 Pitfalls
Magic methods

❙ __autoload()
❙ __call(), __callStatic() (only PHP 5.3)
❙ __construct()
❙ __destruct()
❙ __get()
❙ __isset()
❙ __set()
❙ __set_state()
❙ __sleep()
❙ __toString()
❙ __unset()
❙ __wakeup() „Migration concepts for enterprise
PHP applications“

PHP 5 Pitfalls

❙ get_class(), get_parent_class() and
get_class_methods() now case-sensitive
❙ __CLASS__, __METHOD__, and __FUNCTION__ are also
case-sensitive
❙ Objects are referenced by handle, and not by value
❙ Objects aren’t primitive types like in PHP 4
❙ If you need a copy of a object, use __clone()
❙ Re-declaration of $this isn’t allowed anymore
❙ === operator is more strict than it was in PHP 4
❙ __call()/__set()/__get() are different in PHP 4
❙ Don’t use zend.ze1.compatibility_mode!
❙ Use instanceof instead of is_a() „Migration concepts for enterprise
PHP applications“

Migration strategies

❙ After the release of the PHP 5 ported application
REFACTORING!
❙ Strategies for
❙ „Spaghetti code“
❙ Half procedural – half object-orientated
❙ PHP 4 OOP
❙ Please don‘t try a complete rewrite
❙ Too expensive
❙ Takes too long
❙ Joel on software: „Things You Should Never Do “

PHP applications“

Migration
„Spaghetti Code“

❙ Very old code, maybe developed in the last PHP 3 century
❙ No or just minor separation of code and layout
❙ No use of libraries like PEAR, Zend Framework or eZ
components
❙ No documentation
❙ No tests

PHP applications“

Migration
„Spaghetti Code“: Strategy

❙ Identify recurring code parts and implement classes
❙ Use of standard libraries like Zend Framework, eZ
components or PEAR
❙ Add inline documentation
❙ Fix your coding styles
❙ Add unittests for the new, refactored backend
❙ Add Selenium tests for the frontend

PHP applications“

Migration
„Half procedual – halb object-orientated“

❙ Code with differend quality
❙ Just a few documentation
❙ Maybe some tests
❙ „the typical current PHP 4 project“ ☺

PHP applications“

Migration
„ Half procedual – halb object-orientated“: Strategy

❙ Add inline documentation for all classes and methods
❙ Improve the re-using of duplicate code
❙ Add unittests and Selenium tests
❙ Improve every code part with PHP 5 functions, for example
using file_put_contents() instead of fopen(),
fwrite(), and fclose().

PHP applications“

Migration
PHP 4 OOP

❙ Application was developed object-orientated in PHP 4
❙ Using of
❙ PHP 4 references
❙ Re-declaration of $this

PHP applications“

Migration
PHP 4 OOP: Strategy

❙ Maybe you‘re lucky and there are no problems. Maybe.
❙ If you see problems, they are fatal errors like
❙ Objects are referenced by value
❙ $foo =& new Foo();
❙ Solution:
❙ Implement unittests
❙ Use standard APIs
❙ Fix the PHP 5 problems

PHP applications“

Conclusion

❙ Migration is always possible
❙ Migration can be hard, but usually it isn‘t! ☺
❙ Don‘t shoot yourself in the foot with the migration
❙ First upgrade MySQL
❙ Then upgrade PHP and fix your application
❙ Then do the cleanup for a better future ☺
❙ Stay current in the future and do always small steps
❙ Keep PHP 5.3 and PHP 5.4 in mind!

PHP applications“

Questions and answers

PHP applications“

Thank you very much!

Thorsten Rinne, Dipl.-Inf. (FH)
Mayflower GmbH
Mannhardtstraße 6
D-80538 München
Germany
+49 (89) 24 20 54 – 31
thorsten.rinne@mayflower.de

Migration Concepts For Enterprise PHP Applications

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