"Better Code Design in PHP", Anna Filina

Are you tired of spending hours reading code just to find the right place to make a small change? Are you forced to split your application into several just so that devs don't step on each other's toes? This talk unites theory with practice to show you how to structure your code so that it is easy to read, to test and to maintain. You will step out with concrete ideas of how to improve your code design.

1. Better Code
Design in PHP
PHP FWDAYS’24
@[email protected]

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Anna Filina
•Coding since 1997.
•PHP, Java, C#, etc.
•Legacy archaeology.
•Test automation.
•Talks and workshops.
•YouTube videos.
•Filina Consulting.

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#100

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Object
Back-and-forth
Collaborator

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Object
One-way reference
Collaborator

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Object
Chatty
Collaborator
Step 1
Step 2
Step 3

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Object
Less chatty
CollaboratorTask
Step 1
Step 2
Step 3

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Is the complexity justified?
Object 1
Object 2
Object 3
Object 4
Bus

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Design Drive
•Avoid complexity until I need it.
•Do I understand what’s going on in terms of the business use case?

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Objects should speak business,
not technical.

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$lineItems= $this->orders->getLineItems($pendingOrderNumber);
$taxTotals= $this->taxes->calculateForLineItems($lineItems);

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Project
•Marketplace for short-term rental:
•Search properties for rent by city, date and number of guests.
•Reserve & pay.

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ReservationService
->reserve()
PaymentManager
ReservationManager
processPayment(data)
Templating
saveReservation(data)
confirmReservation(data)
html
EmailManager
payment
savePayment(data)
confirmReservation(html)

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ReservationService
->reserve()
PaymentManager
ReservationManager
processPayment(data)
Templating
saveReservation(data)
confirmReservation(data)
html
EmailManager
payment
savePayment(data)
confirmReservation(html)

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MakeReservation ReservationRepository
add(paidReservation)
ReservationNotifier
PaymentProcessor
capture(charge)
paymentConfirmation
notifyBuyer(paidReservation)

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MakeReservation ReservationRepository
add(paidReservation)
ReservationNotifier
PaymentProcessor
capture(charge)
paymentConfirmation
notifyBuyer(paidReservation)

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MakeReservation ReservationRepository
add(paidReservation)
ReservationNotifier
PaymentProcessor
capture(charge)
paymentConfirmation
notifyBuyer(paidReservation)

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MakeReservation ReservationRepository
add(paidReservation)
notifyBuyer(paidReservation)
ReservationNotifier
PaymentProcessor
capture(charge)
paymentConfirmation

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MakeReservation ReservationRepository
add(paidReservation)
ReservationNotifier
PaymentProcessor
capture(charge)
paymentConfirmation
notifyBuyer(paidReservation)

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Good design needs no diagrams.

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Simple Code
•No need for framework.
•No need to design the database.
•No need to have a UI.
•Code the business rules.

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Handle HTTP Request
Return HTTP Response
2 adults
in Lviv
on Jan 1 to Jan 7
Results containing
“Lviv for 4”

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Handle HTTP Request
Return HTTP Response
2 adults
in Lviv
on Jan 1 to Jan 7
Results containing
“Lviv for 4”

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A complex system that works is
invariably found to have evolved from a
simple system that worked.
—John Gall

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Too reusable becomes unusable.

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Input/output Business rules InfrastructureUse case

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PropertySearchHandler
Lviv, Lviv Oblast, Ukraine
Convert to coordinates.
CitySearchHandler
Lviv
-Lviv, Lviv Oblast, Ukraine
-Lviv Boulevard, Oshawa, ON

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PropertySearchHandler
49.8397, 24.0297 Longitude: -180 to +180
Latitude: -90 to +90
CitySearchHandler
Lviv
Lviv, Lviv Oblast, Ukraine
49.8397
24.0297

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Code is simply a model of
the business rules and knowledge.

57. @[email protected]