ultimate guide to object oriented php for wordpress developers

104 Pages·2017·2.9 MB·English

ULTIMATE GUIDE TO
OBJECT ORIENTED
PHP FOR WORDPRESS
DEVELOPERS
LEVELING UP AS WORDPRESS DEVELOPER
WITH OBJECT-ORIENTED PHP
BY JOSH POLLOCK
WHAT’S INSIDE
INTRODUCTION 5
PHP IN A REST API WORLD 5
PHP 7 — GUEST CHAPTER BY TOM EWER 7
HOW PHP TOK OVER THE WEB 8
PHP 7 FINALY HEAVES INTO VIEW 8
WORDPRES IS ABOUT TO GET WINGS 9
THERE ARE TWO KEY POINTS TO EMPHASIZE HERE 10
WHY DEVELOPERS ARE HOLDING FIRE ON SWITCHING 11
ARE YOU GOING TO USE PHP 7 IN PRODUCTION? 1
WHAT’S NEXT? 12
PHP FUNDAMENTALS 13
VARIABLES AND CONSTANTS 14
DATA TYPES 15
FUNCTIONS AND SCOPE 17
OBJECT-ORIENTED PHP 19
BEFORE WE BEGIN 20
METHODS VS. FUNCTIONS 20
PROPERTIES VS. VARIABLES 2
USING HOKS IN CLASES 2
MORE FUN WITH _CONSTRUCT() 23
WP_QUERY: THE OBJECT-ORIENTED PHP 24
A LITLE BACKGROUND 25
WP_QUERY 26
MAKING YOUR OWN 27
WORDPRES AS A GATEWAY TO OBJECT-ORIENTED 27
VISIBILITY IN OBJECT-ORIENTED PHP 28
ENCAPSULATION AND SCOPE 29
CLASES VS. OBJECTS 30
THE THRE LEVELS OF VISIBILITY 30
RULES OF PROPERTY VISIBILITY 31
RULES OF METHOD VISIBILITY 3
WHY VISIBILITY MATERS 35
A FEW LAST WORDS 36
CLAS INHERITANCE IN OBJECT-ORIENTED PHP 37
CLAS INHERITANCE 38
EXTENDING CLASES AND OVERIDING 38
ABSTRACT CLASES 39
LES CODE, BETER CODE 41
HOW TO USE ASYNCHRONOUS PHP IN WORDPRES 42
HOW IT WORKS 43
THE PROBLEM: AL AT ONCE OR NOTHING 4
SETING IT UP 4
WIRING IT UP 47
MORE ASYNCHRONOUS 46
REST APIS AND PHP 48
DESIGNING THE SYSTEM 49
PUTING IT TOGETHER 5
STARTING IT UP 57
STARTING WITH A SYSTEM 59
PHP MAGIC METHODS 60
CONSTRUCTOR 61
SETING HOKS IN THE CONSTRUCTOR 61
MAGIC SETERS AND GETERS 62
CONVERTING OBJECTS TO STRINGS 6
USE MAGIC, LEARN MORE MAGIC 68
NAMESPACES 69
NAMESPACING YOUR CLAS 70
NESTING NAMESPACES 73
ALIASING NAMESPACES 74
NAMESPACE AL THE THINGS! 75
IMPROVING DEVELOPMENT WORKFLOW WITH COMPOSER 76
WHEN AND WHERE TO USE COMPOSER 7
INSTALING COMPOSER 79
WRITING A COMPOSER FILE 79
WAVING THE BATON 82
USING A CLAS AUTOLOADER TO IMPROVE WORDPRES DEVELOPMENT 83
WHAT IS A CLAS AUTOLOADER? 84
CHOSING A STANDARD 84
NOT CHOSING A STANDARD 85
USING THE COMPOSER AUTOLOADER 85
USING A PSR-4 AUTOLOADER 86
THAT’S AL IT TAKES 87
PHP DESIGN PATERNS FOR WORDPRES DEVELOPERS 8
EVENT DRIVEN VS. MODEL VIEW CONTROLER 89
USEFUL PHP DESIGN PATERNS 90
THE SINGLETON 90
WORDPRES CORE GLOBALS 94
WHY? 95
IT’S TIME TO LEVEL UP YOUR PHP SKILS 96
READ MORE SOURCE 97
MISUSED PATERNS 98
COMPOSER AND CROS-POLINATION 9
YOUR TURN 10
CONCLUSION 10
KOBE s repole veD se rPd ro W ro F PHP detneirO- tcejbO o T ediuG etamit lU
INTROUD TC ION
Tere are a lot of reasons why WordPress is so popular, but one is by far the fexibility and
The first step
ease of use of the two languages it is written in: PHP and JavaScript. Both languages have a
in leveling up fairly low barrier to entry. But, while it is easy to get started, that does not mean it is always
easy to learn. More advanced skills are required to create performant, maintainable, reusable
your skills as and testable code.
a developer Te frst step in leveling up your skills as a developer is learning object-oriented programming
for PHP or OOP.
is learning
OOP is about more than using classes in your code. It’s about creating code that is less
object-oriented focused on a specifc action and more focused on objects — small, reusable containers for
data and functionality.
programming
PHP is the most popular programming language in the world — powering 84 percent of all
for PHP or OOP. websites. Te server-side scripting language is known for its ability to create dynamic websites
and for its use as a general-purpose programming language.
PHP is open source, which combined with its ubiquity and capabilities, make it a perfect
match for WordPress, the CMS that now powers more than 25 percent of the internet.
Although WordPress users don’t need to learn PHP to manage their WordPress-powered
websites, if you’re a plugin or theme developer, or just want to modify the default behavior of
your site, you will need to have a basic understanding of PHP.
There are two types of PHP:
OO PHP vs. Procedural.
Tis ebook will equip you with the knowledge and skills you need to get started with object-
oriented PHP as a WordPress developer, including:
• PHP Fundamentals
• Visibility and inheritance
• PHP 7
• WP_Query
• Magic methods
And more
PHP IN A REST API WORLD
In the era of the API-driven JavaScript interface, becoming the norm for WordPress
development, PHP is more important than ever for WordPress users. Tis may sound strange,
but all of these cool interfaces require a well built server-side application to power that
application. Tat server-side code, written in PHP, will require a PHP developer that is well-
versed in WordPress’ inner workings.
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KOBE s repole veD se rPd ro W ro F PHP detneirO- tcejbO o T ediuG etamit lU
gvni o M r ,d o rf aw WPdro se r ,e r oc sgu ni l p dn a y b a em setme h w i l l ene d ot od a re tb te bj o f o
gnil p u ed oc gol ci dn a RC U D mof r t eh . y l a p s id e� ems a lel-w v ol sme t sys w i l l ene d ot s re ev
tb ho t eh a n lt oi t idar WPdro sse r nimda dn a etme h re ,secaft ni sa l e lw sa RETS PA I .st ni p o d ne
New plugins have an advantage in this
department, but it requires discipline and
more work to make a plugin that meets the
requirements I listed above. Adapting an older
plugin to meet these demands without breaking
backward compatibility is more challenging.
I f er ’ u o y a WPdro se r p reol ed v e dt ic xe t ub ao t eh e ru t f u f o WPdro se r ne vrd i y b PA I-
e dre w p o tSav p rc a i J re ,secaft ni t neh uo y u dl o h s r el na e r o m .tSav p rc a i J dnA se y o gh niso c
a tSav p rc a i J kr oe f m w ar ot r el na — I dnem e oc r SJrug l an A — wi l l p le h hcnu l a u o y ot ni
tSav p rc a i J .t ne m p ol ed v tso M , yt l r p n t o a mi u o y u dl o h s eagh l c nel s flru e o y ot etw r i re tb te PPH
dn a p ol ed v a gn o t rs p se e c r t r o f t eh ntoi s ar pe a f o srec n n oc dn a t eh g elnis
t yiil b is n p se o r . el p r ic ni p
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KOBE s repole veD se rPd ro W ro F PHP detneirO- tcejbO o T ediuG etamit lU
PHP 7
Guest Chapter
by Tom Ewer
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KOBE s repole veD se rPd ro W ro F PHP detneirO- tcejbO o T ediuG etamit lU
WPdro sse r sah e dy l a p a yle gu h t ngis c�in a el o r ni gni p l e h PPH reu q n oc t eh b e w re v o t eh tsl a
In this 21 .sre a y Wih el WPdro sse r sah w ezih d gu ho t rh ev is secu s sn ois re v t a na genis a rc ni- re e v et ar
gru ni d t ta h ,te mi t eh egug a n l a t ta h t is l l sre w p o t eh t yr ij o a m f o t eh r mot f l a p sah e ni dame r
chapter, ylebid rc ni el bt s a b dnih e t eh s .se nec
gi B se g n a h c e r a a yn�l l ni t eh gn� o t hwi t eh r av r a li f o PPH 7 , , re vw o h dn a rj o a m WPdro sse r
we’ll take a stsoh hcu s sa WP Egenin er a ye da a rl gkni ci t eh se t ri fo t eh tse t l a el s e a er dn a gt ni te g ye da r ot
f u yll r p top u s t i ro f t rie h s .s u re
look at the I n t sih , re t p a h c ’ l l e w t ea k a ol ko t a t eh t ne m p ol ed v f o PPH 7 ot ,e t d a t wa h t eh rjo a m se g n a h c
,e r a t wa h t e h y nema r o f WPdro se r s ,su re dn a redis n oc w te reh u o y u dl o h s b e t nih gkni f o
development a gmkni t eh hc t ws i ot t eh e n w n ois re v t gi t h ars t u o f o t eh . e t ag
s ’ L te e et sgt nih p u t hwi a r fei b pt r i w n od r o me m y . e n l a
of PHP 7
HOW PHP TOOK OVER THE WEB
to date.
PPH s ’ t nec ru r se ecne r p inm o si taso ml t nea k r o f e dt n g ar t se h e ,sy d a t u b e tre h saw re v y t elt il ot
tsegu s g t ta h t i u dl o w og n o ot et a nim od t eh be w w neh t i saw ts r� el db b oc te rehgo t y b R su ms a
r f od L re kbca ni .491
I n y n am ,sy aw PPH s ’ rs i e ot t eh p o t sah b e ne a hp mut r i f o o go ,d e n d oih s af-dl o wbl eo e s a g er
re v o t car sb ta t ci a m go ar r p .srec n n oc I n ttsar n oc ot p gte ni m oc sn t oi u s l o hcu s sa av a J
dn a P ,lre t eh egug a n l a saw r dot rf gi aw t h ars gu hone ot t car t t a na ecneidu a e n w ot t eh , be w
dn a el p mis gu hone n o t eh s re re v edis ot k yciu l q ebm e oc a d r d an t s a t s a l ni l ntoi p o t a stso h
.wedi dl r o w P tu , y l p mis PPH el db a ne a ntoi are ne g f o oc sred ot tsu j te g t i . e n od
I st ylr e a nt oi p oda y b a tso h f o rul a p p o SMC sgre ni � o s e a el d t eh ed ,a l t hwi WPdro sse r b gnie
y b raf t eh tso m t ngis c�in a f o t .me h e� PPH x.5 s re sei gn ar p s ot ni efil ni ,402 dn a fi e r ’ u o y
r gninu WPdro se r , y o t d a e r ’ u o y taso ml rec yni t l a r gninu a r onim n ois re v f o t s ih red nu t eh
o h o d sa ew p s e a .k
e� x.5 s re sei sah s re e dv PPH le lw re v o ,te mi t u b 21 sre a y si a gn ol t emi b e nete w rj o a m
.s n ois re v S ren o o r o , re t l a a eg n a h c saw dnub o ot . e m oc
PHP 7 FINALLY HEAVES INTO VIEW
erB o fe ew te g ot ni t eh t ytg-y r t i in f o PPH ,7 s ’ tel te g ems o t i a lne t p o gnim a n nfn ois u oc t u o f o
t eh . y aw e� tsl a el bt s a el s e a er f o PPH saw PPH 6.5 ni 4102 , s o t a t sih ,e tg s a u o y t gim h l e lw b e
gred n ni o w t wa h p e ne dp a h ot PPH .6
T o tcu a gn ol r o t s y r ,to h s e tre h saw a sue v oi r p t p me t t a t a a en w rjo a m n ois re v gnis u t eh em a n
PPH 6 mof r 502 ot 0102 t ta h re n v f u yl l t o g � o t eh ,dnu o g r dn a ot di o v a gyni du m t eh
,s re t aw t eh nedois ic saw u a ylt l ne v eda m ot og t gi t h ars m of r t eh x.5 s re sei ot PPH .7
PPH 7 sah b e ne red nu eca v t i t ne m p ol e ed v ecnis ,4102 dn a saw ic� a ylol el s e a e dr ni Db e remec
.5102 I st t ne m p ol ed v e r dvr a i t a na gtnise re t ni t emi ni t eh w redi PPH ,dlr o w sa e n w
se vt i t i a ini hcu s sa s ’ b eca o k o F p o Hp i H uri a lt V e nih ca M ere w yls u e n o t a u l mis gnid n pxe a t wa h
saw yls ue v oi r p t gu h t o h el bp is so t hwi t eh . e g ug a n l a
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KOBE s repole veD se rPd ro W ro F PHP detneirO- tcejbO o T ediuG etamit lU
PPH 7 sp ih s t hwi a tso h f o f- yrd pnei l re ol ed v .se ru t e a f
d A ni t eh caf t t ta h s ’ t i b e ne re v o a ed c eda ecnis t eh tsl a rj o a m el s e ,a e r dn a e tre h saw
yl b d a n t s a red nu a tol f o t ne me t ic xe dn a nt oi p a t ici n a gel nida p u ot PPH 7 uaca ylt l gnid n l a –
dn a dn l a t i yul d did !
s ’ L te pe t s gu ho t rh t eh ni a m st ni p o t ta h ev a h b e ne gts ni te ’ ps re ol e ed v u s l sep gnicar ecnis t :ne h
• It’s a true major release. A rjo a m el s e a er si yle c �e v t i a nel ac ,e t l a s dn a srel ac t eh sked c r o f
rj o a m t i a yl lne t p( o e a )gkr ni b .se g n a h c Wt hi t eh t nu o m a f o rc �u t ta h PPH sah e dtre h ag
re v o t eh ,s r e a y t sih si t lecnel xe e n sw r o f a l l rec. e n n d oc
• Tere’s a brand new engine under the hood. e� Z dne Eg enin II sah b e ne gni od gnil re t s
kr o w n o t eh PPH x.5 s re sei re v o t eh ,s r e a y t u b PPH 7 wi l l b e gr� ni n o a l l c syred nil
n skt a h ot t eh n gpk nias e n w PPH NG N( txe G)ntoi are ne g eni ne t ta h sre w p o .t i
• A host of powerful new language features are available. e� tse t l a n ois re v f o PPH 7 sp ih s
t hwi t y nel p f o e n w sn t oi p o r o f p sreol ed v ot ,e r ol pxe gnidu l c ni t py e ,s n t oi ar l ed a c
p ecas p ih s ,s r o t p are o dn a yt l ngis c�in a e dv o r p mi r o re r g .dnil a h kCe hc t u o
T s ’ su e o e h e r t lecnel xe w nr od-nu f o t eh ni a m s me t i ro f na t hped-ni re v o v ei w f o t eh
ni am t ngis c�in a .st ni p o
e� ni a m p e p a l a f o t eh e n w n ois re v dn a( t eh gt nih t ta h w i l l b e f o tso m tse re t ni ot t eh egare v a
WPdro sse r s u )re nca b e emu ds ni en o d r o w – p s e .e d s ’ L te ol ko t a t i ni a t i b e r o m t .h ped
WORDPRESS IS ABOUT TO GET WINGS
e drpa C m o ot st i ,s er sed sec or p PPH 7 si yglniza b .t s af e� n om oc su s nen oc s se me ot b e
Compared ttah s ’ t i t a tel s a t w eci sa t s af so rca t eh ,d b r o a dn a se riu e q r t i a yl ln t sb a u s re wf sec ru se o r ot
u aca ylt l ete c xe u oc ed – otw sr caf o t t ta h e r a t lecnel xe e n sw r o f WPdro se r s su re sa w n oh s ni
to its
t eh ylre a tse t st u lse r w b ol e :
predecessors,
PHP 7 is
blazingly fast.
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KOBE s repole veD se rPd ro W ro F PHP detneirO- tcejbO o T ediuG etamit lU
T stse m of r Z d ne dn a WP Egenin gn o m a( y n a m s t re h o ) ev a h r�n e m doc t eh t ngis c�in a
st ne me v o r p mi ew nca pxe e c t ni tb ho p s e e d dn a ,ec n r a mp o re f dn a t eh WPdro sse r e Cr o me at
sah b e ne gre ni v b e a y aw a t a gtni te g t eh r mot f l a p ye da r r o f t eh e n w n ois re v ecnis 5102-dim .
WordPress performance is signifcantly improved.
THERE ARE TWO KEY POINTS TO EMPHASIZE HERE:
.1 e re � e r a d r aw k b ca el tb i p a m oc ni se g n a h c t tah gu ni l p dn a etme h p sreol ed v w i l l ev a h ot
t ea k ot ni t nu oca gni o g r . d o r f aw
.2 WPdro ’ se r w n o t tne m im oc ot d r aw k b ca t yi il t b i p a m oc si sa gn o t rs sa re v – tb ho PPH
7 dn a sue v oi r p sn ois re v w i l l eu t ni n oc ot b e r.pe d t o p u s
From the average end user point of view, it’s fair
to say PHP 7 will be a slow burn in terms of when
they really see the advantages.
taen lodc A e ec v nedi mof r dnu o r a t eh be w st se gu s g e tre h si t is l l a tol f o kr o w ot b e en od n o
rul a p p o setme h dn a sgu ni l p e r ob fe y n a m e r a ye da r r o f t eh e n w .stse n o h WP Eg enin sah
ic� a ylol l el o d r t u o r p top u s f o PPH 7 ot a l l st i .s re m o t c s u gnid r oc A ot t rie h TC O , nsa o J
C ,ne h o W“ ev ’ e eda m t i t on yn l o e ysa ot tse t et is sese nida r r o f PPH 7 tu b yl eb id rc ni e ysa r o f
en o y n a n o ru o r mot f l a p ot et gim ar ot PPH ” .7
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