Dependency Injection for beginners

Slides for my talk at the 16th PHP Belfast Meet-up.

Transcript

1. Dependency Injection David Frame of 31interactive
2. ?
3. Scenario #1 We need to be able to test our order class without sending any emails!
4. Dummy mailer class with a send() method that does nothing!
5. What is dependency injection?
7. Single Responsibility Principle a class should have only a single responsibility Open / Closed Principle “software entities … should be open for extension, but closed for modification.” Liskov Substitution Principle Interface Segregation Principle Dependency Inversion Principle one should “Depend upon Abstractions. Do not depend upon concretions.”
8. Scenario #2 We need to store emails in the database so they can be queued up and sent at a later date!
12. Dependency Injection Containers
14. Thanks for listening! Any questions? :) Email: david.grant.frame@gmail.com Twitter: @DaGrFr Review this talk at https://joind.in/16984